On a new species of mycena from Spain - Robich, G (PERSOONIA, 1996)
Mycena calceata Robich, collected at L'Estartit in Spain in November 1993, during the Mycological Days of the European Confederation of Mediterranean Mycology, is described as new to science. It belongs to section Insignis, characterized by the radiating hairs at the base of the stipe, large spores and growing on thin rotting branches of Quercus suber (Cork oak) in mediterranean forest.
APS
Keywords: Insignis; mediterranean forest; mycology; new species; Quercus suber

Nutrient content and seasonal fluctuations in the leaf component of coark-oak (Quercus suber L.) litterfall - Robert, B.; Caritat, A.; Bertoni, G.; Vilar, L.; Molinas, M. (Plant Ecology, 1996)
Nutrient content and seasonality of the leaf component in cork-oak litterfal were studied over a two year period in two cork-oak forest sites differing in biomass and edaphic condition in the north-eastern Iberian peninsula. Fallen senescent leaves compared to young leaves showed higher non-mobile nutrient concentrations and lower mobile nutrient concentrations, specially P, N, K, and Mg. At both sites, seasonal fluctuations affected both leaf production and leaf mineral content. The maximum leaf fall period correspond to the start of the vegetative growth and to the lowest N and P concentration in the falling leaves. The opposite was true for the winter, when litterfal was minimal and N and P content in falling leaves was at a maximum. The comparison between falling leaves and canopy leaves suggests that the analysis of fallen leaves can be a useful measure of N and P nutrition in cork-oak. We found site dependent differences in nutrient content and nutrient remobilization. In comparison with Q. ilex, although litter production was in the same range, nutrient retranslocation was greater for Q. suber.
Keywords: litterfall; nutrient return; nutrients in leaves; Quercus Suber L; retranslocation; seasonal trends

Nutrient content and seasonal fluctuations in the leaf component of coark-oak (Quercus suber L.) litterfall - Robert, B; Caritat, A; Bertoni, G; Vilar, L; Molinas, M (Plant Ecology, 1996)
Nutrient content and seasonality of the leaf component in cork-oak litterfal were studied over a two year period in two cork-oak forest sites differing in biomass and edaphic condition in the north-eastern Iberian peninsula. Fallen senescent leaves compared to young leaves showed higher non-mobile nutrient concentrations and lower mobile nutrient concentrations, specially P, N, K, and Mg. At both sites, seasonal fluctuations affected both leaf production and leaf mineral content. The maximum leaf fall period correspond to the start of the vegetative growth and to the lowest N and P concentration in the falling leaves. The opposite was true for the winter, when litterfal was minimal and N and P content in falling leaves was at a maximum. The comparison between falling leaves and canopy leaves suggests that the analysis of fallen leaves can be a useful measure of N and P nutrition in cork-oak. We found site dependent differences in nutrient content and nutrient remobilization. In comparison with Q. ilex, although litter production was in the same range, nutrient retranslocation was greater for Q. suber.
Keywords: litterfall; nutrient return; nutrients in leaves; Quercus Suber L; retranslocation; seasonal trends

Nutrient dynamics in crown tissues of cork-oak (Quercus suber L?.) - Oliveira, G; Martins-Loução, M a (Trees-Structure and …, 1996)
The seasonal fluctuation of N, P, K, Ca and Mg in leaves, young stems and fruits of young and mature Quercus suber trees growing at the same site was studied. Nutrient dynamics within the tree appeared to be linked to phenological events. Leaves maximized their nutrient con- tents throughout summer whereas stems maintained rather constant values during most of the year. Before the spring growth flush they apparently acted as temporary reservoirs for some nutrients, translocated from leaves or other organs, so that such nutrients would be easily invested in the new tissues. A significant investment was made in sink organs like flowers and fruits. The tree probably relies not only on leaves but also on other nutrient reservoirs like older branches and roots for an adequate supply to those sinks and to the spring growth. The importance of the sampling dates and the basis of expression used for nutrient concen- trations has also been emphasized. Nutrient contents and seasonal trends of the studied trees were similar to those of other evergreen oaks, although somewhat higher values for N, K, and Mg were found. Moreover, soil nutrient contents in the studied "montado" were much lower than in other Iberic oak stands. However the nutrient status and require- ments of cork-oak suggest high (or at least adequate) nutrient availability to the trees. The mechanisms by which this could be achieved are discussed.
Keywords: Evergreen oaks; macronutrients; montado; seasonal patterns; tissue nutrient contents

Nutrient dynamics in crown tissues of cork-oak (Quercus suber L?.) - Oliveira, G; Martins-Loução, M a (Trees-Structure and …, 1996)
The seasonal fluctuation of N, P, K, Ca and Mg in leaves, young stems and fruits of young and mature Quercus suber trees growing at the same site was studied. Nutrient dynamics within the tree appeared to be linked to phenological events. Leaves maximized their nutrient con- tents throughout summer whereas stems maintained rather constant values during most of the year. Before the spring growth flush they apparently acted as temporary reservoirs for some nutrients, translocated from leaves or other organs, so that such nutrients would be easily invested in the new tissues. A significant investment was made in sink organs like flowers and fruits. The tree probably relies not only on leaves but also on other nutrient reservoirs like older branches and roots for an adequate supply to those sinks and to the spring growth. The importance of the sampling dates and the basis of expression used for nutrient concen- trations has also been emphasized. Nutrient contents and seasonal trends of the studied trees were similar to those of other evergreen oaks, although somewhat higher values for N, K, and Mg were found. Moreover, soil nutrient contents in the studied "montado" were much lower than in other Iberic oak stands. However the nutrient status and require- ments of cork-oak suggest high (or at least adequate) nutrient availability to the trees. The mechanisms by which this could be achieved are discussed.
Keywords: Evergreen oaks; macronutrients; montado; seasonal patterns; tissue nutrient contents

Optimization of carbon gain in canopies of Mediterranean evergreen oaks - Rambal, S.; Damesin, C.; JOFFRE, R.; Méthy, M.; Lo Seen, D. (Ann. For. Sci., 1996)
The main goal of this study was to analyze the depth-distribution of leaf mass per area (LMA) measured in ten canopies of Mediterranean evergreen oaks, five canopies of Quercus coccifera and five canopies of Q ilex, across soil water availability gradients in southern France, Spain and Portugal. There was a significant site effect on LMA with values being lower in mesic sites compared to those on xeric sites. In all canopies, LMA decreased by up to 50% from the top to the bottom. The relationships between cumulative leaf area index and LMA could be represented by an exponential function. For two canopies of Q ilex growing in contrasting environments, we analyzed the interrelationships among LMA, mass-based nitrogen, mass-based metabolic versus structural (total fiber) content, photosynthetic electron transport and carbon isotope composition. There was no difference in mass-based nitrogen or fiber content among upper and lower canopy positions in both locations. The maximum quantum yield of linear electron flow can be considered to be constant within the canopy. The area-based maximal electron transport rate and the carbon isotope composition were significantly linearly related to the LMA. Finally, we tested whether the observed depth-distribution follows the pattern suggested by some optimization theories.
Keywords: Leaf mass per area; Mediterranean evergreen canopy; photosynthesis-related leaf property; Quercus coccifera; Quercus ilex

Optimization of carbon gain in canopies of Mediterranean evergreen oaks - Rambal, S; Damesin, C; Joffre, R; Méthy, M; Lo Seen, D (Ann. For. Sci., 1996)
The main goal of this study was to analyze the depth-distribution of leaf mass per area (LMA) measured in ten canopies of Mediterranean evergreen oaks, five canopies of Quercus coccifera and five canopies of Q ilex, across soil water availability gradients in southern France, Spain and Portugal. There was a significant site effect on LMA with values being lower in mesic sites compared to those on xeric sites. In all canopies, LMA decreased by up to 50% from the top to the bottom. The relationships between cumulative leaf area index and LMA could be represented by an exponential function. For two canopies of Q ilex growing in contrasting environments, we analyzed the interrelationships among LMA, mass-based nitrogen, mass-based metabolic versus structural (total fiber) content, photosynthetic electron transport and carbon isotope composition. There was no difference in mass-based nitrogen or fiber content among upper and lower canopy positions in both locations. The maximum quantum yield of linear electron flow can be considered to be constant within the canopy. The area-based maximal electron transport rate and the carbon isotope composition were significantly linearly related to the LMA. Finally, we tested whether the observed depth-distribution follows the pattern suggested by some optimization theories.
Keywords: Leaf mass per area; Mediterranean evergreen canopy; photosynthesis-related leaf property; Quercus coccifera; Quercus ilex

Origin and early development of secondary embryos in Quercus suber L. - Puigderrajols, P; Fernández-Guijarro, B (International Journal of Plant Sciences, 1996)
Investigates the origin and early developmental patterns of secondary embryos of the cork oak Quercus suber L. Experimental procedure; Signs of secondary embryo formation; Color of proliferation of masses; Cellular isolation.
Keywords: Cork oak; EMBRYOS

An overview of ecology and silviculture of indigenous oaks in France - Timbal, J; AUSSENAC, G (Ann. For. Sci., 1996)
There are nine species of oaks in French forests: Quercus petraea, Q robur, Q pubescens, Q pyrenaica, Q ilex, Q rubra, Q suber, Q coccifera and Q cerris. Among them, five are of major economic and ecological importance, either because of the quality and value of their wood or because of their geographic extension, or both. Two of these species are widespread in the hills and plains of the Atlantic and of the mid-European domains: Q petraea (sessile oak), and Q robur (pedunculate oak). Four are present in the Mediterranean region: Q pubescens (pubescent oak), Q ilex (holm oak), Q suber (cork oak) and Q coccifera (kermes oak). Pubescent oak is also present in the Atlantic and mid-European regions provided the local soil and climate conditions are favorable. The last species is of very limited extent and will not be considered further in this review. First, we will analyze the distributions of these species in France, as they result from the vegetation dynamics in Europe and the long-lasting action of man. Second, their synecology will be described, based on the empirical knowledge accumulated by botanists and phytoecologists. We will then describe the vegetation series to which they are related. We will next consider the results of ecophysiologal studies of the species, carried out in many laboratories in France and in other European countries. Finally, we will review the sylvicultural practices applied to oak forests, their productivity under different local conditions and the diverse products they yield.
Keywords: ecology; ecophysiology; France; oak; Quercus; Sylviculture; taxonomy

Patterns of ecological, chorological and taxonomic diversity at both sides of the Strait of Gibraltar - Ojeda, F; MARAÑÓN, T; Arroyo, J (JOURNAL OF VEGETATION SCIENCE, 1996)
Diversity relations in Mediterranean heathlands and the understorey of oak woodlands on sandstone-derived substrates were studied at both sides of the Strait of Gibraltar. Trends in species composition and cover were analysed by Detrended Correspondence Analysis; the first axis, assumed to reflect a main environmental gradient, was used to analyse the patterns of three aspects of community diversity. Species richness, i.e. number of species along a 100-m transect, shows a humpbacked trend along the gradient, with the highest values in the understorey of evergreen Quercus suber woodlands, associated with soils of intermediate fertility and moisture status. The number of endemic species is highest in open heathlands, associated with more extreme conditions of acid, infertile soils on exposed ridges. The taxonomic singularity, as measured by the inverse of the average number of species per genus at each site, is highest at the most fertile and moist sites occupied by semideciduous Q. canariensis woodlands. A comparison between northern (Spanish) and southern (Moroccan) sides of the Strait of Gibraltar shows a general concordance of the trends of woody plant communities along the main environmental gradient. However, significant differences of the southern samples are: (1) lack of some differential, habitat-specific species and greater abundance of wide spread generalists; and (2) a general reduction in species diversity, number of endemics and taxonomic singularity. We interpret these differences as affected partly by the smaller extent and fragmentation of sandstone areas in the south, and partly by the higher impact of slashing and grazing there.
Keywords: acid soil; Biodiversity; endemism; heathland; Mediterranean; Morocco

Photoinhibition in cork-oak leaves under stress: influence of the bark-stripping on the chlorophyll fluorescence emission inQuercus suber L. - Werner, Christiane; Correia, O. (Trees-Structure and Function, 1996)
Quercus suber is the primary source for industrial cork and becomes bark-stripped every 9 – 10 years. Recurring cork extraction is a major stress factor and the large water loss from the stripped trunk surface may affect the water balance and tree productivity. To evaluate the effect of bark-stripping, fluorescence emission and stomatal conductance of leaves were determined in groups of barkstripped and control trees. Fv/Fm ratio was found to be significantly lower in bark-stripped trees indicating a reduced photosynthetic efficiency of PSII. Photosynthesis was not found to be stomata limited. The reduction in Fv/Fm resulted from a decline in maximum and variable fluorescence while the initial fluorescence of the darkadapted state (Fo) remained constant. A general decline in photosynthetic efficiency of PSII was found in all trees during the summer, probably reflecting the prolonged environmental stresses during a hot and dry season. Additional stress caused by the bark-stripping seems to enhance the susceptibility to photoinhibition of the trees.
Keywords: bark-stripping; fluorescence emission; Quercus Suber L; water relations

Photoinhibition in cork-oak leaves under stress: influence of the bark-stripping on the chlorophyll fluorescence emission inQuercus suber L. - Werner, Christiane; Correia, O (Trees-Structure and Function, 1996)
Quercus suber is the primary source for industrial cork and becomes bark-stripped every 9 – 10 years. Recurring cork extraction is a major stress factor and the large water loss from the stripped trunk surface may affect the water balance and tree productivity. To evaluate the effect of bark-stripping, fluorescence emission and stomatal conductance of leaves were determined in groups of barkstripped and control trees. Fv/Fm ratio was found to be significantly lower in bark-stripped trees indicating a reduced photosynthetic efficiency of PSII. Photosynthesis was not found to be stomata limited. The reduction in Fv/Fm resulted from a decline in maximum and variable fluorescence while the initial fluorescence of the darkadapted state (Fo) remained constant. A general decline in photosynthetic efficiency of PSII was found in all trees during the summer, probably reflecting the prolonged environmental stresses during a hot and dry season. Additional stress caused by the bark-stripping seems to enhance the susceptibility to photoinhibition of the trees.
Keywords: bark-stripping; fluorescence emission; Quercus Suber L; water relations

Phytophthora cinnamomi and oak decline in southern Europe. Environmental constraints including climate change - Brasier, C M (Ann. For. Sci., 1996)
One of the most destructive of all tree root pathogens, the oomycete fungus Phytophthora cinnamomi, is associated with mortality and decline of Quercus suber and Q ilex in the Mediterranean region. The symptoms and distribution of this decline are described. P cinnamomi is a primary pathogen on a very wide range of trees and woody ornamentals worldwide, but is probably a native of the Papua New Guinea region. It is soil borne and requires warm, wet soils to infect roots. Since 1900 it has caused major epidemics on native chestnuts in the United States and Europe, and now threatens the stability of entire forest and heath communities ecosystems in some parts of Australia. Together with drought, it may be a major predisposing factor in the Iberian oak decline. Its possible role in this decline including its interaction with drought is discussed, and a generalised working hypothesis of decline is presented. The potential influence of climate warming on the activity of P cinnamomi is also considered. A model based on the CLIMEX program suggests that warming would significantly enhance the activity of the pathogen at its existing disease locations (such as the western Mediterranean and coastal northwest Europe), but that it would not greatly extend its activity into areas with cold winters such as central and eastern Europe
Keywords: climate change; Drought; Oak decline; phytophthora cinnamomi; root pathogen

Pollen production in anemophilous trees - Molina, Rafael Tormo; Rodríguez, Adolfo Muñoz; Palaciso, Inmaculada Silva; López, Francisco Gallardo (Grana, 1996)
Abstract A study was made of the total pollen production per individual tree in ten anemophilous arboreal species (including wild, cultivated and ornamental species) of considerable aerobiological importance: Pinus pinaster, Ulmus minor, Juglans regia, Platanus hispanica, Quercus rotundifolia, Salix atrocinerea, Populus nigra, Acer negundo, Olea europaea and Fraxinus angustifolia. For each species three isolated well-shaped specimens of medium height were chosen, and the number of flowers per individual tree and the number of pollen grains per anther was estimated. The values of total pollen production varied between a little over 1000 million grains in Juglans regia and more than 500,000 million in one single tree in Quercus rotundifolia. For the production of pollen grains per anther, the values oscillated between 3000 grains in Juglans regia and 100,000 in Olea europaea. There is an exponential correlation between the size of the anthers and the number of pollen grains they contain. A linear correlation is also evident between the volume of the tree crown and the total production of inflorescences, flowers, anthers and pollen grains per individual tree. Based on this, a mean coefficient of the number of grains/meter of diameter of the tree crown is obtained which varies between 3.4 ? 108 for Juglans regia and 550.9 ? 108 for Quercus rotundifolia. The ratio between the number of anthers per inflorescence and the number of pollen grains per anther carries out a hyperbolic function; thus, the inflorescences with the most anthers have the anthers with the least pollen and viceversa. This ratio is also manifest between the number of grains per flower and the number of flowers per tree, as well as the number of grains per inflorescence and the number of inflorescences per tree.
doi: 10.1080/00173139609430499
Keywords: anthers; flowers; inflorescences; pollen production; tree crown (voyant)

Pollen production in anemophilous trees - Molina, Rafael Tormo; Rodríguez, Adolfo Muñoz; Palaciso, Inmaculada Silva; López, Francisco Gallardo (Grana, 1996)
Abstract A study was made of the total pollen production per individual tree in ten anemophilous arboreal species (including wild, cultivated and ornamental species) of considerable aerobiological importance: Pinus pinaster, Ulmus minor, Juglans regia, Platanus hispanica, Quercus rotundifolia, Salix atrocinerea, Populus nigra, Acer negundo, Olea europaea and Fraxinus angustifolia. For each species three isolated well-shaped specimens of medium height were chosen, and the number of flowers per individual tree and the number of pollen grains per anther was estimated. The values of total pollen production varied between a little over 1000 million grains in Juglans regia and more than 500,000 million in one single tree in Quercus rotundifolia. For the production of pollen grains per anther, the values oscillated between 3000 grains in Juglans regia and 100,000 in Olea europaea. There is an exponential correlation between the size of the anthers and the number of pollen grains they contain. A linear correlation is also evident between the volume of the tree crown and the total production of inflorescences, flowers, anthers and pollen grains per individual tree. Based on this, a mean coefficient of the number of grains/meter of diameter of the tree crown is obtained which varies between 3.4 ? 108 for Juglans regia and 550.9 ? 108 for Quercus rotundifolia. The ratio between the number of anthers per inflorescence and the number of pollen grains per anther carries out a hyperbolic function; thus, the inflorescences with the most anthers have the anthers with the least pollen and viceversa. This ratio is also manifest between the number of grains per flower and the number of flowers per tree, as well as the number of grains per inflorescence and the number of inflorescences per tree.
doi: 10.1080/00173139609430499doi: 10.1080/00173139609430499The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: anthers; flowers; inflorescences; pollen production; tree crown (voyant)

Pre-climax epiphyte communities of bryophytes and lichens in Mediterranean forests from the Central Plateau (Spain) - Fuertes, E; Burgaz, A R; Escudero, a (Plant Ecology, 1996)
The pre-climax epiphytic communities of forests from the Spanish Mediterranean region (Central Plateau) were studied by numerical and traditional floristic methods. One hundred phytosociological relev6s were analyzed through a classical numerical approach based on hard partitions improved by PCoA - Principal Coordinates Analysis - ordinations. Two groups easily related to two different suballiances included in Frullanion dilatatae Lecointe 1975, Ulotenion crispae (Barkman 1958)Lecointe 1975 and Fabronienionpusillae Barkman 1958 were detected. Two new syntaxa within the ass. Ortotrichetum lyeUii (Allorge 1922) Lecointe 1975 are proposed. Phytogeography, syntaxonomy and ecology of these communities are discussed.
Keywords: epiphyte communities; frullanion dilatatae; Mediterranean forests; numerical syntaxonomy; Spain

Pyrolysis and thermally assisted hydrolysis-methylation gas chromatography mass spectrometry of sound and degraded wine bottle cork - Galletti, G C; Bocchini, P; Antonelli, A (RAPID COMMUNICATIONS IN MASS SPECTROMETRY, 1996)
The present paper reports on the utilization of pyrolysis/gas chromatagraphy/mass spectrometry (PY/GC/MS) and thermally assisted hydrolysis-methylation/gas chromatography/mass spectrometry (THM/GC/MS) to characterize cork (Quercus suber L.) of wine bottle stoppers, Sound and degraded cork samples were analysed to verify whether structural differences between the two samples are present, A series of p-hydroxyphenyl, guaiacyl and syringyl phenolic compounds, ascribed to cork polyphenols (suberin and lignin), were identified in the pyrograms. Furan-based derivatives were also detected as the dehydration products of structural polysaccharides (cellulose and hemicellulose). A homologous series of saturated and unsaturated hydrocarbons from C9 to C22 was evident, Finally, pyrolysis in presence of a methylating agent, the technique TRM/GC/MS, allowed the determination of saturated and unsaturated fatty acids which probably originated from thermal degradation of suberin aliphatic fraction, Compared to sound cork, the degraded sample showed relatively more odd-chain hydrocarbons and relatively less even-chain fatty acids contents.
APS
Keywords: cork polyphenols; dehydration products; Quercus suber L.; wine botte stoppers

Radial distribution of Ni in stemwood of Quercus ilex L. trees grown on serpentine and sandy loam (umbric leptosol) soils of NE-Portugal - Nabais, C; Freitas, H; Hagemeyer, J; Breckle, S W (Plant and soil, 1996)
Concentrations of Ni were determined in xylem and phloem of Quercus ilex trees growing on serpentine and sandy loam soils of northeast Portugal. Radial distribution patterns of Ni in stemwood were compared to variations in annual growth increments of the trees. Concentrations of Ni in xylem and phloem were higher in Q. ilex from serpentine soil, when compared with Q. ilex of a sandy loam soil. The radial distributions of Ni showed large variations among the trees, although they all grew in the same area within a short distance from each other. These differences can be caused by small-scale spatial variations in the soil. Therefore, the use of such radial Ni distributions for a retrospective biomonitoring of the Ni pollution of larger areas appears questionable.
Keywords: dendrochemistry; Nickel; Quercus ilex; serpentine; tree rings

Root respiration, growth and nitrogen uptake of Quercus suber seedlings - Mata, C; Scheurwater, I; MartinsLoucao, M A; Lambers, H (PLANT PHYSIOLOGY AND BIOCHEMISTRY, 1996)
We tested the influence of two N-sources, NO3- and NH4+, on root growth and respiration of Quercus suber L. Seedlings were grown on hydroponics with 0.5 mM N as NO3- or NH4+ in a growth chamber. Root relative growth rate (RGR) of NO3--fed seedlings ranged from 9 to 34 mg g(-1) day(-1). These values are lower than those described for slow-growing herbaceous and for most woody species. Root respiration and the activity and capacity of the alternative pathway (AP) showed no differences between the two N-sources. Both activity and capacity of the AP were very low and the cytochrome pathway was fully engaged. Specific respiratory costs were calculated for maintenance, 6.3 nmol O-2 g(-1) s(-1), for nitrate uptake, 0.99 mol O-2 mol N-1, and for growth 5.4 mmol O-2 g(-1). These values are similar to those found for slow-growing herbaceous species. The major part of total root respiration, over 64%, was used for maintenance processes, and a much smaller fraction for growth and nitrate uptake.
Keywords: NH4+; NO3-; Relative growth rate; root respiration

Root respiration, growth and nitrogen uptake of Quercus suber seedlings - Mata, C.; Scheurwater, I.; MartinsLoucao, M. A.; Lambers, H. (PLANT PHYSIOLOGY AND BIOCHEMISTRY, 1996)
We tested the influence of two N-sources, NO3- and NH4+, on root growthand respiration of Quercus suber L. Seedlings were grown on hydroponics with 0.5 mM N as NO3- or NH4+ in a growth chamber. Root relative growth rate (RGR) of NO3--fed seedlings ranged from 9 to 34 mg g(-1) day(-1). These values are lower than those described for slow-growing herbaceous and for most woody species. Root respiration and the activity and capacity of the alternative pathway (AP) showed no differences between the two N-sources. Both activity and capacity of the AP were very low and the cytochrome pathway was fully engaged. Specific respiratory costs were calculated for maintenance, 6.3 nmol O-2 g(-1) s(-1), for nitrate uptake, 0.99 mol O-2 mol N-1, and for growth 5.4 mmol O-2 g(-1). These values are similar to those found for slow-growing herbaceous species. The major part of total root respiration, over 64%, was used for maintenance processes, and a much smaller fraction for growth and nitrate uptake.
The following values have no corresponding Zotero field: pub-location: S P E S-JOURNAL DEPT, 120 BD ST GERMAIN, F-75006 PARIS, FRANCE publisher: GAUTHIER-VILLARS
Keywords: NO3-; NH4+; relative growth rate; root respiration

Signatures of lipid assemblages in soils under continental Mediterranean forests - Almendros, G; Sanz, J; VELASCO, F (European Journal of Soil Science, 1996)
The analysis of free lipids in 12 soils from three representative types of Mediterranean forest has been carried out in an attempt to describe diagnostic molecules reflecting differences between the ecosystems and the intensity of the soil organic matter turnover. The study centred on the analysis by gas chromatography–mass spectrometry of the soil compounds extracted with petroleum ether from soils in central Spain, developed under monospecific formations of stone pine (Pinus pined), evergreen oak (Quercus rotundifolia) and Spanish juniper (Juniperus thurifera), the lipid extracts from their leaves also being analysed as reference material. The comparison between the distribution patterns of alkanes and fatty acids in plant lipids and the corresponding soil lipids was used to assess the extent to which the former accumulate in soil or are substituted by other biogenic or diagenetic homologues. In general, the alkane patterns showed the greatest variation in soils under oak, and the differences between lipid patterns in plant and soil were greatest in the juniper forests. As indicators of the vegetation type, the soil fatty acids had little value. Up to 60 major cyclic compounds were identified, including mainly di- and sesquiterpenes, in addition to some monoterpenes and nonterpenic naphthalenes and decalins. Of these major constituents, 33 compounds were found in soil but were not present in plant extracts, and 18 compounds were identified in plants but were not in the soils. The results suggest an arrangement of the soil samples based on the composition of the signature lipid assemblages.
Keywords: GC-MS; Lipids; Lipids assemblage (voyant); mediterranean forest soils

Signatures of lipid assemblages in soils under continental Mediterranean forests - ALMENDROS, G.; Sanz, J.; VELASCO, F. (European Journal of Soil Science, 1996)
The analysis of free lipids in 12 soils from three representative types of Mediterranean forest has been carried out in an attempt to describe diagnostic molecules reflecting differences between the ecosystems and the intensity of the soil organic matter turnover. The study centred on the analysis by gas chromatography–mass spectrometry of the soil compounds extracted with petroleum ether from soils in central Spain, developed under monospecific formations of stone pine (Pinus pined), evergreen oak (Quercus rotundifolia) and Spanish juniper (Juniperus thurifera), the lipid extracts from their leaves also being analysed as reference material. The comparison between the distribution patterns of alkanes and fatty acids in plant lipids and the corresponding soil lipids was used to assess the extent to which the former accumulate in soil or are substituted by other biogenic or diagenetic homologues. In general, the alkane patterns showed the greatest variation in soils under oak, and the differences between lipid patterns in plant and soil were greatest in the juniper forests. As indicators of the vegetation type, the soil fatty acids had little value. Up to 60 major cyclic compounds were identified, including mainly di- and sesquiterpenes, in addition to some monoterpenes and nonterpenic naphthalenes and decalins. Of these major constituents, 33 compounds were found in soil but were not present in plant extracts, and 18 compounds were identified in plants but were not in the soils. The results suggest an arrangement of the soil samples based on the composition of the signature lipid assemblages.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: GC-MS; Lipids; Lipids assemblage (voyant); mediterranean forest soils

Simulations of canopy net photosynthesis and transpiration in Quercus ilex L. under the influence of seasonal drought - Sala, A; Tenhunen, J D (Agricultural and Forest Meteorology, 1996)
A mechanistically based C 3 leaf photosynthesis model combined with an empirical stomatal model and a canopy model of light interception and microclimate was used to simulate Quercus ilex canopy net photosynthesis and transpiration at l'Avic watershed (NE Spain). The model takes into account the sun-shade leaf differentiation of photosynthetic characteristics as affected by depth within the canopy. Based on field studies, simulations were carried out for two locations within the watershed along a gradient in elevation, microclimate and forest structure. Effective predictions of diurnal and seasonal courses of stomatal conductance of sun and shade leaves for different days during the year were obtained by changing a single model variable termed gF- The value of gF determined from least squares of observed vs. simulated time courses was linearly related to pre-dawn xylem water potential over critical ranges of the response curve. Response to gF in the model may to a great extent be thought of as the integrated expression of canopy response to root system generated signals or control mechanisms. For development of predictive capability, gF is extremely useful because it allows seasonal assessments of water use and carbon dioxide uptake with differing patterns in water availability. Based on simulated responses on representative clear, overcast and variable days throughout the year, only small differences in annual totals for net photosynthesis and transpiration were found between the two sites, despite large differences in soil drying. Annual estimates of canopy water loss were in close agreement with independent estimates of evapotranspiration using the hydrological input/output method.
Keywords: canopy net photosynthesis; Empirical model (voyant); Stomatal conductance; water use

