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)

INFLUENCIA DE LAS COBERTURAS DE ENCINAS , Quercus ilex subsp. ballota , EN LA ROTURA DE LOS PERFILES TERMICOS VERTICALES - Escudero Garcia, J. C.; Cabezas Fernández, J.; Lavado Contador, F. (CONGRESO FORESTAL ESPAÑOL - Lourizán 1.993, 1993)
Vegetation cover acts intensely on vertical temperature profiles, breaking up their structure. For the particular case of holm oak parkland (dehesas) forests systems, these will affect the vertical temperature gradient by modifying it more or less sharply as a function funtamenta1ly of the height and characteristics of the canopy, the density of trees ánd of foliage load. The study was carried in Cheles (Badajoz), and consisted in periodic measurements of the temperature variations in the profile. The results show quantitatively the influence of arboreal systems on the vertical structure of air and soil temperatures. A characterlzation is thereJore given of the thermal impact that intense pruning and destruction of holm oaks have on the vertical profIle, especially that of he soil.
The following values have no corresponding Zotero field: periodical: CONGRESO FORESTAL ESPAÑOL - Lourizán 1.993
Keywords: gradients; impact; Quercus ilex; Temperature

INFLUENCIA DE LAS COBERTURAS DE ENCINAS , Quercus ilex subsp. ballota , EN LA ROTURA DE LOS PERFILES TERMICOS VERTICALES - Escudero Garcia, J C; Cabezas Fernández, J; Lavado Contador, F (CONGRESO FORESTAL ESPAÑOL - Lourizán 1.993, 1993)
Vegetation cover acts intensely on vertical temperature profiles, breaking up their structure. For the particular case of holm oak parkland (dehesas) forests systems, these will affect the vertical temperature gradient by modifying it more or less sharply as a function funtamenta1ly of the height and characteristics of the canopy, the density of trees ánd of foliage load. The study was carried in Cheles (Badajoz), and consisted in periodic measurements of the temperature variations in the profile. The results show quantitatively the influence of arboreal systems on the vertical structure of air and soil temperatures. A characterlzation is thereJore given of the thermal impact that intense pruning and destruction of holm oaks have on the vertical profIle, especially that of he soil.
Keywords: gradients; impact; Quercus ilex; Temperature

Influencias de la posición de la copa sobre la fenología y las relaciones hídricas del alcornoque (Quercus suber L.) - Oliveira, G; Werner, C; Mertens, C; Correia, O (Congresos-CARGA FINAL, 1993)

Intraspecific variation of growth and adaptive traits in European oak species - Kleinschmit, J (Ann. For. Sci., 1993)
According to various reports, 200-450 oak species including hybrid populations exist worldwide, with 24 of these - including 3 hybrid forms - having their natural range within Europe. They all belong to the subgenus Lepidobalanus. The most important section is robur with 21 species. The European species belong to both deciduous (15 species) and evergreen (9 species) oaks. Some difficulties in clear morphological and physiological definition of the species involved is caused by hybridization. Most studies into intraspecific variation exist for the species Quercus robur L and Quercus petraea (Matt) Liebl. Some information is available for Quercus cerris L, Quercus virginiana Ten (= Q dalechampii Wenz), Quercus ilex L and Quercus suber L, based on comparative plantations. In addition, a considerable number of morphological, physiological and biochemical studies based on natural populations exist which are not completely covered in this review paper. For most characters observed, oaks exhibit a wide variation. This is not only the case for morphological traits of pollen, seed, wood and plants but also for physiological traits and phenology which have great adaptive importance. Provenance experiments and progeny tests started as early as 1877. Most of these were only of local importance. This is partly due to the fact that acorns can only be stored for a limited period and flowering is irregular. However, the results available show that the choice of provenance can be important for the successful economic management of plantations. Variability of leaves, phenology, form, growth, wood and bark, roots, seed and flowering has been discussed separately. Improvement via selection and testing seems to be promising due to the considerable between-population and within-provenance variation. Vegetative propagation has been developed for some species by grafting, cutting propagation and in vitro propagation. Tree breeding approaches have also been discussed.
Keywords: intraspecific variation; morphology; progeny test; provenance; Quercus; vegetative propagation

LA RELACION ENTRE EL CLIMA, EL CICLO ONTOGENETICO y LA DISTRibUCION DE QUERCUS ILEX L. - Macchia, F; Cavallaro, V; Forte, L (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
Phenologic and ecofisiologic researches have been carriedon the ontogenetic cycle of Quercus ilex L.. The acom gennination has been under observation both in lab at different temperatures and in the field at natural conditions. The results showed that Hol1y Oak has a gennination delay going between 80 days at 5° e, to 28 day'S at 20° C. The delay in dispersal occurring between December and January and in gennination defers the times of the shoot differentiation and growth at the end of April connected with the values . of temperature next to 15° C. The vegetative awakening of fue buds and the anthesis take place between April and May when the soil moisture storage are plentiful. The following phenophases occur from June to the end of November. Holly Oak occupies the stations of the mediterranean area where temperature se'quences make the phenophases synchronous with the water availability of the soil.
Keywords: autoecology; distribution; Quercus ilex

Land degradation in Mediterranean Europe: can agroforestry be a part of the solution? A prospective review - Houérou, H N (Agroforestry Systems, 1993)
Vegetation and land degradation, although less acute than in the Southern Medi- terranean Basin, is still widespread in the North. Degradation results from various kinds of mismanagement of the land. Wildfires, for instance, favoured by ungrazing, play an increas- ingly important role as the mean area annually burnt shifted from an average 200,000 ha in the 1960's to over 600,000 ha in the 1980's. These put a heavy burden on the states and on local communities that amounted to an annual average one billion ECUs (USS 1.2 billion) in the 1980's. The causes and processes of land and vegetation degradation are analysed in the light of the changes in land-use over the past 25 years, as shown in the official statistical data. Forest and shrubland areas are expanding while farmland is shrinking by nearly 1% per annum. An analysis of the foreseeable situation in the early years of the twenty-first century is attempted on the basis of the likely evolution of the EEC agricultural policy. Some guidelines are proposed for sound ecological management of the Northern Mediterranean land and vegeta- tion. These include the introduction or expansion of agroforestry systems with multiple-use of the land to develop tourism, wildlife, hunting and sports, combined with extensive grazing of livestock and game and timber production from elite clones of selected high yielding or highly valued species. Eight to ten million hectares, at present devoted to cereal cropping (i.e. about 50% of the cereal-cropping hectarage), will have to be reconverted to other activities. By 1995, the EEC cereal prices will have to drop in line with the world market, as a result of the recent evolution of the EEC Communal Agricultural Policy (CAP). The warranted EEC cereal prices are at present about 40% above that of the world market. The reconversion of this cereal land to other activities could combine low-input mixed agroforestry systems with extensive livestock and game husbandry, high value timber, tourism and various amenities. These should include forage-shrubs plantations in a strategy which combines inexpensive, albeit nutritionally balanced, ruminant diets with erosion control and the overall uplift of natural land fertility and productivity.
Keywords: agroforestry systems; fodder shrubs; Mediterranean basin; multipurpose production systems; range management; sylvo-pastoralism

LIGNOTUBER ONTOGENY IN THE CORK-OAK (QUERCUS-SUBER, FAGACEAE) .1. LATE EMBRYO - Molinas, M L; VERDAGUER, D (AMERICAN JOURNAL OF BOTANY, 1993)
Changes at the cotyledonary node of the cork-oak (Quercus suber L.) were examined during the embryo maturation phase using light microscopy and scanning electron microscopy techniques. During the maturation phase the embryo axis elongates by diffuse growth, the apical meristem forms the first leaf primordia, and the radicle meristem remains inactive. The primary axis of the embryo bears, axillary to the cotyledons, in the range of five to seven pairs of lateral buds at differing stages of development. Two or three pairs of these buds are visible, occurring on the upper unfused portion of the embryonic axis, while the remaining buds are hidden by the fused cotyledonary tissues. Lateral buds develop from clusters of cells in the peripheral meristem forming a shell zone delimiting the bud meristem. Lateral buds do not undergo much development until germination begins. The results are discussed with reference to the possible role of the cotyledonary node as the source of the lignotuber in the cork-oak.
APS
Keywords: bud merietem; embryo maturation; light microscopy; scanning electron microscopy techniques

LIGNOTUBER ONTOGENY IN THE CORK-OAK (QUERCUS-SUBER, FAGACEAE) .2. GERMINATION AND YOUNG SEEDLING - Molinas, M L; VERDAGUER, D (AMERICAN JOURNAL OF BOTANY, 1993)
Lignotuber origin was studied in cork-oak seedlings at different stages from germination to seedling establishment. By the time germination is completed, the seedling consists of an elongated embryonic axis between the developing first shoot and first root. The cotyledonary insertion divides the axis in two portions: an apical portion, visible between the cotyledonary petioles; and an enlarged lower portion in which the cotyledonary tissues are fused with the axis. Several histological changes take place in the fused portion: initial vascular differentiation occurs; parenchymatous cells contain large amounts of starch; and the vascular cambium and periderm are formed early. In the cotyledonary stage seedlings, axillary buds of the cotyledonary node develop. Buds in the unfused upper portion remain single and form a short stalk and laminar scales. Buds in the fused portion, hidden by the cotyledonary tissues, form hypertrophied scales and multiply to form bud clusters. As development proceeds, the root-shoot transition region becomes woody, bearing both individual buds as well as bud clusters and concentrating food reserves. All of the transition region in the cork-oak is considered equivalent to a lignotuber.
Keys: APS
Keywords: germination; seedling establishment

Litter decomposition and nutrient distribution in humus profiles in some mediterranean forests in southern Tuscany - van Wesemael, Bas (Forest Ecology and Management, 1993)
Decomposition of leaf litter and the distribution of elements in the humus layer were studied in mediterranean deciduous, sclerophyllous and coniferous forests on acid rocks. The results indicate a clear difference in relative decomposition rate between pine needles (Pinus pinaster: 0.12 year−1) and leaves of deciduous and sclerophyllous species (Quercus cerris, Quercus suber and Arbutus unedo: 0.30 year−1). The concentrations of N, P, S and Ca increase upon decomposition, whereas that of K decreases by initial leaching, and those of Mg, Mn (Fe, Al) remain unchanged except for an increase resulting from mineral contamination. In deciduous and sclerophyllous litter, absolute amounts of N, P, S and Ca increase until a critical concentration level is reached, after which net mineralization occurs. For pine needles net mineralization was not observed within 915 days. In analogy with the situation during the litter bag experiments, elemental concentrations are highest in the lower more decomposed part of the humus profiles. In deciduous and sclerophyllous forests net mineralization of N, P, S and Ca starts in the lower part of the fermentation layer. In the coniferous forest elemental concentrations are much lower and no indications of N, P, S and Ca mineralization were found in the ectorganic horizons.
Keywords: forest types; litter decomposition; Mediterranean forest (voyant); mineralization; nutrient concentration

Los alcornocales andaluces: regeneracion y REPOBLACION ARTIFICIAL - Sánchez García, J M (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
After a brief description of the types of cork tree groves that exist in Andalusia, a succint review of the way and necessary conditions in wich the restocking is done at present. Also data referring to the reforestation with Quercus suber in the last decade are collected. Finally a view of the place that the cork oak takes in the framework of the Andalusian Forestry Plan.
Keywords: Andalusian Forestry Plan; Cork Oak Forest; Reforestation; Restocking

Los alcornocales andaluces: regeneracion y REPOBLACION ARTIFICIAL - Sánchez García, J. M. (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
After a brief description of the types of cork tree groves that exist in Andalusia, a succint review of the way and necessary conditions in wich the restocking is done at present. Also data referring to the reforestation with Quercus suber in the last decade are collected. Finally a view of the place that the cork oak takes in the framework of the Andalusian Forestry Plan.
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: Andalusian Forestry Plan; Cork Oak Forest; Reforestation; Restocking

Mediterranean pasture dynamics: the role of germination - Espigares, T.; Peco, B. (Journal of Vegetation Science, 1993)
pastures were arranged along a gradient of sensitivity to temperature on the arrival of the first persistent rain. This sensitivity was manifested in both the total germination success of the species and the germination time profile. The different germination patterns of the species can provide competitive advantages depending on the autumn weather conditions.
Keywords: Autumn rain; Gradient; Phytotron; seed bank; Temperature; Weather fluctuation

Mediterranean pasture dynamics: the role of germination - Espigares, T; Peco, B (Journal of Vegetation Science, 1993)
pastures were arranged along a gradient of sensitivity to temperature on the arrival of the first persistent rain. This sensitivity was manifested in both the total germination success of the species and the germination time profile. The different germination patterns of the species can provide competitive advantages depending on the autumn weather conditions.
Keywords: Autumn rain; Gradient; Phytotron; seed bank; Temperature; Weather fluctuation

New method for treating gastric ulcers etc. - comprises oral admin. of extract of bark of carob and/or encina trees - J, ANTOUN (1993)
New method of treating gastric ulcers comprises oral admin. of extract of encina tree (Queras ilex) and/or carob tree (ceratonia siliqua). Also claimed is compsn. comprising bark extract of encina and/or carob tree. USE/ADVANTAGE-Extract is useful to treat gastric ulcer, gastritis, stomach gas and mouth ulcer. It may also cure cancer. In an example, approx. equal amts. of carob bark and encina bark (250 g total) were boiled in water (2l) for 25 mins. and the mixt. strained and cooled. A man diagnosed with gastric ulcers took 150 ml of this soln. 3 times daily, 15 min. before eating for 3-4 days. After a further 6-7 days the ulcers were diagnosed and healed
APS
Keywords: Bark; cancer; Caratonia siliqua; gastric ulcers; Quercus ilex

OBTENCION DE PLANTAS A PARTIR DE EMBRIONES SOMATICOS DE QUERCUS SUBER L - Fernández Guijarro, B; CELESTINO, C; TORIBIO, M (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
This paper gives a procedure to regenerate plants of cork oak through somatic embryogenesis. The somatic embryos were obtained in leaves from young seedlings and cotyledonary fragments from mature acorns of cork oak. The explants were cultured in three stage process in wich BA and NAA concentration were decreasing. Different methods were used to germinate the embryos. Dessication and culture in low salt concentration medium were chosen to give the best results
Keywords: adventive embryogenesis; Cork oak; culture media; plant regeneration; secondary embryogenesis

OBTENCION DE PLANTAS A PARTIR DE EMBRIONES SOMATICOS DE QUERCUS SUBER L - Fernández Guijarro, B.; Celestino, C.; Toribio, M. (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
This paper gives a procedure to regenerate plants of cork oak through somatic embryogenesis. The somatic embryos were obtained in leaves from young seedlings and cotyledonary fragments from mature acorns of cork oak. The explants were cultured in three stage process in wich BA and NAA concentration were decreasing. Different methods were used to germinate the embryos. Dessication and culture in low salt concentration medium were chosen to give the best results
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: adventive embryogenesis; Cork oak; culture media; plant regeneration; secondary embryogenesis

PLANTEAMIENTO ESTRATEGICO EN EL SECTOR FORESTAL : ESPECIAL REFERENCIA AL SECTOR CORCHERO ESPAÑOL - Lopez Quero, Manuel (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
On base about the strategic analisys of spanish cork sector, we observed a regeneralization of industrial fabric in the finished products specialization. With the application of DELPHI method to expert group, we have obtained several conclusions as the control of industrial production, futural technological changes in the quality control and the denomination of the number of enterprise is going accompanied to fast concentration of the production.
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: cork industry; DELPHI method; Strategical plannig

PLANTEAMIENTO ESTRATEGICO EN EL SECTOR FORESTAL : ESPECIAL REFERENCIA AL SECTOR CORCHERO ESPAÑOL - Lopez Quero, Manuel (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
On base about the strategic analisys of spanish cork sector, we observed a regeneralization of industrial fabric in the finished products specialization. With the application of DELPHI method to expert group, we have obtained several conclusions as the control of industrial production, futural technological changes in the quality control and the denomination of the number of enterprise is going accompanied to fast concentration of the production.
Keywords: cork industry; DELPHI method; Strategical plannig

Possible criteria for selection of Quercus suber plus trees - García-Valdecantos, J L; Catalán, G (Ann. For. Sci., 1993)
The field work for selecting superior trees of cork oak is described. Requirements for selection are different from those employed for timber tree breeding, because the product to be improved is not wood, but bark. The field work is being developed in a natural forest of 16 000 ha, 8 000 of which are pure cork oak. As the trees are debarked once every 9 years, each year an area of 800-900 ha is selected. The characters assessed were tree size and form, resistance to pests and diseases, bulk production of cork, and cork quality. At the time of debarking, every 9 years, 64 superior trees are selected for progeny testing.
Keywords: breeding; Quercus suber; selection

Possible criteria for selection of Quercus suber plus trees - García-Valdecantos, J. L.; Catalán, G. (Ann. For. Sci., 1993)
The field work for selecting superior trees of cork oak is described. Requirements for selection are different from those employed for timber tree breeding, because the product to be improved is not wood, but bark. The field work is being developed in a natural forest of 16 000 ha, 8 000 of which are pure cork oak. As the trees are debarked once every 9 years, each year an area of 800-900 ha is selected. The characters assessed were tree size and form, resistance to pests and diseases, bulk production of cork, and cork quality. At the time of debarking, every 9 years, 64 superior trees are selected for progeny testing.
Keywords: breeding; Quercus suber; selection

Proanthocyanic polymorphism in holm oak (Quercus ilex L) in the Mediterranean region of France - Lebreton, P; Barbero, M; Nader, S (Ann. For. Sci., 1993)
We studied the proanthocyanic diversity of holm oak in France. The percentage of prodelphinidin remains constant for each individual tree, independent of age or location of the leaves. By contrast, this content can be significantly different between trees within the same population. An in-depth analysis of a Languedocian population showed a good relationship between observed and predicted sample structure, according to the hypothesis of 2 alleles, prodelphinidin 'weak' and 'strong', respectively, governing the biosynthesis of this polyphenol. We have probably observed a biochemical polymorphism comparable to that previously demonstrated for several coniferous species.
Keywords: Holm oak; Polymorphism; prodelphinidin

PRODUCCION DE BELLOTA EN QUERCUS ROTUNDIFQLIA LAM.: VARIABILIDAD ANUAL E IMPORTANCIA ECONOMICA - Esparrago, F; Vázquez, F M; Burzaco, A; Perez, M C (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
The acorn production on Q. rotundifolia Lam. has been analyzed from 1989 through 1992 in Extremadura. The efects of different areas, each tree, and the interaction between areas/years are significatives. Genetic, pruning, environment and phytosanitary factors are the possible causes of these differences. Finally, the econornic efects of acorn production on iberian pig feeding (Montanera) has been studied. This is the rnain factor for high quality products.
Keywords: acorn; Econorny; evergreen oak; feeding; iberian pig; production; Quercus

PRODUCCION DE BELLOTA EN QUERCUS ROTUNDIFQLIA LAM.: VARIABILIDAD ANUAL E IMPORTANCIA ECONOMICA - Esparrago, F.; Vázquez, F. M.; Burzaco, A.; Perez, M. C. (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
The acorn production on Q. rotundifolia Lam. has been analyzed from 1989 through 1992 in Extremadura. The efects of different areas, each tree, and the interaction between areas/years are significatives. Genetic, pruning, environment and phytosanitary factors are the possible causes of these differences. Finally, the econornic efects of acorn production on iberian pig feeding (Montanera) has been studied. This is the rnain factor for high quality products.
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: acorn; Econorny; evergreen oak; feeding; iberian pig; production; Quercus

Response of xylem parenchyma by suberization in some hardwoods after mechanical injury - Schmitt, Uwe; Liese, Walter (Trees, 1993)
Wound responses of xylem parenchyma by suberizarion were investigated in some hardwoods by light and electron microscopy. Suberized ray and axial paren- chyma cells form a distinct boundary around the wound in all investigated species. Vessels and fibres within and close behind the suberized area appeared more or less occluded; vessels in Fagus, Quercus, and Populus contained suber- ized tyloses, those in Betula and Tilia contained amor- phous and fibrillar deposits. A common mechanism for suberin deposition in the parenchyma cells became evi- dent. Cisternae of the endoplasmic reticulum were ap- parently involved in suberization. Suberin compounds are extruded by cytoplasmic vesicles, which fused with the plasma membrane, in order to release their content. The suberin layer exhibited the typical lamellated structure; cytoplasmic continuity between suberized cells by plas- modesmata was maintained through the suberin layer. Fagus revealed the most intense suberized area as com- pared with the other species. Within the reaction zone of Fagus and Quercus, some individual ray and axial paren- chyma cells exhibited a subdivision into 2 or 3 compart- ments prior to suberization. Subdivision was achieved by the formation of a primary wall-like layer. Subsequently, the compartments became individually suberized. Wound- ing during winter did not induce suberization. Also, samples wounded and kept under water during the vegeta- tion period showed no response. The role of suberization in the effectivity of wound-associated compartmentalization is discussed.
Keywords: Electron microscopy; hardwoods; suberization; wound responses; xylem parenchyma

RESPONSE TO MICROCLIMATE OF MORPHOLOGICAL LEAF ATTRIBUTES, PHOTOSYNTHETIC AND WATER RELATIONS OF EVERGREEN SCLEROPHYLLOUS SHRUB SPECIES - Gratani, L (PHOTOSYNTHETICA, 1993)
Leaf adaptations of Quercus ilex L., Phillyrea latifolia L. and Pistacia lentiscus L. to various environmental conditions namely from the viewpoint of the differences of leaf area, dry mass, chlorophyll (Chl) content, sclerophylly index, succulence index and net photosynthetic rate (P(N)), are shown. Irradiance was the most important factor to influence P(N), leaf temperature, stomatal conductance (g(s) and transpiration rate (E). Under canopy layer low red-far red ratio reduced P(N). Shade leaves were enriched by Chl b. Chl content and sclerophylly index were good leaf characteristics to express adaptability of plants to microclimate.
Keywords: irradiance; leaf area; microclimate; Phillyrea latifolia L.; Pistacia lentiscus L.; Quercus ilex L.

RESPONSE TO MICROCLIMATE OF MORPHOLOGICAL LEAF ATTRIBUTES, PHOTOSYNTHETIC AND WATER RELATIONS OF EVERGREEN SCLEROPHYLLOUS SHRUB SPECIES - GRATANI, L. (PHOTOSYNTHETICA, 1993)
Leaf adaptations of Quercus ilex L., Phillyrea latifolia L. and Pistacia lentiscus L. to various environmental conditions namely from the viewpoint of the differences of leaf area, dry mass, chlorophyll (Chl) content, sclerophylly index, succulence index and net photosynthetic rate (P(N)), are shown. Irradiance was the most important factor to influence P(N), leaf temperature, stomatal conductance (g(s) and transpiration rate (E). Under canopy layer low red-far red ratio reduced P(N). Shade leaves were enriched by Chl b. Chl content and sclerophylly index were good leaf characteristics to express adaptability of plants to microclimate.
The following values have no corresponding Zotero field: pub-location: NA KARLOVCE 1A, PRAGUE 6, CZECH REPUBLIC CS-160 00 publisher: INST EXPERIMENTAL BOTANY, ACAD SCI CZECH REPUBLIC
Keywords: irradiance; leaf area; microclimate; Phillyrea latifolia L.; Pistacia lentiscus L.; Quercus ilex L.

Responses of the trunk routes of a harvester ant to plant density - Lopez, F; Acosta, F J; Serrano, J M (Oecologia, 1993)
Messor barbarus is a Mediterranean harvester ant that constructs physically defined trunk routes on the ground to connect nest entrances with foraging areas. Some responses of these trunk routes to plant density (and therefore resource abundance) were analyzed by testing the preferential allocation of different parts (trunk route ends, segments and branching points) in a patchy environment. Maps of grass density in four categories and Messor barbarus trunk routes were compiled for a Mediterranean pasture in Central Spain over four con- secutive years. The proportions of the density categories in each year were used to calculate random expected fre- quencies of the trunk route points and the predominance of higher or lower grass densities. Trunk route ends discriminate and selectively reach patches with a greater abundance of resources in all study years. Branching points are also allocated preferentially in areas with higher vegetation density, but only in years with a predom- inance of the higher categories of grass density. In these years, the colonies of Messor barbarus have a "phalanx" strategy at a colonial level, and branching is more profuse. Finally, trunk route segments do not indicate any preference for crossing determined vegetation den- sities, but rather connect successive branching points or trunk route ends by the shortest route. These results concur with a model of structural strategy change ("guerilla" - "phalanx") (Hutchings 1988) at the level of trunk routes. They are probably constituted by "tran- sitory" sections with few branches, that expand other more profusely branched sections which are more dedi- cated to foraging.
Keywords: Guerilla; Harvester ants; Messor barbarus; Phalanx; Trunk routes

Seasonal courses of photosynthetic activity and sublethal temperature tolerance of Quercus ilex leaves - Méthy, M; Trabaud, L (Forest Ecology and Management, 1993)
The reaction of the photosynthetic system of a sclerophyllous tree of the Mediterranean region (Quercus ilex) to three temperature levels (one ambient and two sublethal) was analysed monthly for 1 year. Measurements were carried out on leaves less than 3 months old as well as on leaves older than 3 months by laser-induced chlorophyll fluorescence. Treatments were: control (unheated), 50°C for 30 min, and 60°C 10 min. Both for unheated and treated leaves the vitality index shows a seasonal course depending on the treatments. At 50°C the photosynthetic apparatus of leaves of the two ages is moderately affected. At 60°C the apparatus is severely damaged whatever the season and is unable to recover. The consequences for the management of Q. ilex forests in relation to some thermal stresses are considered.
Keywords: chlorophyll fluorescence; leaves; photosynthetic apparatus; Quercus ilex (PG); thermal stress

STOMATAL DENSITY VARIATION IN BEECH AND HOLM OAK LEAVES COLLECTED OVER THE LAST 200 YEARS - Paoletti, E; GELLINI, R (ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY, 1993)
In leaf samples of Fagus sylvatica L. and Quercus ilex L. collected over the last 200 years a reduction has been observed in the stomatal density of 43% and 28% respectively. The ecological implications, particularly concerning atmospheric CO2 increase and drought tolerance, are discussed.
Keywords: ATMOSPHERIC CO2 INCREASE; FAGUS-SYLVATICA; QUERCUS-ILEX; stomatal density

SUCCESSION OF BACTERIA ATTACHED TO EVERGREEN OAK LEAF SURFACES - Périssol, C; Roux, M; LEPETIT, J (EUROPEAN JOURNAL OF SOIL BIOLOGY, 1993)
Heterotrophic attached bacteria were isolated from evergreen oak leaf surfaces (Quercus ilex L.) on both phylloplane and litter at each season during one year. Few epiphytic bacteria were recovered from the phylloplane (18 %) in comparison with the litter. The data derived from the 324 strains were subjected to cluster analysis. The taxonomic structure displayed 44 phenetic groups. The bacterial communities on leaf surfaces belonged mainly to two genera: Bacillus (31 %), present on both phylloplane and litter, and Pseudomonas (35 %) present only on the litter. Some communities of Bacillus were able to degrade structural chemical components of the leaf, such as pectins or lignin monomers. The Bacillus isolates were generally more numerous in spring and in summer, i.e. during the warm seasons, whereas Pseudomonas predominated in autumn and winter. In vitro measurements of strains growth rates showed moreover that Bacillus strains grew better at 40-degrees-C than Pseudomonas strains. A climate-related factor, namely temperature, has therefore a great influence on the natural selection process of these communities. Another seasonal succession was observed, involving two genera: Xanthomonas predominant in winter and Lactobacillus in summer, as well as the Enterobacteriaceae family in autumn.
Keywords: ATTACHED BACTERIA; leaves; litter; PHYLLOPLANE

SUPERVIVENCIA DE PLANTULAS DE PINO CARRASCA (PINUS HALEPENSIS) y ENCINA (QUERCUS ILEX) EN BOSQUE MIXTOS DE AMBAS ESPECIES - ESPELTA, J M; RETANA, J; Gené, C; Riba, M (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
In this paper, survival of holm oak and Aleppo pine seedlings in holm oak stands, Aleppo pine stands and mixed stands, both in cut and uncut plots, is analized. Survival of holm oak seedlings in uncut plots is greater than that of Aleppo pine seedlings in the three types of forest considered. Mortality of seedlings of both species in 9ut plots is considerably smaller than that of uncut plots. K.W.:
Keywords: Aleppo pine; Holm oak; mixed forest; Seedling; survival curve