The SLOSS dilemma: A butterfly case study - Baz, A; GarciaBoyero, A (BIODIVERSITY AND CONSERVATION, 1996)
Butterfly species richness is examined on simulated archipelagoes of 2, 3, 4 and 5 holm oak forest fragments in the Guadalajara Province (central Spain). It is shown that there are more species on several small `islands' than on a single island. Also, species number increases with the number of fragments that form the archipelago, and with the average distance between islands within the archipelago. Thus, we conclude, at least for butterflies in a system of fragmented helm oak forests in central Iberia, that the best strategy in order to maximize the conservation of species richness is the creation of a net of some small and scattered reserves.
Keywords: average distance; butterflies; Central Spain; simulated archipelagoes; SLOSS

The SLOSS dilemma: A butterfly case study - Baz, A.; GarciaBoyero, A. (BIODIVERSITY AND CONSERVATION, 1996)
Butterfly species richness is examined on simulated archipelagoes of 2, 3, 4 and 5 holm oak forest fragments in the Guadalajara Province (central Spain). It is shown that there are more species on several small `islands' than on a single island. Also, species number increases with the number of fragments that form the archipelago, and with the average distance between islands within the archipelago. Thus, we conclude, at least for butterflies in a system of fragmented helm oak forests in central Iberia, that the best strategy in order to maximize the conservation of species richness is the creation of a net of some small and scattered reserves.
The following values have no corresponding Zotero field: pub-location: 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN publisher: CHAPMAN HALL LTD
Keywords: average distance; butterflies; Central Spain; simulated archipelagoes; SLOSS

Studies on Mediterranean Hyphomycetes .3. Quadracaea mediterranea anam-gen and sp nov - Lunghini, D; Pinzari, F; Zucconi, L (MYCOTAXON, 1996)
Quadracaea mediterranea anam.-gen. et sp. nov., an hyphomycete recorded on leaves of Quercus ilex L. from central Italy, is described, discussed and illustrated, also by means of SEM.
Keywords: Endophragmi; Hyphomycetes; Quadracaea mediterranea

Trace metal biomonitoring in the soil and the leaves of Quercus ilex in the urban area of Naples. - Alfani, a; Bartoli, G.; Rutigliano, F. a; Maisto, G.; De Santo, a V. (Biological trace element research, 1996)
The concentrations of Pb, Cu, Fe, and Mn were analyzed in surface deposit and tissue of Quercus ilex leaves from several sites of the urban area of Naples, exposed to different degrees of air pollution. These included some major roads with heavy traffic loads, squares, and three urban parks. The soil from the trunk base area of Q. ilex trees in the same sites was also analyzed for total and available metal contents. Pb, Cu, and Fe contents in the surface deposit and leaf tissue were significantly higher (p < 0.01) in leaves from roadside sites than in leaves from parks; significant correlations were found between deposit- and tissue-contents of Pb, Cu, and Fe. Mn content in leaves from roadside sites and in leaves from parks were similar and Mn content in the leaf deposit was irrelevant. Significant differences (p < 0.001) in both total and available Pb and Cu soil content were found between sampling sites. Also for available Fe and Mn soil content differences among sites were relevant, although the highest values were measured in soil from urban parks. A positive correlation between leaf and soil metal content was found only for Pb, thus suggesting that trace metal contents of leaves directly depend on atmospheric depositions. Seasonal variations of Pb, Cu, and Fe were pronounced at a polluted site, whereas no relevant seasonal variation was observed at a control site; moreover, metal accumulation was high at the polluted site. Mn content and seasonal dynamics were comparable at control and polluted sites.
The following values have no corresponding Zotero field: accession-num: 8834387
Keywords: Air Pollutants; Air Pollutants: analysis; biomonitoring; copper; Copper: analysis; Environmental Monitoring; Holly Oak; Iron; Iron: analysis; lead; Lead: analysis; leaves; Manganese; Manganese: analysis; Plants; Plants: chemistry; seasonal dynamics; Soil; Soil: analysis; Trace Elements; Trace Elements: analysis; urban area pollution

Trace metal biomonitoring in the soil and the leaves of Quercus ilex in the urban area of Naples. - Alfani, a; Bartoli, G; Rutigliano, F a; Maisto, G; De Santo, a V (Biological trace element research, 1996)
The concentrations of Pb, Cu, Fe, and Mn were analyzed in surface deposit and tissue of Quercus ilex leaves from several sites of the urban area of Naples, exposed to different degrees of air pollution. These included some major roads with heavy traffic loads, squares, and three urban parks. The soil from the trunk base area of Q. ilex trees in the same sites was also analyzed for total and available metal contents. Pb, Cu, and Fe contents in the surface deposit and leaf tissue were significantly higher (p < 0.01) in leaves from roadside sites than in leaves from parks; significant correlations were found between deposit- and tissue-contents of Pb, Cu, and Fe. Mn content in leaves from roadside sites and in leaves from parks were similar and Mn content in the leaf deposit was irrelevant. Significant differences (p < 0.001) in both total and available Pb and Cu soil content were found between sampling sites. Also for available Fe and Mn soil content differences among sites were relevant, although the highest values were measured in soil from urban parks. A positive correlation between leaf and soil metal content was found only for Pb, thus suggesting that trace metal contents of leaves directly depend on atmospheric depositions. Seasonal variations of Pb, Cu, and Fe were pronounced at a polluted site, whereas no relevant seasonal variation was observed at a control site; moreover, metal accumulation was high at the polluted site. Mn content and seasonal dynamics were comparable at control and polluted sites.
Keywords: Air Pollutants; Air Pollutants: analysis; biomonitoring; copper; Copper: analysis; Environmental Monitoring; Holly Oak; Iron; Iron: analysis; lead; Lead: analysis; leaves; Manganese; Manganese: analysis; Plants; Plants: chemistry; seasonal dynamics; Soil; Soil: analysis; Trace Elements; Trace Elements: analysis; urban area pollution

Trees as a homogenizing factor of the herbaceous community structure and nutrient content in Mediterranean grasslands - Puerto, A; Rico, M (AGROCHIMICA, 1996)
The dehesa system consists of two subsystems, situated under the tree crowns and in the open spaces. They differ clearly in structure and function. The locations under trees are less variable, tending to greater similarity in species diversity, homogeneity, plant biomass, percentage of biomass of constituent families, and plant tissue nutrient content (N, P, K, Na, Ca and Mg), thus showing a certain independence in relation to the topographic situation. By contrast, the open spaces are very much influenced by the position they occupy in the slope gradients. It seems that homogenizing factors interact with others which tend to intensify heterogeneity. The less variable structures (under trees) could be interpreted as agents pumping fertility from the subsoil and presenting it for the use of herbaceous species. The most influenced structures are undoubtedly those situated under the tree crowns, but the whole system is influenced in this way. Consequently, topography and trees create a large number of habitats for herbaceous species, especially due to the overlapping of both factors. The harmony of the combination of the two factors gives stability to the system and has permitted its survival, without degradation, for many centuries.

Urban Green and Atmospheric Pollution: A Biomonitoring Study on Leaves of Quercus Ilex L. - Anselmi, S; Giannini, M A; Allegrini, I; Manes, F (Giornale botanico italiano, 1996)
doi: 10.1080/11263509609439723
Keywords: air quality; atmospheric pollution; leaf functional conditions; Quercus ilex (PG)

Urban Green and Atmospheric Pollution: A Biomonitoring Study on Leaves of Quercus Ilex L. - Anselmi, S.; Giannini, M. A.; Allegrini, I.; Manes, F. (Giornale botanico italiano, 1996)
doi: 10.1080/11263509609439723doi: 10.1080/11263509609439723The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: air quality; atmospheric pollution; leaf functional conditions; Quercus ilex (PG)

Variabilité des nutriments foliaires de Quercus suber L dans différentes situations écologiques dans le massif des Maures (Var, France), et relations avec la production de liège - Orgeas, J; Bonin, G (Ann. For. Sci., 1996)
Variability of foliar nutrient contents of Quercus suber L in several ecological conditions in the Maures Mountains (Var, France), and relations with cork production. A monitoring of foliar nutrients has been undertaken on cork-oaks (Quercus suber L), in the Maures Mountains (Var, France). Simultaneously, the thickness of cork age rings has been studied to define the relationship of the cork production to nutrient contents under different ecological conditions. Foliar concentrations of ions evolved according to the season, the degradation state and the xericity of plots. Nitrogen appeared proportional to the physiological activity of the leaf, while calcium and potassium were stocked gradually. The calcium-magnesium antagonism was confirmed. Furthermore, changes of the nutrient concentrations in the undergrowth-clearing sites are reduced from the spring resumption of the metabolism. The growth of primary cork is linear with time, irrespective of year, climatic conditions and perturbations. The secondary (or reproductive) cork production is not linear with time and the age of trees, but it remains much higher than the primary cork production. The higher secondary cork productions are linked to the high contents of potassium and nitrogen, and to the moist and weakly disturbed plots. Magnesium is linked to small width thicknesses of cork age rings. Sodium and calcium do not appear to influence this cork production.
Keywords: Cork Production; disturbance; ecological conditions; foliar nutrients; Quercus Suber L

Vegetation history and climate of the last 15,000 years at Laghi di Monticchio, southern Italy - Watts, W A; Allen, J R M; Huntley, B; Fritz, S C (Quaternary Science Reviews, 1996)
In southern It;aly, vegetation contemporary with the end of the last glacial maximum, from 15,000 to 12,000 years ago, is shown by pollen-analysis to have been treeless and steppe-like in character. At 12,500 BP (years before present), Betula (birch) expanded into the steppe, quickly followed by Quercus (oak), Fugus (beech), Tilia (lime) and other tree genera of mesic forest. High percentages of lUia point to a rich mesic forest that was contemporary with the ‘Allerod’ intersta- dial of northern Europe. A major decline in mesic trees with an accompanying return of Beth and steppe genera dated to 10,500 years ago identifies a ‘Younger Dryns’ climatic reversal. Betula and steppe genera were replaced by forest of Quercus and other mesic trees, notably Ulmus (elm), as the Holocene began. In the later Holocene, ca. 4000 years ago, Abies (fir), Curpinus betulus (hom- beam) and Taxus (yew) appeared. Abies and Tuxus became extinct locally about 2500 years ago, either because of climatic change, or perhaps because of the effects of early agriculture. The Full- glacial climate is thought to have been cold and summer-dry with mainly winter precipitation. The Lateglacial ‘Boiling-Allereld’ Interstadial was summer-wet and warm. The response-surface based climate reconstruction indi’zates an early Holocene climate with markedly colder winter conditions than today, about -5°C compared with 3.9-C today as a mean temperature for the coldest month. The annual temperature sum is reconstructed as somewhat higher than today, 3500 degree days as compared with a calculated value of 2900 for today. The later Holocene had a climate like today’s, Rainfall, and variation in iis seasonal distribution, has been a critical determinant of the vegetation cover. The fossil pollen record at Laghi Di Monticchio has been complemented by diatom and plant macrofossil studies which provide evidence of former lake environments as well as data on the upland forest. Lake levels remained high during the Full- and Lateglacial with encroachment of shore vegetation during th,e Holocene. The sediments also have an exceptionally rich record of tephra falls which are of importance in dating and core correlation. Twenty-one macroscopically visible tephras occur in sediments of the last 15,000 years
Keywords: climate reconstruction; FOREST; Holocene (voyant); Pollen analysis; vegetation history

Water relations of oak species growing in the natural CO2 spring of Rapolano (central Italy) - Tognetti, R; Giovannelli, A; Longobucco, A; Miglietta, F; Raschi, A (Ann. For. Sci., 1996)
The effect of elevated atmospheric carbon dioxide on water relations was examined on downy oak (Quercus pubescens) and holm oak (Q ilex) trees. The study was conducted on trees growing in a naturally enriched CO2 spring. Sap velocity and sap flow were measured by the heat pulse technique. On the same trees, daily courses of xylem water potential, leaf conductance and transpiration were monitored. Plant water relations were evaluated by pressure-volume analysis method on shoots; on the same branches, relative conductivity of xylem was measured. Both species exhibited increased osmotic potential and decreased symplasmic fraction of water in trees adapted to increased CO2. Downy oak showed lower stomatal conductance under elevated CO2, but holm oak did not. Both species displayed higher sap flow in control trees. In both species, increased carbon dioxide did not influence xylem embolism formation.
Keywords: Drought; Elevated CO2; embolism; Quercus ilex; Quercus pubescens; sap flow; water relations

Water relations of six sclerophylls growing near Trieste (Northeastern Italy): has sclerophylly a univocal functional significance? - Nardini, Andrea; Gullo, Maria Assunta Lo; Tracanelli, Stefano (Giornale botanico italiano, 1996)
Abstract The annual time course of the water relations of six sclerophylls has been studied with the aim of: a) defining strategies adopted for withstanding summer water stress and b) to check whether their common sclerophyllous habitus could represent a case of convergent evolution devoted to a univocal functional role. In particular, Phillyrea latifolia L. showed to behave like a drought tolerant as indicated by deep summer drop in leaf water potential (?1) to near the full turgor loss point (?lp) and in leaf relative water content (RWC) as caused by xylem cavitation. Prunus laurocerasus L. and Laurus nobilis L. showed to be drought avoiding water spenders in that their ?1 dropped in summer causing prompt recovery in RWC. This was made possible by low cavitation in their twigs. Ilex aquifolium L. was a typical drought avoiding water saver in that both ?1 and RWC remained at very high levels throughout the year. Quercus ilex L. behaved like a drought avoiding water spender which switched to drought tolerance in the warmest period of the year. This was explained by its high vulnerability to cavitation. The extreme heterogeneity of the six species studied suggested that sclerophylly cannot be interpreted as an anatomical feature leading to a specific and unifying functional role, at least as regards drought resistance.
doi: 10.1080/11263509609438352
Keywords: drought tolerance (PG); sclerophylls; water relations

13C solid-state nuclear magnetic resonance and Fourier transform infrared studies of the thermal decomposition of cork. - Pascoal Neto, C.; Rocha, J.; Gil, A.; Cordeiro, N.; Esculcas, a P.; Rocha, S.; Delgadillo, I.; de Jesus, J. D.; Correia, a J. (Solid state nuclear magnetic resonance, 1995)
The thermal decomposition of cork has been studied by Fourier transform infrared (FTIR) spectroscopy and 13C solid-state nuclear magnetic resonance (NMR) spectroscopy with cross-polarization and magic-angle spinning (CP-MAS), high-power 1H decoupling (HPDEC) and cross-polarization depolarization-polarization (CPDP). Waxes and other soluble components of cork begin to decompose at ca. 150 degrees C. This is accompanied by partial decomposition of suberin, probably initiated at the points of attachment to the cell wall. The carbohydrates begin to decompose at ca. 200 degrees C. The decomposition of lignin begins at 250-300 degrees C, while suberin undergoes further degradation. Significant amounts of coke are formed in the process. At 400 degrees C cork has been transformed into coke with traces of partially decomposed suberin. The thermal decomposition of cork is dependent on the calcination time, particularly in the 200-350 degrees C range.
The following values have no corresponding Zotero field: accession-num: 7773647
Keywords: Fourier Transform Infrared (citation); Hot Temperature; Lignin; Lignin: chemistry; Lipids; Magnetic Resonance Spectroscopy; Membrane Lipids; Membrane Lipids: chemistry; Polysaccharides; Polysaccharides: chemistry; Spectroscopy

Absorbed water in the cork structure. A study by thermally stimulated currents, dielectric relaxation spectroscopy, isothermal depolarization experiments and differential scanning calorimetry - Dionísio, M. S. C.; Correia, N. T. (Journal of materials …, 1995)
This paper reports on a modification of the dielectric properties of cork which occurs as a consequence of heating above 60 ~ C or evacuation for several days. This phenomenon was observed using different experimental techniques (thermally stimulated currents, dielectric relaxation spectroscopy, isothermal depolarization experiments and differential scanning calorimetry), and the corresponding kinetics were analysed. It was observed that the original properties of cork were recovered if the sample was exposed to room air for several weeks. It is suggested that the reported modification of the dielectric properties arises from desorption, induced by heating or evacuation, of water molecules absorbed in the cork structure.
Keywords: Cellular structure (voyant); Cork; dielectric loss; dielectric relaxation; TSDC; water desorption

Acorn predation and seedling production in a low-density population of cork oak (Quercus suber L.) - Herrera, Javier (Forest Ecology and Management, 1995)
Prospects for cork oak recruitment were examined in a scrub-dominated area with low tree density in southern Spain by sowing acorns experimentally in a variety of sites. Seeds placed on the ground surface were invariably eaten within a few months by a variety of vertebrate herbivores (cattle, red deer, fallow deer, wild boar and rabbits). Predation reached 100% whether acorns were placed beneath trees or more than 100 m away from trees. Seeds placed under dense heath scrub were also rapidly removed, although their final fates could not be ascertained. Single acorns buried under open or dense scrub experienced the lowest predation (52% and 0%, respectively) and had relatively high emergence rates (38% and 60%, respectively). Heavy shoot browsing occurred in both scrub types, and out of the 49 buried acorns which produced a shoot, only two seedlings were alive 1 year after germination. None survived 2 years after sowing.
Keywords: herbivory; Predation; Quercus suber; seedling production

Actividad espacio-temporal de Polietes meridionalis Peris & Llórente , 1963 ( Díptera : Muscidae ) en un ecosistema de encinar * - Rojo, S; Marcos-garcía, M A (Boletín de Sanidad Vegetal Plagas, 1995)
Some aspects of the biology of Polietes meridionalis Peris & Llórente 63 have been analysed in a holm-oak ecosystem (dehesa) located in the Tberian Mediterranean área. The specimens were caught with pit-fall traps baited with cattle dung, placed according to habitat gradient. They were collected at dífferent hourly periods to fix a distribution model in space and time and its variation during the year.
Keywords: coprophagous diptera; Diptera; holm-oak; Muscidae; Polietes meridionalis; space-temporal distribution

Adiciones a la flora de la Dehesa de la Albufera (Valencia) - Sanz, Gonzalo Mateo; Andrés, Isabel Mateu (Flora Montiberica, 1995)
Se comentan los hallazgos de tres especies raras de plantas vasculares en la Dehesa de la Albufera (Valencia). Por un lado Centaurium littorale (D. Turner) Gilmour subsp. littorale, planta de óptimo atlántico que se aporta como novedad para la flora española y de las costas mediterráneas. Por otro Polygonum mite Schrank, novedad para la flora valenciana y para la España media y Kickxia cirrhosa (L.) Fritsch, de la que se ofrece una pri- mera localidad valenciana concreta
Keywords: Dehesa de la Albufera; especies raras; Valencia (PG)

Assessment of sensitization to holm oak (Quercus ilex) pollen in the Mérida area (Spain) - Prados, M; Aragon, R; Carranco, M I; Martínez, a; Martínez, J (Allergy, 1995)
Sensitization to Quercus ilex(holm oak) was studied in 760 patients with clinical suspected sensitization to aeroallergens. Prick tests with commercial extracts of Q. ilex proved positive in 27 patients; none were monosonsitive. Nasal and conjunctival provocation tests and specific IgE (RAST) performed with Q. ilex extracts in these patients were negative in all hut one patient, who exhibited specific IgE: liter by RAST) of 7 PRU ml (class 3). We conclude that Q. ilex pollen, though obtained in considerable quantities by our collector, docs not cause allergies in our area.
Keywords: Holm oak; Mérida; Quercus ilex; sensitization

Bases para um programa de melhoramento florestal da espécie Quercus suber L. - Ribeiro, M M A (Revista Florestal, 1995)
The existing symptoms of degradation in cork oak stands requires the improvement on them, namely with plants that might produce cork in quantity and of good quality. It is urgent to develop an improvement program for this species spread in 664 thousand ha in our country (i. e. 1/3 of the whole area covered with cork oak in the world). Fifty five per cent of the world cork production comes from that area whose size could be extended more than 200 thousand ha. In the present work improvement programs for forestry species are brought into focus, and so are the different techniques of vegetative propagation, due to the importance they have in the development of these programs related either to the mass phenotypic selection (to estimate heritability and genetic gain) or to the clonal propagation of improved material. Maturative process in forest trees is questioned once it might condition the use of vegetative propagation and the techniques used to overcome that process are referred. Finally strategies for the improvement of cork oak, in the short and long term, are named.
Keywords: Cork oak; forest tree improvement; Quercus suber L.; vegetative propagation

Biodiversity components and conservation of mediterranean healthlands in Southern Spain - Ojeda, F.; Arroyo, J.; MARAÑON, T. (Biological Conservation, 1995)
Biodiversity is a complex issue which has frequently been extremely simplified both by equating it with species richness, and by addressing it at the level of regional floras or faunas. In this paper we carry out a detailed assessment of biodiversity for conservation of Mediterranean heathlands and related woodland understoreys on acidic ‘islands’ in the Gibraltar Strait region which are remarkable for their high species richness, high endemism and low ratio of species per genus. The relationship between the cover of woody plant species and environmental variables was studied by multivariate (DCCA) analysis of 30 samples. Species richness shows a unimodal relationship along the main environmental gradient primarily determined by physiological tolerance to low pH and ecological competition. Quercus suber woodland understoreys under intermediate environmental conditions are highest in species richness. Woody plant species are assigned to one of seven types of geographic ranges, and distributional spectra of community samples are represented. Open heathlands on nutrient-poor soils on mountain ridges are highest in endemism. Species distinctness was estimated as the inverse of the average number of species per genus (‘taxonomic singularity’) within the Mediterranean Basin, Ibero-North African and Southwestern Spain ranges. Quercus canariensis woodland understoreys on more fertile soils on valley bottoms present the highest taxonomic singularity. The analysis at the community level of the three proposed biodiversity components (species richness, endemism richness and taxonomic singularity) is interpreted with the aim of formulating sound conservation strategies of the communities examined. Although we use communities in the Gibraltar Strait area as a particular case study, we suggest that this methodology would help conservation efforts in other areas.
Keywords: acid soils; endemism; Gibraltar Strait; historical biogeography; Species richness

Biodiversity components and conservation of mediterranean healthlands in Southern Spain - Ojeda, F; Arroyo, J; MARAÑÓN, T (Biological Conservation, 1995)
Biodiversity is a complex issue which has frequently been extremely simplified both by equating it with species richness, and by addressing it at the level of regional floras or faunas. In this paper we carry out a detailed assessment of biodiversity for conservation of Mediterranean heathlands and related woodland understoreys on acidic ‘islands’ in the Gibraltar Strait region which are remarkable for their high species richness, high endemism and low ratio of species per genus. The relationship between the cover of woody plant species and environmental variables was studied by multivariate (DCCA) analysis of 30 samples. Species richness shows a unimodal relationship along the main environmental gradient primarily determined by physiological tolerance to low pH and ecological competition. Quercus suber woodland understoreys under intermediate environmental conditions are highest in species richness. Woody plant species are assigned to one of seven types of geographic ranges, and distributional spectra of community samples are represented. Open heathlands on nutrient-poor soils on mountain ridges are highest in endemism. Species distinctness was estimated as the inverse of the average number of species per genus (‘taxonomic singularity’) within the Mediterranean Basin, Ibero-North African and Southwestern Spain ranges. Quercus canariensis woodland understoreys on more fertile soils on valley bottoms present the highest taxonomic singularity. The analysis at the community level of the three proposed biodiversity components (species richness, endemism richness and taxonomic singularity) is interpreted with the aim of formulating sound conservation strategies of the communities examined. Although we use communities in the Gibraltar Strait area as a particular case study, we suggest that this methodology would help conservation efforts in other areas.
Keywords: acid soils; endemism; Gibraltar Strait; historical biogeography; Species richness

Carbon dioxide efflux and pCO 2 in soils of threeQuercus ilex montane forests - Piñol, J; Alcañiz, J M; Rodà, F (Biogeochemistry, 1995)
Soil CO2 efflux and pCO2 in the soil atmosphere were measured during one year at three montane sites of Mediterranean sclerophyllous forests in NE Spain. Two sites were located in the upper and lower slopes of a small catchment in the Prades mountains (mean precipitation 550 mm year-'), and a third site was located on a lower slope in the Montseny mountains (mean precipitation 900 mm year-'). The three sites were similar in bedrock and vegetation, but differed in soil characteristics and water availability. Seasonal variation of CO2 efflux and soil pCO2 were affected by soil temperature and, to a lesser extent, by soil moisture. Annual mean soil CO2 efflux (considered as soil respiration) was similar at Montseny and at the comparably located site at Prades (83 ± 18 S.E. vs. 75 4 9 mg CO2 m - 2 hour- , respectively), and was highest at the Prades upper slope site (122 ± 22 mg CO2 m -2 hour-l). Despite those relatively similar CO 2 effluxes, mean soil pCO2 was much higher at both Prades sites than at Montseny. Soil pCO2 always increased with depth at Prades while maxima pCO2 at Montseny were often at 20-30 cm depth. A model based on gas diffusion theory was able to explain why soil pCO2 was much higher at Prades than at Montseny, and to reproduce the shape of the vertical profile of pCO2 at the Prades soils. Nevertheless, the model failed to simulate the soil pCO2 maximum found at 20-30 cm depth at the Montseny site. Model simulations using a time-variable CO2 production rate suggested that pCO2 maxima at intermediate depth could be the result of a transient situation instead of an equilibrium one.
Keywords: carbon cycle; Carbon dioxide; Mediterranean ecosystems; soil atmosphere; Soil respiration

Carbon dioxide efflux and pCO 2 in soils of threeQuercus ilex montane forests - Piñol, J.; Alcañiz, J. M.; Roda, F. (Biogeochemistry, 1995)
Soil CO2 efflux and pCO2 in the soil atmosphere were measured during one year at three montane sites of Mediterranean sclerophyllous forests in NE Spain. Two sites were located in the upper and lower slopes of a small catchment in the Prades mountains (mean precipitation 550 mm year-'), and a third site was located on a lower slope in the Montseny mountains (mean precipitation 900 mm year-'). The three sites were similar in bedrock and vegetation, but differed in soil characteristics and water availability. Seasonal variation of CO2 efflux and soil pCO2 were affected by soil temperature and, to a lesser extent, by soil moisture. Annual mean soil CO2 efflux (considered as soil respiration) was similar at Montseny and at the comparably located site at Prades (83 ± 18 S.E. vs. 75 4 9 mg CO2 m - 2 hour- , respectively), and was highest at the Prades upper slope site (122 ± 22 mg CO2 m -2 hour-l). Despite those relatively similar CO 2 effluxes, mean soil pCO2 was much higher at both Prades sites than at Montseny. Soil pCO2 always increased with depth at Prades while maxima pCO2 at Montseny were often at 20-30 cm depth. A model based on gas diffusion theory was able to explain why soil pCO2 was much higher at Prades than at Montseny, and to reproduce the shape of the vertical profile of pCO2 at the Prades soils. Nevertheless, the model failed to simulate the soil pCO2 maximum found at 20-30 cm depth at the Montseny site. Model simulations using a time-variable CO2 production rate suggested that pCO2 maxima at intermediate depth could be the result of a transient situation instead of an equilibrium one.
Keywords: carbon cycle; Carbon dioxide; Mediterranean ecosystems; soil atmosphere; Soil respiration

Changes in litter during the initial leaching phase: an experiment on the leaf litter of Mediterranean species - Ibrahima, Adamou; Joffre, Richard; Gillon, Dominique (Soil biology and biochemistry, 1995)
A laboratory experiment was carried out with the litter of 7 Mediterranean species of plants to compare their mass losses during the initial leaching phase of decomposition. To this end, the leaf and needle litter of deciduous, marcescent (deciduous species in which the withered leaves remain on the tree. for several months) and evergreen broad-leaved species and pine was immersed for 10 days in demineralized water, in the dark at 22°C. Samples were taken at 1,6, 24,72, 168 and 240 h. Depending on the species, the litter lost between ‘T-15% of initial dry mass, and water content values were between 130-360% of dry mass. The water absorption rate was positively correlated with the initial cellulose content of the litter and negatively correlated wil:h the initial leaf density, but the water content at the end of the experiment, the leaching rate and the total mass loss were uncorrelated with any of the initial litter characteristics studied. For 100 g of litter at the start (as dry matter), the losses after 240 h of immersion in water were, when they were significant, 5-8 g of C, 70-l 30 mg of N (significant for 3 species), 4-40 mg of soluble sugars and 3 g of inorganic elements (significant for only 2 species). In contrast, the quantities of lignin and cellulose in the litter remained unchanged. Most of the leaching losses (SCrSO%) therefore consisted of C. During leaching, the litter showed a tendency to become more concentrated in cellulose and lignin and poorer in sugars. Pine needle litter was distinguished by its low water absorption and low mass loss during leaching. In general, the litters of deciduous species were more absorbent than the litters of evergreen species. In contrast, the losses of water-soluble substances were not significantly different between these 2 groups of litters. In the broad-leaved species, the losses of water-soluble substances were slower and 2-3 times lower, compared to results already published for species from mesic biomes
Keywords: litter decomposition; mediterranean species; Temperature; water availability (voyant)