THE SURFACE-TENSION OF CORK FROM CONTACT-ANGLE MEASUREMENTS - GOMES, CMCPS; Fernandes, A C; DEALMEIDA, B D (JOURNAL OF COLLOID AND INTERFACE SCIENCE, 1993)
The surface tension of cork is evaluated from contact angle measurements in cork-water-air and cork-methylene iodide-air systems, using the geometric and the harmonic mean methods. The contact angles were studied as a function of time and, in each case, the extrapolated value for t = 0 was used in the calculations to obtain γs. In spite of the chemical and physical complexity of cork, it was possible to obtain an average value for its surface tension γs = 32 ± 3 dyne cm-1 and polarity γPS/γS= 0.25. These values were compared to others obtained for several natural products such as wood or cellulose derivatives.
APS
Keywords: chemical complexity; geometric method; harmonic method; physical complexity

Threatened landscape in Alentejo, Portugal: the 'montado'and other 'agro-silvo-pastoral'systems - Correia, T. P. (Landscape and Urban Planning, 1993)
In Portugal agro-silvo-pastoral systems correspond to the mixed land use types characteristic of the region of Alentejo, in the southern part of the country. There is a triple and complementary use of the land, adapted to the low potentialities of the soil and to the Mediterranean climate: open evergreen forest (oaks, olive and chestnut trees), grazing and cultivation. Due to their mixed characteristics and to the extensive form of exploitation, these systems constitute varied landscapes of high biological diversity. They have been managed through decades as an almost self-maintained system, with a minimum of human work input, but furnishing nevertheless the necessary outputs for the dispersed rural population of the area. Actually, due to the decrease in the economic value of some of the products concerned and to the changing context for Portuguese agriculture, these agro-silvo-pastoral systems have registered perturbations by intensification or extensification; in both cases there is a degradation or disappearance of the corresponding landscapes.
Keywords: land use (voyant); landscape; montado

Threatened landscape in Alentejo, Portugal: the 'montado'and other 'agro-silvo-pastoral'systems - Correia, T P (Landscape and Urban Planning, 1993)
In Portugal agro-silvo-pastoral systems correspond to the mixed land use types characteristic of the region of Alentejo, in the southern part of the country. There is a triple and complementary use of the land, adapted to the low potentialities of the soil and to the Mediterranean climate: open evergreen forest (oaks, olive and chestnut trees), grazing and cultivation. Due to their mixed characteristics and to the extensive form of exploitation, these systems constitute varied landscapes of high biological diversity. They have been managed through decades as an almost self-maintained system, with a minimum of human work input, but furnishing nevertheless the necessary outputs for the dispersed rural population of the area. Actually, due to the decrease in the economic value of some of the products concerned and to the changing context for Portuguese agriculture, these agro-silvo-pastoral systems have registered perturbations by intensification or extensification; in both cases there is a degradation or disappearance of the corresponding landscapes.
Keywords: land use (voyant); landscape; montado

UTILIZACION DE LOS RESIDUOS DE LA INDUSTRIA DEL CORCHO COMO SUSTRATO HORTICOLA - Ortega, M C; Moreno, M T; Aguado, M T; Ordovas, J; Ordovás, M T Aguado J (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
It has been studied the waste of the cork industry as a new horticultural substrat. Results about physical, chemical and biological analyses of cork are presented. Also it has been studied germination, rooting and growth of different horticultural and ornamental plants on cork as potting media
Keywords: Cork; Industrial wastes; substrate

VALORACION DE EXISTENCIAS DE CORCHO EN ARBOL MEDIANTE PROCESO FOTOGRAFICO CON JALON DE CONTRASTE - Velasco Fernández, Luís (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
This work has as objetive to show a new method to obtain the amount of cork in cork-trees, by mean of theirs photographies, together with a graduated indicator to can get the valour of geometric measures by contrast comparison between them.
Keywords: Cork; Cork cartography; Photography

Water as a determinant of the distribution of trees at the boundary of the Mediterranean zone. - Pigott, C D; Pigott, S (Journal of Ecology, 1993)
Investigates the water relations of two species, Quercus ilex and Tilia cordata (T. cordata) in southern France. Effect of drought on the growth in height and stem diameter of T. cordata; Importance of water supply in controlling both the small and large scale pattern of distribution of T. cordata.
Keywords: Quercus ilex; Tilia cordata; water potential

WATER-ABSORPTION BY CORK - ROSA, M. E.; FORTES, M. A. (WOOD AND FIBER SCIENCE, 1993)
A study of liquid water absorption by cork was carried out in which the anisotropy of cork was taken into account. The changes with time of the mass, volume, and linear dimensions were measured for different orientations of the sections in cork exposed to liquid water at room temperature (20 C) and at 90-100 C. Two regimes of water absorption were identified, namely, a period involving dimensional change and a period with only mass change. Diffusion coefficients at both temperatures were estimated using a special technique. There is a small anisotropy with a faster diffusion in the radial direction. Diffusion coefficients at 90 C are two orders of magnitude larger than at room temperature. Water absorption in the cell walls causes the expansion of cork, which (for the boiled specimens tested) is slightly smaller in the radial direction. The volume increase is proportional to the mass increase and ceases after relatively short immersion times. At this stage, the cell walls are apparently saturated with water. Further immersion results in penetration of water into the cells. The kinetics of absorption is rather slow at long times, but eventually the cells become full of water, the density increases above that of water, and the cork sinks.
The following values have no corresponding Zotero field: pub-location: ONE GIFFORD PINCHOT DR, MADISON, WI 53705 USA publisher: SOC WOOD SCI TECHNOL
Keywords: Cork; DIFFUSION COEFFICEIENTS; DIMENSIONAL CHANGE; WATER ABSORPTION

WETTING OF CORK BY POLYMERIC ADHESIVES - ADAO, M H; CABRITA, G M; GOMES, C M; ALMEIDA, B S; FERNANDEZ, A C; Bordado, J C (JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY, 1993)
The cohesion of cork agglomerates is determined by the strength of the adhesive joint established between the polymeric adhesive and the cork particles. The ability of adhesives to form good joints depends, among other factors, on the wetting of cork by the adhesives. The main objective of this research was to study the behaviour of adhesive drops deposited on cork substrates through measurements of contact angles and their time dependence. Several polyurethane prepolymers were tested to establish a correlation between the wetting characteristics and the chemical structure and physical properties of the adhesives. The effect of the morphology of cork on the interfacial properties was also investigated. The initial contact angles were related to the chemical nature of the adhesive. The kinetics of the wetting process were found to depend mainly on the viscosity of the adhesive.
Keywords: CONTACT ANGLE; CORK AGGLOMERATES; POLYMERIC ADHESIVES; WETTING

Anatomía y caracterización del sistema radicular del alcornoque - VERDAGUER, D; Molinas, M L (SCIENTIA gerundensis, 1992)
In this paper we describe the root system of a mature cork oak (Quercus suber L). The roots were excavated by hand methods, seccioned and weighed. Large sections were described anatomically and sections smaller than 10 mm of diameter by histological tecniques. The root system components were distributed into central root system (CRS) and peripheral root system (PRS). The CRS was located at the base of the tree and embraced an area of 1'5 m and a depth of 60 cm; it consisted of the root crown, thick horizontal or descending roots and thin roots. The PRS extended in a circle of 12 m in diameier. In the PRS, the thick roots were distributed more laxly and the thin roots predominated. At their basal portion, the descending roots were eccentric and eliptic and rapidly forked into two or more small- diameter branches. Grafting between root axes was frequent. The horizontal roots were perpendicular to the tree axis, they were quite circular and kept thickness more or less constant since they forked. Large-diameter root tips, white coloured were observed and their primary structure described. Neither on the root crown nor at the base of the roots, lateral huds were observed.
Keywords: Cork oak; Quercus suber L.; root; root anatomy; root system

Antioxidant activity in leaves of some Mediterranean plants - Chevolleau, S.; Mallet, J. F.; Ucciani, E. (Journal of the American Oil Chemists' Society, 1992)
{{Hexane and methanol leaf extracts of sixteen Mediter- ranean plant species were obtained by percolation. Higher yields were observed for m e t h a n o l (16.4-47.8%} than for hexane extracts (1.3-13%}. Antioxidant activity of these extracts w a s determined by a rapid spectrophotometric method involving the combined oxidation of beta-carotene and linoleic acid. Leaf extracts were thus characterized by an Antioxidant Activity Coefficient (AAC) ranging from 0 to 1000. Hexane extracts gave m u c h higher A A C values than the corresponding methanol extracts. In both cases, myrtle (Myrtus communis) showed the best antiox- idant effectiveness.
Keywords: antioxidant activity; hexane extracts; Mediterranean plant leaves; methanol extracts

Aproveitamento de plantas espontâneas (aromáticas e mediciais), em montado de sobro - Lopes Borges, A E; Afonso Morais, M H; Bernardo, A; Azevedo Gomes, A; Saraiva Lopes, A M (Scientia gerundensis, 1992)
In a previous paper the phenological evolution of aromatic and medicinal species in the understory of open forest of cork oak was studied, localised in two <<vis-a-visn hillsides with NW and SE exposition in Odemira. In this paper the effect of exposition in biological cycle of species is apreciated. A comparative analysis between the vegetation of the two stations was made in funtion of the phenological evolution, biomass prodution, floristic list and recovery by species. The characteristic of the organic and inorganic fractions are emphasized related with the present phenophases.
Keywords: aromatic plants; biomass; cork-oak stands; Medicinal plants; Phenology

Aproveitamento de plantas espontâneas (aromáticas e mediciais), em montado de sobro - Lopes Borges, A. E.; Afonso Morais, M. H.; Bernardo, A.; Azevedo Gomes, A.; Saraiva Lopes, A. M. (Scientia gerundensis, 1992)
In a previous paper the phenological evolution of aromatic and medicinal species in the understory of open forest of cork oak was studied, localised in two <<vis-a-visn hillsides with NW and SE exposition in Odemira. In this paper the effect of exposition in biological cycle of species is apreciated. A comparative analysis between the vegetation of the two stations was made in funtion of the phenological evolution, biomass prodution, floristic list and recovery by species. The characteristic of the organic and inorganic fractions are emphasized related with the present phenophases.
Keywords: aromatic plants; biomass; cork-oak stands; Medicinal plants; Phenology

BREEDING ECOLOGY OF THE BLUE TIT PARUS-CAERULEUS IN EASTERN SPAIN - A COMPARISON WITH OTHER LOCALITIES WITH SPECIAL REFERENCE TO CORSICA - GILDELGADO, J A; López, G; BARBA, E (ORNIS SCANDINAVICA, 1992)
Aspects of the breeding ecology of the Blue Tit Parus caeruleus were studied in intermediate stages of succession in a holm oak forest at Monte Poblet (eastern Spain) from 1985 to 1991. In different years the density in two plots without nest-boxes varied between 1.0 and 6.5 pairs per 10 ha. Nestbox introduction seems to have increased the density of breeding pairs. The mean laying date was earlier (6 vs. 13 May) in low altitude (500-750 m a.s.l.) plots than in a high altitude (900-1000) m a.s.l.) plot, but clutch size (6.9 vs. 6.5 eggs) was not significantly different (mean 6.6 eggs). No differences in mean laying dates were found between years. Significant differences in clutch size were found only between two years at the high altitude site. There was a slight, non-significant, seasonal decline in clutch size. No second clutches were laid. These results are discussed in the context of other Mediterranean studies with special focus on the differences and similarities between Corsican and mainland populations. It is shown that most of the characteristics of the Corsican population (i.e. density, habitat use, laying date, clutch size, number of broods per year) are shared by some populations on the mainland. On the other hand, some breeding traits of Blue Tit populations in southern France are closer to those of Central and North European populations than to the Iberian ones.
APS
Keywords: Blue tit; breeding ecology; Holm oak forest; nest-boxes; Parus cearuleus; Spain; succession stages

Comparative genet survival after fire in woody Mediterranean species - López-Soria, L; Castell, Caries (Oecologia, 1992)
Using data from three fires in northeastern Spain, we tested a condition necessary to support the idea that fire has been a factor in the evolution of the res- prouting habit: populations of all resprouting species within a community should show high levels of genet survival after fires and show a low coefficient of varia- tion. Species with high mean survival values were: Quer- cus ilex L., Phillyrea latifolia L., and Viburnum tinus L., with 88, 86 and 83% survival respectively; these groups had resprouts emerging from rootcrowns. Then followed Arbutus unedo L. (75%), Pistacia lentiscus L. (73 %), Erica arborea L. (77 %), Erica multiflora L. (57 %) and Juniperus oxycedrus L. (55%). This last group had resprouts from lignotnbers or burls. These two groups also differed in the variability around the mean: the first showed a lower coefficient of variation, 6-12, and the second ranged from 19 to 26. Slope exposure had no significant in- fluence on the process of resprouting, but soil depth did, with precipitation as a covariate. In the shallow soil category, the difference in genet survival between south- ern and northern exposures was 14% (71% vs. 57%); while the difference in the deep soil category was low, 5 % (87% vs. 82%). There was no significant interaction. The component of variance for soils was larger than that for species-specific effects; substantial overlap of the within- species variance indicated that species responded as if they were a single hypothetical population, in which most of the variation in chances of survival was due to the soil conditions. The possession of the resprouting habit did not ensure a high performance. Hence, we find weak support for fire as a factor in the evolution of the res- prouting habit.
Keywords: evolutionary convergence; fire-adapted trait; Mediterranean climate; regenerative types; resilience

Comparative phenology and growth in different species of the Mediterranean maquis of central Italy - Lillis, M; Fontanella, A (Plant Ecology, 1992)
A phenomorphological survey was carried out in central Italy to study the effects of increasing water stress on some characteristic species of the Mediterranean maquis. Nutrient content and leaf water potential were examined. The results show that three different groups exist which diverge in the mod- ulation of growth activity. 1) Evergreen sclerophyllous species (e.g. Pistacia lentiscus, Phillyrea media, Arbutus unedo, Ruscus aculeatus), which were supposed to be drought-tolerant, in fact limited their growth activity to a brief period before aridity increased. A similar growth pattern was exhibited by those spe- cies (e.g. Quercus ilex, Erica arborea, Smi/ax aspera) that stopped producing new leaves and branches during the driest season and that recovered after the first rain; i.e., their growth period lasted longer. 2) Drought-deciduous species (e.g. Calicotonw villosa) that adopted the drought-avoidance strategy had two vegetative periods interrupted by a phase during which they completely shed their leaves. 3) Semi- deciduous species (Cistus monspeliensis) with mesophitic leaves adopted an intermediate response. These grew even in the dry and cold season.
Keywords: mediterranean species; nutrient use; phenomorphology; water use

Comparative water relations of four Mediterranean oak species - Acherar, M.; Rambal, S. (Plant Ecology, 1992)
The water relations and responses of two evergreen (Quercus ilex L. and Q. suber L.) and two decidu- ous (S. afares Pomel. and Q. faginea Will.) Quercus species were studied under experimental conditions. Two-year old seedlings grown in 30 1. pots were subjected to a drying period during which stomatal conductance, pre-dawn potential and minimum foliar potential were measured. The results shows that, for all species, the daily course of stomatal conductance agrees with the patterns proposed by Hinckley et al. (1978 & 1983). Concurrent with the species responses to short-term variation in water availability, it was found that pre-dawn leaf water potential controlled the maximum daily leaf conductance. There was a strong correlation between pre-dawn leaf potential and maximum daily conductance as described by the reciprocal function g ........ = ( -0.47 + 2.61.~bp) 1 for the evergreen oaks and g ......... (-1.94+7.39.~bp) 1 for the deciduous species. These differences between the two groups may partialy explain their geograhic distributions, and suggest general questions concerning the mechanisms which optimize water-use efficiency in Mediterranean oak species.
Keywords: mediterranean species; Quercus; Stomatal conductance; water-potential; water-stress

COMPARISON OF THE HYDROLOGICAL CHARACTERISTICS OF 3 SMALL EXPERIMENTAL HOLM OAK FORESTED CATCHMENTS IN NE SPAIN IN RELATION TO LARGER AREAS - Piñol, J; Avila, a; Escarre, A; LLEDO, M J; Rodà, F (VEGETATIO, 1992)
Precipitation and streamflow have been measured in three small (0.04-0.52 km2) experimental catchments covered by dense holm oak (Quercus ilex L.) forests. Two of them are in the Prades mountains and one in the Montseny mountains (NE Spain). Here we test the hydrological representativeness of these catchments against the streamflow record at two nearby larger (34-60 km2) catchments, one from each massif. Comparisons of (i) annual streamflow, (ii) seasonal distribution of streamflow, and (iii) flow duration curves were made. At Prades, for the period of common record, mean annual precipitation was about 580 mm, and mean annual streamflow 44-81 mm at the two experimental catchments and 102 mm at the larger one. Most streamflow occurred during winter and spring in the three catchments. At Montseny, rainfall was higher, and mean annual streamflow was 495 mm in the experimental catchment, and 760 mm in the larger catchment, though these data were obtained in different periods in each catchment. Streamflow was roughly equal in autumn, winter and spring. At both sites flow duration curves were fairly similar in the small experimental catchments and the larger catchments. The higher streamflow at Montseny is reflected in its flow duration curves being well above those at Prades. The experimental catchments at Prades are thus fairly representative of the investigated hydrological characteristics. At Montseny, hydrological differences between the experimental catchment and the larger catchment are probably due to the higher mean altitude of the latter and to the non-overlapping periods of their streamflow records.
Keywords: EXPERIMENTAL CATCHMENT; montseny; prades; QUERCUS-ILEX; STREAMFLOW; Water budget

CONIFEROUS REPOPULATION EFFECTS ON QUERCUS-ROTUNDIFOLIA L FORESTS IN THE NW IBERIAN PENINSULA - GONZALEZ, M E G; SIERRA, G G; MERINO, A P (RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES, 1992)
A study has been made of the floristic composition and the edaphic chracteristics of Q. rotundifolia forests and pine repopulations made on the holm-oak climax area. The number of taxa in the repopulations is 40% less than in the holm-oak forests. The pH values are also higher in the holm-oak forests samples.
Keywords: climax area; edaphic characteristics; Floristic composition; Quercus ilex

CONSIDERAçõES SOBRE OS RESULTADOS JA OBTIDOS NA PROPAGACAO VEGETATIVA DO SOBREIRO. ESTACARIA E ENXERTIA - Roldão, I F; Alpuim, M H; Bohm, J (Scientia gerundensis, 1992)
This work documents the first results of cork oak vegetative propagation by cuttings in a controlled envuonment. The followings traits are analyzed : substrates, hormones, au and substrate temperature andrelative bumidity etc.. Results from bud graftings in the multiplication of plus trees are also referenced
Keywords: Cork oak; Cuttings; grafting; Quercus Suber L; vegetative propagation

CONTRIBUTION OF CHARCOAL ANALYSIS TO THE STUDY OF VEGETAL PALEOENVIRONMENT IN CATALONIA (SPAIN) - MORA, M T R (BULLETIN DE LA SOCIETE BOTANIQUE DE FRANCE-ACTUALITES BOTANIQUES, 1992)
Charcoal analysis of seventeen archaeological sites in Catalonia (north-east of Spain) gives an approach to the Holocenic vegetation history for this area. We establish four regionals patterns for the vegetation evolution : interior non continental, north-mediterranean, south-mediterranean and interior continental. We also notice the effects of anthropic action and the ancient distribution of particular species : Olea europeae, Fagus sylvatica, Pinus halepensis, Quercus suber.
Keywords: CHARCOAL ANALYSIS; REGIONAL PATERNS; vegetation history

Coroebus undatus (Coleoptera: Buprestidae) sur chêne liège dans le Sud-Est de la France : estimation des dégâts, relations entre ceux-ci et certains facteurs du milieu - Du Merle, P.; Attié, M. (Ann. For. Sci., 1992)
Coroebus undatus (Coleoptera: Buprestidae) on cork oak in southeastern France: an estimate of damage and its relationship to environmental factors. In 52 plots distributed throughout the cork oak stands (Quercus suber L) of the Maures-Esterel region in southeastern France (fig 1) 5-15 oaks were selected from those whose cork had been removed less than 1 year before. On such trees, galleries made by the late-instar larvae of the last generation of Coroebus undatus (Fabr) are clearly visible at the surface of the stripped part of the stem. On each tree, the 4 vertical lines running through the middle of the north, east, south and west sides of the stripped part of stem were divided into 50-cm long sections from soil surface, and intersections between galleries and each of these segments of lines were counted. For each tree and each plot a damage index was calculated as follows: the damage index of a tree (IA) was the mean total number of intersections per stem side counted on the first basal 1.50 m of the stem, that of a plot (IP) was the mean value of IA. IA may be considered to be roughtly proportional to the percentage of damaged stem surface (A%), ie, the ratio, expressed as a percentage, between the total surface of the galleries and the surface of the stem; both variables are approximately linked by the relationship: A % = 0.4 IA. C undatus occurred everywhere in the investigated area, but IA and IP ranged from 0 to 27.6 and 1.2 to 14.8 respectively, according to the trees and the plots (figs 2, 3). The first basal 0.50 m of stems was on average ≈ twice less damaged than the rest of their surface, while their south and west sides were slightly more damaged than the 2 others. Within plots, trees were equally damaged (same mean IA value) whatever the diameter and probably also the shade degree of their stems. Between-plot variation in IP was not explained by the mean diameter nor probably by the mean shade degree of stems. IP value tended to vary inversely with elevation, and was higher on average on southern slopes
Keywords: Coroebus undatus; damage assessment; environmental factor; inner-bark boring insect; Quercus suber; tree factor

Daily and seasonal variation in water relations of macchia shrubs and trees in France (Montpellier) and Turkey (Antalya) - Duhme, F.; Hinckley, T. M. (Vegetatio, 1992)
Based upon two different research studies in the mediterranean regions of France and Turkey, drought resistance strategies were investigated in a broad group of species. The diurnal and seasonal patterns of the water relations of different lifeforms from the thermo-mediterranean to submediterranean lifezones were compared. Three sites near Montpellier, in Southern France, and five sites near Antalya, Turkey were used for this comparison. Xylem pressure potential and relative stomatal aperture were the key water relations parameters collected in France while these parameters as well as osmotic potential and leaf conductance were studied in Turkey. From the 26 different study species investigated in France, 7 distinct types of stomatal control were observed, with the deciduous lifeforms showing the least control, the sclerophyllous and coniferous evergreens the greatest control and the malacophyllous shrublets intermediate levels of control. Predawn water potential values provided a means of classifying species according to their temporal and spatial utilization of site water reserves. The comparison of turgor potentials (difference between water and osmotic potentials) gave an insight into leaf adaptations to site moisture. Species with high predawn water potentials generally maintain positive turgor even at midday during the summer, whereas species with low predawn values were frequently at zero turgor even at predawn. Phlomis grandiJtora was the most extreme species with mid-summer predawns and midday water potentials of -6 MPa and osmotic potentials never more negative than -2.4 MPa.
Keywords: Drought resistance; Malacophyllous shrubs; Osmotic potential; Stomata control types; Turgor loss point; Xylem water potential

de la quema, corte, arranque, abandono o pastoreo del matorral de escoba blanca (Cytisus multiflorus) sobre la producción y estructura de la comunidad herbácea - Fernández-Santos, B; Gomez Gutiérrez, J M; Garcia Mares, R T (Pastos, 1992)
The effects of burning, cutting , pulling out, field abandonment or grazing on the pro- duction and structure of a dehesa pasture invaded by Cytisus multiflorus were studied. Significant differences in the biomass of herbaceous species were found between pastu- res and treatments when cutting was done in February. The highest total biomass pro- duction was in the "abandoned" plot. No differences were found between the burned and cut plots. All the treatments, except abandonment, gave rise to higher biomass in herbaceous plants compared to control plots, i.e. on which grazing was continued. After 3 years there was no effect of treatment on the appearance of new species. A decrease in species number was observed with the burned plot being the least affected. The área with traditional grazing showed the highest diversity, specific heterogeneity and propor- tion of leguminous species. The negative effect of cutting the above-ground biomass in winter is discussed. Key
Keywords: Biomass production; Community structure; Human disturbances treatments; Matorral pasture; Salamanca

Decomposition rate of Quercus rotundifolia leaves in an evergreen oak forest of the Duero Basin (Province of Zamora, Spain) - HERNÁNDEZ, I; Gallardo, J F; Regina, I Santa; Quilchano, C (Plant Ecology, 1992)
Experimental litter decomposition of Quercus rotundifolia leaves in an evergreen oak forest of the semiarid area of the Duero Basin has been carried out. The loss of weight of the decomposing oak leaves was 623, j, after 24 months. In general, it is physical factors (mainly precipitation) which limit the decompo- sition of the evergreen oak leaves. Different patterns of bioelement losses were observed, increasing the relative content of N and P, and decreasing the amounts of Mg, K and Na in the decomposing leaves.
Keywords: forest ecosystems; leaf decomposition

Dinámica de la descomposición de la hojarasca forestal en bosques de la cuenca del duero (provincia de zamora): Modelización de la pérdida de peso - Hernandez, I M; Santa Regina, I; Gallardo, J E (Arid Soil Research and Rehabilitation, 1992)
Resumen Se ha estudiado la pérdida de peso en el proceso de descomposición de hojarasca en tres ecosistemas forestales de la zona semiárida Cuenca del Duero: un encinar climácico de Quercus rotundifolia Lam., un pinar paraclimácico de Pinus pinea L., y un pinar disclimácico de P. pinaster Ait. No se encuentran diferencias significativas entre la dinámica de descomposición de las hojas en cada ecosistema, salvo cuando las hojas de encina se colocan en otros ecosistemas. La pérdida de peso se ajusta a una curva exponencial negativa. En todos los casos, durante los cuatro primeros meses de experimentación, el peso original se reduce en un 30%. Ello parece indicar que es la climatología quien dirige fundamentalmente, a corto plazo, el proceso de descomposición. En condiciones naturales, los índices de descomposición (K j y K o) siguen la secuencia: encina > pino piñonero > pino marítimo, tanto en hojas como en hojarasca total.
doi: 10.1080/15324989209381328
Keywords: forest ecosystems; semiarid area; wight loss modeling

DRY-MATTER INTAKE PER MOUTHFUL BY GRAZING DAIRY GOATS - PEINADOLUCENA, E; SANCHEZRODRIGUEZ, M; GOMEZCASTRO, A G; MATAMORENO, C; GALLEGOBARRERA, J A (SMALL RUMINANT RESEARCH, 1992)
Mouthful grass intake varied widely from season to season, with minimal values in winter (0.09 g DM) that increased to 0.51 g DM in Spring and decreased in Summer (0.21 g DM). Mouthful intake for shrubby species ranged between lowest for Cistus salvifolius (0.16-0.33 g DM) to C. ladanifer (0.95-3.57 g DM), followed by C. albidus (0.33-1.46 g DM). Quercus rotundifolia was the most frequently ingested arboreal species throughout the year, although the maximum DM content per mouthful (1.58 g) was for Olea europaea. These results show that the greatest weight per mouthful of grass was in spring. The largest amount of DM on a year-round basis was provided by the shrub (C. ladanifer, and the tree O. europaea. Differences in DM intake per mouthful for each species suggest that studies of comparative palatability based on grazing time or number of mouthfuls may lead to errors when estimating actual DM intake for different species studied. Such estimates should be corrected in the light of relative weight per mouthful for each food species.
APS
Keywords: Grazing; Olea europaea; Quercus rotundifolia