Characterization of the cork surface by inverse gas chromatography - Cordeiro, N; Neto, C P; Gandini, A; Naceur Belgacem, M (Journal of colloid and interface science, 1995)
Inverse gas chromatography (IGC) at infinite dilution has been used to study the surface properties of cork from Quercus suber. The dispersive component of its surface energy was determined at different temperatures using n-alkanes as probes, and a GDS value of 38+-1mJ.m-2 at 40ºC was obtained. The surface acid (A)/base(B) properties were also evaluated by using polar probes and the results indicate that cork has an amphoteric character, with a KA/KB=1.1. The advantages of IGC, compared with the technique of contact angle measurements in the characterization of the cork surface, are discussed
Keywords: Cork; Inverse Gas Chromatography (IGC); surface properties (PG)

Characterization of the cork surface by inverse gas chromatography - Cordeiro, N.; Neto, C. P.; Gandini, A.; Naceur Belgacem, M. (Journal of colloid and interface science, 1995)
Inverse gas chromatography (IGC) at infinite dilution has been used to study the surface properties of cork from Quercus suber. The dispersive component of its surface energy was determined at different temperatures using n-alkanes as probes, and a GDS value of 38+-1mJ.m-2 at 40ºC was obtained. The surface acid (A)/base(B) properties were also evaluated by using polar probes and the results indicate that cork has an amphoteric character, with a KA/KB=1.1. The advantages of IGC, compared with the technique of contact angle measurements in the characterization of the cork surface, are discussed
Keywords: Cork; Inverse Gas Chromatography (IGC); surface properties (PG)

Coupling water sources and carbon metabolism of natural vegetation at integrated time and space scales - Valentini, R; Scarascia Mugnozza, G; De Angelis, P; Matteucci, G (Agricultural and Forest Meteorology, 1995)
The linkage between water utilization and photosynthetic processes is investigated using stable isotopes and eddy covariance techniques, allowing integration of physiological pro- cesses both at time and space scales, respectively. Using the ratio of the stable isotopes of hydrogen (hydrogen vs. deuterium) and discrimination of 13C vs. ~2C, the relationship between water sources (rain water vs. ground water) utilization and intercellular carbon dioxide con- centration is analysed for various species of two different ecosystems: an alpine forest and a Mediterranean macchia. As an example of space scale integration of water-carbon coupling, the relationship between canopy carbon dioxide assimilation and bulk stomatal conductance, measured with eddy covariance, is presented for a macchia community and a low-productivity grassland.
Keywords: canopy conductance; canopy photosynthesis (voyant); carbon isotope discrimination; water use

Crown status of holm oak (Quercus ilex L.) trees as related to phenology and environmental stress - Bussotti, F; Ferretti, M; Cozzi, A (Water, Air, & Soil …, 1995)
In order to study the possible interactions between air pollution and climate coaditions in Mediterranean evergream broadleaf species, since 1987 we have been monitoring the annual and infra-annual variations in crown density of Quercus ilex L. (holm oak) in a permanent sample plot. The behaviour of crown density has been compared with litterfall pattern and aging processes in leaves. The results of this study confirm the important impact of climate on crown condition in Meditea-raneeaa broadleaves, so that even the role of non- acute pollution can be disguised. Xeromorph adaptations in holm oak leaves are also a mechanism providing a greater protection against poltutants.
Keywords: abscission; crown condition; holm oak (voyant); leaves

Crown status of holm oak (Quercus ilex L.) trees as related to phenology and environmental stress - Bussotti, F.; Ferretti, M.; COZZI, A. (Water, Air, & Soil …, 1995)
In order to study the possible interactions between air pollution and climate coaditions in Mediterranean evergream broadleaf species, since 1987 we have been monitoring the annual and infra-annual variations in crown density of Quercus ilex L. (holm oak) in a permanent sample plot. The behaviour of crown density has been compared with litterfall pattern and aging processes in leaves. The results of this study confirm the important impact of climate on crown condition in Meditea-raneeaa broadleaves, so that even the role of non- acute pollution can be disguised. Xeromorph adaptations in holm oak leaves are also a mechanism providing a greater protection against poltutants.
Keywords: abscission; crown condition; holm oak (voyant); leaves

Dating natural gaps in the holm oak forest (Quercus ilex L) in Fango MAB Reserve (Corsica) by reading rings of maquis components - Panaiotis, C; Loisel, R; Paradis, G (Ann. For. Sci., 1995)
This work is related to the study of natural gaps in a Quercus ilex Mediterranean forest in Corsica, France. The aim was to find a way to precisely date the volis to obtain a chronological sample which corresponded to the time of vegetation opening due to the fall of a holm oak and up to complete vegetation closure. The best marker appeared to be Phillyrea latifolia, a typical maquis tree found in association with the holm oak, which has a high capacity to produce stem sprouts after the breakage. In order to date the chablis, rings from the stem sprouts must be counted and a careful observation of the other species must be made to confirm results.
Keywords: Corsica; Dendrochronology; Maquis; natural gap; Quercus ilex

Dung Beetles (Coleoptera: Scarabaeidae, Geotrupidae) Attracted to Fresh Cattle Dung in Wooded and Open Pasture - Galante, Eduardo; MENA, JAVIER; LUMBRERAS, CARLOS (Environmental Entomology, 1995)
The biomass of dung beetles attracted to fresh cattle dung was studied in a Mediterranean holm oak pasture ecosystem with a continental Mediterranean climate (supramediterranean level). Results indicated a nonuniform biomass distribution of dung beetles throughout the year. Major peaks of species activity and biomass concentration of dung beetles occurred in open areas of the pasture in the spring followed by minor peaks in the fall. Beetle biomass in the open pasture was greater than that in the wooded pasture. The species of dung beetles comprising the greatest amount of biomass and the most important species available to destroy cattle dung pats in Mediterranean ecosystemswith a continental climate were Bubas bubalus Olivier, Onthophagus opacicollis d'Orbigny, Copris hispanus (L.), Copris lunaris (L.), and Onthophagus vacca (L.).
Keywords: biomass; dung beetles; Holm oak; Mediterranean ecosystem; pastureland

Dung Beetles (Coleoptera: Scarabaeidae, Geotrupidae) Attracted to Fresh Cattle Dung in Wooded and Open Pasture - Galante, Eduardo; MENA, JAVIER; LUMBRERAS, CARLOS (Environmental Entomology, 1995)
The biomass of dung beetles attracted to fresh cattle dung was studied in a Mediterranean holm oak pasture ecosystem with a continental Mediterranean climate (supramediterranean level). Results indicated a nonuniform biomass distribution of dung beetles throughout the year. Major peaks of species activity and biomass concentration of dung beetles occurred in open areas of the pasture in the spring followed by minor peaks in the fall. Beetle biomass in the open pasture was greater than that in the wooded pasture. The species of dung beetles comprising the greatest amount of biomass and the most important species available to destroy cattle dung pats in Mediterranean ecosystemswith a continental climate were Bubas bubalus Olivier, Onthophagus opacicollis d'Orbigny, Copris hispanus (L.), Copris lunaris (L.), and Onthophagus vacca (L.).
Keywords: biomass; dung beetles; Holm oak; Mediterranean ecosystem; pastureland

Dynamics of bioelements during leaf decomposition in three forest ecosystems of semiarid climate in the Duero Basin - Hernández, M I; Santa Regina, I; Gallardo, J F (Arid Soil Research and Rehabilitation, 1995)
The dynamics of bioelements lost during leaf litter decomposition were experimentally determined in three forest ecosystems located in a semiarid zone of the Duero Basin, Province of Zamora, Spain, during 2 years. The three ecosystems were a climax Quercus rotundifolia (evergreen oak) woodland, a paraclimax Pinus pinea (stone pine) forest, and a disclimax P. pinaster (maritime pine) forest. The total content of bioelements found in the litter was low in relation to other forest ecosystems: 27, 14, and 8 kg N ha?1 in Q. pyrenaica, P. pinea, and P. pinaster, respectively; 17, 10, and 9 kg Ca ha?1, respectively; about 2 kg P ha?1, 4 kg K ha?1, and 5 kg Mg ha?1 in the three forests. The Q. rotundifolia woodland potentially returns a greater amount of N and Ca than both Pinus forests. An in situ litter bag method was used for the determination of dynamics of the decomposing leaves. A progressive loss of C, P, and Mg in the decomposing oak leaves and pine needles, and a sharp loss of K were observed; by comparison, a tendency to maintain N and Ca was seen. Pinus pinaster forest had the lowest annual N and P return.
doi: 10.1080/15324989509385911
Keywords: biogeochemical cycles; litter decomposition; pine forests; Quercus rotundifolia; semiarid forests

Eastern Mediterranean Quaternary paleoclimates from pollen and isotope records of marine cores in the Nile Cone Area - Cheddadi, Rachid; Rossignol-Strick, M (Paleoceanography, 1995)
Pollen spectra from three eastern Mediterranean cores have been used to document the paleoclimates of the Levantine Basin borderlands over the last 250 kyr to establish the relationship between this regional climate data set and the global climate as recorded by foraminiferal δ18O and to compare it with proximal land pollen records. Core MD 84 642 with eight sapropels covers the last two climatic cycles up to the early Holocene, MD 84 627 with four sapropels goes back to 125 kyr, and MD 84 629 with one sapropel covers the last 70 kyr. The sedimentation rate decreases from core 629, located at the shallowest depth beneath the Nile River plume, to cores 627 and 642. During the interglacials defined by a low 18O/16O ratio, the abundance of tree pollen is maximum and points to an optimum Mediterranean climate with greatest humidity, including some summer rainfall. During glacial maxima, with highest 18O/16O ratio, the pollen abundance is high for steppe and semidesert plants and low for trees, indicating a definitely more arid, more continental, and probably colder climate. The variations of pollen abundance occur in phase with those of the foraminifer δ18O record. This signifies that the regional climate of the Levantine Basin borderlands had the same temporal pattern as the global ice volume documented by the ice volume curve.
Keywords: climate; Eastern Mediterranean; Evergreen and deciduous forests; isotopic stratigraphy (voyant); pollen spectra

Effect of geographical discontinuity on genetic variation in Quercus ilex L.(holm oak). Evidence from enzyme polymorphism - Michaud, H.; Toumi, L.; Lumaret, R.; Li, T. X. (Heredity, 1995)
Allozymes at a maximum of eight loci were used to analyse the spatial patterns of genetic variation in 1942 hoim oak trees (Quercus ilex L.) from 57 provenances distributed in the six main disjunct areas of the species distribution area. Polymorphism and genetic diversity were high except in the six marginal populations growing in various locations under unfavourable climatic conditions. Ten per cent of the total genetic diversity (H =0.262) was accounted for by among-population variation. In this long-lived species, the effect of geographical discontinuities on gene flow restriction was shown by the occurrence of: (i) numerous rare alleles limited to a single disjunct region; and (ii) allele frequency variation among the disjunct regions for four alleles. This result was obtained by comparing spatial autocorrelograms from the 57 populations of the entire distribution area and from the 31 populations of the Mediterranean continental region which constitutes the largest continuous area in that distribution. Life history traits (e.g. long life span and high outcrossing rate) and past changes in climate and geographical continuity are assumed to be the main factors responsible for the present genetic variation patterns observed in the species.
Keywords: allozyme differentiation; long-term isolation; Quercus ilex

Effect of geographical discontinuity on genetic variation in Quercus ilex L.(holm oak). Evidence from enzyme polymorphism - Michaud, H; Toumi, L; Lumaret, R; Li, T X (Heredity, 1995)
Allozymes at a maximum of eight loci were used to analyse the spatial patterns of genetic variation in 1942 hoim oak trees (Quercus ilex L.) from 57 provenances distributed in the six main disjunct areas of the species distribution area. Polymorphism and genetic diversity were high except in the six marginal populations growing in various locations under unfavourable climatic conditions. Ten per cent of the total genetic diversity (H =0.262) was accounted for by among-population variation. In this long-lived species, the effect of geographical discontinuities on gene flow restriction was shown by the occurrence of: (i) numerous rare alleles limited to a single disjunct region; and (ii) allele frequency variation among the disjunct regions for four alleles. This result was obtained by comparing spatial autocorrelograms from the 57 populations of the entire distribution area and from the 31 populations of the Mediterranean continental region which constitutes the largest continuous area in that distribution. Life history traits (e.g. long life span and high outcrossing rate) and past changes in climate and geographical continuity are assumed to be the main factors responsible for the present genetic variation patterns observed in the species.
Keywords: allozyme differentiation; long-term isolation; Quercus ilex

Effects of forest fragmentation on a guild of wintering passerines: the role of habitat selection - Tellería, J L; Santos, T (Biological conservation, 1995)
This study analyses the winter colonization of an archipelago of 31 forests (0.1-350 ha) in central Spain by the guild of pariforms (Parus, Aegithalos, Regulus, Sitta and Certhia). Two hypotheses are considered: (a) that birds with similar habitat preferences tend to disap- pear simultaneously with the reduction in forest size, leading to a ‘nested’ pattern of species distribution; or (6) that the species in the smallest forests are a random sample of those found in the larger ones. The results sup- port hypothesis (a). The species that depend on rela- tively scarce resources, such as tree trunks and junipers Juniperus thurifera (Sitta europaea, Certhia brachy- dactyla, Parus cristatus and P.ater) only occupied the largest forests. On the other hand, species that exploit abundant, ubiquitous resources, such as holm oak Quercus ilex foIiage (Regulus ignicapillus and Parus caeruleus), were distributed uniformly throughout all the fragments. These results emphasize the need for a better understand- ing of habitat selection by species when designing conser- vation strategies for fragmented populations.
Keywords: Forest fragmentation; habitat selection; Spain; wintering passerines

Effects of oak ( Quercus ilex) tannins on digestion and nitrogen balance in sheep and goats - Narjisse, H; Elhonsali, M A; Olsen, J D (Small Ruminant Research, 1995)
Sheep and goats exhibited different levels of tolerance to the effects of tannins extracted from oak leaves (Quercus ilex) Feed intake, N balance, and rumen ammonia concentrations decreased by 8%, 159% and 50%, respectively, in sheep infused intraruminally with tannins (P <0.05). Similar measurements were not depressed (P> 0.05) in goats although mean rumen ammonia content was 39% less. In vivo DM digestibility was not significantly different for either sheep or goats. Averaged in vitro fermentation capacity was depressed 10% by tannin (8-12% concentration) in the rumen fluid from non-infused sheep given the same diet, but was improved by 9% for goats. Finally, tannin-infused goats lost in urine only 17% of the N ingested, while tannin-infused sheep excreted as much as 44%. The superiority of goats in dealing with tannin might result from the greater ability of their microbial population to degrade tannins, and/or their higher urea recycling and salivary secretion capabilities. Results derived from this study indicate that goats may be more suitable for grazing in oak woodland, especially during the season when alternative forage availability is scarce.
Keywords: digestibility; Feed intake; Goats; Quercus; Sheep; tannin

Effects of urban heavy metal pollution on organic matter decomposition in Quercus ilex L. Woods - Cotrufo, M. F.; Santo, A. V. De; Alfani, Anna (Environmental Pollution, 1995)
Decomposition of oak (Quercus ilex) leaves containing different concentrations of Fe, Zn, Cu, Cr, Ni and Pb was measured in laboratory microcosms. The leaves were collected from a polluted site inside the city of Naples and from a control site away from the city. Soil was sampled from the upper A horizon (0-5 cm) at both sites and analyzed for respiration, microbial biomass and abundance of fungal mycelia. The soils from the two sites differed significantly in heavy metals concentrations. The accumulated mass loss reached an asymptotic value after four months both for the control and polluted litters. However, control and polluted litters significantly differed in accumulated mass loss, that was respectively 40 % and 29 % of the initial weight, after 10 months. Moreover decomposition rates appeared to be strongly influenced by metal contamination in the early stages, while in later stages, they did not differ significantly. Litter respiration appeared to be inhibited by metal contamination and showed pattern and rates consistent with those found for litter decomposition. Fungal mycelia were significantly less abundant both in litter and soil from the polluted site than from the con- trol site. Metabolic activity (both as soil respiration and degree of mineralization) was lower in the polluted soil. Soil respiration and amount of soil mycelia correlated negatively with soil Pb, Zn and Cr concentration.
Keywords: Fungal biomass (voyant9; Heavy metals; litter decomposition; pollution; Soil microbial biomass; Soil respiration

Foliar trichomes of the evergreen and semi-deciduous species of the genus Quercus (Fagaceae) in the Iberian Peninsula - LLAMAS, F.; PEREZ-MORALES, C.; ACEDO, C.; PENAS, A. (Botanical Journal of the Linnean Society, 1995)
The leaf trichomes of the evergreen and semi-deciduous species of the genus Quercus living in the Iberian Peninsula were studied by means of SEM and LM. The SEM has been particularly useful because of the high quality of the illustrations and the possibility of recognizing the structures under I,M or the stereomicroscope afterwards. The studied species were: Quercus coccifera, Q ilex, Q rotundifolia, Q suber, Q canariensis, Q faginea, Q brateroi and Q lusitanica. All species show some exclusive particularities that permit their identification using these characters. The abaxial surface of the leaf always has more trichomes than the adaxial and hence provides more characters for identification. Quercus alpestris Boiss. shows the same features in the leaf trichomes as Q faginea Lam. A key for identification using these characters is provided.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: key; leaf; LM; SEM

Foliar trichomes of the evergreen and semi-deciduous species of the genus Quercus (Fagaceae) in the Iberian Peninsula - LLAMAS, F; PEREZ-MORALES, C; ACEDO, C; PENAS, A (Botanical Journal of the Linnean Society, 1995)
The leaf trichomes of the evergreen and semi-deciduous species of the genus Quercus living in the Iberian Peninsula were studied by means of SEM and LM. The SEM has been particularly useful because of the high quality of the illustrations and the possibility of recognizing the structures under I,M or the stereomicroscope afterwards. The studied species were: Quercus coccifera, Q ilex, Q rotundifolia, Q suber, Q canariensis, Q faginea, Q brateroi and Q lusitanica. All species show some exclusive particularities that permit their identification using these characters. The abaxial surface of the leaf always has more trichomes than the adaxial and hence provides more characters for identification. Quercus alpestris Boiss. shows the same features in the leaf trichomes as Q faginea Lam. A key for identification using these characters is provided.
Keywords: key; leaf; LM; SEM

Herbivorous mammals as seed dispersers in a Mediterranean dehesa - Malo, Juan E; Suárez, Francisco (Oecologia, 1995)
Endozoochorous seed dispersal by herbivo- rous mammals has been verified repeatedly and its possi- ble influence on the structure and function of herbaceous communities has been suggested. Quantitative studies, however, are lacking in the field of seed dispersal via the dung of herbivore guilds in little-altered environments. The present paper analyses seed dispersal via rabbit, fal- low deer, red deer and cow dung in a Mediterranean de- hesa (open woodland used for hunting and ranching) during the seeding season. Dung seed content was deter- mined by the glasshouse cultivation of eight dung sam- ples from each herbivore, collected fortnightly between February and August. The four herbivores disperse many seeds (spring averages are 6-15 seeds per gram of dry dung and maxima of 25-70) from a large number of spe- cies (totals between 52 and 78). Dispersal seems to be mainly determined by seed production of the plant com- munity. This is reflected in (i) the dissemination of a high percentage of the species present in the dehesa, (ii) great seasonal variability, related to seed production, in the amount of seeds and number of species dispersed, and (iii) a high semi-quantitative similarity of seed con- tent in the four types of herbivore dung throughout the year. There is also important quantitative variation that depends on animal traits and feeding habits. These re- sults and the characteristics of species found in dung suggest the adaptation of plant species to the dispersal of their seeds via herbivore gut. This process may well have profound implications for vegetation dynamics and the evolution of plant traits.
Keywords: endozoochory; mediterranean grasslands; pasture dynamics; seed dispersal; Therophytes

IMPACT OF CHRONIC GAMMA-IRRADIATION ON THE LITTER DECAY OF A MIXED MEDITERRANEAN FOREST IN CADARACHE - FRANCE MICROARTHROPODS RESPONSE - POINSOTBALAGUER, N; TABONE, E (PEDOBIOLOGIA, 1995)
An area of mixed forest containing white oak (Quercus pubescens W.) and evergreen oak (Quercus ilex L.) in Cadarache has been irradiated for 16 years, since 1969, by a 137 cesium source of 31.45 TBq. Mass loss of experimental litter over a period of 22 months and its recolonization by soil microarthropods was studied at five stations receiving decreasing radiation levels (100 mGy/h(-1) to 0.3 mGy/h(-1)) and in a control area. At the end of the experimentation, the mass loss of the litter was substantially lower in the three most irradiated stations. Additionally recolonization of litter by microarthropods was low in these three stations compared with the three others. Population density of Oribatids, `'other Acarina'', Collembola and various Arthropods, was considerably lower. These results were dependant upon direct and indirect consequences of irradiation on the ecosystem. Destruction of trees and shrubs in the most irradiated areas (100-60 mGy/h(-1)) did in fact lead to the reduction of soil moisture and an absence of organic matter input. Microflora could not develop and insufficient trophic resources did not allow for recolonization by fauna, which in turn slowed down the eventual disappearance of the litter.
Keywords: CHRONIC GAMMA IRRADIATION; microarthropods; mixed forest

Impact of feeding habits of Corsican red deer (Cervus elaphus corsicanus) on vegetation at Quenza Park in Corsica - Maillard, D; Casanova, J B; Gaillard, J M (MAMMALIA, 1995)
Following the translocation of Corsican red deer (Cervus elaphus corsicanus) in Quenza enclosures in 1985, we tried to assess the impact of red deer on woody mediterranean species. We found that sempervirent species with persistent leaves like Calytcotome villosa, Arbutus unedo, Quercus ilex and Cistus salviaefolius were eaten by deer all the year along. In fact, we identified three different categories of plant species according to the different levels of use by deer. A first groupe includes species highly and quickly consumed by deer like Calycotome villosa, Fraxinus ornus and Lonicera etrusca. These plants can even disappear when deer density becomes very high. A second group was composed of plant species red deer ate but searched for in a lesser extent like Arbutus unedo and Quercus ilex. Consumption of some of them showed a peak during summer (Rosa canina and Rubus sp.). in the last groupe, we pooled species weakly consumed by red deer, like Erica arborea and Cistus salviaefolius.
APS
Keywords: Arbutus unedo; Calytcotome villosa; Cervus elaphus corsicanus; Cistus salviaefolius; comsumption; Mediterranean; Quercus ilex; red deer

Influence of external factors on secondary embryogenesis and germination in somatic embryos from leaves of Quercus suber - Fernández-Guijarro, Bárbara; Celestino, Cristina; Toribio, Mariano (Plant Cell, Tissue and Organ Culture, 1995)
Somatic embryogenesis was obtained in cultures of leaves from young seedlings of Quercus suber L. A two- stage process, in which benzyladenine and naphthaleneacetic acid were added first at high and then at low concentrations, was required to initiate the process. Somatic embryos arose when the explants were subsequently placed on medium lacking plant growth regulators. The embryogenic lines remained productive, by means of secondary embryogenesis, on medium without growth regulators. However, this repetitive induction was influenced by the macronutrient composition of the culture medium. Both low total nitrogen content and high reduced nitrogen concentration decreased the percentage of somatic embryos that showed secondary embryogenesis. Our results suggest that alternate culture on medium that increases embryo proliferation and a low salt medium prohibiting embryo formation will partially synchronize embryo development. Chilling slightly reduced secondary embryogenesis but gave a modest increase in germination. Maturation under light followed by storage at 4 °C for at least 30 days gave the best results in switching embryos from an embryogenic pathway to a germinative one. Under these conditions 15% of embryos showed coordinated root and shoot growth and 35% formed either shoots or mostly roots. These percentages were higher than those of embryos matured in darkness. This result indicates that a specific treatment is required after maturation and before chilling to activate the switch from secondary embryo formation to germination.
Keywords: Cork oak; culture media; plant regeneration; recurrent embryogenesis; repetitive embryogenesis; Somatic embryogenesis

Influence of external factors on secondary embryogenesis and germination in somatic embryos from leaves of Quercus suber - Fernández-Guijarro, Bárbara; Celestino, Cristina; Toribio, Mariano (Plant Cell, Tissue and Organ Culture, 1995)
Somatic embryogenesis was obtained in cultures of leaves from young seedlings of Quercus suber L. A two- stage process, in which benzyladenine and naphthaleneacetic acid were added first at high and then at low concentrations, was required to initiate the process. Somatic embryos arose when the explants were subsequently placed on medium lacking plant growth regulators. The embryogenic lines remained productive, by means of secondary embryogenesis, on medium without growth regulators. However, this repetitive induction was influenced by the macronutrient composition of the culture medium. Both low total nitrogen content and high reduced nitrogen concentration decreased the percentage of somatic embryos that showed secondary embryogenesis. Our results suggest that alternate culture on medium that increases embryo proliferation and a low salt medium prohibiting embryo formation will partially synchronize embryo development. Chilling slightly reduced secondary embryogenesis but gave a modest increase in germination. Maturation under light followed by storage at 4 °C for at least 30 days gave the best results in switching embryos from an embryogenic pathway to a germinative one. Under these conditions 15% of embryos showed coordinated root and shoot growth and 35% formed either shoots or mostly roots. These percentages were higher than those of embryos matured in darkness. This result indicates that a specific treatment is required after maturation and before chilling to activate the switch from secondary embryo formation to germination.
Keywords: Cork oak; culture media; plant regeneration; recurrent embryogenesis; repetitive embryogenesis; Somatic embryogenesis

Influence of leaf litter type on the chemical evolution of a soil parent material (sandstone) - Madeira, M; Ribeiro, C (Biogeochemistry, 1995)
The influence of leaves of Quercus suber L. and Eucalyptus globulus Labill. and needles of Pinuspinaster Ait. on a sandstone substrate was assessed through lysimetric studies during a ten-year period at a site in Central Portugal. The decomposition rate of Q. suber leaf litter was similar to that of E. globulus and higher than that of P pinaster needle litter. The proportion of nitrogen released from the Q. suber leaf litter was higher than that lost from the other organic species. Such a release was proportional to the initial nitrogen content in the substrates. The concentrations of both NHa-N and NO3-N were much higher in leachates collected under Q. suber leaf litter than in those collected under the other organic substrates. A similar trend was found in the leachates collected under the mineral substrate influenced by the studied organic substrates. The leachate concentrations of mineral N (especially NOs-N) were higher from the mineral substrate under Q. suber leaf litter than from this organic substrate itself. The mineral substrate under leaf litter of E. globulus or needle litter of P pinaster showed an increase in exchangeable base cations and pH values, and a decrease in extractable Al. Conversely, in the substrate with Q. suber leaf litter there was only a slight increase in exchangeable base cations and pH values, and a decrease in extractable Al. These results combined with those obtained in soils underE. globulus plantations indicate that changes found in these soils are due to soil and forest m
Keywords: decomposition rate; elemental fluxes; EUCALYPTUS; Leaching; leaf litter; Pinus pinaster; Quercus suber; soil chemistry

Leaf metabolism during summer drought in Quercus ilex trees with lifetime exposure to elevated CO2 - Chaves, M. M.; Pereira, J. S.; Cerasoli, S.; CliftonBrown, J.; Miglietta, F.; Raschi, A.; Chaves J. S. ;Cerasoli, S. ;Clifton Brown (JOURNAL OF BIOGEOGRAPHY, 1995)
A marginal improvement in the response of Quercus ilex adult trees to drought appears to occur under a long-term natural CO2 enrichment. This is expressed, for example, by the absence of midday stomatal closure in trees growing under elevated CO2. Some protection against high irradiance and high temperature seems also to occur at the photochemical level, presumably as a result of more carbon available to the consumption of excess light energy. This would allow a better performance of the plants grown under elevated CO2 during the warmer hours of the day and therefore playing an important adaptation role under drought conditions. A marginal increase in the concentration of soluble sugars and starch was observed in the leaves of trees growing at elevated CO2 as compared with plants at ambient CO2, mainly during the midday hours. We may speculate that this will be advantageous both in terms of carbohydrate reserves for growth (e.g. more roots) and osmotic adjustment.
From Duplicate 2 (Leaf metabolism during summer drought in Quercus ilex trees with lifetime exposure to elevated CO2 - Chaves, M M; Pereira, J S; Cerasoli, S; CliftonBrown, J; Miglietta, F; Raschi, A)From Duplicate 2 (Leaf metabolism during summer drought in Quercus ilex trees with lifetime exposure to elevated CO2 - Chaves, M M; Pereira, J S; Cerasoli, S; CliftonBrown, J; Miglietta, F; Raschi, A)The following values have no corresponding Zotero field: pub-location: OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL publisher: BLACKWELL SCIENCE LTD label: Fisiologia - CO2 elevado
Keywords: Elevated CO2; Fisiologia - CO2 elevado; fluorescence; long-term acclimation; stomata; sugars; water deficits

Leaf metabolism during summer drought in Quercus ilex trees with lifetime exposure to elevated CO2 - Chaves, M M; Pereira, J S; Cerasoli, S; CliftonBrown, J; Miglietta, F; Raschi, A; Chaves J. S.;Cerasoli,S.;Clifton Brown,J.;Miglietta,F.;Raschi,A., M M ;Pereira (JOURNAL OF BIOGEOGRAPHY, 1995)
A marginal improvement in the response of Quercus ilex adult trees to drought appears to occur under a long-term natural CO2 enrichment. This is expressed, for example, by the absence of midday stomatal closure in trees growing under elevated CO2. Some protection against high irradiance and high temperature seems also to occur at the photochemical level, presumably as a result of more carbon available to the consumption of excess light energy. This would allow a better performance of the plants grown under elevated CO2 during the warmer hours of the day and therefore playing an important adaptation role under drought conditions. A marginal increase in the concentration of soluble sugars and starch was observed in the leaves of trees growing at elevated CO2 as compared with plants at ambient CO2, mainly during the midday hours. We may speculate that this will be advantageous both in terms of carbohydrate reserves for growth (e.g. more roots) and osmotic adjustment.
From Duplicate 2 (Leaf metabolism during summer drought in Quercus ilex trees with lifetime exposure to elevated CO2 - Chaves, M M; Pereira, J S; Cerasoli, S; CliftonBrown, J; Miglietta, F; Raschi, A)
Keywords: Elevated CO2; Fisiologia - CO2 elevado; fluorescence; long-term acclimation; stomata; sugars; water deficits

METAL CONTENT AND COMMUNITY STRUCTURE OF CRYPTOGAM BIOINDICATORS IN RELATION TO VEHICULAR TRAFFIC IN MONTSENY-BIOSPHERE-RESERVE (CATALONIA, SPAIN) - GLENN, M G; GOMEZBOLEA, A; LOBELLO, R (LICHENOLOGIST, 1995)
The health, abundance, metal content and species richness of corticolous macrolichens and bryophytes of Quercus ilex were compared at nine roadside stations in Montseny Biosphere Reserve, 40 km NNE of Barcelona, and at a control site outside the industrial metropolis. Stations were characterized by traffic levels and the correlated parameter airborne particles. Corticolous flora at all stations was dominated by sorediate Parmelia species (P. caperata, P. soredians, P. subrudecta, P. subaurifera, P. sulcata and P. perlata). Damage, mainly due to arthropod feeding and fungal parasites, ranged from 14 to 33% of mean cover per station in the park and was 10% at the control site. Elevated levels of Pb, Zn and Cu were found in large thalli near the roadsides. (C) 1995 The British Lichen Society
APS
Keywords: airborn particles; bryophytes; corticolous macrolichens; metal content; Montseny Biosphere Reserve; Parmelia; Quercus ilex; traffic level

MICROMORPHOLOGICAL, PHYSICAL, AND CHEMICAL CHARACTERISTICS OF LEACHING POORLY DRAINED FLAT SOILS OF CENTRAL SPAIN - Martin, A; MENDIZABAL, T; ZABALLOS, J P; BENAYAS, J (ARID SOIL RESEARCH AND REHABILITATION, 1995)
The eluviation process has been analyzed in horizons of Luvisols, Cambisols, and Acrisols on rana surfaces and in one Luvisol from the uppermost terraces of the Henares River. The soils are located in the supra- and meso-Mediterranean, dry and subhumid bioclimatic areas. Some now have vegetation of Quercus rotundifolia Lam. and Quercus pyrenaicae Willd. in serial stages, while others are used for cereal crops. The most indicative morphological variables of the eluviation process and their interrelationship with laboratory variables were studied (microstructure, texture, porosity, organic matter, and soluble salts). The E horizons have a loss of micromass in the thin section that coincides with a reduction in chlorides, sulfates, and electrical conductivity of the extract, as well as a very low ratio of Ca/Al water-soluble elements. Leaching is occasionally not shown in the granulometric analyses, but the transfer of matter due to biological activity and/or soil management is observed in the thin soil section. The Na+/Ca ratio greater than or equal to 1 matches a less stable microstructure, with a predominance of planar voids over vughs and channels. Sail use must be considered in the interpretation of this ratio. The eluviation horizons not described morphologically as such, namely Ap, Au, and Bw horizons in the rana formations and Au2, AB, and Bt1 horizons on the terrace, are always located in the upper 40 cm of soils that are used by plants. These are distinguished from the E horizons in their greater retention of available water and, depending on the eluviation intensity, a macroporosity higher than textural porosity.
Author
Keywords: micromorphology; organic matter; Porosity; soil leaching; soluble salts; transfere of matter

Modelling the long-term impacts of atmospheric pollution deposition and repeated forestry cycles on stream water chemistry for a holm oak forest in northeastern - Neal, C; Avila, a; Rodà, F (Journal of Hydrology, 1995)
Estimates based on the MAGIC model of the long-term effects on stream water quality of forest management cycles as well as of atmospheric pollutant inputs for a holm oak catchment in northeastern Spain, show that despite high pollutant sulphur inputs as well as substantial base cation loss from the catchment owing to forest harvesting, stream water has not deteriorated in any major way. Acidification of the catchment will continue, to a limited degree, unless either sulphur deposition is reduced by more than 60% or forest harvesting schemes are terminated. The detrimental changes in water quality owing to acid deposition and forestry harvesting practice in other parts of Europe are not observed in this region, because of high base inputs from the atmosphere and high base cation weathering rates within the catchment.
Keywords: atmospheric deposition; forestry practices (voyant); pollution; soil chemistry; stream water chemistry

The molecular relaxation mechanisms in cork as studied by thermally stimulated discharge currents - Mano, J F; Correia, N T; Moura Ramos, J J; Saramago, B (Journal of Materials Science, 1995)
The dielectric relaxation mechanisms present in cork have been investigated in the temperature range -100 to 100~ using the technique of thermally stimulated discharge currents. A relaxation mechanism was detected which showed a compensation behaviour as observed for the a-relaxation (or glass transition relaxation) of synthetic polymers and which lead us to attribute to cork a glass transition-like temperature of 18~ One lower temperature mechanism was also observed, with low activation enthalpy and entropy, which is presumably originated by local motions (internal rotations) of polar molecular groups. An upper Tg relaxation of higher intensity was also detected which was attributed to large-scale non-cooperative motions of polymeric segments.
Keywords: Cork; dielectric relaxation (Voyant); thermally stimulated discharge currents (TSDC)

MULTIPURPOSE GENE CONSERVATION IN QUERCUS-SUBER - A PORTUGUESE EXAMPLE - VARELA, M. C.; ERIKSSON, G. (SILVAE GENETICA, 1995)
Quereus suber, the native forest tree of highest economic value to Portugal is continuously declining. Creating good conditions for future evolution is the most important gene conservation objective for Quercus suber A simple breeding programme to improve the production of good cork is also included in the gene conservation objective. Gene conservation of species accompanying Quercus suber, or even dependent on Quercus suber, is a third objective. The suggested sampling of gene resource populations is mainly based on climatic, soil and management conditions of Quercus suber populations. Active selection of trees with good cork in small multiple populations growing over a broad array of site conditions is suggested to match the joint evolutionary and breeding objective in gene conservation. Management of large natural populations to create maximum habitat diversity is suggested to take care of the gene conservation of accompanying species. Knowledge of the genetic structure of Quercus suber and of gene now is urgently needed and ought to be given priority in genetic research.
AuthorAuthorThe following values have no corresponding Zotero field: pub-location: FINKENHOFSTRASSE 21, D-60322 FRANKFURT, GERMANY publisher: J D SAUERLANDERS VERLAG
Keywords: Cork oak; GENE CONSERVATION OBJECTIVES AND METHODS; Quercus suber; RESEARCH NEEDS

MULTIPURPOSE GENE CONSERVATION IN QUERCUS-SUBER - A PORTUGUESE EXAMPLE - Varela, M C; ERIKSSON, G (SILVAE GENETICA, 1995)
Quereus suber, the native forest tree of highest economic value to Portugal is continuously declining. Creating good conditions for future evolution is the most important gene conservation objective for Quercus suber A simple breeding programme to improve the production of good cork is also included in the gene conservation objective. Gene conservation of species accompanying Quercus suber, or even dependent on Quercus suber, is a third objective. The suggested sampling of gene resource populations is mainly based on climatic, soil and management conditions of Quercus suber populations. Active selection of trees with good cork in small multiple populations growing over a broad array of site conditions is suggested to match the joint evolutionary and breeding objective in gene conservation. Management of large natural populations to create maximum habitat diversity is suggested to take care of the gene conservation of accompanying species. Knowledge of the genetic structure of Quercus suber and of gene now is urgently needed and ought to be given priority in genetic research.
Author
Keywords: Cork oak; GENE CONSERVATION OBJECTIVES AND METHODS; Quercus suber; RESEARCH NEEDS

Nutrient content in Quercus ilex canopies: seasonal and spatial variation within a catchment - Sabate, S; Sala, Anna; Gracia, C A (Plant and Soil, 1995)
Spatial and temporal changes in canopy nutrient content were studied in 1988 and 1989 in a Mediterranean Quercus ilex ssp. ilex L. forest in north-eastern Spain. Sampling was conducted in parallel at two sites which represent endpoints along a slope gradient within a small catchment (ridge top at 975 m and valley bottom at 700 m). Deeper soils resulted in significantly higher N and P concentrations, and N content on a leaf area basis at the valley bottom site. In contrast, K concentration in leaves was significantly higher at the ridge top site, where soil K concentration was also higher. At both sites, N and P content on a leaf area basis was highest at the top of the canopy, where leaf area is highest. N resorption efficiency decreased from top to bottom of the canopy. Results suggested a minor role of shaded leaves as nutrient storage sites. Lower P resorption efficiency was found at the ridge top site. Seasonal changes of P and N concentration on a leaf area basis suggest P replenishment, and to a lesser degree N, during periods of lower growth activity due to low temperatures, but coinciding with higher water availability (autumn-early spring period). Thus, N and P resorption from the remaining foliage in the canopy took place, and to a larger degree at the valley bottom site, coinciding with a slightly higher leaf area index and productivity at this site.
Keywords: Canopy; nutrient content and dynamics; nutrient resorption; Quercus ilex

THE NUTRITIONAL CARRYING-CAPACITY OF 4 MEDITERRANEAN HABITATS FOR FALLOW DEER (DAMA-DAMA) - Focardi, S; Poli, B M; Tinelli, A (REVUE D ECOLOGIE-LA TERRE ET LA VIE, 1995)
The assessment of the trophic value of the most consumed feed by fallow deer in a coastal mediterranean landscape (Rubus ulmifolius, Cistus salvifolius, Phyllirea latifolia, Quercus ilex and graminoids) was based on in vitro digestibility trials, performed throughout the year (1 set of samples per season) using rumen inocula from wild fallow deer from the Preserve of Castelporziano, collected simultaneously with the vegetal samples. Moreover, in vivo digestibility coefficients have been estimated by using standard feed (for fallow deer) of known in vivo digestibility. Using the digestibility coefficients, the metabolizable energy yield of studied forage items was computed. Information about plant biomass, structure of fallow deer population, metabolizable energy yields, estimates of forage intake and energy requirements were combined using the model presented by Hobbs and Swift (1985) to evaluate the nutritional carrying capacity of four typical mediterranean habitats (natural evergreen oak wood, scrub mixed plantations of Quercus ilex and Pinus pinea, open pastures). Spring represents the most favourable situation, while summer, autumn and winter exhibit similar values of carrying capacity of about 15-20 deer/100 ha. Mixed plantations of Pinus pinea and Q. ilex seem to be the most productive condition for fallow deer.
APS
Keywords: Cistus salvifolius; digestibility; fallow dear; mediterranean landscape; Phyllirea latifolia; Quercus ilex; Rubus ulmifolius; trophic value

Patterns of seedling recruitment in West-Mediterranean Quercus ilex forest influenced by canopy development - Espelta, Josep Maria; Riba, Miquel; Javier, Retana (Journal of Vegetation Science, 1995)
Abstract. Quercus ilex (holm oak) coppice forests belong to the most representative communities in the western part of the Iberian Peninsula. Due to the high sprouting potential of holm oak after coppicing, the dynamics of recruitment of new individuals in existing populations has been largely overlooked. In these forests, the density of seedlings increases in old stands, as a result of the remarkable increase in the recruitment of 1-yr and 2-yr old seedlings, probably due to better environmental conditions for germination. Older seedlings show a tendency towards increasing survival under some degree of canopy closure, since their density appears to be higher just before complete canopy closure takes place. Nevertheless, the reduced growth of seedlings in older stands due to low light levels causes age distributions of holm oak seedlings to change drastically, with saplings older than 15 yr becoming very unusual in these stands. Therefore, a bottleneck of recruitment appears at this sapling stage and prevents vigorous regeneration just before thinning. Present conditions of genet density and management tend to prevent population renewal. Dynamics of the seedling bank reinforce the role of gap formation through small or large scale perturbations in population turnover.
Keywords: Holm oak; Regeneration; Seeder; Seedling dynamics; Sprouter; thinning

Plant species as indicators of geochemical anomalies: Experiences onIlex aquifolium (holly) - Legittimo, P Cellini; Ducceschi, L; Martini, M (Environmental Geology, 1995)
The distribution of Zn, Cd, Pb, and Cu, in plants growing in mineralized and sterile areas of Tuscany has been studied to verify if and to what extent metal- accumulating species represent evidence of geochemical anomalies in soils. Samples of leaves and twigs from trees were collected, and analyzed by means of differential pulse anodic stripping voltammetry (DPASV). Hollies, bram- bles, and Holm oaks in particular were considered in the mineralized area of Bottino, and the special aptitude of hollies in concentrating Cd with respect to the other metals has been verified. Cadmium has been previously recog- nized as a pathfinder for zinc ore bodies; the results of this investigation appear to point out the relevance of holly as a bioindicator of geochemical zinc anomalies. Lower metal concentration characterizes the same species from other mineralized and sterile zones, with the exception of the urbanized area of Florence, where relatively higher Zn concentrations in hollies appear to be due to atmospheric pollution.
Keywords: biogeochemical prospecting; Heavy metals; Plants

Plant species as indicators of geochemical anomalies: Experiences onIlex aquifolium (holly) - Legittimo, P. Cellini; Ducceschi, L.; Martini, M. (Environmental Geology, 1995)
The distribution of Zn, Cd, Pb, and Cu, in plants growing in mineralized and sterile areas of Tuscany has been studied to verify if and to what extent metal- accumulating species represent evidence of geochemical anomalies in soils. Samples of leaves and twigs from trees were collected, and analyzed by means of differential pulse anodic stripping voltammetry (DPASV). Hollies, bram- bles, and Holm oaks in particular were considered in the mineralized area of Bottino, and the special aptitude of hollies in concentrating Cd with respect to the other metals has been verified. Cadmium has been previously recog- nized as a pathfinder for zinc ore bodies; the results of this investigation appear to point out the relevance of holly as a bioindicator of geochemical zinc anomalies. Lower metal concentration characterizes the same species from other mineralized and sterile zones, with the exception of the urbanized area of Florence, where relatively higher Zn concentrations in hollies appear to be due to atmospheric pollution.
Keywords: biogeochemical prospecting; Heavy metals; Plants

Predators of Lymantria dispar (Lep. Lymantriidae) egg masses: Spatio-temporal variation of their impact during the 1988-89-pest generation in the Mamora cork oak forest (Morocco). - Villemant, C; Ramzi, H (ENTOMOPHAGA, 1995)
In the Mamora cork oak forest (Morocco), oophagous predators of the gypsy moth Lymantria dispar (L.) (Lepidoptera: Lymantriidae) are one of the main mortality factors influencing pest population dynamics. The predators destroy egg masses more by disrupting their cohesiveness than by predation. From 1987 to 1990, the impact of oophagous enemies significantly contributed to the collapse of a localized gypsy moth outbreak. Variation of egg mass dislocation intensity was greater between trees than among the different strata of a tree. The number of gypsy moth egg masses and egg predator attacks increased when oaks were large and unhealthy. Forest degradation probably explains why egg mass destruction rates were so high (60 to 90% of the eggs) in the infested forest. Oophagous predators find food and shelter under the dehiscent bark of unhealthy cork oaks.
Keywords: Cork oak; egg predator; Gypsy moth; Population Dynamics; spatial distribution

Presente y futuro de la producción de vacuno de aptitud cárnica en extensivo - Bellido, M. Martín (Archivos de zootecnia, 1995)
Se presenta la producción de carne a nivel mundial, europeo y nacional, haciendo énfasis en los datos de The meat production of the world, Europe and Spain is presented, with enphasis on the Extremadura data. In this region, the number of cattle in 1994 was 462553, of which 319508 were beef cows, managed under extensive conditions. The beef meat produced in extensive system, reached 55199.8 t with a value of 19201.7 millions of pesetas, representing a 20.26 per cent of the total meat produced in the region and the 26.24 per cent of the total value. The steers are feedlot mainly outside the region, due to different causes. The importance of the subsidies coming from the beef cows Commom Market Organization, in the farmers income maintenance, is pointed out. Also, the necessity to improve the breeders association, to comercialize this quality beef, produced under extensive systems compatible with the environment conservation, with the goat to get quality tags for this meat, their promotion and to organice their offer in the market.
Keywords: Dehesa; meat marketing; Quality meat

Presente y futuro de la producción de vacuno de aptitud cárnica en extensivo - Bellido, M Martín (Archivos de zootecnia, 1995)
Se presenta la producción de carne a nivel mundial, europeo y nacional, haciendo énfasis en los datos de The meat production of the world, Europe and Spain is presented, with enphasis on the Extremadura data. In this region, the number of cattle in 1994 was 462553, of which 319508 were beef cows, managed under extensive conditions. The beef meat produced in extensive system, reached 55199.8 t with a value of 19201.7 millions of pesetas, representing a 20.26 per cent of the total meat produced in the region and the 26.24 per cent of the total value. The steers are feedlot mainly outside the region, due to different causes. The importance of the subsidies coming from the beef cows Commom Market Organization, in the farmers income maintenance, is pointed out. Also, the necessity to improve the breeders association, to comercialize this quality beef, produced under extensive systems compatible with the environment conservation, with the goat to get quality tags for this meat, their promotion and to organice their offer in the market.
Keywords: Dehesa; meat marketing; Quality meat

Primera cita ibérica de Brachypalpus valgus ( Panzer , 1798 ) y Chrysotoxum parmense Rondani , 1845 ( Diptera : Syrphidae ): caracterización polínica de su dieta * - Marcos-garcía, M A; Isidro, P M (Boln. Asoc. esp. Ent, 1995)
The first Iberian specimens of the genus Brachypalpus and species Chrysotoxum parmense ha ve been caught in the Font Roja Natural Park (Alicante, Spain). The presence of these two species and the Psilota anthracina, indícales the importance of this Mediterranean holm oak sheltering threatened species in nearby countries like France and Germany. The pollen Lypes found in the alimentary canal of syrphids, are indicated for the first time.
Keywords: Brachypalpus valgus; Chrysotoxum parmense; Font Roja Natural Park; pollen content; Spain; Syrphidae

Red deer (Cervus elaphus hispanicus) management in the dehesa system in central Extremadura, Spain - Vargas, J D; Calvo, J C; Aparicio, M A (Agroforestry systems, 1995)
In this paper we report the results of a study on the suitability of the dehesa (Mediterranean woodlands) as habitat of red deer (Cervus elaphus hispanicus) in a closed country estate of about 4300 ha total surface situated in the San Pedro Mountain, in Central Extremadura, Spain. We have described the d e e r management with respect to habitat, exploitation mode, deer feeding, population control and production of goods and services. It is concluded that the dehesa system is a rich natural resource that preserves and improves the degraded environment.
Keywords: antlers; Dehesa; red deer (Cervus elaphus); Spain; wildlife habitat

Red deer (Cervus elaphus hispanicus) management in the dehesa system in central Extremadura, Spain - Vargas, J. D.; Calvo, J. C.; Aparicio, M. A. (Agroforestry systems, 1995)
In this paper we report the results of a study on the suitability of the dehesa (Mediterranean woodlands) as habitat of red deer (Cervus elaphus hispanicus) in a closed country estate of about 4300 ha total surface situated in the San Pedro Mountain, in Central Extremadura, Spain. We have described the d e e r management with respect to habitat, exploitation mode, deer feeding, population control and production of goods and services. It is concluded that the dehesa system is a rich natural resource that preserves and improves the degraded environment.
Keywords: antlers; Dehesa; red deer (Cervus elaphus); Spain; wildlife habitat

Role of carbohydrates in micropropagation of cork oak - Romano, A; Noronha, C; Martins-Loução, M a (Plant cell, tissue and organ …, 1995)
The influences of carbon sources, fructose, glucose, sorbitol and sucrose on shoot proliferation and in vitro rooting of cork oak (Quercus suber L.) were compared at a wide range of concentrations (1-6%, w/v). The highest number of shoots occurred on glucose-containing medium. Nevertheless, we have chosen 3% sucrose which induced a similar rate of proliferation but favoured shoot elongation, permitting an effectively higher number of shoots during transfers. Sorbitol and autoclaved fructose did not stimulate shoot proliferation. Adventitious root formation was strongly dependent on carbohydrate supply. Sorbitol and autoclaved fructose were completely ineffectively on rooting induction. Glucose was the most effective carbon source on rooting promotion followed by sucrose and filter-sterilized fructose. The rooting response induced by fructose was dependent on the sterilizing procedure. The number of adventitious roots produced per shoot increased with increasing glucose and sucrose concentration. The content of reducing sugars in leaves of proliferation cultures and in leaves and roots of rooted plantlets was more dependent on carbon concentration than on glucose or sucrose supplement. The results presented here show that carbohydrate requirements during cork oak micropropagation depend upon the phase of culture. Sucrose (3%) and glucose (4%) were the best carbon sources respectively during proliferation and rooting phases.
Keywords: carbon source; micropropagation; Quercus suber; reducing sugars; rooting

The role of marine salt and surfactants in the decline of tyrrhenian coastal vegetation in Italy - Bussotti, F.; Grossoni, P.; Pantani, F. (Annales des Sciences Forestières, 1995)
The decline of coastal vegetation is a phenomenon affecting some areas of the Mediterranean region and Australia; it is due to the presence of surfactants in marine aerosols, a consequence of sea pollution by detergents. This paper gives some observations made at various sites along the Tyrrhenian coast in Italy. The authors show that the presence of surfactants in the environment correlates with the presence of sea salt, and that the impact of surfactants on vegetation is local and occurs in association with strong sea winds. The study of the synergistic effect of surfactants and sea salt on the crowns of trees exposed to aerosols suggests that the surfactant can cause direct damage, while the absorption of sea salt is enhanced by the presence of the surfactant only when exposure to aerosol is prolonged, or if it is administered in very high concentrations.
Keywords: crown damage; leaf absorption; marine aerosol; NaCl; Pinus pinea L; surfactant

The role of marine salt and surfactants in the decline of tyrrhenian coastal vegetation in Italy - Bussotti, F; Grossoni, P; Pantani, F (Annales des Sciences Forestières, 1995)
The decline of coastal vegetation is a phenomenon affecting some areas of the Mediterranean region and Australia; it is due to the presence of surfactants in marine aerosols, a consequence of sea pollution by detergents. This paper gives some observations made at various sites along the Tyrrhenian coast in Italy. The authors show that the presence of surfactants in the environment correlates with the presence of sea salt, and that the impact of surfactants on vegetation is local and occurs in association with strong sea winds. The study of the synergistic effect of surfactants and sea salt on the crowns of trees exposed to aerosols suggests that the surfactant can cause direct damage, while the absorption of sea salt is enhanced by the presence of the surfactant only when exposure to aerosol is prolonged, or if it is administered in very high concentrations.
Keywords: crown damage; leaf absorption; marine aerosol; NaCl; Pinus pinea L; surfactant

SEASONAL ABUNDANCE OF MILLIPEDES IN A MEDITERRANEAN OAK FOREST (SOUTHERN FRANCE) - DAVID, J. F. (ISRAEL JOURNAL OF ZOOLOGY, 1995)
The millipede community of a helm oak forest (Quercus ilex) in southern France was sampled seasonally for 2 yr, at two depths in the forest floor. Despite the strong seasonality of climatic conditions, both recruitment periods and vertical displacements in the soil change markedly according to species; contrasting examples are provided by Glomeris marginata, which breeds in summer and burrows in winter, and by Opisthocheiron elegans, which behaves the opposite way. At the community level, biomass changes significantly between a spring minimum and an autumn maximum. Such a pattern results from the high abundance of G. marginata, a drought-resisting species which grows and reproduces during summer but experiences substantial winter mortality. The seasonal pattern is different in number of individuals due to the minute litter-dweller Polyxenus lagurus, which has a low population density in early autumn. The biomass of macrosaprophagous millipedes on the site (annual mean of 10.5 g live weight m(-2); autumn peak of 14.6 g live weight m(-2)) is much higher than that recorded further north in Europe, and its significance for litter consumption in Mediterranean forest is discussed.
The following values have no corresponding Zotero field: pub-location: PO BOX 50257, JERUSALEM 91502, ISRAEL publisher: LASER PAGES PUBL LTD
Keywords: Bioclimatic limit; Elevation gradient; Oak trees; Regeneration; Shrub encroachment; Species distribution

SEASONAL ABUNDANCE OF MILLIPEDES IN A MEDITERRANEAN OAK FOREST (SOUTHERN FRANCE) - David, J F (ISRAEL JOURNAL OF ZOOLOGY, 1995)
The millipede community of a helm oak forest (Quercus ilex) in southern France was sampled seasonally for 2 yr, at two depths in the forest floor. Despite the strong seasonality of climatic conditions, both recruitment periods and vertical displacements in the soil change markedly according to species; contrasting examples are provided by Glomeris marginata, which breeds in summer and burrows in winter, and by Opisthocheiron elegans, which behaves the opposite way. At the community level, biomass changes significantly between a spring minimum and an autumn maximum. Such a pattern results from the high abundance of G. marginata, a drought-resisting species which grows and reproduces during summer but experiences substantial winter mortality. The seasonal pattern is different in number of individuals due to the minute litter-dweller Polyxenus lagurus, which has a low population density in early autumn. The biomass of macrosaprophagous millipedes on the site (annual mean of 10.5 g live weight m(-2); autumn peak of 14.6 g live weight m(-2)) is much higher than that recorded further north in Europe, and its significance for litter consumption in Mediterranean forest is discussed.
Keywords: Bioclimatic limit; Elevation gradient; Oak trees; Regeneration; Shrub encroachment; Species distribution

Soilwater chemistry in a holm oak ( Quercus ilex) forest: inferences on biogeochemical processes for a montane-Mediterranean area - Avila, Anna; Bonilla, David; Rodà, F; Piñol, J; Neal, C (Journal of Hydrology, 1995)
Soil solution and free-flowing soilwater were sampled at various depths for 3 years in a plot of holm oak (Quercus ilex L.) in the Montseny mountains (NE Spain). The soil solution retained at -65M kPa in the mineral soil at depths of 20 and 40 cm had a different chemistry from that of throughflow under the humic layer (H-layer throughflow) and, to a lesser extent, from deep subsurface flow. The dominant mobile anion in the soil solution and the deep flow was SO:-, whereas in the H-layer, SOi- was overridden by alkalinity. H-Layer throughflow chemistry was extremely variable, in consequence of the large number of biogeochemical processes affecting it (e.g. rainfall chemistry, dry deposition, leaching from canopy and litter, decomposition), and of the quantity of water available for transport of solutes. The chemistry of the soil solution was more predictable, as it was governed mainly by nutrient uptake, cation exchange reactions and the seasonal wetting and drying cycles. The chemistry of the deep subsurface flow was often intermediate between that of the soil solution and that of the H-layer throughflow; this suggested a mixture of displaced pre-event soil solution and of H-layer throughflow circulating through preferential flow paths. With humid antecedent conditions, the chemistry of the deep subsurface flow approached that of the soil solution. The cation concentration relationships in the soil solution were strongly linear. In a homogeneous soil, cation exchange theory predicts this to be expected only for cations of the same charge, whereas cations of different charges should follow power relationships. Our results, however, are consistent with a theoretical approach involving cation exchange reactions in a highly heterogeneous environment. Indeed, our study illustrates the heterogeneous nature of the soils, as the power relationship has been obscured completely. Soilwater chemistries were markedly different from those of streamwater, particularly under dry conditions. During baseflow, the stream is fed by groundwater, and the soils are probably disconnected from the stream. During humid periods, the chemistry of the streamwater tends toward that of the deep subsurface flow. Chemical hydrograph separation indicates that, on average, stormflow water comprises an approximately one to one mixture of groundwater and deep subsurface flow.
Keywords: biogeochemistry; chemical composition; forest soils (citation); Ions; Soil depth; soil pH; soil water; temporal variation

STRUCTURAL AND ECOPHYSIOLOGICAL PLASTICITY OF SOME EVERGREEN SPECIES OF THE MEDITERRANEAN MAQUIS IN RESPONSE TO CLIMATE - Gratani, L (PHOTOSYNTHETICA, 1995)
The most representative evergreen shrub species growing in the low mediterranean maquis modified their leaf characteristics during the year, but the response to climate varied among the species. The real sclerophyllous species, Quercus ilex L., Phillyrea latifolia and Pistacia lentiscus, showed a convergence in higher leaf thickness and lower, net photosynthetic rate (PN) compared with Arbutus unedo L. and Cistus incanus L. Under summer stress they maintained a substantial positive carbon balance. Pistacia was one of the most tolerant species to the drought, it maintained a substantial positive balance over a wide range in temperature. Arbutus and Cistus had relatively thin leaves with a higher succulence index and higher PN over the more characteristic sclerophyllous species. The superiority of Cistus in carbon uptake over all the spacies was maintained throughout most of the year by its morphological leaf properties. low leaf thickness, high chlorophyll contents. Besides, Cistus shed most of its leaves before summer, thus reducing its evaporative surface.
Keywords: ARBUTUS UNEDO L; CISTUS INCANUS L; leaf area index

THE STRUCTURE AND DYNAMICS OF AN ABIES PINSAPO FOREST IN SOUTHERN SPAIN - ARISTA, M (FOREST ECOLOGY AND MANAGEMENT, 1995)
The forest composition and age-diameter relationships of Abies pinsapo were studied in a natural forest in the Nature Reserve of the Sierra de Grazalema (southern Spain). The composition and structure of the forest was very different with respect to gaps and closed forest. Altitudinal differences in forest composition were also found. Abies pinsapo was the dominant species, Quercus rotundifolia and Quercus faginea were the other important overstorey species. The diameter distributions of A. pinsapo were skewed toward the larger size classes, with a large seedling proportion of about 70%. Abies pinsapo establishment rates were higher in the gaps. Seedlings of Abies pinsapo established under the closed canopy forest had suppressed growth, as indicated by their relatively advanced ages. Seedlings and saplings with suppressed growth can survive for a mean of 40 years, constituting a pool from which canopy trees may be recruited. Results show that the pinsapo forest of the Sierra de Grazalema is in equilibrium and that its dynamics are conditioned by a small-sapling bank and canopy gap formation.
Keywords: ABIES PINSAPO; forest dynamics; MEDITERRANEAN FIR; Regeneration; SIZE STRUCTURE

THE STRUCTURE AND DYNAMICS OF AN ABIES PINSAPO FOREST IN SOUTHERN SPAIN - ARISTA, M. (FOREST ECOLOGY AND MANAGEMENT, 1995)
The forest composition and age-diameter relationships of Abies pinsapo were studied in a natural forest in the Nature Reserve of the Sierra de Grazalema (southern Spain). The composition and structure of the forest was very different with respect to gaps and closed forest. Altitudinal differences in forest composition were also found. Abies pinsapo was the dominant species, Quercus rotundifolia and Quercus faginea were the other important overstorey species. The diameter distributions of A. pinsapo were skewed toward the larger size classes, with a large seedling proportion of about 70%. Abies pinsapo establishment rates were higher in the gaps. Seedlings of Abies pinsapo established under the closed canopy forest had suppressed growth, as indicated by their relatively advanced ages. Seedlings and saplings with suppressed growth can survive for a mean of 40 years, constituting a pool from which canopy trees may be recruited. Results show that the pinsapo forest of the Sierra de Grazalema is in equilibrium and that its dynamics are conditioned by a small-sapling bank and canopy gap formation.
The following values have no corresponding Zotero field: pub-location: PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS publisher: ELSEVIER SCIENCE BV
Keywords: ABIES PINSAPO; forest dynamics; MEDITERRANEAN FIR; Regeneration; SIZE STRUCTURE

Treatment of wine bottle corks to reduce potential microorganism growth - by immersing cork pieces in conc. suspension of liq. pure culture of rapid growth, tasteless and odourless mould, eliminating possible effects on the wine - GROSSMANN, M (1995)
Treatment of cork tree (Quercus suber L.) bark for bottle stoppers, comprises adding a conc. suspension of a pure culture of a rapid growth, odourless and tasteless mould to the cork pieces. Stored, pre-boiled cork pieces are added to an immersion bath of culture contg. conc. pure culture suspension which contains at least 100000 colony forming units per ml. Culture is mixt. of at least two mould types, pref. penicillium type. Prior to use, the dry embryos are reactivated and rehydrated for 12 hrs. using 0.1% cooking salt soln. and 0.1% peptone. USE-Useful for treating corks for wine or champagne bottles. ADVANTAGE-Growth of microorganisms that affect the taste or smell of wine is reduced.
APS
Keywords: bottle stopers; Quercus suber L.