DYNAMIC OF ORGANIC-MATTER IN FORESTS SUBJECT TO A MEDITERRANEAN SEMIARID CLIMATE IN THE DUERO BASIN (SPAIN) - LITTER PRODUCTION - Hernandez, I M; Gallardo, J F; SANTA-REGINA, I (ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY, 1992)
The production of litter was determined in three forest ecosystems in the Duero basin (Spain): a climax oak forest of Quercus rotundifolia and two repopulated pine forests of Pinus pinea and P. pinaster. The time-course of the litter fall both from the different organs of the trees and as a total was followed. The mean total production of litter in the oak forest was 2,320 kg/ha-1/yr-1, slightly lower than the situation in the P. pinea pine forest, which was 2,400 kg/ha-1/yr-1 and higher than that of the P. pinaster pine forest 1,728 kg/ha-1/yr-1; the leaves and needles account for most of this total production (78, 89 and 96%, respectively).
Keywords: forest ecosystems; LITTER PRODUCTION

DYNAMIC STAGES IN EXTRAZONAL COENOSIS OF QUERCUS-ILEX IN ABRUZZO (CENTRAL ITALY) - CORBETTA, F; PIRONE, G (RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES, 1992)
This note has as its objective the study of extrazonal communities of Quercus ilex, found in the inner valleys of Abruzzo (Central Italy) and of the coenosis of substitution dynamically linked to them: Some valleys in the mountains of Abruzzo, and particularly those at Sulmona and Capestrano, to which this research refers, represent, from a climatic point of view, small bounded areas which are thermically high and which interrupt the continuity of the line of low temperatures which characterize the ridge of the Apennines. Other features of these inner areas (whose bottom is about 300–400 m) are the high annual temperature range of about 18°–20°C, and the quite low rate of rainfall (often below 700mm; below 500mm at Capestrano) because of the mountains which stop the wet winds.
Keywords: APS; climate; extrazonal comunities; Italy; Quercus ilex

The dynamics of a therophytic community in relation to self-regulation, herbivores and environmental variation - Acosta, F. J.; López, F.; Serrano, J. M. (Vegetatio, 1992)
The dynamics of a therophytic plant community in Central Spain has been studied, taking into account endogenous and exogenous factors. Using a simplified descriptive resolution a multi-species grass community and four canopy density types have been described in permanent quadrats. Transition matrices expressing the changes of vegetation state have been constructed. The importance of self- regulation was shown by the dependence of successive transitions on each other (highly significative log-linear models). The functioning cannot however be explained through a strict Markovian model because the transition probabilities are not stationary. The external local factors tested (microtopography, compactness and granivory) do not have a consistent effect on the vegetation dynamics, being variable over years, implying the importance of other more general factors on vegetation dynamics. Making transition probabilities dependent on external environmental factors rep
Keywords: Ants; Environmental influence; Granivory; Grasses; Markovian models; Vegetation dynamics

Dynamics of holm oak (Quercus ilex L.) coppices after clearcutting in southern France - Floret, C.; Galan, M. J.; Floc'h, E.; Romane, F. (Plant Ecology, 1992)
Holm oak (Quercus ilex L.) forest is one of the most widespread biocoenoses in the southern part of France. Until recently, clearcutting of wood for domestic use was carried out every 20 years or so in these coppice stands. In order to study coppice stand dynamics after cutting this paper presents results of observations of some items describing the vegetation structure, the floral composition, and the life cycles in a holm oak coppice stand during a six year period after clearcutting. One of the questions addressed in this study was whether these coppice stands reach a 'steady' state based on auto-succession, or if they continue to change. The results of the floristic changes after cutting suggest that the model of auto-succession best fits with the vegetation dynamics, even if changes in the density and life cycles of herbaceous species still exist six years after clearcutting.
Keywords: Life cycles; Mediterranean climate; vegetation succession

Edge effects on nest predation in Mediterranean fragmented forests - Santos, Tomds; Tellería, J L (Biological Conservation, 1992)
Edge effects on predation of artificial avian nests were studied in a forest archipelago mixed with agricultural land in Central Spain. Predation rates were lower on farmland than in the forest habitat. There was a trend towards lower predation on the forest edge than in the interior. This edge-core predation gra- dient differed from the usual pattern of nest predation found in other temperate fragmented forests. Predation by rodents was almost completely restricted to the forest habitat. We suggest that in very small fragments, such as those studied here, a 'packing effect' of small specialist forest predators could be the cause of high predation rates throughout the forest.
Keywords: edge effect; forest habitat; fragmentation (voyant); nest predation

Effect of cleaning and thinning on height growth and girth increment in holm oak coppices (Quercus ilex L.) - Ducrey, M.; Toth, J. (Plant Ecology, 1992)
This article studies the influence of cleaning or thinning intensity and of coppice age at the time of silvicultural treatment, on the growth of shoots remaining on the stool, in Quercus ilex coppices. Two experimental designs were used to answer these questions. The first studied the effect of two cleaning intensities on 4, 8, 15, 20, and 25 year old coppices. The second studied the effect of 4 thin- O O/ ning intensities (26 o, 42.0, 58%, or 78 °,/o removal of the initial basal area) on 43 and 57 year old coppices. In both cases, control plots undergoing no silvicultural treatment were maintained for each age class. The results, 4 and 5 years after silvicultural treatment, concerned girth increment and height growth of coppice shoots. Cleaning or thinning consistently had a positive influence on girth increment. In young coppices, less than 25 years old, mean annual girth increment was approximately 6 mm in the controls and double that under heavy cleaning. In older coppices, girth increment was lower in controls (3 mm per year) but the effect of thinning was very positive and, under very heavy thinning, growth was more than 11 mm per year. Cleaning and thinning often modify height growth. This effect was found to be either positive or negative and no general trend could be defined which was valid for all the age classes. Silvicultural treatments also had a positive effect on the appearance and growth of epicormic shoots on the holm oak trunks. The results were also analysed at the stool level. The number or percentage of shoots removed had a positive effect on the individual growth of selected shoots
Keywords: cleaning; coppice; Growth; Quercus ilex; thinning

THE EFFECT OF GROWTH-RATE ON THE STRUCTURE AND COMPRESSIVE PROPERTIES OF CORK - Pereira, H; Graça, J; Baptista, C (IAWA BULLETIN, 1992)
Cork samples with an age of 9 years and with different growth rates, corresponding to calibre classes `small', `medium' and `large', were observed by scanning electron microscopy and tested mechanically in compression. Differences in calibre correspond to different widths of annual growth rings; widths differ because both the number of cells produced per year and cell dimensions differ. For instance, small and large calibre cork had, respectively, 50 and 151 cells in one row of an annual growth ring, with an average prism height of 32.6 and 39.8 mum. The stress-strain curves obtained in compression parallel to the three main directions showed that cork with the higher growth rate (large calibre) has lower strength in compression for all strains and lower Young's moduli.
Keywords: COMPRESSION PROPERTIES; Cork; GROWTH RATE; QUERCUS-SUBER L; YOUNG's MODULI

The effect of individual tree shelters in growth and morphology of cork oak seedlings - Dias, A. S.; Tomé, J.; Tavares, P.; Nunes, J.; Pereira, J. S. (SCIENTIA gerundensis, 1992)
To study the effects of the tree shelters in growth and morphology of cork oak ( Quercus suber L.) seedlings two types of plastic shelters were used in this work: A, transparent PVC shelters (brown) reinforced withawhitepolyesternet, 75 cmofheight; B, translucentbrownpolypropilene, double w$led, square cross section and 120 cm of height. The plants were grown in 120 cm long tubes in Evora, Portugal and growth of sheltered and control plants was evaluated based upon measurements of height, branch lenght, number and area of leaves and biomass. Additionally the anatomy and morphology and heat tolerance of leaves of sheltered andcontrolplants was studied. The results sbow that prowth in beight was stimulated by shelters. The amount of branches was greater in seedlings with shelters seedlings in shelters B were not significant. The shootíroot ratio was higher in sheltered plants than in controls because of the above-ground biomass increased in the former whereas root biomass remained unchanged. Foliage developed inside the shelters showed characteristics of acclimation to shade and were less tolerant to heat being killed at lower temperatures than those of unsheltered controls. A than in controls but the differences between the latter and
Keywords: Acclimation to shade; heat tolerance; Quercus suber; tree shelters

Effects of acidity and detergent on in vitro pollen germination and tube growth in forest tree species - Paoletti, Elena (Tree Physiology, 1992)
The presence of 1 to 3 mg 1−1 sodium dodecylbenzensulfonate detergent, or a growth medium pH of 4.0–5.0, inhibited pollen germination and pollen tube elongation more in broad-leaved trees than in conifers. In the broad-leaved species, pollen germination and pollen tube elongation showed similar sensitivities to detergent and acidity, whereas in the conifers, pollen tube elongation was more sensitive than pollen germination to detergent and acidity. Although the germination percentage was low, conifer pollen germinated in the presence of detergent concentrations up to 15 mg l−1 and at acidities as low as pH 2.5 or 3.0. Pollen germination of most broad-leaved species was completely inhibited in the presence of detergent concentrations of more than 3–5 mg l−1; the only exceptions were some entomophilous species (e.g., Salix caprea L.) in which the ability of the pollen to germinate in high pollutant concentrations could be related to the presence of tryphyne.
10.1093/treephys/10.4.357
Keywords: acidity; detergent (voyant); pollen germination; tube elongation

Effects of bark-stripping on the water relations of Quercus suber L - Correia, O A; Oliveira, G; Martins-Loução, M a; Catarino, F M (Scientia gerundensis, 1992)
Quercus suber is the primary source of industrial cork and can produce cork every 9-10 years. The main objective of this work was to investigate the influence of bark stripping on the stomatal activity and water relations of cork-oak. For this purpose, diurnal changes on transpiration, stomatal conductance and water potencial were measured before and after bark stripping during July and August 1989 and 1990. The stripping on the trees had been done at various intensities. The water loss by the stripped surface was also measured. These results show that severe bark-stripping may lead to a decrease in stomatal conductance and considerable water losses. The stripping stress is not clearly dependent on the stripping coefficients, but rather on the water lost by the trunk which varies from tree to tree probably according to the phloemic tissues composition.
Keywords: bark-stripping; Quercus suber; Transpiration; water relations

Effects of bark-stripping on the water relations of Quercus suber L - Correia, O. A.; Oliveira, G.; Martins-Loução, M. A.; Catarino, F. M. (Scientia gerundensis, 1992)
Quercus suber is the primary source of industrial cork and can produce cork every 9-10 years. The main objective of this work was to investigate the influence of bark stripping on the stomatal activity and water relations of cork-oak. For this purpose, diurnal changes on transpiration, stomatal conductance and water potencial were measured before and after bark stripping during July and August 1989 and 1990. The stripping on the trees had been done at various intensities. The water loss by the stripped surface was also measured. These results show that severe bark-stripping may lead to a decrease in stomatal conductance and considerable water losses. The stripping stress is not clearly dependent on the stripping coefficients, but rather on the water lost by the trunk which varies from tree to tree probably according to the phloemic tissues composition.
Keywords: bark-stripping; Quercus suber; Transpiration; water relations

Effects of fire and of clearing in a Mediterranean Quercus ilex woodland: An experimental approach - Soler, Montserrat; Sala, Maria (CATENA, 1992)
The object of the study is to compare the importance of soil and nutrient losses from plots in an ever green oak (Quercus ilex) woodland under different environmental conditions; namely under undisturbed forest and at sites that had been clear felled and burnt under controlled conditions. At each site, the plots were instrumented with 10 Gerlach troughs located at the footslope of each plot, and with 12 troughs in the upper part of the burned plot inserted at regular intervals from the water divide. Raingauges were subsequently added and data on rainfall intensity collected at a nearby station. Results indicate that burning has a significant effect with respect to runoff and nutrient and sediment losses. The impact of clear-felling is much less. Sediment transport on the slope is not only caused by surface runoff but by other agents of erosion as well.
Keywords: disturbance regimes (PG); evergreen oak woodlands; Nutrient losses; soil loss

Effects of leaf longevity and retranslocation efficiency on the retention time of nutrients in the leaf biomass of different woody species - Escudero, a; Arco, J. M.; Sanz, I. C.; Ayala, J. (Oecologia, 1992)
A study was made of the retention times of N and P in the leaf biomass and their relationship with the retranslocation percentages and the leaf longevities in some woody species in Central Spain. The retention times of both nutrients were strongly related to the nu- trient status of each species. These results suggest that a prolonged retention time is a way of increasing nutrient use efficiency in conditions of low nutrient availability. Plants can increase the retention time of nutrients in their leaf biomass by means of an increase in leaf longevity and/or by means of an increase in retranslocation effi- ciency. However, the effect of the retranslocation effi- ciency on retention times was almost negligible compared with the effect of leaf longevity. This suggests that an increase in leaf longevity is probably the best adaptation for increasing efficiency in the use of nutrients.
Keywords: leaf longevity; nitrogen; Nutrient use efficiency; phosphorus; retranslocation

Effets de températures sub-létales sur l'appareil photosynthétique du chêne vert (Quercus ilex L) - Trabaud, L; Méthy, M (Ann. For. Sci., 1992)
Effects of sub-lethal temperatures on the photosynthetic apparatus of Quercus ilex L. Resistance to high temperatures by the photosynthetic system of leaves of a sclerophyllous tree growing in the Mediterranean basin (Quercus ilex) has been studied using the fluorescence induction technique. Registration of the kinetics with determination of fluorescence decrease ratio was carried out every month for 1 year. According to the dates of sampling, leaves were sorted into 2 categories: > 3 months and < 3 months. They were heated at temperatures of 50, 55 and 60 °C for periods ranging from 0 to 30 min. After sclerification was established (≈ 1 month old) leaves withstood heat with only limited damage at 50 °C. In contrast, the photosynthetic system was totally destroyed when exposed to 60 °C for 30 min. Leaves collected in July displayed some adaptation to high temperatures. The consequences on the functioning of Q ilex in an environment with high temperatures have been examined.
Keywords: fluorescence; photosynthesis; Quercus ilex; thermal stress