Vegetational response to holocene climatic change: Pollen and palaeolimnological data from the Middle Atlas, Morocco - Lamb, H F; VanderKaars, S (HOLOCENE, 1995)
Pollen data from a radiocarbon-dated lake-sediment core from the Middle Atlas of Morocco show that forests of evergreen and winter-deciduous oaks (Quercus rotundifolia, Q. canariensis), present from the start of the Holocene, were invaded at 6200 BP by Cedrus atlantica in low numbers. Two thousand years later, after a short period characterized by higher deciduous oak frequency, Cedrus increased to its present abundance. These changes may have been in response to increasing effective moisture as summer temperatures decreased with declining northern-hemisphere seasonality, under the influence of precessional forcing. Palaeolimnological data from the same core show that the lake level fell sharply in five 200-400 yr-long and intervals, but the pollen data show little or no evidence of a vegetational response. This suggests that summer (growing-season) rainfall remained adequate during the dry intervals, whereas depletion of the groundwater aquifer was the result of reduced winter precipitation. Anthropogenic exploitation since c. 1300 BP has had a greater effect on the forest ecosystem than any of the Holocene and intervals.
Keywords: climatic change; Environment; Palaeolimnology; pollen

Aerodynamic characterisation of model tree canopies in a wind tunnel - Kinnersley, R P; Farrington-Smith, J G; Shaw, G; Minski, M J (Science of The Total Environment, 1994)
The aerodynamic characteristics of ‘model’ tree canopies within a wind tunnel are reported. Wind speed profiles above and within canopies comprising Norway spruce (Picea abies) and Holm oak (Quercus ilex) saplings were determined by hot wire and hot film anemometry at a free-stream air velocity subsequently used for experiments on the dry deposition of aerosol particles to both canopies. Friction velocities (U∗) of 128 and 104 cm s−1 were observed for Norway spruce and Holm oak, respectively. Vertical distributions of wind speed (U) and turbulence intensity (i) within the canopies were similar in form and magnitude to those reported in the literature for full-sized forest canopies, suggesting that the sapling canopies provide a realistic ‘model’ with which to investigate the process of dry deposition.
Keywords: Boundary Layer; Dry deposition; Forest canopy; Turbulence

AERODYNAMIC CHARACTERIZATION OF MODEL TREE CANOPIES IN A WIND-TUNNEL - Kinnersley, R P; FARRINGTONSMITH, J G; Shaw, G; Minski, M J (SCIENCE OF THE TOTAL ENVIRONMENT, 1994)
The aerodynamic characteristics of `model' tree canopies within a wind tunnel are reported. Wind speed profiles above and within canopies comprising Norway spruce (Picea abies) and Holm oak (Quercus ilex) saplings were determined by hot wire and hot film anemometry at a free-stream air velocity subsequently used for experiments on the dry deposition of aerosol particles to both canopies. Friction velocities (U{*}) of 128 and 104 cm s-1 were observed for Norway spruce and Holm oak, respectively. Vertical distributions of wind speed (U) and turbulence intensity (i) within the canopies were similar in form and magnitude to those reported in the literature for full-sized forest canopies, suggesting that the sapling canopies provide a realistic `model' with which to investigate the process of dry deposition.
Keywords: Boundary Layer; Dry deposition; Forest canopy; Turbulence

Analisis de los recursos de pastoreo aportados por el medio en dos Dehesas caracteristicas del sur de la provincia de Badajoz (España) - Sánchez, M Escribano; García, F Pulido (Archivos de zootecnia, 1994)
En este trabajo se analizan los recursos de pastoreo en dos explotaciones características de dehesa de Extremadura en el año 1992, Desde el punto de vista de la evaluación técnica, se observa que el sistema cubre, con recursos propios, entre el 54 y el 56 p.100 de las necesidades de la ganadería doméstica en el año de estudio, que se caracterizó por una climatología adversa, Por otro lado, los recursos de pastoreo suponen una de las principales utilidades económicas del sistema dehesa, cuya efectividad económica dependerá de la posibilidad de sustitución y del precio de mercado de las materias primas energéticas comerciales.
Keywords: agroforestry systems; Economic analysis; Extensive systems; natural resources; pastures

BASIS AND ORGANIZATION OF THE EUROPEAN FOREST TREE GENE CONSERVATION NETWORKS - ARBEZ, M. (GENETICS SELECTION EVOLUTION, 1994)
The first ministerial conference on the protection of forests in Europe, held in Strasbourg in 1990, engaged 32 signatory countries to initiate or to follow a concerted policy for forest tree gene conservation and to establish a provisional monitoring structure. This resolution has resulted in an international survey on the present status of forest tree genetic resources in Europe and relevant technical and regulatory measures. In parallel the first 4 pilot gene conservation networks concerning Norway spruce (Picea abies), Cork oak (Quercus suber), black poplar (Populus nigra) and the noble hardwoods (Rosaceaes essentially) were established. Each species or group of species represents a distinct model of spatial distribution and mating system. The second ministerial conference on the protection of forests, held in Helsinki in June 1993, has confirmed these orientations and has proposed the creation of a permanent European cooperative programme under the aegis of the International Board for Plant Genetic Resources and the forest department of the Food and Agriculture Organization. Further research is necessary on the structure of the genetic variability, the mechanisms to maintain this variability in natural forests, and management and sylvicultural methods able to generate maximum adaptability.
The following values have no corresponding Zotero field: pub-location: 141 RUE JAVEL, 75747 PARIS CEDEX 15, FRANCE publisher: EDITIONS SCIENTIFIQUES ELSEVIER
Keywords: EUROPE; FOREST; GENETIC RESOURCE; INTERNATIONAL COOPERATION; NETWORK

BASIS AND ORGANIZATION OF THE EUROPEAN FOREST TREE GENE CONSERVATION NETWORKS - ARBEZ, M (GENETICS SELECTION EVOLUTION, 1994)
The first ministerial conference on the protection of forests in Europe, held in Strasbourg in 1990, engaged 32 signatory countries to initiate or to follow a concerted policy for forest tree gene conservation and to establish a provisional monitoring structure. This resolution has resulted in an international survey on the present status of forest tree genetic resources in Europe and relevant technical and regulatory measures. In parallel the first 4 pilot gene conservation networks concerning Norway spruce (Picea abies), Cork oak (Quercus suber), black poplar (Populus nigra) and the noble hardwoods (Rosaceaes essentially) were established. Each species or group of species represents a distinct model of spatial distribution and mating system. The second ministerial conference on the protection of forests, held in Helsinki in June 1993, has confirmed these orientations and has proposed the creation of a permanent European cooperative programme under the aegis of the International Board for Plant Genetic Resources and the forest department of the Food and Agriculture Organization. Further research is necessary on the structure of the genetic variability, the mechanisms to maintain this variability in natural forests, and management and sylvicultural methods able to generate maximum adaptability.
Keywords: EUROPE; FOREST; GENETIC RESOURCE; INTERNATIONAL COOPERATION; NETWORK

BIRD-DISPERSED SEED RAIN AND SEEDLING ESTABLISHMENT IN PATCHY MEDITERRANEAN VEGETATION - Debussche, M.; Isenmann, P. (OIKOS, 1994)
The composition and spatial patterns of the seed rain produced by bird dispersers and of the seedlings of fleshy-fruited plants have been studied in patchy Mediterranean vegetation in southern France. The seeds of fleshy-fruited plants were collected in seed traps during a 17-month period (1981-1983) and the fecal samples of bird dispersers mist-netted on the same 2.5-ha site over a 25-month period (1981-1984) were analysed. The locations of the 5 sets of seed traps and the 6 mist-nets were chosen in order to take into account the various plant communities and the successional gradient from old fields to Quercus ilex coppice. Seedling establishment of fleshy-fruited plants was censused in 1983 adjacent to the seed traps. In 1992 seedlings were again censused in the open coppice and in the old fields. The seeds of 38 fleshy-fruited plants were collected, including 13 alien and cultivated species. Among them, 25 species were dispersed by Sylvia atricapilla, which dispersed the most diverse and mixed seed rain of the various bird dispersers. Species richness of the seed rain increased log-linearly with seed density, ranging from 3 to 21 species per 0.25 m2. Seed density was very heterogeneous in space. The maximum density of seeds was observed under the canopy of isolated trees and saplings in the old fields (up to 829 per 0.25 m2) which are the favoured perching places for the dispersers. Minimum density was observed in the same old fields outside the canopy of these same trees and saplings (down to 12 per 0.25 m2). In the Quercus ilex coppice, the higher the canopy, the higher the seed density. Dispersal was a short distance process. A large majority of the seeds of Pyracantha coccinea and Sambucus nigra were dispersed by birds less than 100 m from the maternal plant. However, a dispersal distance of > 300 m was observed for a seed of Ligustrum vulgare, In 1983 the < 1 yr-old seedlings of 17 fleshy-fruited plants, including only one alien species, and the 1-2 yr-old seedlings of 7 native species were censused. Though important components of the seed rain, no 1-2 yr-old seedlings of several alien (e.g. Pyracantha coccinea) or native (e.g. Rhus coriaria) species were observed in the studied vegetation. Seedlings were more numerous under tree cover than in the coppice clearings. In the old fields, < 1 yr-old seedlings were more numerous under the canopy than in open areas. No such difference was observed under saplings in 1983 and very few seedlings were observed in the old fields. The 1992 census suggested that the positive role of the cover of pioneer plants on seedling establishment progressively increased with successional development. This is probably due to an increase in the nurse effect and a decrease in the herbaceous cover under the canopy. It is suggested that. in old fields. the establishment of fleshy-fruited plants is favoured when seeds are deposited under pioneer woody plants rather than in open areas. The bird dispersers thus trigger dynamic processes initiated by the pioneer woody plants in Mediterranean old field succession. More generally, dispersal of fleshy-fruited plants by birds is more significant in the central stages of succession gradient than it is in open herbaceous communities and in dense forest when both have an homogeneous structure.
APSAPSThe following values have no corresponding Zotero field: pub-location: 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK publisher: MUNKSGAARD INT PUBL LTD
Keywords: bird dispersers; fleshy-fruited; France; Mediterranean; Quercus ilex; seedlings

Canopy nutrient content of a Quercus ilex L. forest: fertilization and irrigation effects - SABATE, Santiago; Gracia, Carlos a; Ecology, Forest; Barcelona, Universitat De (Forest Ecology and Management, 1994)
A multifactorial ANOVA experiment was designed for a Quercus ilex L. forest at the Prades Experimental Complex of Catchments in Tarragona (northeast Spain). The purpose of this study was to clarify the relative importance of water, nitrogen and phosphorus as factors controlling primary production. Eight plots comprising all possible combinations of the three factors (including a control) were laid out in three replicate blocks. Fertilizers were applied in March 1989 (125 kg ha−1 P, 250 kg ha−1 N). Irrigation was applied at a rate of 20 mm week−1 during the warm season. Nitrogen and phosphorus contents and their distribution in leaves and stems as a response to the experiment are presented in this paper. These variables as well as the structural characteristics were selected because they are among the most dynamic and should present changes over short time periods following changes in environmental conditions. The values before initial treatments (autumn 1988) and after treatments (summer 1990) were analysed. Results showed that water treatments affect the nutrient content; the lower concentrations found in water treatments may probably be explained as a dilution effect after an increase of production. Nitrogen treatments significantly increase the nitrogen concentration in young leaves while phosphorus treatments do not have significant effect on the phosphorus concentrations. Nevertheless, phosphorus treatment significantly lowers the potassium concentration.
Keywords: Canopy; fertilization; irrigation; nutrient content; Quercus ilex

Canopy structure within a Quercus ilex forested watershed: variations due to location, phenological development, and water availability - Sala, A; Sabate, S; Gracia, Carlos; Tenhunen, J D (Trees-Structure and Function, 1994)
Spatial and temporal changes in canopy structure were studied in 1988 and 1989 in a Mediterranean Q u e r c u s ilex forest in north-eastern Spain. Due to differences in precipitation patterns the 1989 growing season was drier than the 1988 growing season. Sampling was conducted in parallel at two sites which represent endpoints along a slope gradient within a watershed (ridge top at 975 m, and valley bottom at 700 m). At both sites, similar inter-annual changes in canopy structure were observed in response to differences in water availability. Samples harvested in the upper 50 cm of the canopy during 1989 exhibited a de- crease in both average leaf size and the ratio of young to old leaf and stem biomass relative to samples obtained in 1988. At the whole canopy level, a decrease in leaf pro- duction efficiency and an increase in the stem to leaf bio- mass ratio was observed in 1989. Temporal changes in canopy leaf area index (LAI) were not statistically sig- nificant. Average LAI values of Q. ilex at the two sites were not significantly different despite differences in tree stature and density (4.6 m 2 m -2 at the ridge top, and 5.3 m 2 m -2 at the valley bottom). Vertical distribution of leaves and stems within the canopy was very similar at the two locations, with more than 60% of the total LAI in the uppermost metre of the canopy. The possible significance of such an LAI distribution on the canopy carbon budget is discussed.
Keywords: Canopy structure; leaf area index; Mediterranean sclerophylls; Quercus ilex; water deficit

Chlorophyll fluorescence as a tool for management of plant resources - Méthy, M; Olioso, A; Trabaud, L (Remote Sensing of Environment, 1994)
Light-induced chlorophyll fluorescence has become a tool which has ever-increasing potential application to experimental plant physiology. The effects of frost, heat, and drought have been analyzed using the kinetics of individual leaves of two representative types of life form: an evergreen tree (holm oak) dominant in the Mediterranean Basin and an annual cultivated legume (soybean). Various indices were used to quantify their response to environmental stress. Canopy fluorescence for the two types of plants was simulated. For two levels of measurement, leaf or canopy, light-induced fluorescence appears to be helpful for forest or crop management in the Mediterranean area.
Keywords: chlorophyll fluorescence induction; crop management (PG); environmental stress; Forest management

Contribution to the syntaxonomic knowledge of Quercus suber woodlands of Latium - Testi, a; Lucattini, C (Rendiconti Lincei, 1994)
This study is a contribution to the knowledge and syntaxonomic definition of Q. suber forests of the Latium region, which represent the last traces Of a forestal belt that at one time was certainly much more developed. In ten sites representative of the Q. suber vegetation, 33 relev& were taken using the Braun-Blanquet phytosociological method (1952). The matrix of 90 species x 33 retev& was placed un- der multivariate analysis (Wildi and Orloci, 1987). From the overall elaboration of the data, a structured table was obtained which allowed for an ecological and phytosociol0gical interpretation of the results. The Q suber woodlands of Latium were attributed to the new association Cytiso-Quercetum suberis, concentrat- ed in the subhumid belt and diffused on markedly acid soils.
Keywords: Latium; Quercus suber woodlands; Syntaxonomy

Crecimiento radial del corcho de reproducción de los alcornocales catalanes y valencianos - Fos, S; BARRENO, E (Scientia gerundensis, 1994)
Eastern cork-oak forests are present in territories with different environmental characteristics, allowing to raise comparative studies between them. This work is an attempt to evaluate the radial growt differences of the reproduction cork, using tschniques of optical microscopy, having developed a new methodology. Thus, severa1 sites from catalonian and valencian cork-oak forests have been selected. In the quantification of this growth, the contribution of each cork type (early cork and late cork) in the annual growing rings have been differentia- ted. The annual increments measwed in catalonian corks have an average of 2.958 mm, being a bit lower in Castell6n with 1.622 mm. These differences in the annual growing rings are due to the early development higher in catalonian cork (2.623 mm) than in valencian ones (1.235 mm), late cork thickness is similar in the two areas. These differences seem to be related with the escarce summer dry period in catalonian cork-oak forests. Important anato- mical differences related with the mentioned ombroclimatic asimetries have been observed too.
Keywords: Anatomy; bioclimatology; cork-oak; Quercus suber L.; Radial growth

Crecimiento radial del corcho de reproducción de los alcornocales catalanes y valencianos - Fos, S.; Barreno, E. (Scientia gerundensis, 1994)
Eastern cork-oak forests are present in territories with different environmental characteristics, allowing to raise comparative studies between them. This work is an attempt to evaluate the radial growt differences of the reproduction cork, using tschniques of optical microscopy, having developed a new methodology. Thus, severa1 sites from catalonian and valencian cork-oak forests have been selected. In the quantification of this growth, the contribution of each cork type (early cork and late cork) in the annual growing rings have been differentia- ted. The annual increments measwed in catalonian corks have an average of 2.958 mm, being a bit lower in Castell6n with 1.622 mm. These differences in the annual growing rings are due to the early development higher in catalonian cork (2.623 mm) than in valencian ones (1.235 mm), late cork thickness is similar in the two areas. These differences seem to be related with the escarce summer dry period in catalonian cork-oak forests. Important anato- mical differences related with the mentioned ombroclimatic asimetries have been observed too.
Keywords: Anatomy; bioclimatology; cork-oak; Quercus suber L.; Radial growth

Datos sobre la vegetación de andalucía. III. Series de vegetación caracterizadas por "Quercus suber" L. - Pérez Latorre, Andrés V.; Nieto, José M.; Cabezudo, Baltasar (Acta botánica malacitana, 1994)
Data about andalusian vegetation. III. Vegetation series with Quercus suber L. presence. Quercus suber woods are one of the natural forests with more diversity and more expanse in Andalusia (Spain). Quercus suber is a dominant or common species in eight vegetation series or subseries: Myrto communis-Querceto suberis S, Teucrio baetici-Querceto suberis S, Smilaci mauritanicae-Querceto rotundifoliae quercetoso suberis subsigmetum, Tamo communis-Oleeto sylvestris quercetoso suberis subsigmetum, San guisorbo hybridae-Querceto suberis S, Pyro bourgaeanae-Querceto rotundifoliae quercetoso suberis subsigmetum, Paeonio coriaceae-Querceto rotundifoliae quercetoso fagineae subsigmetum, var. of Quercus suber, Adenocarpo decorticantis-Querceto rotundifoliae quercetoso suberis subsigmetum. These vegetation series show peculiar sucesional dynamism of their communities depending on their traditional use, environmental factors and biogeographical location. Two new subasociations, Ulici eriocladi-Cistetum ladamferi cistetosum albidi and Phyllireo angustifoliae-Quercetum lusitanicae cytisetosurn tribracteojati, are described in this paper.
Keywords: Andalusia; Quercus suber woods; Spain; vegetation series

Datos sobre la vegetación de andalucía. III. Series de vegetación caracterizadas por "Quercus suber" L. - Pérez Latorre, Andrés V; Nieto, José M; Cabezudo, Baltasar (Acta botánica malacitana, 1994)
Data about andalusian vegetation. III. Vegetation series with Quercus suber L. presence. Quercus suber woods are one of the natural forests with more diversity and more expanse in Andalusia (Spain). Quercus suber is a dominant or common species in eight vegetation series or subseries: Myrto communis-Querceto suberis S, Teucrio baetici-Querceto suberis S, Smilaci mauritanicae-Querceto rotundifoliae quercetoso suberis subsigmetum, Tamo communis-Oleeto sylvestris quercetoso suberis subsigmetum, San guisorbo hybridae-Querceto suberis S, Pyro bourgaeanae-Querceto rotundifoliae quercetoso suberis subsigmetum, Paeonio coriaceae-Querceto rotundifoliae quercetoso fagineae subsigmetum, var. of Quercus suber, Adenocarpo decorticantis-Querceto rotundifoliae quercetoso suberis subsigmetum. These vegetation series show peculiar sucesional dynamism of their communities depending on their traditional use, environmental factors and biogeographical location. Two new subasociations, Ulici eriocladi-Cistetum ladamferi cistetosum albidi and Phyllireo angustifoliae-Quercetum lusitanicae cytisetosurn tribracteojati, are described in this paper.
Keywords: Andalusia; Quercus suber woods; Spain; vegetation series

Deposition on holm oak leaf surfaces of accidentally released radionuclides - Rauret, G.; Llauradó, M.; Tent, J.; Rigol, A.; Alegre, L. H.; Utrillas, M. J. (Science of The Total Environment, 1994)
The retention of aerosols by canopies of holm oak trees in a typical Mediterranean forest is studied. Firstly, dry deposition is measured both under and outside the canopy during several months. No clear differences are observed either in the amount or in the chemical composition of the particles collected under and outside the canopy. Secondly, the leaf morphology and anatomy as well as the aerosol deposited onto the leaf surfaces are studied by scanning electron microscopy. Cuticle thickness is measured and differences are observed between young and old leaves. The distribution of aerosol particles over leaf surface is also established. Finally, the possible incorporation into leaves of a radioactive aerosol released in an accidental situation is studied, by means of a sequential extraction procedure using water and an organic solvent. From the results it can be deduced that neither the abiotic layer nor the cuticle play any important role in the retention of caesium. The studied radionuclides are mainly found in particulate form, soluble in water, or incorporated into leaves.
Keywords: Cuticle thickness; Holm oak; Leaf surface; Radionuclide deposition; Radionuclide incorporation; Sequential extraction

Deposition on holm oak leaf surfaces of accidentally released radionuclides - Rauret, G; Llauradó, M; Tent, J; Rigol, A; Alegre, L H; Utrillas, M J (Science of The Total Environment, 1994)
The retention of aerosols by canopies of holm oak trees in a typical Mediterranean forest is studied. Firstly, dry deposition is measured both under and outside the canopy during several months. No clear differences are observed either in the amount or in the chemical composition of the particles collected under and outside the canopy. Secondly, the leaf morphology and anatomy as well as the aerosol deposited onto the leaf surfaces are studied by scanning electron microscopy. Cuticle thickness is measured and differences are observed between young and old leaves. The distribution of aerosol particles over leaf surface is also established. Finally, the possible incorporation into leaves of a radioactive aerosol released in an accidental situation is studied, by means of a sequential extraction procedure using water and an organic solvent. From the results it can be deduced that neither the abiotic layer nor the cuticle play any important role in the retention of caesium. The studied radionuclides are mainly found in particulate form, soluble in water, or incorporated into leaves.
Keywords: Cuticle thickness; Holm oak; Leaf surface; Radionuclide deposition; Radionuclide incorporation; Sequential extraction

Differences between oligotrophic communities resulting from old-field succession in relation to bedrock - Puerto, A; Rico, M (Plant Ecology, 1994)
Dehesa ecosystems on granite and on slate clearly differ in soil characteristics. Our aim was to find out whether floristic composition differed too. We selected an equal number of plots, on both granite and slate, in different successional stages of development and at various ages after field abandonment (the youngest 15-20 years). Plots with rock-outcrops, which had never been cultivated, were also included in the study. The results showed that floristic differences between granite and slate communities were not detectable in the younger successional stages. However, they showed up with time and on stabilized grasslands became significant. But on plots with rock-outcrops the differences were not observable. This was undoubtedly influenced by the peculiar features of these plots, characterised by poor arid soils and surface parent material. In fact they did not show significant differences in the analysed soil parameters either. Species diversity and biomass showed a similar pattern of differences to floristic composition. The highest species diversity was found on plots with lower biomass (the youngest ones). The lowest biomass in conjunction with quite low species diversity was found on plots with rock-outcrops, which again is consistent with their peculiar features.
Keywords: biomass; diversity; granite; mediterranean grasslands; slate

Differences between oligotrophic communities resulting from old-field succession in relation to bedrock - Puerto, A.; Rico, M. (Plant Ecology, 1994)
Dehesa ecosystems on granite and on slate clearly differ in soil characteristics. Our aim was to find out whether floristic composition differed too. We selected an equal number of plots, on both granite and slate, in different successional stages of development and at various ages after field abandonment (the youngest 15-20 years). Plots with rock-outcrops, which had never been cultivated, were also included in the study. The results showed that floristic differences between granite and slate communities were not detectable in the younger successional stages. However, they showed up with time and on stabilized grasslands became significant. But on plots with rock-outcrops the differences were not observable. This was undoubtedly influenced by the peculiar features of these plots, characterised by poor arid soils and surface parent material. In fact they did not show significant differences in the analysed soil parameters either. Species diversity and biomass showed a similar pattern of differences to floristic composition. The highest species diversity was found on plots with lower biomass (the youngest ones). The lowest biomass in conjunction with quite low species diversity was found on plots with rock-outcrops, which again is consistent with their peculiar features.
Keywords: biomass; diversity; granite; mediterranean grasslands; slate

Diversite de la banque de semences du sol d'une foret mediterraneenne de Quercus ilex - Trabaud, Louis (Biological Conservation, 1994)
Résumé La banque de semences du sol a été étudiée dans une futaie de Quercus ilex. La richesse des semences est relativement faible (500/m2); par contre, sa richesse floristique est élevée (56 espèces/m2). Les types de dispersion les plus utilisés sont l'anémochorie, l'autochorie et l'ornithochorie. La plupart des semences enfouies dans le sol appartiennent à des espèces étrangères à la futaie, provenant de milieux (sources) voisins ou lointains. On a constaté aussi une convergence de la flore des semences des banques du sol de diverses communautés. A la faveur d'une perturbation (feu ou coupe) ces semences trouvent des conditions favorables (car héliophiles pour la plupart), germent et produisent de nombreuses plantules constituant des stades transitoires. The soil seed bank has been studied in a Quercus ilex forest. Seed richness was relatively low (500/m2); in contrast, specific richness was high (56 species/m2). Anemochory (wind-borne), autochory (self-dispersion) and ornithochory (birds) were the dissemination types encountered most. Most of the seed buried in the soil belonged to species alien to the forest, coming from neighbouring or distant (sources) environments. A convergence between the soil seed bank floras of different communities could be noticed. When a disturbance (fire or cutting) occurs, creating favourable conditions, seeds germinate producing numerous seedlings representing transitory stages.
Keywords: dissemination; FOREST; Quercus ilex; seed; Soil

Effect of hot pressing densification on the cellular structure of black agglomerated cork board - Gil, L (European Journal of Wood and Wood Products, 1994)
Samples of black cork agglomerate boards were observed by scanning electron microscopy, prior and after different densifi- cations. These boards were densified under conditions previous- ly defined, and were observed in two directions, parallel and per- pendicular to the compression axis. The relationship between the average cell wall distance and the compression applied was stud- ied and it was found that the maximum densification is achieved with a pressure of ca. 3 MPa. Some aspects of the influence of densification treatments on the chemical composition of the material were also broached.
Keywords: black cork agglomerate; cell walls; Cork; densification (Voyant)

THE EFFECT OF LONG-TERM TREATMENT AT 100-DEGREES-C-150-DEGREES-C ON STRUCTURE, CHEMICAL-COMPOSITION AND COMPRESSION BEHAVIOR OF CORK - Rosa, M E; Pereira, H (HOLZFORSCHUNG, 1994)
The effects of heating of cork in air at 100-degrees-C and 150-degrees-C for up to 42 days have been studied. Dimensional and mass changes induced by heat treatment were measured and the chemical composition was analysed. The thermal degradation of cork is small for short periods of treatment but increases with time and temperature. Cork looses after 42 days of treatment 6.8 % of its mass at 100-degrees-C and 19.9 % at 150-degrees-C. Cork extractives and polysaccharides were found to be the most temperature labile components. The cellular structure, observed by scanning electron microscopy, did not change with treatment in these conditions. Compression curves of untreated and heat treated cork samples were obtained, which show an increase of compression strength upon heating for short exposure periods and a decrease for longer ones. The changes observed in the compression behaviour of cork treated at 100-degrees-C and 150-degrees-C were related to the chemical composition changes induced by heat treatment.
Keywords: c; Cellular materials; Cork; mechanical properties

Effect of topographic and temporal (maturity) gradients on the nutritive quality of semiarid herbaceous communities - Perez-Corona, M E; García-Criado, B; Vazquez de Aldana, B R; Garcia-Ciudad, A (Communications in Soil Science and Plant Analysis, 1994)
Abstract Five slopes representative of the ?dehesa?; grassland communities in the semi?arid zones of Central?Western Spain (province of Salamanca) were studied. Above?ground biomass production was recorded from April to June and the NDF (neutral detergent fibre), ADF (acid detergent fibre), hemicellulose, cellulose, lignin, and digestibility were determined in the dry matter. Principal component analysis was applied to the data. The changes with time along the growth period show a parallel effect on the three positions of the slope, although the effect tended to be greater on the middle and upper zones. There were decreases in the levels of protein, cellular content, and digestibility, and an increase in cell wall components. The variability in nutritive characteristics induced by the phenology and time changes in the communities was reflected in the first factor of analysis, whereas the topographic gradient was related to the second component.
doi: 10.1080/00103629409369171
Keywords: dehesa grasslands; digestibility (PG); Nutritive quality; Semi-arid areas

Effects of irrigation and fertilization on stem diameter growth in a Mediterranean holm oak forest - Mayor, Xavier; Rodà, Ferran (Forest Ecology and Management, 1994)
The effects of irrigation and fertilization on stem diameter growth are reported for holm oak (Quercus ilex L.), an evergreen tree that is a common dominant in Mediterranean forests. The experiment was conducted at Prades (northeastern Spain) in a holm oak stand with a high density of stems of resprout origin (x = 18275 stems ha−1), a widespread stand structure in the abandoned coppices that cover extensive tracts of Mediterranean mountains. Mean annual rainfall is 580 mm. Eight treatments were used in each of three blocks, resulting from the factorial combination of: (i) irrigation at rates of about 20 mm week−1 during three consecutive warm seasons; (ii) nitrogen fertilization in a single application of 250 kg N ha−1; (iii) phosphorus fertilization in a single application of 125 kg P ha−1. Stem diameters at 50 cm from the ground were measured before and 3 years after treatment application began. Stem diameter increments in control plots were very low (x ± SE 0.27 ± 0.07 mm year−1), probably as a result of the high stand density and low water availability. Stem diameter growth was positively but loosely correlated with initial stem diameter. Irrigation significantly (P < 0.01) increased mean stem diameter growth by 66%, but N and P fertilization did not. Surprisingly, there were no significant interactions between irrigation and fertilization, i.e. irrigated and fertilized trees did not grow significantly faster than irrigated-only trees. Effects of irrigation were larger on plots having lower initial basal area of holm oak. Irrigation increased stem diameter growth more in large trees than in smaller ones, thus enhancing the pre-existent inequalities in growth rates. Stem diameter growth in this high density stand is limited by water availability but has not responded to N or P additions during the first 3 years after fertilization.
Keywords: fertilization; Growth; irrigation; Quercus ilex; Stem diameter growth

EFFECTS OF IRRIGATION AND FERTILIZATION ON STEM DIAMETER GROWTH IN A MEDITERRANEAN HELM OAK FOREST - Mayor, X; Rodà, F (FOREST ECOLOGY AND MANAGEMENT, 1994)
The effects of irrigation and fertilization on stem diameter growth are reported for helm oak (Quercus ilex L.), an evergreen tree that is a common dominant in Mediterranean forests. The experiment was conducted at Prades (northeastern Spain) in a helm oak stand with a high density of stems of resprout origin (($) over bar x = 18275 stems ha(-1)), a widespread stand structure in the abandoned coppices that cover extensive tracts of Mediterranean mountains. Mean annual rainfall is 580 mm. Eight treatments were used in each of three blocks, resulting from the factorial combination of: (i) irrigation at rates of about 20 mm week(-1) during three consecutive warm seasons; (ii) nitrogen fertilization in a single application of 250 kg N ha(-1); (iii) phosphorus fertilization in a single application of 125 kg P ha(-1). Stem diameters at 50 cm from the ground were measured before and 3 years after treatment application began. Stem diameter increments in control plots were very low (($) over bar x+/-SE 0.27+/-0.07 mm year(-1)), probably as a result of the high stand density and low water availability. Stem diameter growth was positively but loosely correlated with initial stem diameter. Irrigation significantly (P<0.01) increased mean stem diameter growth by 66%, but N and P fertilization did not. Surprisingly, there were no significant interactions between irrigation and fertilization, i.e. irrigated and fertilized trees did not grow significantly faster than irrigated-only trees. Effects of irrigation were larger on plots having lower initial basal area of helm oak. Irrigation increased stem diameter growth more in large trees than in smaller ones, thus enhancing the pre-existent inequalities in growth rates. Stem diameter growth in this high density stand is limited by water availability but has not responded to N or P additions during the first 3 years after fertilization.
Keywords: fertilization; Growth; irrigation; Stem diameter growth

European oak declines and global warming: a theoretical assessment with special reference to the activity of Phytophthora cinnamomi - Brasier, C. M.; SCOTT, J. K. (EPPO Bulletin, 1994)
Causes of current severe declines of the deciduous oaks Quercus robur and Q. petraea in northern and central Europe and of the evergreen Q. ilex, Q. suber and other Quercus spp. in the Mediterranean area are reviewed. Factors implicated include drought, pollution, winter cold, flooding, and stress-related attacks by insects and fungi. Additional factors in Mediterranean oak declines include changing land-use patterns and root disease caused by the aggressive, exotic oomycete root pathogen Phytophthora cinnamomi. Under conditions of global warming the survival and degree of root disease caused by this fungus seems likely to be enhanced, while the host range of the organism might also be increased. Application of the CLIMEX climate-matching program suggests that with a mean increase in temperatures of 1.5–3°C the fungus might considerably increase its disease activity in its existing locations, and to some extent spread northwards and eastwards. However, it seems unlikely to become significantly active in areas of Europe with colder winters such as parts of Scandinavia, Russia and the central Danube. The predictive value of research on major environmental problems such as oak declines could be enhanced by more highly coordinated European forestry research programmes.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Global warming; Oak decline; phytophthora cinnamomi; range expansion (PG); root disease

European oak declines and global warming: a theoretical assessment with special reference to the activity of Phytophthora cinnamomi - Brasier, C M; SCOTT, J K (EPPO Bulletin, 1994)
Causes of current severe declines of the deciduous oaks Quercus robur and Q. petraea in northern and central Europe and of the evergreen Q. ilex, Q. suber and other Quercus spp. in the Mediterranean area are reviewed. Factors implicated include drought, pollution, winter cold, flooding, and stress-related attacks by insects and fungi. Additional factors in Mediterranean oak declines include changing land-use patterns and root disease caused by the aggressive, exotic oomycete root pathogen Phytophthora cinnamomi. Under conditions of global warming the survival and degree of root disease caused by this fungus seems likely to be enhanced, while the host range of the organism might also be increased. Application of the CLIMEX climate-matching program suggests that with a mean increase in temperatures of 1.5–3°C the fungus might considerably increase its disease activity in its existing locations, and to some extent spread northwards and eastwards. However, it seems unlikely to become significantly active in areas of Europe with colder winters such as parts of Scandinavia, Russia and the central Danube. The predictive value of research on major environmental problems such as oak declines could be enhanced by more highly coordinated European forestry research programmes.
Keywords: Global warming; Oak decline; phytophthora cinnamomi; range expansion (PG); root disease

Fungal endophytes from the leaves and twigs of Quercus ilex L. from England, Majorca and Switzerland - FISHER, P J; PETRINI, O; PETRINI, L E; SUTTON, B C (New Phytologist, 1994)
Leaves of Quercus ilex taken from sites in England, Majorca and Switzerland have been studied to detect the influence of the geographic position of the host within and outside its native range on the composition of its endophytic fungal assemblages. Samples of stem tissue of Q. ilex collected from the Swiss trees were also studied to confirm tissue-specific differences. Sixty different fungal taxa were isolated, but only 28 were frequent. Of the total number of isolates from the leaves from the Swiss, British and Spanish sites 87%, 31% and 63%, respectively, were coelomycetes. Four species of Phomopsis, which includes Phyllosticta ilicina (=Phomopsis ilicina v. d. Aa, ined.), were the most frequent endophytes of leaves and were either absent or rare in the twig units. Two distinct kinds of sterile mycelia were common in twigs. Swiss and Spanish trees possessed fungal assemblages distinct from those present in Britain. Naturalized stands were distinguished from native stands by the presence of rather cosmopolitan and non-specific fungal taxa, rare or absent in the samples collected in the native stands. Samples derived from the native stands were colonized by more host-specific fungi. The relative frequency of two sterile mycelia in the Swiss and Spanish sites determined their separation. Phyllosticta (Phomopsis) ilicina, the most numerous leaf colonizer, was virtually absent from the bark and the xylem. The frequent occurrence of coelomycetes as endophytes of woody trees is briefly discussed.
Keywords: coelomycetes; fungal distribution; fungal ecology; Quercus ilex (oak)

Fungal endophytes from the leaves and twigs of Quercus ilex L. from England, Majorca and Switzerland - FISHER, P. J.; PETRINI, O.; PETRINI, L. E.; SUTTON, B. C. (New Phytologist, 1994)
Leaves of Quercus ilex taken from sites in England, Majorca and Switzerland have been studied to detect the influence of the geographic position of the host within and outside its native range on the composition of its endophytic fungal assemblages. Samples of stem tissue of Q. ilex collected from the Swiss trees were also studied to confirm tissue-specific differences. Sixty different fungal taxa were isolated, but only 28 were frequent. Of the total number of isolates from the leaves from the Swiss, British and Spanish sites 87%, 31% and 63%, respectively, were coelomycetes. Four species of Phomopsis, which includes Phyllosticta ilicina (=Phomopsis ilicina v. d. Aa, ined.), were the most frequent endophytes of leaves and were either absent or rare in the twig units. Two distinct kinds of sterile mycelia were common in twigs. Swiss and Spanish trees possessed fungal assemblages distinct from those present in Britain. Naturalized stands were distinguished from native stands by the presence of rather cosmopolitan and non-specific fungal taxa, rare or absent in the samples collected in the native stands. Samples derived from the native stands were colonized by more host-specific fungi. The relative frequency of two sterile mycelia in the Swiss and Spanish sites determined their separation. Phyllosticta (Phomopsis) ilicina, the most numerous leaf colonizer, was virtually absent from the bark and the xylem. The frequent occurrence of coelomycetes as endophytes of woody trees is briefly discussed.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: coelomycetes; fungal distribution; fungal ecology; Quercus ilex (oak)

Long term effects of naturally elevated CO 2 on mediterranean grassland and forest trees - Körner, C; Miglietta, Francesco (Oecologia, 1994)
We investigated the carbon supply status in species-rich mediterranean plant communities growing in a bowl-shaped 1-ha "CO2 spring" area near Sienna, Italy. A geothermic "lime-kiln" has provided these communities, for as long as historical records are avail- able, with pure CO2 that mixes with ambient air at canopy level to daytime means of 500-1000 ppm CO2. Immediately outside the spring area similar plant com- munities are growing on similar substrate, and in the same climate, but under ca. 355 ppm CO2. We found no evidence that plants in the CO2 spring area grow faster, flower earlier or become larger. However, we found very large differences in tissue quality among the 40 species studied inside and outside the spring area. Depending on weather conditions, the mean concentra- tion of total non-structural carbohydrates (TNC, sugars and starch) in leaves of herbaceous plants was 38-47% higher in the spring area. Fast growing ruderals growing on garden soil inside and outside the spring area show the same response. Among trees, leaves of the deciduous Quercus pubscens contain twice as much TNC inside as outside the vent area, whereas evergreen Q. ilex leaves show no significant difference. TNC levels in branch wood paralleled leaf values. TNC in shade leaves was also higher. Elevated CO2 had no effect on the sugar fraction, therefore differences in TNC are due to starch accumulation. Leaf nitrogen concentration decreases under elevated CO2. These observations suggest that the commonly reported TNC accumulation and N depletion in leaves growing under elevated CO2 are not restricted to the artificial condi- tions of short-term COz enrichment experiments but persist over very long periods. Such an alteration of tissue composition can be expected to occur in other plant communities also if atmospheric COz levels con- tinue to rise. Effects on food webs and nutrient cycling are likely
Keywords: carbohydrates; Global change; leaf nitrogen; natural-co2 springs; photosynthesis

MIGRATION STUDY OF RADIONUCLIDES IN A MEDITERRANEAN FOREST SOIL USING SYNTHETIC AEROSOLS - SAURAS, T; ROCA, M C; Tent, J; Llauradó, M; VIDAL, M; Rauret, G; Vallejo, V R (SCIENCE OF THE TOTAL ENVIRONMENT, 1994)
Radionuclide migration in a Mediterranean forest was studied in field conditions. Fresh Holm oak leaves were exposed to a synthetic aerosol including Cs-134, Sr-85 and Ag-110m, and were incubated in the original Holm oak forest in two types of cylinder: (1) cylinders in which the contaminated litter lies directly on the original F layer; (2) cylinders with an exchange resin bag inserted between the contaminated litter and the underlying F layer. The results for 232 days of incubation showed that Cs-134 presented an initial rapid leaching period, which corresponded to the fraction extracted with water from the initially contaminated leaves. Further Cs-134 release was related to litter decompostiion. Sr-85 migration was studied for only 76 days, and its behaviour appeared to be similar to Cs-134. Both radionuclides migrated within the litter leachates. After 3 months of incubation, around 70% of the initial Cs-134 was transferred to the underlying layers, mainly to the F layer. Cs-134 absorbed into the leaves was released at the same rates as K. The Ag-110m activity lost from the contaminated litter amounted to around 45% in the open cylinders, from which 15-20% was attributed to the effect of soil faunal activity. The field method proposed proved to be useful in describing radionuclide migration in situ and the mechanisms involved.
Keywords: litter; mediterranean forest; RADIONUCLIDE MIGRATION

MYCOLOGICAL STUDY IN THE NATURAL-PARK-OF-THE-ALCORNOCALES (ANDALUSIA, SPAIN) .1. AGARICALES - Moreno, G; ESTEVERAVENTOS, F; Ortega, a (CRYPTOGAMIE MYCOLOGIE, 1994)
This work includes the first results about the Agaricales s. lato collected mostly in Quercus suber forest in the Natural Park of the Alcornocales (Andalucia, Spain). The most outstanding taxa are: Hebeloma danicum, H. sacchariolens var. pallidoluctuosum, H. mesophaeum var. pallidum, H. sacchariolens var. pallidoluctuosum, Lactarius luteolus, Pluteus plautus, Russula bresadoliana, R. fragrantissima, R. graveolens var. megacantha, R. graveolens var. purpurata. A microscopical study under the S.E.M. of the spore ornamentation of the most interesting taxa is given.
Keywords: AGARICALES S-LATO; chorology; ecology; taxonomy

NATURAL GERMINATION AS RESILIENCE COMPONENT IN MEDITERRANEAN COPPICE STANDS OF CASTANEA-SATIVA MILL AND QUERCUS-ILEX L - Bacilieri, R; Bouchet, M A; Bran, D; Grandjanny, M; Maistre, M; Perret, P; Romane, F (ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY, 1994)
In the Mediterranean basin, most of the present forests derive from original forests where the dominant species was different from the present one. These changes are largely due to human activities reflecting millenia of management and, often, overexploitation. In southern France, for example, palaeoecologists believe that the original malacophyllous deciduous forest of downy oak (Quercus pubescens) was replaced by a sclerophyllous evergreen holm oak (Quercus ilex) coppice in the driest areas, and chestnut (Castanea sativa) orchards or coppices in the `'wettest'' areas. However, for the last several decades, exploitation of these coppice stands has been decreasing. In this study, we addressed the question of the resilience of these managed ecosystems in the fact of changing management schemes, and to determine appropriate strategies and criteria of sustainable development. We present some aspects of the auto-succession after clearcutting of holm oak coppice stands and aspects of the natural regeneration of 4 species (Q. ilex, Q. pubescens, C. sativa, and P. pinaster). The consequences of the contrasted life history strategies are compared to estimate the future of these coppices.
Keywords: ABANDONED LAND; CASTANEA-SATIVA MILL; Coppice stands; germination; Mediterranean climate; Regeneration

NO EFFECTS OF A FOREST SPRAYING OF MALATHION ON BREEDING BLUE TIPS (PARUS-CAEREULEUS) - Pascual, J A (ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY, 1994)
Ultra low volume (ULV) aerial spraying of the organophosphorus insecticide malathion is widely used in Spain to control Tortrix viridana, the most important lepidopteran pest of Spanish holm oak forests (Quercus ilex). A field study was carried out in spring 1988 to analyze the short-term effects of a standard application rate of malathion (1, 160 g a.i./ha) on the breeding success of the blue tit (Parus caeruleus). Several blue tit reproductive parameters and seasonal variation of arthropod densities in canopy trees (focusing on caterpillars, the main food resource for breeding blue tits) were compared between a malathion-treated plot and a control plot. None of the breeding parameters (nest abandonment, nest success, hatching success, nestling mortality, daily survival rate, and nestling weight) showed differences between the treated and the control plots. Malathion spraying caused nearly a 100% mortality of the target pest Tortrix viridana, but it did not reduce availability of another Tortricidae (Archips xylosteana), with the result that food supply was similar or higher in the treated plot than in the control plot. The main conclusion of this study is that a forest standard application of malathion did not cause adverse short-term effects on breeding blue tits. Moreover, this work focused on the indirect effects of insecticides via food depletion; its results suggest that in these kinds of studies it is more important to assess the abundance of arthropods remaining alive after treatment than the degree of arthropod mortality caused by the insecticide.
Keywords: BLUE TIT (PARUS-CAERULEUS); breeding success; FOREST SPRAYING; Indirect effects; MALATHION

Phenological and growth patterns of the Mediterranean oak Quercus suber L. - Oliveira, Graca; Correia, Otflia (Trees-Structure and …, 1994)
The phenology of Quercus suber L., a dominant species of the montados in the Iberian Peninsula, was studied for 2 years in southwest Portugal. The seasonal progression of phenological events was analyzed in seven trees. Selected branches were examined monthly for shoot elongation, leaf number, branching, flowering, and fruiting. Radial stem growth and specific leaf weight were also studied. Active growth was observed from early spring to early summer. Reserves accumulated during winter and high photosynthetic activity in early spring apparently supported this strong development. The growth flush started with stem radial increment, which seemed to be impaired by spring rainfall. Male inflorescence production was the next phenological event. Old leaves were shed during new twig and leaf emergence. Shoot elongation and the number of new leaves produced were well correlated with the previous-year shoot's length, and were not clearly related to climatic factors. Radial growth resumed in au- tumn at a lower rate than in the previous spring, a possible consequence of a reserve depletion due to lower photo- synthetic production in summer and investment on fruit maturation, which was complete by late autumn. Premature and excessive new leaf production were apparently sub- jected to self-pruning strategies related to the development of each tree's crown. Younger cork-oaks produced shorter and fewer shoots per module, and more sclerophyllous leaves than the older ones. A high intra-specific variability was observed in all the results.
Keywords: Growth; Phenology; Quercus suber; specific leaf weight; Trees

Phenological and growth patterns of the Mediterranean oak Quercus suber L. - Oliveira, Graca; Correia, Otilia; Martins-Loução, Maria Amélia; Catarino, Fernando M (Trees, 1994)

Phenological and growth patterns of the Mediterranean oak Quercus suber L. - Oliveira, Graca; Correia, Otflia (Trees-Structure and …, 1994)
The phenology of Quercus suber L., a dominant species of the montados in the Iberian Peninsula, was studied for 2 years in southwest Portugal. The seasonal progression of phenological events was analyzed in seven trees. Selected branches were examined monthly for shoot elongation, leaf number, branching, flowering, and fruiting. Radial stem growth and specific leaf weight were also studied. Active growth was observed from early spring to early summer. Reserves accumulated during winter and high photosynthetic activity in early spring apparently supported this strong development. The growth flush started with stem radial increment, which seemed to be impaired by spring rainfall. Male inflorescence production was the next phenological event. Old leaves were shed during new twig and leaf emergence. Shoot elongation and the number of new leaves produced were well correlated with the previous-year shoot's length, and were not clearly related to climatic factors. Radial growth resumed in au- tumn at a lower rate than in the previous spring, a possible consequence of a reserve depletion due to lower photo- synthetic production in summer and investment on fruit maturation, which was complete by late autumn. Premature and excessive new leaf production were apparently sub- jected to self-pruning strategies related to the development of each tree's crown. Younger cork-oaks produced shorter and fewer shoots per module, and more sclerophyllous leaves than the older ones. A high intra-specific variability was observed in all the results.
Keywords: Growth; Phenology; Quercus suber; specific leaf weight; Trees

Photosynthetic acclimation in trees to rising atmospheric CO2: a broader perspective - Gunderson, C A; Wullschleger, S D (Photosynthesis Research, 1994)
Analysis of leaf-level photosynthetic responses of 39 tree species grown in elevated concentrations of atmospheric CO 2 indicated an average photosynthetic enhancement of 44% when measured at the growth [CO2]. When photosynthesis was measured at a common ambient [CO2], photosynthesis of plants grown at elevated [CO2] was reduced, on average, 21% relative to ambient-grown trees, but variability was high. The evidence linking photosynthetic acclimation in trees with changes at the biochemical level is examined, along with anatomical and morphological changes in trees that impact leaf- and canopy-level photosynthetic response to CO 2 enrichment. Nutrient limitations and variations in sink strength appear to influence photosynthetic acclimation, but the evidence in trees for one predominant factor controlling acclimation is lacking. Regardless of the mechanisms that underlie photosynthetic acclimation, it is doubtful that this response will be complete. A new focus on adjustments to rising [COz] at canopy, stand, and forest scales is needed to predict ecosystem response to a changing environment.
Keywords: elevated atmospheric CO 2; global carbon cycle; photosynthetic acclimation; Trees

Photosynthetic acclimation in trees to rising atmospheric CO2: a broader perspective - Gunderson, C. A.; Wullschleger, S. D. (Photosynthesis Research, 1994)
Analysis of leaf-level photosynthetic responses of 39 tree species grown in elevated concentrations of atmospheric CO 2 indicated an average photosynthetic enhancement of 44% when measured at the growth [CO2]. When photosynthesis was measured at a common ambient [CO2], photosynthesis of plants grown at elevated [CO2] was reduced, on average, 21% relative to ambient-grown trees, but variability was high. The evidence linking photosynthetic acclimation in trees with changes at the biochemical level is examined, along with anatomical and morphological changes in trees that impact leaf- and canopy-level photosynthetic response to CO 2 enrichment. Nutrient limitations and variations in sink strength appear to influence photosynthetic acclimation, but the evidence in trees for one predominant factor controlling acclimation is lacking. Regardless of the mechanisms that underlie photosynthetic acclimation, it is doubtful that this response will be complete. A new focus on adjustments to rising [COz] at canopy, stand, and forest scales is needed to predict ecosystem response to a changing environment.
The following values have no corresponding Zotero field: accession-num: 24311130
Keywords: elevated atmospheric CO 2; global carbon cycle; photosynthetic acclimation; Trees

PRELIMINARY DATA ON THE ECOLOGY OF WOODMOUSE APODEMUS-SYLVATICUS LINNE, 1758, NEAR TALA-GUILEF, DJURDJURA-NATIONAL-PARK ALGERIA - HAMDINE, W; POITEVIN, F (REVUE D ECOLOGIE-LA TERRE ET LA VIE, 1994)
Wood mice (n = 166) were sampled in 1989-1990 by line trapping in the Djurdjura National Park, Algeria. Most were observed in forests of sclerophyllous oaks (Quercus ilex, Quercus suber) and in mountain grasslands. The species was scarcer in cedar forests. Most (70 %) of the captured individuals were adults with a large number of males. Furthermore, most of the individuals were captured in spring (ca. 52 %).
Keywords: Algeria; Apodemus sylvaticus; Ecological abundance; Plant cover; population structure; seasonal variation; Sex ratio

Propagação do sobreiro (Quercus suber) por estacaria - Ribeiro, Maria Margarida Chagas de Ataíde (1994)
Realizaram-se ensaios de enraizamento com estacas provenientes de jovens sobreiros, durante dois anos consecutivos. A aplicação de AIB à base da estaca melhorou a percentagem de enraizamento e a sobrevivência em relação à testemunha, na época de enraizamento de Abril. Na época de fins de Junho, já não se verificou a referida resposta positiva. Este tratamento não teve efeito no número de raízes formadas, por estaca enraizada, mas influenciou o comprimento da maior raiz, também por estaca enraizada, independentemente da época de enraizamento. A utilização de 0,1% ANA não provocou resultados diferentes da testemunha para qualquer dos parâmetros avaliados. O descasque na base da estaca aumentou a percentagem de enraizamento e a sobrevivência. Este tratamento, juntamente com a aplicação de 0,5% de AIB conduziu a percentagens de enraizamento superiores a 60%, ao fim de três meses de ensaio, na época de enraizamento de Abril. Quer a origem da estaca (topo ou base da planta) quer os tratamentos dos pés-mãe (colocação das plantas às escuras ou o escurecimento - uso de uma fita preta na base da futura estaca) não influenciaram a percentagem de enraizamento. A sobrevivência das estacas é comprometida na época de enraizamento de fins de Junho, pelo facto de entrarem em dormência. A aplicação de BAP às estacas enraizadas, em dormência, estimulou o abrolhamento de gomos axilares e não se observaram efeitos fitotóxicos. Realizaram-se cortes histológicos na base de estacas sujeitas ao tratamento de escurecimento (com ou sem aplicação de AIB na banda preta). No dia 0 observaram-se diferenças na estrutura devidas a esse tratamento especialmente ao nível da periderme e do xilema. Até ao dia 20 as diferenças estruturais das estacas submetidas ao tratamento de escurecimento foram-se acentuando com perda de coerência e aparecimento, por vezes abundante, de callus. Em geral as modificações surgiam na zona do nó e só depois na zona do entrenó. A aplicação de AIB à base da estaca antes de esta ser posta a enraizar não conduziu a diferenças tão evidentes como o tratamento de escurecimento
Keywords: Anatomy; Cork oak; Cuttings; Quercus suber L.; rooting; vegetative propagation

RUPTURE IN A COLLEMBOLA COMMUNITY STRUCTURE FROM A QUERCUS-ROTUNDIFOLIA LAM FOREST DUE TO THE REAFFORESTATION WITH EUCALYPTUS-GLOBULUS LABILL - Sousa, J P; DaGama, M M (EUROPEAN JOURNAL OF SOIL BIOLOGY, 1994)
Here we compare Collembola populations from a Quercus rotundifolia forest and an Eucalyptus globulus plantation. The overall analysis of data (using both diversity and similarity measures) have shown clear signs of rupture on the structure of collembola populations, with the fauna associated with the Quercus stand being richer (in exclusive and preferential species) and more abundant than the one connected with the Eucalyptus. Data also reflects the faunal stratification between organic and mineral horizons, with the majority of species being associated with upper soil layers in detriment of mineral horizon. These disruptions may be related to profound alterations of habitat characteristics, particularly the frequent removal of shrub vegetation and leaf layer, result of the forestry practices connected with the preparations and management of the eucalyptus plantation.
Keywords: Collembola; EUCALYPTUS; holm-oak; REAFFORESTATION