The efficiency of nitrogen retranslocation from leaf biomass in Quercus ilex ecosystems - Escudero, a; Arco, J M; Garrido, M V (Plant Ecology, 1992)
Nitrogen retranslocation from senescing leaves represents a crucial adaptation by tree species towards a more efficient use of this nutrient. As a result, this part of the nitrogen cycle has received increasing attention in recent years. However, there remain strong discrepancies with respect to the factors re- sponsible for interspecific differences in the efficiency of this process. In the present work the seasonal pattern of leaf growth and the movement of nitrogen in leaves have been studied in a series of Quercus ilex plots with different levels of rainfall and soil quality in central- western Spain, as well as in 20 other woody species typical of this area. The percentage of nitrogen retranslocated was estimated from the difference between the maximum mass of nitrogen stored in the leaf biomass and the amount of this nutrient returned annually to the soil through leaf fall. Q. ilex appears as one of the least efficient species in the Mediterranean region in the recovery of nitrogen from senescing leaves (29.7°0 of the maximum pool). Furthermore, the older leaves of Q. ilex do not s h o w the cycles of nitrogen withdrawal during new flushes of shoot growth, such as occurs in Pinus spp. This suggests that older leaves in Q. ilex do not play an important role as nitrogen storage organs.
Keywords: leaf demography; Leaf fall; nutrient cycling; Pinus pinea; Quercus ilex; Quercus pyrenaica

El crecimiento radial del alcornoque en cinco parcelas de alcornocal de Girona - Caritat, A.; Molinas, M.; Oliva, M. (Scientia gerundensis, 1992)
Tree rings of Quercus suber L. are porous and difficult to read because of the irregular growth rhythm. Radial growth has been measured in five experimental plots situated in the region of Girona (Catalonia, NE Spain). Cores of ten standard trees of each plot were extracted using a Pressler borer. In three plots woody disks from standard trees were also obtained. Tree rings were examinated under binocularlens. The CATRAS computer program (Anio1,1983 ) was used to find statistical parameters. Tree rings have an average width changing from 1,21 to 3,74 mm, while average standard deviation varies from 0,24 to 1,88 mm. and autocorrelation from 0,008 to 0.894 . These values are similar to those found in other Mediterranean Quercus, like Q. ilex L. The studied cork-oak plots ,with diametrical classes between 5 and 57 cm, show regular growth characteristic of young forest. The St. Hilari plot has the maturest trees, (diametrical classes from 24 to 57 cm) and this fact was reflectedin thegrowthcurve. Suddengrowthincreases are attributed to forestry management measures like clearing or selective cutting down. The effects of periodic cork extractions could no be clearly appreciated in this study.
Keywords: cork-oak; Mediterranean sclerophylls; Quercus suber L.; Radial growth; wood rings

ENTOMOLOGICAL ASPECTS OF THE PROTECTION OF QUERCUS-SUBER L FORESTS IN SARDINIA - PROTA, R; DELRIO, G; FLORIS, I; LENTINI, A; LUCIANO, P (RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES, 1992)
In the Sardinian cork oak forests, more than 300 species of Lepidoptera have been found, 10% of which develop on Quercus suber L. trees. The population density of these insects varies greatly, and, in some cases, is so high that causes total defoliation on large scale. Three species in particular cause serious damage: Lymantria dispar L., and Malacosoma neustria L. with periodic infestations and Tortrix viridana L. with temporary ones. There are also other, less harmful species, such as Dryobota labecula Esp., Dryobotodes monochroma Esp., Dryobotodes eremita Fabr., Orthosia cruda Den. & Schiff., Spudaea ruticilla Esp. and Phalera bucephala (L.) that have different fluctuations which can be described as latent or periodic (3).
Keywords: Cork oak; defoliation; lepidoptera; Sardinia

Estudos de hidrologia em povoamentos de Quercus suber e caracterizaçao mesológica do ecossistema - Almeida, A. P. (Scientia gerundensis, 1992)
The main objective of the project is to assess the effect of different types of soil management under cork-oak tree stands on water use and cork productivity. The study utilized a 5.5 ha watershed near the town of Mora, center of Portugal. The watershed contained scattered cork- oak with natural pasture, which is probably the most representative formof landuse in the region. de 1990, que va mostrar la The project used the basic water balance equation, being evaluated incident rainfall, runoff, evapotranspiration and changes in soil water storage. Measurements of the tree stands and canopies were included for the characterization of throughfall and stemflow. Interception was estimated to evaluate its effects onrainfallredistribution and onthe dynarnics of evapotranspiration. Collection of data for the intensive hydrologic study begun in October 1, 1988. During 1989, surface runoff was 10.8 percent of annual rainfall. For the same period, canopy interception by the Quercus suber stand was 15.4 percent and throughfall accounted for 84.6 percent of annual rainfall, as stemfiow was considered negligible. Statistical analysis of data related to the period January, 1990 to May, 1990 is now being undertaken. Itis apparent, however, from the study, that the data sets should be extended through further research to confirm the tentative hydrological trends of the first period.
Keywords: cork-oak; land use; pasture; productivity; water balance

Étude de la productivité des parcours de la zone d'Ain-Leuh (Moyen Atlas, plateau Central). II. Modélisation de la production d'herbe : interactions climats × sol × recouvrement arboré - Qarro, M; de Montard, F X (Agronomie, 1992)
A study of dry matter production in rough pastures of Ain-Leuh (Middle Atlas, central plateau). II. Model of herbage production: climate-soil-tree cover interactions. Herbaceous production was measured in 1983 and 1984 in the Middle Atlas and central plateau rangelands and grazed forests, in the Aïn-Leuh region, at 4 characteristic sites in 4 bioclimatic zones: semi-arid (Quercus ilex and Juniperus oxycedrus forest), sub-humid (pure Quercus ilex forest), and humid (Cedrus atlanticus and Quercus ilex forest, unsylvatic low grass at the highest site); measurements were made in areas protected from sheep and goat grazing, through 5 successive cuts from late February to mid-July, on plots varying in tree cover from 0 to 90%. Late February yield was mainly explained through the degree of precipitation occurring in both September plus October, interacting with the levels of soil nitrogen in poor soils of the Quercus and Juniperus zone, or level of rough sand in clay soils of the 3 upper zones. Yields from 4 successive cuts from the end of March to mid-July were mainly explained through interactions between radiative energy and a function of tree cover rate (100-R) eR/B; the B value was 50 in the semi-arid zone, and 90 for non-legume and 50 for legume plants in the sub-humid/humid zone). A climate humidity factor, the ETR/ETP ration in sub-humid and humid zone or the frequency of rainy days in the semi-arid zone, had an additive and an interactive effect respectively.
Keywords: climatic factor; dry matter; nitrogen output; production; range; silvopastoral agriculture; tree cover rate

Evaluation of actual evapotranspiration of a Quercus ilex L. stand by the Bowen ratio-energy budget method - Pitacco, A; Gallinaro, N; Giulivo, C (Plant Ecology, 1992)
Actual evapotranspiration from a closed-canopy Quercus ilex L. stand has been estimated by applying the Bowen Ratio-Energy Budget method. Daily water loss was 3.5 mm day ~, with a peak rate near 0.6 mm hour ~. The phenomenon of thermal inversion, quite common in mediterranean climates, seemed to play a significant role in reducing evapotranspiration, by promoting dew formation and delaying the establishment of fluxes of latent and sensible heat away from the canopy. Dew, which may form over many hours in the night, appears to be a major sink of available energy in the early morning and may represent a useful water source for stressed foliage. The alternating processes of condensation and evaporation may have a beneficial effect on the closed stand micro-environment.
Keywords: actual evapotranspiration; bowen ratio; energy balance; Quercus ilex L

Evidence for hybridization between sympatric holm-oak and cork-oak in Spain based on diagnostic enzyme markers - Elena-Rossello, J. A.; Lumaret, R.; Cabrera, E.; Michaud, H. (Plant Ecology, 1992)
Hybridization has been detected in mixed populations of juvenile cork-oak and holm-oak individuals using three diagnostic enzyme loci coding for esterases, leucine amino peptidases and acid phosphatases respectively. Among the 35 studied individuals, 29, 5 and 1 were identified as holm-oak, cork-oak and hybrid respectively. Such diagnostic markers are likely to be useful to detect and remove hybrids at the juvenile stage in areas where the holm-oak is grown for acorn production and the cork-oak is cultivated for cork. This is necessary since hybrid adults produce neither cork nor acorns of high quality.
Keywords: cork-oak; enzyme markers; holm-oak; Hybridization; Quercus

Factors affecting radial growth of Quercus ilex L. in a coppice stand in southern France - Cartan-Son, M.; Floret, C.; Galan, M. J. (Plant Ecology, 1992)
Quercus ilex woodlands in the south of France are characterized by low productivity. Several hypo- theses have been put forward to provide an explanation for this phenomenon: (i) senescence of coppice stumps; (ii)limited availability of water and nutrient resources; (iii)intershoot and inter-plant compe- tition. To test some of these hypotheses, growth response to rainfall distribution and nutrient supply (NPK), and the influence of edge effects after clear-cutting were studied in a 40-yr old stand. Curves of radial increment were compared with precipitation and umbrothermic patterns for the 6 years studied. Water availability apparently accounted for some inter-annual differences in growth. However, it was not mean annual rainfall, but rather rainfall occurring in late spring-summer (June, July) which played a large role in determining radial growth. Radial growth was also increased by nutrient supply. Its positive effect was strengthened by favourable rainfall in 1987. Edge-effects following a clear-cut were also found, both in the first year and in four succeeding years following the cut. This comprised in greater radial growth rate for all shoots, with reduced repression of smaller shoots by the larger ones. The effect decreased over a distance of 10 m with increasing distance from the cut field. This could be explained by increased availabiDLy of water, nutrient resources, and light.
Keywords: clear-cutting; edge effect; Mediterranean climate; nutrient supply; productivity

FITOMASA SUBTERRÁNEA Y AÉREA EN PASTOS DE DEHESA - Puerto Martín, A; Puerto, A (Pastos, 1992)
A study has been conducted on the spatial variations undergone by root biomass, aerial phytomass and the root/shoot ratio in grassland communities (dehesa systems). These variations are governed by the prevailing gradients: topographic and the effect of the tree canopy. The greatest biomass, both underground and aerial, and the lowest root/shoot ratio are usually found in the more fertile sites (deposition sector of slope) and shaded áreas (under the crowns of the trees), in contrast to the results of some researchs performed in cultures or at the laboratory. In the case of natural or semi-natural groupings of herba- ceous species in severe environments, the adaptive responses of each species appear to predomínate over any generalized type of response. Key
Keywords: España; fitomasa; Grasslands; influencia del arbolado; ladera; pastos; phytomass; Salamanca; Salamanca (Spain); slope; tree canopy ¡nfluence

Gradients of anatomy and morphology of leaves in the crowns of cork oak - Nóbrega, C M; Pereira, J S (SCIENTIA gerundensis, 1992)
Stomatal frequency, anatomical characteristics and specific leaf area (ratio dry weight. area-l) of ashadeleavesn and asunleavesw of Quercussuber L., were studiedineight adult trees inthe field with two types of soil utilization, plot E with subterraneum clover pasture and plot G with tradicional agriculture in Besteiros near Vendas Novas, in Portugal. in boths plots the stomatal frequency is higher in leaves of upper stratum than in the lower part of the crown. The length of guard cells is higher in the proximal position of middle and superior stratra than in the inferior stratum. The dry weight.area-I does not vary significantly between two types of leaves. The trees belong to an open stand where shading among trees is minimal. However, the dry weight.area- ratio of leaves of plot with traditional agriculture is significantly higher than that of leaves of the plot with pasture probably as a consequence of the depletion of soil nitrogen caused by agriculture.
Keywords: Acclimation to shade; Quercus suber; stomatal frequency

Growth and yield of young Quercus ilex coppice stands in the Tafferte forest (Morocco) - Khatouri, M (Plant Ecology, 1992)
The coppice method is the silvicultural system commonly applied to Quercus ilex (holm oak) forests for the production of firewood and charcoal. Although the holm oak is the species that covers the largest area in Morocco (1400000 hectares), little is known about its growth and yield. The objective of this study is to quantify the stand growth and yield of young coppice holm oak stands in the Tafferete for- est in the eastern part of the Middle Atlas (Morocco). Equations relating dominant height to age, and basal area, volume, and number of trees to dominant height were developed and used to derive young holm oak coppice yield estimates. The growth and yield information developed in this study may have a greater utility in defining cul- tural measures that should be applied in the early stage of holm-oak coppice stands.
Keywords: Diameter Distribution; Growth Curves; Holm oak; middle atlas; production

Growth patterns of cork-oak (Quercus suber L.) under natural conditions - Oliveira, G; Correia, OA; Martins-Loução, MA; Catarino, FM (Responses of Forest Ecosystems to Environmental Changes, 1992)

Growth stresses and strains in cork - FORTES, M A; Rosa, M E (Wood science and technology, 1992)
A detailed study of the growth stresses and strait~s in the cork sheI1 of the cork-oak was undertaken based on experimentally determined constitutive relations for cork in tension and compression. The stresses depend on the thicknesses of the cork shell and of the back layer around the cork shell, on the radius of the trunk and on its increase due to growth. The circumferential stresses in the cork shell and back layer are tensile and increase with increasing distance to the tree axis. The radial stresses are compressive and decrease with increasing distance to the tree axis. The strains due to growth are not recovered when the cork boards are removed, unless the boards are heated, for example, by immersion in boiling water. Other consequences of the growth stresses are analysed, such as the occurrence of corrugations in the lateral cell walls of cork, the variation of width of the successive growth rings and the occurrence of cracks in the back layer and outer cork layers.
Keywords: back layer; Cork; growth stresses (voyant)

GROWTH-PATTERN AND ARCHITECTURE IN QUERCUS-ILEX L AND FRAXINUS-ORNUS L VEGETATIVE REGENERATION AFTER COPPICING IN MAREMMA-NATURE-PARK (CENTRAL ITALY) - SALBITANO, F; UGOLINI, M (RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES, 1992)
Growth pattern and architecture have been studied in Quercus ilex L. and Fraxinus ornus L. stools as main phenomena, testing the space occupation dynamics by the new population of shoots after coppicing. In the early years after coppicing, Fraxinus ornus L. rapidly occupies the vertical space by long spring flushes, while Quercus ilex L. occupies both the vertical and horizontal available space by a complex network of primary meristems.
Keywords: Fraxinus ornus L.; growth pattern; meristems; Quercus ilex L.