RUPTURE IN A COLLEMBOLA COMMUNITY STRUCTURE FROM A QUERCUS-ROTUNDIFOLIA LAM FOREST DUE TO THE REAFFORESTATION WITH EUCALYPTUS-GLOBULUS LABILL - SOUSA, J. P.; DAGAMA, M. M. (EUROPEAN JOURNAL OF SOIL BIOLOGY, 1994)
Here we compare Collembola populations from a Quercus rotundifolia forest and an Eucalyptus globulus plantation. The overall analysis of data (using both diversity and similarity measures) have shown clear signs of rupture on the structure of collembola populations, with the fauna associated with the Quercus stand being richer (in exclusive and preferential species) and more abundant than the one connected with the Eucalyptus. Data also reflects the faunal stratification between organic and mineral horizons, with the majority of species being associated with upper soil layers in detriment of mineral horizon. These disruptions may be related to profound alterations of habitat characteristics, particularly the frequent removal of shrub vegetation and leaf layer, result of the forestry practices connected with the preparations and management of the eucalyptus plantation.
The following values have no corresponding Zotero field: pub-location: DEPT UNIV PROFESSIONNEL REVUES SCIENTIFIQUES TECHNIQUE 11 RUE GOSSIN, F-92543 MONTROUGE, FRANCE publisher: GAUTHIER-VILLARS
Keywords: Collembola; EUCALYPTUS; holm-oak; REAFFORESTATION

SEARCH FOR FACTORS MAINTAINING TERRICOLOUS BRYOFLORA RICHNESS IN ISOLATED HABITATS - THE CASE OF SCLEROPHYLLOUS OAK GROVES OF THE OCCIDENTAL BORDER OF THE MAURES MASSIF (VAR, FRANCE) - Hebrard, J P; Loisel, R (CRYPTOGAMIE BRYOLOGIE LICHENOLOGIE, 1994)
Processing (FAC) of 25 bryophytoecological releves and quantitative analysis of bryofloristical inventories from 4 forest structures (surface values respectively 3976, 6160, 13115 and 77617 m2) isolated within the vineyard near Pierrefeu-du-Var (siliceous substratum) show that, for what concerns sclerophyllous oaks ecosystems (Quercus ilex, more rarely Quercus suber), the more humid the local microclimate is, the greatest are richness and diversity of terricolous communities of bryophytes. The optimal conditions for preservation of richness in forest bryophytes are here realized at the Defens du Becasson (surface: 77617 m2, maximum width: 151 m), a north-facing side which is well protected against the drying action of dominant winds and where the architecture of the ligneous formations is heterogeneous. On the other hand, the diversity of available microhabitants in the 2 largest isolates (strong slope, presence of clearings and disturbed skirts) contributes to increase their global richness in bryophytes. Furthermore, the presence of a dense layer of shrubs limits the accumulation of dead leaves on soil surface, allowing a good spread of the bryophyte layer and correlatively an enrichment in forest taxa when ambient humidity is high enough.
APS
Keywords: bryophytes; Microhabitats; Quercus ilex; Quercus suber

Seasonal water potential changes and proline accumulation in Mediterranean shrubland species - Lansac, A R; ZABALLOS, J P; Martin, A (Plant Ecology, 1994)
We studied the water relations of 6 shrub and 3 tree species typical of the mediterranean climate region of central Spain to identify differential responses to water stress between and within species, and to determine if free proline concentration in leaves could be used as a water stress indicator. Predawn and midday water potentials (ffdw) on a seasonal basis, relative water content (RWC), leaf mass per area, foliar nitrogen and free proline concentrations were measured. The lowest water potentials were observed at the end of the summer, with recovery to higher water potentials in the fall and winter seasons. Species differed regarding the annual qdw fluctuation. Thymus zygis, Halimium viscosum, Genista hirsuta and Juniperus oxycedrus exhibited the most negative midday and predawn ~ w (both less than -6 MPa) with a large magnitude of response to changing conditions in soil moisture of the upper horizon of the soil. Lavandula pedunculata and Cistus ladanifer showed a moderate response. Quercus rotundifolia, Quercus faginea and Retama sphaerocarpa showed a modest response. The ~ w of different size individuals of Quercus rotundifolia and Cistus ladanifer were compared. The annual fflw fluctuation was greater in small individuals as compared to large individuals. In every species, there was an increase in proline concentration of bulk leaf tissues when predawn kVw dropped below -5 MPa. Small plants of Cistus ladanifer reached lower water potentials and also higher concentration of proline than bigger plants. Proline could possibly be used as a drought stress indicator in every species except Q. rotundifolia. It is suggested that in addition to water stress avoidance due to deep root systems, some mechanisms of water stress tolerance may operate among shrub and tree species of central Spain.
Keywords: Cistus ladanifer; Genista hirsuta; Halimium viscosum; Juniperus oxycedrus; Lavandula pedunculata; Leaf mass per area; nitrogen; Proline; Quercus faginea; Quercus rotundifolia; Relative water content; retama sphaerocarpa; Thymus zygis; water potential

A simple radiometric correction model to improve automatic mapping of vegetation from multispectral satellite data - Pons, Xavier; Solé-Sugrañes, Lluís (Remote Sensing of Environment, 1994)
A simplified model for radiometric corrections has been used to improve nonsupervised classification of vegetation cover in a hilly area near Barcelona, Spain. A digital elevation model and standard parameters for exoatmospheric solar irradiance, atmospheric optical depth, and sensor calibration are the only inputs required. Radiometric classes obtained by cluster classification of Landsat TM images from nonradiometrically corrected images include several classes related to terrain illumination, but not to vegetation or thematic cover differences. The use of radiometric correction allows identifying all radiometric classes obtained as vegetation or thematic classes with 83.3% global accuracy. Classes obtained include Pinus halepensis, Quercus ilex, and Quercus cerrioides forests, shrublands, grasslands, urban areas with vegetation, urban areas without vegetation, and denuded areas. Radiometric correction helps in estimating surfaces and spectral features of these classes. The results are discussed considering botanical composition, date (phenology), and vegetation dynamics.

Site-specific water relations and stomatal response of Quercus ilex in a Mediterranean watershed - Sala, Anna; Tenhunen, John D (Tree Physiology, 1994)
Intraspecific variations in the water relations and stomatal response of Quercus ilex L. were analyzed under field conditions by comparing trees at two locations within a Mediterranean watershed (l'Avic, Catalonia, NE Spain). Distinct environmental gradients exist between the two sites (referred to as ridge top at 975 m and valley bottom at 700 m) with greater soil depth for water storage, reduced radiation, reduced wind and higher water vapor pressure deficits at the valley bottom than at the ridge top. Osmotic adjustment and changes in tissue elasticiity did not significantly increase drought resistance in the trees studied. The leaf-to-air vapor pressure difference (Δw) threshold for inducing stomatal closure was higher at the ridge top (15.6 kPa MPa−1 ± 0.5 SE) than at the valley bottom (9.8 kPa MPa−1 ± 1.0 SE). However, increases in Δw beyond the threshold were followed by greater reductions in leaf conductance of trees at the ridge top than at the valley bottom. At both sites, maximum leaf conductance was related to predawn shoot water potential which, in turn, was related to watershed stream flow. The effects of water deficits during the dry summer of 1989 were more severe in trees at the valley bottom than at the ridge top. During periods of high evaporative demand, site-specific differences in the control of water loss led to more conservative water use by trees at the ridge top and, thus, to even greater drought avoidance (higher predawn water potentials) in late summer.
10.1093/treephys/14.6.601
Keywords: Mediterranean sclerophylls; oak forest; oak watershed; Osmotic potential; Stomatal conductance; water potential

TREE CANOPY EFFECTS ON COMMUNITY STRUCTURE IN SLOPES OF MEDITERRANEAN RANGELANDS - Puerto, A; Rico, M (EKOLOGIA-BRATISLAVA, 1994)
In the dehesa systems there are considerable differences in community structure between grassland situated under trees and in the open spaces between them. This difference is superimposed by another one based on a trophic gradient in the form of sectors which develop along slopes. We studied these differences and our results show that: 1. Community diversity decreased and spatial heterogeneity increased from the higher to the lower sectors of the slope gradient. 2. These trends were significantly smaller under trees. 3. In the open spaces there was a contrast in community structure; fine grain in high sectors and coarse grain in the lower ones. 4. Community heterogeneity in pares of consecutive sectors of the slope gradient was lower under trees than in the open spaces. That means that trees act as a homogenizing factor on slopes, maintaining a basic herbaceous structure which tends to be similar in various sectors. Steady conditions are thus created, which influence both the same sector of different slopes as well as various sectors of each of the slopes. The alternation of one relatively uniform structure (under trees) with another much more variable one (open spaces) is considered as essential for the functioning of the system; just as it has developed following the traditional land-use practices in the area.

UV-B protective potential and flavonoid content of leaf hairs of Quercus ilex - Skaltsa, Helen; Verykokidou, Evmorphia; Harvala, Catherine; Karabourniotis, George; Manetasi, Yiannis (Phytochemistry, 1994)
Flavonoids of non-glandular leaf hairs from Quercus ilex were analysed. The main compounds were acylated kaempferol glycosides. Acylation shifted the absorption peak into the ultraviolet-B region of the spectrum in which intact trichome layers absorbed strongly. Ultraviolet-B radiation caused a considerable reduction of photosystem II photochemical efficiency only in dehaired leaves. It is suggested that leaf hairs, besides other roles, may function as an effective filter against the harmful ultraviolet-B radiation.
Keywords: Fagaceae; flavonoids; Holly Oak; leaf hairs; Quercus ilex; UV-B damage

Vegetation changes and human action from the Neolithic to the Bronze Age (7000–4000 BP) in Alicante, Spain, based on charcoal analysis - Badal, Ernestina; Bernabeu, Joan; VERNET, J. L. (Vegetation History and Archaeobotany, 1994)
Charcoal analysis reveals various palaeo-eco- logical phases from the Neolithic to the Bronze Age. Ag- riculture starts about 7000 B.P. in favourable ecological conditions. Most of the charcoal spectra from sites iin the coast represent thermomediterranean holm-oak forest; those from the inland mountains represent mesome- diterranean holm-oak forest. The Neolithic I Impressed Ware people were the first to clear the forest to plant their crops. This clearance of primary woodland resulted in the development of secondary vegetation of pine woods or scrub. The scrub reached its maximum during the Bell Beaker phase and Bronze Age in the Cova de les Cendres. In the Neolithic II open air sites, the percent- ages of Quercus ilex/coccifera remain high. This may be the result of a different exploitation of the land, or suit- able conditions for the growth and survival of the vegeta- tion.
Keywords: bronze; CHARCOAL ANALYSIS; human impact; Neolithic; Spain

Vegetation history and human activity during the last 6000 years on the central Catalan coast (northeastern Iberian Peninsula) - Riera-Mora, S; Esteban-Amat, A (Vegetation History and Archaeobotany, 1994)
In this paper, we present the results of four pollen diagrams obtained from the northeastern coast of the Iberian Peninsula. These data, together with a set of 11 radiocarbon dates, allow us to make some suggestions about human activity in this area mainly during the last 6000 years. We have established four main stages of this activity. Phase I (7000-3000 B.P.) shows some sporadic human clearance without qualitative and/or quantitative changes inside the natural woodland, except for slight oscillations in AP values. These clearances are synchro- nous with Neolithic and Bronze Age settlements. Phase II (3000-1500/1300 B.P.) demonstrates a different hu- man action on the landscape along the Catalan coast. Sampling sites located in rich agricultural plains and close to urban centres show continuous woodland clear- ance during the Iberian period and especially during Ro- man times. In contrast, at boring sites far from these towns, the irregular and sporadic woodland disturbances continue, although these become more common. Phase III (1500/1300-850 B.P.) shows further woodland clear- ance fires along the coast. Pollen, archaeological and historical evidence allow us to relate this to the introduc- tion of grazing in the coastal area, connected with sea- sonal transhumance between the littoral and mountain regions. Phase IV (850-300/150 B.P.) is characterised by the final clearance of woodland and the development of olive farming. During this phase the agrarian Mediterra- nean landscape was definitively formed.
Keywords: Fires; Human disturbances; northeast Iberian Peninsula; olive; Seasonal transhumance

Water relations, gas exchange, and growth of resprouts and mature plant shoots of Arbutus unedo L. and Quercus ilex L. - Castell, Carles; Terradas, Jaume; Tenhunen, J D (Oecologia, 1994)
Resprout and mature plant shoot growth, leaf water status and gas exchange behavior, tissue nutrient content, flowering, and production were studied for co- occurring shallow-rooted (Arbutus unedo L.) and deep- rooted (Quercus ilex L.) Mediterranean tree species at the Collserola Natural Park in Northeast Spain. Resprouts showed higher growth rates than mature plant shoots. During fall, no differences in eco-physiological perfor- mance of leaves were found, but mobilization of carbo- hydrates from burls strongly stimulated growth of fall re- sprouts compared to spring resprouts, despite low expo- sed leaf area of the fall shoots. During summer drought, resprouts exhibited improved water status and carbon fixation compared to mature plant shoots. Shoot growth of Q. iIex was apparently extended due to deep rooting so that initial slower growth during spring and early summer as compared to A. unedo was compensated. Tis- sue nutrient contents varied only slightly and are postula- ted to be of minor importance in controlling rate of shoot growth, perhaps due to the relatively fertile soil of the site. Fall flowering appeared to inhibit fall shoot growth in A. unedo, but did not occur in Q. ilex. The results de- monstrate that comparative examinations utilizing vege- tation elements with differing morphological and physio- logical adaptations can be used to analyze relatively complex phenomena related to resprouting behavior. The studies provide an important multi-dimensional back- ground framework for further studies of resprouting in the European Mediterranean region.
Keywords: Growth; photosynthesis; Resprouts; Sclerophyll shrubs and trees; water relations

ALGUNAS FORMACIONES BOSCOSAS DEL SUDESTE DE LA PENINSULA IBERICA: LOS ALCORNOCALES DEL HAZA DEL LINO (LA CONTRA VIESA) y DE LA SIERRA DEL JARAL (LUJAR) - Valle, F; Madrona, M T; Salazar, C (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
Two corks oak groves, placed in the south-east of the Iberian Peninsule (province of Granada: Sierra del Jaral and Sierra de la eontraviesa) are analysed. Ecologic and floristic characterics are cornmented on,' and their correct phytosociologic nomlnation is discussed. Finally, vegetation's restoration models are proposed to be applied in degradated areas.
Keywords: eork oak grove; Oriental Andalusia; phytosociology; Restoration

Antioxidant activity of mediterranean plant leaves: Occurrence and antioxidative importance of A-tocopherol - Chevolleau, S; Mallet, J F; Debal, A; Ucciani, E (Journal of the American Oil …, 1993)
a-Tocopherol was identified as the main antioxidant in hexane extracts of leaves of sixteen Mediterranean plant species. The a-tocopherol content was determined by a two-step procedure involving column and gas chromatog- raphy with a-tocopherol acetate as internal standard. The tocopherol content of the extracts was in the range of 0.0-4.7%, and that of the dry leaves was 0-846 ppm. The highest a-tocopherol content was found in the leaves of a Mediterranean oak, Quercus ilex. The antioxidative ac- tivity, which was previously investigated, was correlated with the a-tocopherol content. Correlation coefficients were 0.947 and 0.904 for extracts and leaves, respectively.
Keywords: antioxidant activity; hexane extracts; Mediterranean plant leaves; o-tocopherol

Antioxidant activity of mediterranean plant leaves: Occurrence and antioxidative importance of A-tocopherol - Chevolleau, S.; Mallet, J. F.; Debal, A.; Ucciani, E. (Journal of the American Oil …, 1993)
a-Tocopherol was identified as the main antioxidant in hexane extracts of leaves of sixteen Mediterranean plant species. The a-tocopherol content was determined by a two-step procedure involving column and gas chromatog- raphy with a-tocopherol acetate as internal standard. The tocopherol content of the extracts was in the range of 0.0-4.7%, and that of the dry leaves was 0-846 ppm. The highest a-tocopherol content was found in the leaves of a Mediterranean oak, Quercus ilex. The antioxidative ac- tivity, which was previously investigated, was correlated with the a-tocopherol content. Correlation coefficients were 0.947 and 0.904 for extracts and leaves, respectively.
Keywords: antioxidant activity; hexane extracts; Mediterranean plant leaves; o-tocopherol

APLICACION DEL ANALISIS DIGITAL DE IMAGENES AL ESTUDIO DE LA CALIDAD DEL CORCHO - Molinas, M; Campos, M (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
Digital Image Processing and Analysis (lA) es a computerized technique that permits to measure defined regions of interest of an image. For Al, digital images of the specimens are examined with appropiate software programs. In the present study an lA program for the quuantitative anatomy of cork has been developed. For this purpose IMAGE 1.41 VDM software for Macinstosh and Statview statistic software have been selected. Specimens from different cork populatins have been compared. The following cork parmeters: thickness, cork-rings and prososity have been measured in transverse and tangential sections. The results are analysed comparatively on each population and between populations.
Keywords: Cork quality; image analysis; morphometry; Quantitative anatomy; Quercus suber L.

ASPECTOS ECOFISIOLOGICOS RELACIONADOS CON LA PRODUCCION DE LOS ENCINARES MEDITERRANEOS - Gracia, C A; Sala, A; Sabate, S (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
The productivity of Quercus ilex forests is low in relation to other tree species. Waterand nutrients are often the most important limiting factors. Nevertheless the ecophysiological traits of this specie could help to explain the observed patterns of productivity. Leaf area index of european evergreen-oak forests is rather constant with values about 5. The energetic cost of formation and maintenance of the leaves of Quercus ilex accounts for more than 50 per cent of total carbon fixed by the trees. The resproutig ability of evergreen oaks could explain the high density and low mean diameter of these populations. The high proportion of living tissues in this type of structuni increases the respiration costs of the stems and branches. As a consequence, an important fraction of carhon fixed by leaves is used to maintain the structure of the community which contribute to explain the low observed net primary production of Quercus ilex forests
Keywords: ecophysiology; L.A.I.; productivity; Quercus ilex

The behavior of oaks in response to natural and induced exposure to the surfactant ABS - Moricca, S; Paoletti, E; Comparini, C (Ann. For. Sci., 1993)
Quercus pubescens, Q frainetto, Q ilex and Q robur were sprayed with ABS (sodium dodecyl benzenesulfonate, a surfactant often found in marine aerosols) over 2 growing seasons to test the effect of the surfactant on the leaf wax structure. Though all species were affected, they differed in their tolerance to ABS. The effect of ABS was also tested on the pollen quality of Q ilex. Pollen from declining and apparently healthy individuals was germinated in cultures with different concentrations of ABS. A negative effect on pollen germination and pollen tube length was noted. The reduction in pollen viability could affect the genetic resources of holm oak populations in the future.
Keywords: ABS; oak spp; pollen; wax structure

Biochemical diversity and systematics of Mediterranean evergreen oak from South East France - Rafii, Zara A; Dodd, Richard S; Pelleau, Yvonne (Biochemical Systematics and Ecology, 1993)
Fatty acids, steroids and inorganic and organic constituents of acorns of French Mediterranean evergreen oak (70 trees from five ecogeographically contrasting locations) were analyzed, and compared with Italian and Spanish oak. French populations were heterogeneous and, for most characters, were intermediate between Spanish and Italian oak, suggesting this to be a zone of hybridization and introgression between Quercus ilex L. and Q. rotundifolia Lamk. The population from Les Maures showed a closer affinity morphologically and chemically to Italian oak suggesting the presence of Q. ilex at this locality.
Keywords: acorns; chemosystematics; fatty acids; organic inorganic constituents; Quercus ilex L.; Quercus rotundifolia Lamk. Fagaceae; steroids

CARACTERIZACION ESTRUCTURAL DE LOS ENCINARES DE CATALUÑA Marc - Gracia, Marc; Retana, Javier; Espelta, Josep Maria; Gené, Caries (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
In this paper, a characterization of structure of holm-oak forests in the Northeastem Iberian Peninsula is proposed. The study is based on different features of these forests, both at the stand and at the individuallevel.
Keywords: Basal area; density of stems; Forest structure; holm-oak; Quercus ilex; size distri bu ti on

CHARCOAL ANALYSIS and the VEGETATIONAL EVOLUTION of NORTH-WEST PORTUGAL - FIGUEIRAL, I (Oxford Journal of Archaeology, 1993)
Summary: The palaeoenvironment of north-west Portugal is investigated from the late Bronze Age to Roman times. This research is based on the analysis of charcoal from seven archaeological sites. the results contain important information for a better understanding of the vegetational environment of man during this period. Man-environment relations are also examined.
APS
Keywords: charcoal; paleoecology; Portugal; vegetational environment

CHARCOAL ANALYSIS and the VEGETATIONAL EVOLUTION of NORTH-WEST PORTUGAL - FIGUEIRAL, I. (Oxford Journal of Archaeology, 1993)
Summary: The palaeoenvironment of north-west Portugal is investigated from the late Bronze Age to Roman times. This research is based on the analysis of charcoal from seven archaeological sites. the results contain important information for a better understanding of the vegetational environment of man during this period. Man-environment relations are also examined.
APSAPSThe following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: charcoal; paleoecology; Portugal; vegetational environment

CRECIMIENTO DE LAS POBLACIONES DE INSECTOS DEL GRUPO <;ERAMBYX CERDO EN LA DEHESA ARBOLADA EXTREMEÑA - del Moral de la Vega, J; Casado Ponce, D; Gallego Girón, M (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
This comunication gives the results of a study cat.:fied out on the damages caused by the Cerambyx cerdo beetles on the cork oaks Quercus suber, Quercus rotundifolia, in the oak forest of Estremadura (Southwest Spain), mainly in the Badajoz province. These species were taxonomicaly identified and their population examined in relation to different variable agrosystems. K.W.:
Keywords: Cerambyx cerdo; Estremadura; Quercus; Spain

CRECIMIENTO DE LAS POBLACIONES DE INSECTOS DEL GRUPO <;ERAMBYX CERDO EN LA DEHESA ARBOLADA EXTREMEÑA - del Moral de la Vega, J.; Casado Ponce, D.; Gallego Girón, M. (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
This comunication gives the results of a study cat.:fied out on the damages caused by the Cerambyx cerdo beetles on the cork oaks Quercus suber, Quercus rotundifolia, in the oak forest of Estremadura (Southwest Spain), mainly in the Badajoz province. These species were taxonomicaly identified and their population examined in relation to different variable agrosystems. K.W.:
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: Cerambyx cerdo; Estremadura; Quercus; Spain

CROWN STRUCTURE MODIFICATIONS IN RELATION TO AIR-POLLUTION - Bussotti, F.; BROGI, L.; Grossoni, P.; COZZI, A.; GELLINI, R. (LANDSCAPE AND URBAN PLANNING, 1993)
Analysis of crown structure and crown modifications plays a role of primary importance in surveys of `new types of forest damage', since it is a decisive parameter in assessing the health status of a tree. Several forms of ramification alterations have been described in central and northern European species (Norway spruce, beech, Durmast oak, English oak, birch). This study examines the situation in Tuscany and offers a description of the alterations found in the main species typical of the Mediterranean region (Turkey oak, pubescent oak, holm oak, stone pine). The article discusses the potential impact of these alterations on the most typical forest formations, the ones which characterize the Tuscan landscape, and it describes the modifications already under way.
The following values have no corresponding Zotero field: pub-location: PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS publisher: ELSEVIER SCIENCE BV
Keywords: crown structure; forest formations; Mediterranean

CROWN STRUCTURE MODIFICATIONS IN RELATION TO AIR-POLLUTION - Bussotti, F; BROGI, L; Grossoni, P; Cozzi, A; GELLINI, R (LANDSCAPE AND URBAN PLANNING, 1993)
Analysis of crown structure and crown modifications plays a role of primary importance in surveys of `new types of forest damage', since it is a decisive parameter in assessing the health status of a tree. Several forms of ramification alterations have been described in central and northern European species (Norway spruce, beech, Durmast oak, English oak, birch). This study examines the situation in Tuscany and offers a description of the alterations found in the main species typical of the Mediterranean region (Turkey oak, pubescent oak, holm oak, stone pine). The article discusses the potential impact of these alterations on the most typical forest formations, the ones which characterize the Tuscan landscape, and it describes the modifications already under way.
Keywords: crown structure; forest formations; Mediterranean

Different vulnerabilities of Quercus ilex L. to freeze- and summer drought-induced xylem embolism: an ecological interpretation - Lo Gullo, M. A.; Salleo, S. (Plant, Cell & Environment, 1993)
Quercus ilex L. growing in the southern Mediterranean Basin region is exposed to xylem embolism induced by both winter freezing and summer drought. The distribution of the species in Sicily could be explained in terms of the different vulnerability to embolism of its xylem conduits. Naturally occurring climatic conditions were simulated by: (1) maintaining plants for 3h at ambient temperatures of 0, -1.5, -2.5, -5.0 and -11°C; and (2) allowing plants to dry out to ratios of their minimum diurnal leaf water potentials (Ψ1) to that at the turgor loss point (Ψtlp) of 0.6, 0.9, 1.05, 1.20 and 1.33. The loss of hydraulic conductivity of one-year-old twigs reached 40% at -1.5°C and at Ψ1/ΨtlP= 1.05. Recovery from these strains was almost complete 24 h after the release of thermal stress or after one irrigation, respectively. More severe stresses reduced recovery consistently. The percentages of xylem conduits embolized following application of the two stresses, were positively related to xylem conduit diameter. The capability of the xylem conduits to recover from stress was positively related to the conduit diameter in plants subjected to summer drought, but not in the plants subjected to winter freezing stress. The ecological significance of the different vulnerabilities to embolism of xylem conduits under naturally occurring climatic conditions is discussed.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: conduit diameter; Fagaceae; holm-oak; hydraulic conductivity; Quercus ilex L.; summer drought; winter freezing; xylem embolism

Different vulnerabilities of Quercus ilex L. to freeze- and summer drought-induced xylem embolism: an ecological interpretation - LO GULLO, M A; Salleo, S (Plant, Cell & Environment, 1993)
Quercus ilex L. growing in the southern Mediterranean Basin region is exposed to xylem embolism induced by both winter freezing and summer drought. The distribution of the species in Sicily could be explained in terms of the different vulnerability to embolism of its xylem conduits. Naturally occurring climatic conditions were simulated by: (1) maintaining plants for 3h at ambient temperatures of 0, -1.5, -2.5, -5.0 and -11°C; and (2) allowing plants to dry out to ratios of their minimum diurnal leaf water potentials (Ψ1) to that at the turgor loss point (Ψtlp) of 0.6, 0.9, 1.05, 1.20 and 1.33. The loss of hydraulic conductivity of one-year-old twigs reached 40% at -1.5°C and at Ψ1/ΨtlP= 1.05. Recovery from these strains was almost complete 24 h after the release of thermal stress or after one irrigation, respectively. More severe stresses reduced recovery consistently. The percentages of xylem conduits embolized following application of the two stresses, were positively related to xylem conduit diameter. The capability of the xylem conduits to recover from stress was positively related to the conduit diameter in plants subjected to summer drought, but not in the plants subjected to winter freezing stress. The ecological significance of the different vulnerabilities to embolism of xylem conduits under naturally occurring climatic conditions is discussed.
Keywords: conduit diameter; Fagaceae; holm-oak; hydraulic conductivity; Quercus ilex L.; summer drought; winter freezing; xylem embolism

ECOLOGIA DE LOS BOSQUES DE QUERCUS DEL PARQUE NATURAL DE LOS ALCORNOCALES (CADIZ) - Jurado Doña, V; Ojeda Rivera, J F (Congreso Forestal Español, 14 e 18 Junho de 1993, Lourizán, 1993)
The floral importance of the most southern mountains of Europe is determined by several orographic, climatic and edaphic factors. This article deals with the ecologic and phitogeographic study of the forests of Quercus of this area that still have a remarkable degree of conservation and that reflects an ancient forest exploitation according to the data of the historie files.
Keywords: Cádiz; conservation; ecology; Quercus

Ecological aspects of the floral phenology of the cork-oak (Q suber L): why do annual and biennial biotypes appear? - Elena-Rossello, J. A.; de Rio, J. M.; Valdecantos Garcia, J. L.; Santamaria, I. G. (Ann. For. Sci., 1993)
Phenological observations (periods of flowering and pollination, floral structures, etc) were made over a 3-year period in natural populations of Q suber. We demonstrated the existence of 2 different types of seed cycles in the cork-oak. The 'annual biotype', requires only 1 season to complete its reproductive cycle (ie, similar to that of the Lepidobalanus group), whereas the 'biennial biotype' requires 2 full years (similar to Erythrobalanus). The variability observed in the cork-oak, during the reproductive cycle, and the meaning of the existence of 2 different reproductive strategies in the same species, are discussed
Keywords: annual and biennial biotypes; cork-oak; ecological variability; floral phenology; Quercus; reproductive strategies

Ecological aspects of the floral phenology of the cork-oak (Q suber L): why do annual and biennial biotypes appear? - Elena-Rossello, J A; de Rio, J M; Valdecantos Garcia, J L; Santamaria, I G (Ann. For. Sci., 1993)
Phenological observations (periods of flowering and pollination, floral structures, etc) were made over a 3-year period in natural populations of Q suber. We demonstrated the existence of 2 different types of seed cycles in the cork-oak. The 'annual biotype', requires only 1 season to complete its reproductive cycle (ie, similar to that of the Lepidobalanus group), whereas the 'biennial biotype' requires 2 full years (similar to Erythrobalanus). The variability observed in the cork-oak, during the reproductive cycle, and the meaning of the existence of 2 different reproductive strategies in the same species, are discussed
Keywords: annual and biennial biotypes; cork-oak; ecological variability; floral phenology; Quercus; reproductive strategies

Effect of in vitro cold storage on surviving and proliferation of cork-oak (Quercus suber L.) cultures - Romano, A; Noronha, C; Martins-Loução, M a (Congreso Forestal Español, 14 e 18 Junho de 1993, Lourizán, 1993)
Cork-oak cultures were stored in vitro without na intervening subculture, at 5º C in the dark for 5 months without loosing their capacity to regenerate when subcultured under standard conditions. The viability, proliferation rate and elongation of the explants were evaluated during 5 months of storage. Proliferation rate of stored cultures was observed during 5 months of storage. Proliferation rate of stored cultures was observed during the following 3 profileration cycles and compared to unstored controls of the same age. Shoot cultures survived with 100% viability and the proliferation rate was not statistically different from the controls. The results here described indicate the feasibility of establishing na in vitro active gene bank for Quercus suber.
Keywords: Cold storage; cork-oak; Germplasm; Medium-term storage; micropropagation; Quercus suber L.

EFFECTS OF FOOD ABUNDANCE AND HABITAT STRUCTURE ON SEED-EATING RODENTS IN SPAIN WINTERING IN MAN-MADE HABITATS - Diaz, M; González, E; MUNOZPULIDO, R; NAVESO, M A (ZEITSCHRIFT FUR SAUGETIERKUNDE-INTERNATIONAL JOURNAL OF MAMMALIAN BIOLOGY, 1993)
The patterns of abundance and seed (acorn) predation races were analyzed in granivorous rodents (mainly the wood mouse Apodemus sylvaticus L.) wintering in two man-made habitats: cereal croplands, and a kind of wood-pasture exclusive to the western Mediterranean basin, the dehesas. Both seed (acorn) abundance ana vegetation structure were also measured. Within dehesas, neither rodent abundance nor acorn predation rates were related to acorn abundance, whereas there Tvas a significant. association between rodent abundance and shrub cover at the end of winter. These results were coincident with previous findings in croplands. Both rodent abundances and seed predation rates were lower in dehesas than in croplands, despite the better structural and trophic conditions of the first habitat for rodents (larger shrub cover and food abundance). However, the body condition of animals was better in dehesas, to the extent that we found strong evidence for mincer reproduction. Rodent predator communities appear to be more diverse and denser in dehesas than in croplands. This suggests a heavier predation pressure in dehesas which would have culled rodent populations in such a way chat food Tvas plentiful for survivors, rhus explaining their scarcity, good body condition, and low dependence on food resources.
APS
Keywords: abundance patterns; acorn predation; Mediterranean; montado; rodents

EFFECTS OF FOOD ABUNDANCE AND HABITAT STRUCTURE ON SEED-EATING RODENTS IN SPAIN WINTERING IN MAN-MADE HABITATS - Díaz, M.; González, E.; MUNOZPULIDO, R.; NAVESO, M. A. (ZEITSCHRIFT FUR SAUGETIERKUNDE-INTERNATIONAL JOURNAL OF MAMMALIAN BIOLOGY, 1993)
The patterns of abundance and seed (acorn) predation races were analyzed in granivorous rodents (mainly the wood mouse Apodemus sylvaticus L.) wintering in two man-made habitats: cereal croplands, and a kind of wood-pasture exclusive to the western Mediterranean basin, the dehesas. Both seed (acorn) abundance ana vegetation structure were also measured. Within dehesas, neither rodent abundance nor acorn predation rates were related to acorn abundance, whereas there Tvas a significant. association between rodent abundance and shrub cover at the end of winter. These results were coincident with previous findings in croplands. Both rodent abundances and seed predation rates were lower in dehesas than in croplands, despite the better structural and trophic conditions of the first habitat for rodents (larger shrub cover and food abundance). However, the body condition of animals was better in dehesas, to the extent that we found strong evidence for mincer reproduction. Rodent predator communities appear to be more diverse and denser in dehesas than in croplands. This suggests a heavier predation pressure in dehesas which would have culled rodent populations in such a way chat food Tvas plentiful for survivors, rhus explaining their scarcity, good body condition, and low dependence on food resources.
APSAPSThe following values have no corresponding Zotero field: pub-location: VILLENGANG 2, D-07745 JENA, GERMANY publisher: GUSTAV FISCHER VERLAG
Keywords: abundance patterns; acorn predation; Mediterranean; montado; rodents

EFFECTS OF TANNIN COMPOUNDS ON 2 SPECIES OF COLLEMBOLA - POINSOTBALAGUER, N; RACON, L; SADAKA, N; LEPETIT, J (EUROPEAN JOURNAL OF SOIL BIOLOGY, 1993)
The effects of condensed and hydrolysable tannin extracted from evergreen oak leaves (Quercus ilex L.) were tested on two species of Collembola. Concentrations lower than those present in the litter leaves were toxic to these insects. Detoxification by washing with rainwater and biodegradation of tannic compounds are necessary for litter decomposition, in which microarthropods participated, to occur.
Citation
Keywords: Collembola; evergreen oak; Tannins

EFFECTS OF TANNIN COMPOUNDS ON 2 SPECIES OF COLLEMBOLA - POINSOTBALAGUER, N.; RACON, L.; SADAKA, N.; LEPETIT, J. (EUROPEAN JOURNAL OF SOIL BIOLOGY, 1993)
The effects of condensed and hydrolysable tannin extracted fromevergreen oak leaves (Quercus ilex L.) were tested on two species of Collembola. Concentrations lower than those present in the litter leaves were toxic to these insects. Detoxification by washing with rainwater and biodegradation of tannic compounds are necessary for litter decomposition, in which microarthropods participated, to occur.
CitationCitationThe following values have no corresponding Zotero field: pub-location: S P E S-JOURNAL DEPT, 120 BD ST GERMAIN, F-75006 PARIS, FRANCE publisher: GAUTHIER-VILLARS
Keywords: TANNINS; EVERGREEN OAK; COLLEMBOLA

EL ALCORNOCAL EN ANDALUCIA. COMPORTAMIENTO ECOLOGICO, FITOCENOLOGIA, FENOMORFOLOGIA, REGENERACION POSTFUEGO, USOS Y CONSERVACION - Pérez Latorre, A V; Nieto Caldera, J M; Cabezudo Artero, B (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
We llave carried out a study about Quercus suber forests in Andalusia (Spain). This study was made under the following points of view: ecological behaviour, flora, fitosociology, successional dynamism, vegetal s'cenery, eco-morphology, pheno-morphology, post-fire regeneration, conservation, ethnobotany and biogeography. We have obtained interesting data and conclusions about them. They have been quite summed up in this papero
Keywords: Andalusia; Cork oak forests; Quercus suber; Spain

EL ARCHIVO DE MUESTRAS DE CORCHO Y SU USO PARA LA OBSERVACION DE LA INFLUENCIA DE DETERMINADOS FACTORES SOBRE LA CALIDAD - Gamero Guerrero, F (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
Annually, between April and July, is carry out the estimation in field of Cork Quality Works. That consist in several random sampling in those plots which turn cutting is over in the current year. In IPROCOR, since prepared and stored the samples obtained, are b~ing carried out, to define possible relations between several silvicultural and industrial operations and environmental factors, and cork quality, a set of measures and observations
Keywords: Cork; Cork quality

Ensayo de enraizamiento de estaquillas del alcornoque (Quercus suber L.) - Ribeiro, M M A (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
An experiment was made in order to study the tooting process in cuttings of young cork oaks. Different treatments with indol butiric acid (IBA) in different concentrations, two different origins of the cutting (basal and apical) and two different base of the cutting treatements (with or without bark removal) were performed. The best performances were achieved with 0.5% and 1 % of IBA (not significatively different) with 54 and 52 % of rooting, respectivly, after 3 months. The first treatment not only produces more roots by cutting but longer ones as well. Bark removal has the same effect but it does not improve rooting. The origin of the cutting had no influence in the studied parameters.
Keywords: Cork oak; Cuttings; Quercus suber L.; rooting; vegetative propagation

Estimating tree density in oak savanna-like lsquo;dehesa’ of southern Spain from SPOT data - Joffre, R; Lacaze, B (International Journal of Remote Sensing, 1993)
Abstract The main objective of this study was to establish a method of estimating tree density in savanna-like vegetation systems using the highest spatial resolution available from satellite data (SPOT-1 panchromatic = 10 m resolution) based on the assumption that for sparse trees on a contrasting herbaceous background, spatial filters may provide a direct mapping of tree cover. The study was performed in the ?dehesas? oak-woodland of southern Spain. This particular landscape is characterized by the presence of scattered evergreen oak trees (Quercus ilex and Q. suber) whose density ranges from 0 to 80 even-aged mature trees per hectare which gives the appearance of a savanna-like vegetation. Tree density can be accurately estimated by SPOT-1 panchromatic data after numerical filtering. This method allows the mapping of tree density of the dehesas, a key parameter reflecting the functional vegetation-soil-climate equilibrium which exists for both woody and herbaceous strata.
doi: 10.1080/01431169308904368
Keywords: Dehesa; oak; savanna-like; SOPT data; southern Spain; tree density

Estimating tree density in oak savanna-like lsquo;dehesa’ of southern Spain from SPOT data - JOFFRE, R.; LACAZE, B. (International Journal of Remote Sensing, 1993)
Abstract The main objective of this study was to establish a method of estimating tree density in savanna-like vegetation systems using the highest spatial resolution available from satellite data (SPOT-1 panchromatic = 10 m resolution) based on the assumption that for sparse trees on a contrasting herbaceous background, spatial filters may provide a direct mapping of tree cover. The study was performed in the ?dehesas? oak-woodland of southern Spain. This particular landscape is characterized by the presence of scattered evergreen oak trees (Quercus ilex and Q. suber) whose density ranges from 0 to 80 even-aged mature trees per hectare which gives the appearance of a savanna-like vegetation. Tree density can be accurately estimated by SPOT-1 panchromatic data after numerical filtering. This method allows the mapping of tree density of the dehesas, a key parameter reflecting the functional vegetation-soil-climate equilibrium which exists for both woody and herbaceous strata.
doi: 10.1080/01431169308904368doi: 10.1080/01431169308904368The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: Dehesa; oak; savanna-like; SOPT data; southern Spain; tree density

ESTUDIO DE LA REGENERACION DE LOS SABINARES DE SABINA ALBAR (JUNIPERUS THURIFERA L.) EN LA PROVINCIA DE ALBACETE - Orozco Bayo, E; López Serrano, F R; de las Heras Ibáñez, J (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
61 plots selected using photographs were studies in one Juniperus thurifera forest located in the W of the Albacete Province (SE Spain). In each plot, the regeneration of this species was measured considering a key of three patems of regeneration. Also, sorne ecological factors linked to this process were also measured. A very high regeneration was pro ved in those plots that represented forests of J. thurifera and Quercus rotundifolia highly mixed. In those plots with only individual s of J. thurifera there was a minor regeneration of this species. A better protection against livestock, edaphic moisture, and luminosity conditions can be adduced as sorne causes of this difference in the regeneration.
Keywords: evergreen oak; Plots; Protection against liverwort; Regeneration

ESTUDIO EXPERIMENTAL DE LAS CARACTERISTICAS FISICO-MECANICAS DE LOS TAPONES DE CORCHO NATURAL - Hernández Fernández, Antonio (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
The present experimental study tries to evaluate the best way to cuantify cap natural cork quality by standardized experiments measuring different physical and chemical parameters. Within the cork sector, the cap industry is the broadest extended and the most representative, since it represents the most significant manufacture. Its economic value is a 70-80% of the final sale price. This study is referred to the cilindric cap, made from natural cork, boiled in water at 100°C, at atmospheric pressure.
Keywords: CAP; Cork; Physical and Chemical parameters; Standardization

THE EUROPEAN PINE MARTEN MARTES-MARTES IN THE BALEARIC-ISLANDS, SPAIN - CLEVENGER, A P (MAMMAL REVIEW, 1993)
Between March and December 1990, a survey of Pine Marten Martes martes L. on the Balearic Islands of Minorca and Majorca was carried out. Pine Marten were found distributed over 55% of Minorca and occupied Aleppo Pine and Holm Oak forests, mediterranean shrublands and riparian/cliff habitats. In Majorca, Pine Marten were found on 48% of the island and three broad physiographic areas, the Sierra de Tramuntana, Sierra de Levant and the Massif de Randa. Droppings were collected along four designated routes during five bimonthly intervals in Minorca to describe the Pine Marten's differential use of habitat types. The upland/open pine forest had the highest use index while the Holm Oak forest had the lowest. The number of Pine Marten faeces collected was greatest during the months of July-August. The Balearic Island Pine Marten populations were once on the verge of extinction; however, protection during the last 20 years has enabled the species to recover throughout most of the forested habitats on both islands. Resource managers must carefully monitor the Pine Marten populations to provide the species and its habitat with adequate protection and management in the future.
APS
Keywords: Aleppo pine; Balearic Islands; Holm oak; Martes martes L.

THE EUROPEAN PINE MARTEN MARTES-MARTES IN THE BALEARIC-ISLANDS, SPAIN - CLEVENGER, A. P. (MAMMAL REVIEW, 1993)
Between March and December 1990, a survey of Pine Marten Martes martes L. on the Balearic Islands of Minorca and Majorca was carried out. Pine Marten were found distributed over 55% of Minorca and occupied Aleppo Pine and Holm Oak forests, mediterranean shrublands and riparian/cliff habitats. In Majorca, Pine Marten were found on 48% of the island and three broad physiographic areas, the Sierra de Tramuntana, Sierra de Levant and the Massif de Randa. Droppings were collected along four designated routes during five bimonthly intervals in Minorca to describe the Pine Marten's differential use of habitat types. The upland/open pine forest had the highest use index while the Holm Oak forest had the lowest. The number of Pine Marten faeces collected was greatest during the months of July-August. The Balearic Island Pine Marten populations were once on the verge of extinction; however, protection during the last 20 years has enabled the species to recover throughout most of the forested habitats on both islands. Resource managers must carefully monitor the Pine Marten populations to provide the species and its habitat with adequate protection and management in the future.
APSAPSThe following values have no corresponding Zotero field: pub-location: OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL publisher: BLACKWELL SCIENCE LTD
Keywords: Aleppo pine; Balearic Islands; Holm oak; Martes martes L.

Evidence for Phytophthora cinnamomi involvement in Iberian oak decline - Brasier, C. M.; ROBREDO, F.; FERRAZ, J. F. P. (Plant Pathology, 1993)
Rapid and sometimes extensive mortality and decline of oak, principally Quercus suber and Q. ilex, has occurred in parts of southern Spain and Portugal in recent decades. We report here isolation of the aggressive root pathogen Phytophthora cinnamomi from roots of diseased oaks or from soil at eleven out of thirteen decline foci examined. It is proposed that the introduction and spread of P. cinnamomi may be a major factor in the Iberian oak decline, interacting with drought and other site factors, and leading to stress-related attacks by insects and other fungi. By analogy, it may also be involved in the similar oak declines occurring elsewhere on the Mediterranean.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Drought; Oak decline; phytophthora cinnamomi; site factors (PG)

Evidence for Phytophthora cinnamomi involvement in Iberian oak decline - Brasier, C M; ROBREDO, F; FERRAZ, J F P (Plant Pathology, 1993)
Rapid and sometimes extensive mortality and decline of oak, principally Quercus suber and Q. ilex, has occurred in parts of southern Spain and Portugal in recent decades. We report here isolation of the aggressive root pathogen Phytophthora cinnamomi from roots of diseased oaks or from soil at eleven out of thirteen decline foci examined. It is proposed that the introduction and spread of P. cinnamomi may be a major factor in the Iberian oak decline, interacting with drought and other site factors, and leading to stress-related attacks by insects and other fungi. By analogy, it may also be involved in the similar oak declines occurring elsewhere on the Mediterranean.
Keywords: Drought; Oak decline; phytophthora cinnamomi; site factors (PG)

FACTORES QUE DETERMINAN LA CALIDAD DEL CORCHO - González Adrados, José Ramón (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
Cork quality, strongly related with economical profit 9f Quercus suber stands, is today determined by the visual characteristics of corkwood planks, mainly porosity and thickness. Variance in those'parameters is imputed to ecologic?l, selvicultural and genetic factors. Relationship between environmental factors and cork qua lit y is studied in this work. Data from two samples obteined in Extremadura and Catalonia show that this dependence is significati ve.
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: Cork; Cork quality; Quercus suber stands

FACTORES QUE DETERMINAN LA CALIDAD DEL CORCHO - González Adrados, José Ramón (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
Cork quality, strongly related with economical profit 9f Quercus suber stands, is today determined by the visual characteristics of corkwood planks, mainly porosity and thickness. Variance in those'parameters is imputed to ecologic?l, selvicultural and genetic factors. Relationship between environmental factors and cork qua lit y is studied in this work. Data from two samples obteined in Extremadura and Catalonia show that this dependence is significati ve.
Keywords: Cork; Cork quality; Quercus suber stands

Geographical variation in the density of the white stork Ciconia ciconia in Spain: Influence of habitat structure and climate - Carrascal, L M; Bautista, L M; Lázaro, E (Biological Conservation, 1993)
The spatial variation in the density of white storks Ciconia ciconia in Spain is analysed with respect to landscape and meteorological variables. The density of breeding pairs in 1985 was negatively correlated with surface cover of woodlands and shrublands, and posi- tively correlated with the area of dry or wet grasslands, reflecting .food availability and foraging preferences of the storks. Average minimum temperature in April-May (the first .few days after hatching) was also negatively correlated with stork density, and the reproductive success in a colony at El Tietar (Avila) was inversely correlated with the number of days with precipitation in May. The negative influence of minimum temperature and precipitation on breeding density appears to be linked with the mortality of recently born nestlings. Practical recommendations are made for the conserva- tion of the Spanish population of white storks through incentive use of pastures, meadows and 'dehesas' for cattle grazing. Reintroduction efforts must be direct towards zones having large areas of these habitats, and mild weather
Keywords: climate; distribution; habitat; Spain; white stork

Geographical variation in the density of the white stork Ciconia ciconia in Spain: Influence of habitat structure and climate - Carrascal, L. M.; Bautista, L. M.; Lázaro, E. (Biological Conservation, 1993)
The spatial variation in the density of white storks Ciconia ciconia in Spain is analysed with respect to landscape and meteorological variables. The density of breeding pairs in 1985 was negatively correlated with surface cover of woodlands and shrublands, and posi- tively correlated with the area of dry or wet grasslands, reflecting .food availability and foraging preferences of the storks. Average minimum temperature in April-May (the first .few days after hatching) was also negatively correlated with stork density, and the reproductive success in a colony at El Tietar (Avila) was inversely correlated with the number of days with precipitation in May. The negative influence of minimum temperature and precipitation on breeding density appears to be linked with the mortality of recently born nestlings. Practical recommendations are made for the conserva- tion of the Spanish population of white storks through incentive use of pastures, meadows and 'dehesas' for cattle grazing. Reintroduction efforts must be direct towards zones having large areas of these habitats, and mild weather
Keywords: climate; distribution; habitat; Spain; white stork

Germination and regeneration mechanisms in Mediterranean degenerate forests - Bacilieri, R.; Bouchet, M. A.; Bran, D.; Grandjanny, M.; Maistre, M.; Perret, P.; Romane, F. (Journal of Vegetation Science, 1993)
Abstract. Germination and developmental behaviour during juvenile stages are of importance in relation to succession mechanisms acting on plant communities. This is particularly so in the Mediterranean region, where the climatic summer drought causes stress. We investigated and compared germination and development of four tree species in two parts of the French Mediterranean region where the original dominant tree species (Quercus pubescens) has been largely replaced by Quercus ilex in the southern part, and Castanea sativa in the northern part. Observed differences in germination rates and developmental behaviour, especially shootroot ratio and the role of water supply, suggest that other species may eventually replace the current dominant species.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Castanea sativa; Pinus pinaster; Quercus ilex; Quercus pubescens

Germination and regeneration mechanisms in Mediterranean degenerate forests - Bacilieri, R; Bouchet, M A; Bran, D; Grandjanny, M; Maistre, M; Perret, P; Romane, F (Journal of Vegetation Science, 1993)
Abstract. Germination and developmental behaviour during juvenile stages are of importance in relation to succession mechanisms acting on plant communities. This is particularly so in the Mediterranean region, where the climatic summer drought causes stress. We investigated and compared germination and development of four tree species in two parts of the French Mediterranean region where the original dominant tree species (Quercus pubescens) has been largely replaced by Quercus ilex in the southern part, and Castanea sativa in the northern part. Observed differences in germination rates and developmental behaviour, especially shootroot ratio and the role of water supply, suggest that other species may eventually replace the current dominant species.
Keywords: Castanea sativa; Pinus pinaster; Quercus ilex; Quercus pubescens

Growth response of holm oak (Quercus ilex L) to commercial thinning in the Montseny mountains (NE Spain) - Mayor, X; Rodà, F (Ann. For. Sci., 1993)
Growth responses of holm oak (Quercus ilex) to commercial thinning were studied in the Montseny Biosphere Reserve (northeast Spain), where selection thinning for firewood production is currently the dominant form of management in holm oak forests. Thinning significantly increased mean stem diameter increment by 83% over that of unthinned plots during the 6-9-yr period after thinning, and by 48% from 9-12 yr after thinning. Absolute diameter increment was positively correlated with initial diameter at 1.30 m from the ground (dbh) both in thinned and unthinned plots. Thinning increased growth in large trees more than in smaller trees. Relative diameter growth was negatively correlated with initial dbh. It is concluded that individual holm oak stems in previously coppiced stands respond vigourously to thinning, and still do so 6-9 yr after thinning. The growth response diminishes 9-12 yr after thinning due to canopy closure. However, absolute rates of stand growth, as well as basal area and stem biomass increments, were unaffected by thinning during these time intervals, an example of density compensation.
Keywords: Canopy closure; Quercus ilex = holm oak; selection thinning; stand growth; tree growth

HOW TREE COVER INFLUENCES THE WATER-BALANCE OF MEDITERRANEAN RANGELANDS - Joffre, R; Rambal, S (ECOLOGY, 1993)
Dehesa ecosystems of the southwestern Iberian Peninsula are characterized as a savanna-like rangeland dominated by scattered mediterranean evergreen oak trees. We investigated whether isolated trees modify the water balance of this ecosystem and if so, what implications this finding might have on models that assume homogeneity of soil water resources. The water balance of the two ecological components of the dehesas-(1) the tree-grass component, and (2) the open areas between the tree canopies with unshaded grass vegetation-was studied for three consecutive years in three locations in the Sierra Norte de Sevilla region of Andalusia in southern Spain. In this region, annual rainfall was generally between 600 and 800 mm, and the summer drought lasted almost-equal-to 130 d. Soil water storage was measured with a neutron moisture gauge outside and under the tree canopy. Deep drainage between two consecutive census dates was calculated using field-measured drainage characteristics. Evapotranspiration (Ea) and surface runoff were computed from the water balance equation assuming that Ea is limited by Penman potential evapotranspiration. Monthly Ea by annual species in open areas was poorly correlated with rainfall levels in the autumn and was limited during the spring by availability of water in the top 40 cm of soil. During summer, monthly Ea by trees ranged from 30 to 50 mm. Mean annual Ea was 400 mm outside and 590 mm under the tree cover. In open areas, water yield (WY), defined as the sum of deep drainage and surface runoff, ranged from 65 to 100% of total Ea, whereas under the tree canopy WY was only 20 to 40% of the Ea. Under the tree canopy, when annual precipitation was < 570 mm, WY was negligible and all precipitation was lost by evapotranspiration. Outside the tree canopy, WY occurred as soon as annual precipitation exceeded 250 mm. Models of competition between trees and grass generally assume a spatial homogeneity of soil hydrodynamic properties. Our results, however, show that both soil water storage and evapotranspiration are greater for the tree-grass component. Consequently, these models must account for this spatial variability in water resources according to species.
Keywords: DEEP DRAINAGE; Dehesa; Evapotranspiration; Grasses; hydrological equilibrium; MEDITERRANEAN OAK WOODLANDS; Quercus ilex; Quercus-suber; surface runoff; Trees; water balance

INDUSTRIAS FORESTALES DE PRODUCTOS NO MADERABLES: CORCHO, RESINAS, ETC. - Solis Sánchez, W (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
Within the whole of the forest industries based on secondary forest products, regarding' in Cork and Resins, reviewing to its more characteristics topics, showing its unequal tendency and the meaning role exercised by both in the European' Cornmunity .
Keywords: Cork; E.E.C.; Marketing; Resins

Influence of raw-material quality and process parameters in the production of insulation cork agglomerates - Pereira, H; Baptista, C (European Journal of Wood and Wood Products, 1993)
{Insulation cork agglomerates are produced with different low-cost raw-materials unsuitable for other products: virgin corks (from prunmgs, thinnings anti dead trees), reproduction corks (refuse and underaged) and industrial byproducts (corkback strips). These materials were analysed in relation to chemical composition, struc- ture and trituration behaviour. The industrial byproducts diffcr significantly from the other materials due to the presence of an important amount of the unsubcriscd lignocellulosic phlocm (the back of the corkboards) in a way that is detrimental to the agglomeration process. The influence of raw-material, granulometry and process parameters (time, temperature and pressure} were studied using an experimental autoclave. Temperature is the deter- mining factor for agglomeration. Insufficient adhesion is obtained under 230 ~C and adequate agglomeration is attained only with temperatures in the range 230 300 "C. corresponding to inass losses of 10 25%.
Keywords: chemical composition; CORK AGGLOMERATES; Raw materials; structure; trituration behaviour (Voyant)

Influence of raw-material quality and process parameters in the production of insulation cork agglomerates - Pereira, H.; Baptista, C. (European Journal of Wood and Wood Products, 1993)
{Insulation cork agglomerates are produced with different low-cost raw-materials unsuitable for other products: virgin corks (from prunmgs, thinnings anti dead trees), reproduction corks (refuse and underaged) and industrial byproducts (corkback strips). These materials were analysed in relation to chemical composition, struc- ture and trituration behaviour. The industrial byproducts diffcr significantly from the other materials due to the presence of an important amount of the unsubcriscd lignocellulosic phlocm (the back of the corkboards) in a way that is detrimental to the agglomeration process. The influence of raw-material, granulometry and process parameters (time, temperature and pressure} were studied using an experimental autoclave. Temperature is the deter- mining factor for agglomeration. Insufficient adhesion is obtained under 230 ~C and adequate agglomeration is attained only with temperatures in the range 230 300 "C. corresponding to inass losses of 10 25%.
Keywords: chemical composition; CORK AGGLOMERATES; Raw materials; structure; trituration behaviour (Voyant)

INFLUENCIA DE LA DENSIDAD DE LA MASA EN LA CALIDAD Y PRODUCCION DE CORCHO EN LOS ALCORNOCALES DE CORTES DE LA FRONTERA (MALAGA) - Montero, G; TORRES, E; Suárez, M A; Ortega, C (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
The influence of stand density on cork yield was evaluated for the Cortes de la Frontera (Spain) cork oak stand. Fifty five experimental plots were installed. The modular values of several variables which define cork oak yield potential of a tree, are presented by stand densitY'clusters (basal area groups). Likewise, many stand variables for different basal areas were studied
Keywords: cork-oak; silviculture; stand density

INFLUENCIA DE LA POSICION DE LA COPA SOBRE LA FENOLOGIA y LAS RELACIONES HIDRICAS DEL ALCORNOQUE (QUERCUS SUBER L.) - Oliveira, G.; Werner, C.; Mertens, C.; Correia, O. (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
A tree crown may be seen as a large and heterogeneous population of branches and leaves, unequally subjected to the environmental factors. It is thus questionable if studies on a few leaves or a branch will be a good approach to the whole canopy. This is particularly important in the field, where the applieation of ecophysiological measurements to mature (and generally large) trees presents obvious human and financial problems. The purpose of this study was to determine the effeet of different levels and directions within the' crown on the phenology and water relations of a typieal cork-oak in south Portugal. Our preliminary results show that the parts of the erown exposed to higher radiation value~ present a stronger growth and biomass production (direetion effect). Crown level was not clearly related to the results, suggesting that the "height effect" is not very important in trees with wide and diffuse crowns like the ones occurring in the montado systems.
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: Crown position; Phenology; Quercus suber; Stomatal eonductance 1)

INFLUENCIA DE LA POSICION DE LA COPA SOBRE LA FENOLOGIA y LAS RELACIONES HIDRICAS DEL ALCORNOQUE (QUERCUS SUBER L.) - Oliveira, G; Werner, C; Mertens, C; Correia, O (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
A tree crown may be seen as a large and heterogeneous population of branches and leaves, unequally subjected to the environmental factors. It is thus questionable if studies on a few leaves or a branch will be a good approach to the whole canopy. This is particularly important in the field, where the applieation of ecophysiological measurements to mature (and generally large) trees presents obvious human and financial problems. The purpose of this study was to determine the effeet of different levels and directions within the' crown on the phenology and water relations of a typieal cork-oak in south Portugal. Our preliminary results show that the parts of the erown exposed to higher radiation value~ present a stronger growth and biomass production (direetion effect). Crown level was not clearly related to the results, suggesting that the "height effect" is not very important in trees with wide and diffuse crowns like the ones occurring in the montado systems.
Keywords: Crown position; Phenology; Quercus suber; Stomatal eonductance 1)