HABITAT PREFERENCE OF SPANISH IBEX AND OTHER UNGULATES IN SIERRAS DE CAZORLA Y SEGURA (SPAIN) - ESCOS, J.; Alados, C. L. (MAMMALIA, 1992)
Studied the habitat preference in Autumn and Spring periods of Spanish ibex (Capra pyrenaica), fallow deer (Dama dama) and red deer (Cervus elaphus) in the Sierras de Cazorla y Segura Park (Spain). Spanish ibex occupied most altitude range studied, especially highest parts and avoiding areas below 800 m, red deer selected lowest elevations between 700 to 1100 m and fallow deer (between 1200-1600 m) occupied an intermediate annual altitudinal range. All the ungulates studied showed, except the red deer populations, a descent of altitudinal levels in the Spring period. Ibex used more covered areas specially females and young in Spring period, fallow deer occupied open habitats and red deer preferred holm-oak woods. In general terms the rut occurred in more open areas while in the birth season, females and young especially occupied covered areas. According to the overlap index (Pianka 1973) ibex with fallow deer could get a high risk of competition, while Spanish ibex and red deer, the only endemic species show the lowest level of overlapping on the resources studied. Segregation of the sexes studied in different habitats was observed. In Autumn, Spanish ibex and fallow deer showed a tendency to occupy sunny areas at dawn and dusk and this tendency occurred in red deer only at dawn but not at dusk. However in Spring, Spanish ibex, fallow and red deer occupied sunny slopes at dusk but only fallow deer do so at dawn.
The following values have no corresponding Zotero field: pub-location: 55 RUE DE BUFFON, 75005 PARIS, FRANCE publisher: MUSEUM NAT HIST NATURELLE
Keywords: APS; Capra pyrenaica; cervus elaphus; Dama dama; habitat prefference; Holm oak; Spain; ungulates

HUMAN-PLANT RELATIONSHIPS DURING THE COPPER AND BRONZE AGES IN THE BAZA AND GUADIX BASINS (GRANADA, SPAIN) - ARIZA, M O R (BULLETIN DE LA SOCIETE BOTANIQUE DE FRANCE-ACTUALITES BOTANIQUES, 1992)
The anthracological study of six sites in the north of province of Granada (Spain) has uncovered vegetation for the Copper Age formed by a dense oak grove belonging to the association Rhamno-Quercetum cocciferae. In the Bronze Age, the intensification of agriculture caused changes in the vegetation, reflected in the anthracological diagrams by the increase in Pinus halepensis and the decrease of Quercus ilex-coccifera, as well a decline in the woodlands and an expansion of the legumes. The different species present in the vicinity of the site (or in a greater radius), servings such specific functions as the making of tools and utensils, house construction, and firewood for the hearth or for fours, give us preliminary insights into the ways in which these populations used space and their vegetal environment
Keywords: CHARCOAL ANALYSIS; COPPER AGE; Granada; Spain

HYDROCHEMICAL BUDGETS, NUTRIENT CYCLES AND HYDROLOGICAL RESPONSES IN THE QUERCUS-ILEX-FOREST OF PRADES CATCHMENTS - Bellot, J.; Lledó, M. J.; Piñol, J.; Escarré, A. (RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES, 1992)
In this paper we present a perspective of the objetives in the Prades project, as well as some results of 7 years of study on Hydrochemical budgets, and water and nutrient fluxes in the holm-oak forest (bulk deposition, throughfall, stemflow, primary production, litterfall, runoff, etc)
The following values have no corresponding Zotero field: periodical: RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES pub-location: BARKING ESSEX
Keywords: Hydrochemical budgets; nutrient fluxes; water fluxes

Impacte das principais micoses no montado de sobro - Fonseca Neves, N. (SCIENTIA gerundensis, 1992)
Several factors have been found to contribute for the weakness o€ cork-oak stands, and among thosefactors, diseases have animportantrole. In this paper, the main diseases, their causal agents, symptoms and damages are described. Bioecological aspects of the causal agents and protection measures are referred.
Keywords: cork oak stands; diseases

Impacte do Platypus cylindrus F.(Coleoptera, Platypodidae) en Quercus suber L - Ferreira, M. C.; Ferreira, G. W. S. (Scientia gerundensis, 1992)
The main symptoms of attacked trees by Platypus cylindrus F. are given. Data on bioecology, dispersion and impact of this species on Quercus suber L. are presented. Protection mesures.
Keywords: Cork oak; Platypus cylindrus F.; Quercus Suber L

Influence of cutting methods and dates on stump sprouting in Holm oak (Quercus ilex L) coppice - Ducrey, M; Turrel, M (Ann. For. Sci., 1992)
The goals of this study were to compare height growth of stump sprouts in Quercus ilex stools cut by different methods at various times during the year. Four cutting methods were compared: chain saw at ground level and at 15 cm above ground, axe, and 'saut du piquet' ('stump breaking'). Cuttings were carried out every 2 months for a period of 1 year. Several important results can be described 4 years after cutting. Cuttings performed during the dormant season resulted in minimum stool mortality, and maximum new sprout number, height and diameter growth. An exception was cutting made during a winter frost period. Summer cuttings led to the poorest growth which, however, tended to be regained in subsequent years. Axe and chain saw cuttings yielded better results than 'saut du piquet' cutting. This last method resulted in high stool mortality and both fewer and smaller sprouts. Sprouts appeared to be more numerous and grew better when the stools initially had large and numerous shoots.
Keywords: coppice; cutting date; cutting method; Quercus ilex L; stump sprout

Influence of Growth Regulators on Shoot Proliferation in Quercus suber L. - Romano, A; Noronha, C; Martins-Loução, M a (Annals of Botany, 1992)
Procedures have been developed to standardize the multiplication stage during mature cork-oak (Quercus suber L.) micropropagation. Axillary and terminal buds were established on Gresshoff and Doy basal medium containing 1 mg I−1 of 6-benzylaminopurine (BAP). Initiation of cultures was possible all over the year. The effects of BAP, Z, IBA, 1AA and NAA and various nutrient formulae on shoot growth and proliferation was investigated. BAP was more suitable than zeatin. Shoot proliferation and elongation were strongly improved by the combination BAP/IAA in the presence of low salt media, like Gresshoff and Doy or Woody Plant medium. Both rates were significantly increased when a double-phase culture system was used. Shoots have been multiplied for 1 year at the rate of three to four-fold every 4 weeks without any decline of vigour. Rooting was achieved by briefly dipping the basal ends of in vitro regenerated shoots in an IBA concentrated solution. The results here reported constitute a promising step towards large scale in vitro propagation of a species in which conventional vegetative propagation by cuttings is very difficult.
Keywords: Auxins; browning; cork-oak; cytokinins; Forestry; multiplication; Quercus suber L.; re-invigoration; re-multiplication; two-phase medium

The influence of summer and winter stress and water relationships on the distribution of Quercus ilex L. - Terradas, J; Savé, R (Plant Ecology, 1992)
Several aspects of plant-water relationships and canopy behaviour have been studied over several years in two experimental areas of Quercus ilex E. forests in the northeastern Iberian Peninsula. Water requirements, water status limits necessary for a positive carbon budget and the functional canopy be- haviour in the face of abiotic stress were evaluated, in order to determine which factors influence the geographical range of these forests. The results showed that holm oak has a conservative water use, a low cuticular transpiration, a high capacity for osmotic adjustement and xerophytic characteristics in leaf morphology and canopy arrange- ment. More than 440 mm of annual rainfall are required for these forests to persist. Summer drought and winter cold are thus important abiotic factors limiting the distribution of Quercus ilex. In both cases, drought stress is involved.
Keywords: canopy behaviour; Evapotranspiration; gaseous exchange; leaf morphology; plant-water

Las técnicas de selección y propagación en la mejora genética del alcornoque - García Valdecantos, J. L. (Scientia gerundensis, 1992)
The role and importance of the techniques of propagation and selection in the cork oak breeding programs are discussed. In the field of propagation, the characteristics of sexuai reproduction are discussed. The author recommends the use of medium or small acorns and empbasizes the need of improving acorn storage procedures. Considering vegetative propagation as the best method to obtain maximal genetic gains, the author emphasizes the difficulties found in the use of cuttings, the fairly good results obtained with grafts, and the promising experiences of tissue culture. The importance of rejuvenating techniques using stump sprouts and suckers for vegetative propagation is strongly emphasized. The selection superior trees for breeding programs in the cork oak is difficult because of the lack of previous experience in genetics of bark production. An experimental method, developed in the province of Cidiz with the help of ICONA, is described. This method is based in an accurate measurement of a number of tree pararneters which are evaluated at the end of a complete harvest cycle (9 years).
Keywords: Cork oak; provenances; seed orchards; tree breeding; vegetative propagation

Late glacial and Holocene vegetation of the Corbières based on charcoal analysis at the Cova de l'espérit (Salses, Pyrénées orientales, France) - Solari, Maria-Eugenia; Vernet, Jean-Louis (Review of Palaeobotany and Palynology, 1992)
Charcoal analysis from the end of the Würm Glaciation and the Holocene at Cova de l'Espérit reveals the coexistence, in the Corbières region, of thermo-and meso-Mediterranean taxa. Three principal paleoecological phases are described: the first corresponds to the Upper Paleolithic (Würm III), the period of maximum cold, dominated by Juniperus assemblages. The second phase includes levels from the end of the Mesolithic and early Neolithic. It shows the appearance of mesothermic species such as Buxus sempervirens, Acer sp. and Quercus ilex, at the same time as the development of a thermophilic suite of species e.g. Olea europaea, Rosmarinus officinalis and Pistacia. During this period, the effect of man on the environment remained slight. The third phase consists of the middle Neolithic and more recent periods and reveals the degradation of the environment due to the development of agriculture and animal husbandry. The Garrigue—a mediterranean open human-influenced vegetation—has persisted up to the present.
Keywords: CHARCOAL ANALYSIS; Cova de l'Espérit; Holocene; human influence; vegetation history (PG)

Litter dynamics in post-fire successional forests of Quercus ilex - FERRAN, A.; Vallejo, V. R. (Plant Ecology, 1992)
Forest floor regeneration after fire in a holm oak forest was studied in a chronosequence in Catalonia (NE Spain). The sampled area represented situations of high fire disturbance because of the frequency of wildfires and the high impact of erosive processes. Forest floor bulk samples from the L, F and H layers were taken in 5 burned plots, aging from 0 to 35 years. They were analyzed for dry standing weight, and organic carbon and N content. Plant cover reached almost 100°o two years after the fire. During the first 20 years, shrubs and herbs had the highest surface covering, and thereafter, holm oaks became dominant. Holm oak litterfall stabilized by the fourth year after burning. The major shrub species which were present in the chronosequence had two different patterns with respect to nitrogen: 1) a low litter C/N ratio (i.e. nitrogen fixing species); 2) a high litter C/N ratio. The litter decay coefficients were relatively high, allowing for a rapid structuration and formation of the L and F layers after the fire. Indeed, 95 ° o of the maximum steady standing weight accumulates in 8-9 years. The pattern of cover in the different strata influenced the lateral distribution and variable accumulation of the forest floor layers and determined different turnover rates.
Keywords: C/N ratio; Decay coefficient; Holm oak; mediterranean forest; plant regeneration

Litterfall as a measure of primary production in Mediterranean holm-oak forest - Bellot, J.; Sánchez, J. R.; Lledó, M. J.; Martínez, P.; Escarré, A. (Plant Ecology, 1992)
In this paper we discuss the use of litterfall as a method to measure primary production and its between year relation to climatic fluctuation. Seven years of study in a mediterranean holm-oak forest showed a moderate inter-annual variability of litterfall (C.V. 11°;), while the annual variability of the actual or evapotranspiration was three times higher (C.V. 30/o). Furthermore, the inter- and intra-annual vari- ability of nutrient content in the various fractions are presented in relation to water availability. Monthly and seasonal variability was higher than the annual variability for all analyzed elements.
Keywords: holm-oak; litterfall; litterfall nutrient contents; mediterranean forest; primary production; Quercus ilex; temporal variability

A mass spectrometry study of thermal dissociation of cork - Filomena Bento, M.; Aurea Cunha, M.; Moutinho, A. M. C.; Pereira, H.; FORTES, M. A. (International Journal of Mass Spectrometry and Ion Processes, 1992)
Mass spectrometry has proved a convenient technique for the analysis of plant cell-wall material. In this work a comparative study is made of chemically treated cork and untreated cork, applying a method in which samples were continuously heated in vacuum. The outgassing products, upon electron-induced fragmentation, are analysed by a quadrupole mass spectrometer. Sequence of spectra at increasing temperatures were obtained for each sample, which allowed identification of the main groups of fragmentation. From such sequences of spectra one may derive intensity—temperature curves for each peak. Analysis of these curves for samples subjected to different treatments proved useful to identify the peaks, to assign the component which originates the species and even to derive activation energies.
Keywords: Cork; electron-induced fragmentation; thermal dissociation

Matter transfer and land use by cattle in a dehesa ecosystem of Central Spain - Gómez-Sal, A; Rodríguez, M a.; Miguel, J M (Vegetatio, 1992)
The transfer of matter by cattle in a 'dehesa' patureland in Central Spain has been quantified by map- ping the distribution of dung and different types of cattle behaviour in several areas distinguished by their geomorphological position, vegetation structure and management regime. Cattle show a clear preference for feeding and dung depositing in the low parts of the estate. This leads to an increase in the productivity and a rapid recycling of nutrients in the pasture communities of these areas. Comparing the relative importance of both processes in each vegetational unit, dung accumula- tion is greater in the higher zones, while in the lower areas biomass consumption is more important. This means that movement of matter by cattle tends to favour the higher ground, in a contrary direction to the downward leaching of nutrients and related processes. In the studied dehesa, this phenomena rep- resents an 'exploitation' factor of the lowland areas, which maintains productive pasture communities more immature in successional terms, by the higher woodland areas, less grazed and with low turnover. This result supports claims made in other studies that animal activity - assessed in our case by the relative impacts of herbivory and dung depositions - connect adjacent ecosystems and thus tends to improve the net energy balance of the more successionally mature part of the system. Livestock movements differ in their spatial pattern during different periods of the year: dispersing in spring and becoming more concentrated and predictable during winter. The clear seasonal differences of herbaceous production in Mediterranean climates and the management activities (basically plough- ing, tree pruning and fodder supply) are the main causes of this pattern.
Keywords: cattle behaviour; dehesa pastureland; distribution of dung; habitat preference

A MEDITERRANEAN BIRD DISPERSER ASSEMBLAGE - COMPOSITION AND PHENOLOGY IN RELATION TO FRUIT AVAILABILITY - Debussche, M.; Isenmann, P. (REVUE D ECOLOGIE-LA TERRE ET LA VIE, 1992)
This study deals with a fleshy-fruited plant-bird dispersal system at a site in Mediterranean France, characterized by Quercus ilex coppices, shrublands and old fields. Among the 19 bird dispersers recorded, 14 were of small size (< 25 g), with Sylvia atricapilla, Erithacus rubecula and S. melanocephala accounting for 86.6 % of those caught in mist nets. The importance of small-sized dispersers seems to characterize the Mediterranean shrublands and evergreen woodlands in the whole of the temperate systems. The highest numbers of dispersers occurred from October to January. The seeds of 38 fleshy-fuited plants (native, cultivated and alien) were collected in seed traps. Seed rain occurred throughout the year except in May, with a maximum fruiting period extending from September to early December and the greatest number of native species being dispersed in October. When we compare our data to those collected in Spain, England and Sweden a shift of the peak of fruit availability in relation to latitude (the higher the latitude the earlier the peak) is very likely in Europe. Such a shift is obvious in the United States. We suggest that 1) this shift is the result of climatic constraints on plants rather than that of the selective pressures of dispersers, and 2) that the coincidence between high fruit availability and dispersers' abundance can simply result from the opportunist behaviour of frugivorous birds.
Keys: APSKeys: APSThe following values have no corresponding Zotero field: pub-location: 57 RUE CUVIER, 75005 PARIS 5, FRANCE publisher: SOC NATL PROTECTION NATURE ACCLIMATATION FRANCE
Keywords: birds; dispersal system; evergreen woodlands; Mediterranean; Quercus ilex

Mediterranean evergreen oak diversity: morphological and chemical variation of acorns - Afzal-Rafii, Zara; Dodd, Richard S.; Pelleau, Yvonne (Canadian Journal of Botany, 1992)
Acorns of mediterranean evergreen oak were collected from eight ecogeographically contrasting localities in Italy and Spain. Biometrical analysis of acorns and their cupules showed much greater variation among Spanish populations, encompassing the variation in Italy. The Spanish population at El Pardo, considered the type locality for Quercus rotundifolia, separated from all others. Multivariate analyses of the chemical data indicated, on the one hand, separation of Spain from Italy, and on the other hand, a separation of interior Spanish populations from coastal populations. The importance of lipid composition in the former separation may reflect genetic differentiation between these two origins. Coastal populations were closer to Italian and we suggest were a zone of introgression and hybridization between Quercus ilex and Q. rotundifolia and probably also Quercus coccifera at Bonete Albacete
doi: 10.1139/b92-184doi: 10.1139/b92-184The following values have no corresponding Zotero field: publisher: NRC Research Press
Keywords: biometry; chemistry; diversity; ecogeography; Quercus ilex; Quercus rotundifolia

MEDITERRANEAN VEGETATIONS AND PREHISTORIC CIVILIZATIONS - THE CASE OF FONT-JUVENAL - THIEBAULT, S; Vernet, J L (BULLETIN DE LA SOCIETE BOTANIQUE DE FRANCE-ACTUALITES BOTANIQUES, 1992)
The Font-Juvenal thick stratigraphy allowed the identification of several thousand pieces of charcoals and gives vegetation assemblages very significant of the mediterranean forest evolution and human and environment relationship. Charcoal analysis results confirms the evolutiv pattern proposed and three periods are evidenced : the first one covers the early Neolithic and deciduous oak forest is prevalent; the second, during middle and recent Neolithics, puts out decreases in the oaks representation and an increase of Buxus and Ouercus ilex-coccifera. The third period, at the end of Neolithic, evidences the importance of Buxus and Quercus ilex-coccifera assemblages. The deciduous oak forest was the most important element of early Neolithic vegetal landscape. The gap between man and his environment is revealed by the presence of open areas taxa as Buxus and Quercus ilex-coccifera during the Chasseen.
Keywords: CHARCOAL ANALYSIS; mediterranean forest

Micropropagation of mature cork-oak (Querqus suber L.): establishment problems - Romano, A; Martins-Loução, M a (Scientia gerundensis, 1992)
Procedures have been developed to standardize the establishment stage during mature cork-oak (Quercus suber L.) micropropagation. Axillary and terminal buds cultured in Gresshof and Doy (1972) (GD) medium were used as first explant. Establishment of cultures was very difficult due to browning of the tissue and/or the medium and bacterial contamination. Browning problems, probably due to phenolic compounds exudation of the primary explant, were found to be higher in winter. Nevertheless, initiation of cultures was possible all over the year, presumably due to the preconditioning of cuttings. Explants were established in a GD medium containing 6-benzlaminopurine (BAP) 1 mgl-1. Every 4 weeks the cultures were subcultured to the same GD medium and induced to proliferate being 4:1 the multiplication rate. Shoots were induced to elongate by decreasing BAP concentration. In vitro rooting on agar-solidified medium suplemented with 1 mgl-1 indolacetic acid (IAA) gave the best results. Liquid medium (sorbarod system) and in vivo rooting were also assayed.
Keywords: browning; contaminants; cork-oak; micropropagation; phenolic compounds; Quercus suber L.; tissue culture

Morphological adaptions of Quercus ilex leaves in the Castelporziano forest - Gratani, L; Marzi, P; Crescente, M F (Plant Ecology, 1992)
The annual course of vegetative growth of the most representative species of a Ouercus ilex L. forest in Castelporziano (Latium, Italy) was studied through periodical analysis of selected ecophysiological leaf indexes, for the period 1987-1990. The results demonstrate that the local climate facilitates continuous vegetative activity of the sclerophyllous species without a latent phase. The variable morphology of sun and shade leaves of (2- ilex illustrates the plant's response to environmental stress.
Keywords: Macro and microclimate; Morphological leaf analysis; Quercus ilex L.; Soil; Sun and shade leaves

NATURAL DEGENERATE MEDITERRANEAN FORESTS - WHICH FUTURE - THE EXAMPLES OF THE HOLM OAK (QUERCUS-ILEX L) AND CHESTNUT (CASTANEA-SATIVA MILL) COPPICE STANDS - Romane, F; BACILLIERI, R; Bran, D; Bouchet, M A (RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES, 1992)
Primarily derived from the Quercus pubescens forest destroyed by overexploitation, the Quercus ilex and Castanea sativa coppice stands are two of the most widespread biocoenoses in the European Mediterranean area. Two of the questions we sought to answer were (i) in the case where the same disturbance persists, whether these coppice stands reach a state of “equilibrium” based on auto-succession or they continue to change, and (ii) in the case where disturbance stops, whether the present dominant species (Q. ilex or C. sativa) continues to be dominant (high resilience) or an other species (Q. pubescens ?) could replace it. A third case exists, i.e. a change of the “disturbance” in order to obtain a “sustainable” development, but, in that case, biological or socio-economical criteria must be defined. In order to highlight the first stages of these possible changes, germination abilities of these species were studied and compared. For Q. ilex coppice stands, it can be said that there would appear to be a partial allelopathic inhibition of Q. ilex germination, to which Q. pubescens is less sensitive. For C. sativa, this phenomenon was not found. We also briefly discuss the main characteristics of a programme which tests some biological criteria for a sustainable development.
Keywords: CASTANEA-SATIVA MILL; COPPICE STAND; management; Mediterranean climate; NATURAL DEGENERATE FOREST; QUERCUS-ILEX L; QUERCUS-PUBESCENS WILLD; sustainable development; Vegetation dynamics

New type of damage to Quercus ilex: pollen germination and hydration ability - Bellani, Lorenza M.; Paoletti, E. (European Journal of Forest Pathology, 1992)
Pollen grains collected from trees of Quercus ilex L. belonging to different classes of new type damage were analyzed. Five parameters were taken into account: viability, germinability, tube lengthening, grain volume of the dehydrated state and after rehydration. Damage to mother plants clearly influences the above mentioned parameters, causing a reduction in pollen grain viability, germinability, and in the ability of the grains to rehydrate.
Keywords: damage; germination (voyant); pollen; pollution; viability

Nitrogen immobilization in leaf litter at two Mediterranean ecosystems of SW Spain - Gallardo, Antonio; Merino, J (Biogeochemistry, 1992)
Nitrogen immobilization in relation to the dynamics of lignin and tannins in nine different types of leaf litter was investigated during a 2-yr study at two Mediterranean ecosystems of SW Spain. Net nitrogen immobilization for all the species was higher in a forest than in the more nutrient-poor soil of a shrubland. Absolute amount of lignin increased in both ecosystems in the first 2-4 months whereas tannin rapidly decreased in the same time period. Increases in lignin were significantly correlated to losses of tannins during decomposition. Initial tannin content was the best predictor of the maximum amount of immobilized nitrogen in litter in both ecosystems. Mechanisms that could explain the immobilization of nitrogen in litter are discussed.
Keywords: immobilization; leaf litter decomposition; Lignin; Mediterranean ecosystem; nitrogen; tannin

A NONDESTRUCTIVE METHOD TO DETERMINE CHLOROPHYLL CONTENT OF LEAVES - Gratani, L (PHOTOSYNTHETICA, 1992)
A reliable non-destructive method for determining leaf chlorophyll (Chl) content on site uses a simple instrument, the Minolta SPAD-502. Calibration curves plotting Chl-meter readings against Chl content extracted were obtained for various sclerophyllous species of a Quercus ilex L. evergreen forest.
APS
Keywords: calibration curves; Chl content; chlorophyll; Quercus ilex L.

Notes on Quercus ilex L. in Liguria (NW Italy) - Barberis, G.; Peccenini, S.; Paola, G. (Plant Ecology, 1992)
The climatic characteristics of the Liguria region have been outlined by means of raw data and derived indices (water balance related to potential evapotraspiration, Rivas-Martinez's index of mediterraneity and thermicity, De Martonne's index of dryness, and Emberger's pluviothermic quotient and index of summer dryness). Their interpretation suggests that Liguria is a boundary region between two different climatic areas: the Mediterranean and that of Central Europe. The distribution of Quercus ilex communities in Liguria have suffered the heavy consequences of human activity on the coastal belt of the region. There is, however, sufficient evidence to show that their presence is closely linked to climatic conditions. Quercus ilex communities are absent from the western coastal belt where the annual water balance is below -50 mm and high mean temperatures occur. They are also absent from marly limestone dominated areas where annual water balance is below 300 ram. Quercus ilex woods show a preference for water balance values between 0 and 600, with the better de- veloped forests being found in central and eastern coastal Liguria. The Ligurian Quercus ilex woods are ascribed to Quercetum ilicis Br.-BI. 1915. Given that the pres- ence within their floristic composition of a group of species of Querco-Fagetea (more species in eastern stands, few in western ones) is an almost constant characteristic, the subass, fraxino-ostryetosum Mariotti 1984 can be retained for many of them. Quercus ilex is not present in the initial succession stages of Mediterranean Liguria vegetation. It can be found in later stages when the vegetation is more fully de- veloped towards a maquis type structure. In this case it tends to become dominant and the community develops (if no fire or other human interference occurs) into a Quercus ilex forest. Frequently, this succession takes place under an old tree layer cover (generally Pinus sp.), a remnant of man's past management of the vegetation in the area.
Keywords: Mediterranean climate; quercus ilex communities; quercus ilex ecology

Oak wine bottle stopper|comprises oak cylindrical part inserted in compressible hollow cork or silicon part - Jacquemin, Pascal (1992)
A full cylindrical part (2) and a hollow compressible cylindrical part (3) form the stopper for the bottle. The cylindrical part is inserted in the compressible hollow part which allows perfect sealing of the bottle stopper. The full cylindrical part is made of oak, and the hollow cylindrical part is made from an elastically deformable material such as silicon or cork. USE - Corking of wine bottles.
APS
Keywords: bottle stopper; oak; wine bottles

Old holm oak coppices... new sylvopastoral practices - Bellon, S.; Guerin, G. (Plant Ecology, 1992)
In the south of France, holm oak (Quercus ilex L.) woodlands, particularly coppices, are currently used by livestock farmers. For this vegetation, a grazing allowance is available, based on the relationship between various layers. As far as livestock is concerned, such woodlands can be utilized for many purposes, e.g. stock feeding during critical periods and to provide flexibility to the pasture grazing se- quence. Furthermore, the related grazing intake patterns determine the level of holm oak utilization. Practices integrating both wood and livestock production provide a new perspective to the management of these woodlands in that the presence of livestock promotes specific operations which can lead to more diversified forestry. The renewal of both wood and pastoral resources depends on: (i) the initial level of integration of these two activities and (ii) subsequent technical operations. In the present paper a mid- term management scenario is developed which describes the likely development of woodlands with multiple use and periodic thinning.
Keywords: grazing allowance; resource management; sylvopastoral; thinning; Vegetation dynamics

Organic matter distribution and fluxes within a holm oak (Quercus ilex L.) stand in the Etna volcano - LEONARDI, S.; RAPP, M.; Denes, A. (Plant Ecology, 1992)
Located at 1100 m above sea level, on the western site of the Etna volcano, the ecophysiology of the Mount Minardo holm oak coppice has been investigated for more then twenty years. In this stand, now 31 years old, the above ground biomass amounts to 15000 g m 2 of organic material, including leaves and perennial woody material. During these 31 years, the mean annual production has been around 775 g m 2. The yearly mean litterfall amounts to 310 g m 2, including 200 g m -2 of leaves, mostly two years old. The soil surface is covered by a litter layer amounting to 3150 g m-2. Each year, following Jenny's decomposition rate and field measurements, 290 g m- 2 of the litter turns into CO2, or becomes incorporated in the soil organic matter.
Keywords: Mediterranean forests; organic matter cycling; Quercus ilex L

Organic matter distribution and fluxes within a holm oak (Quercus ilex L.) stand in the Etna volcano - LEONARDI, S; Rapp, M; DENES, A (Plant Ecology, 1992)
Located at 1100 m above sea level, on the western site of the Etna volcano, the ecophysiology of the Mount Minardo holm oak coppice has been investigated for more then twenty years. In this stand, now 31 years old, the above ground biomass amounts to 15000 g m 2 of organic material, including leaves and perennial woody material. During these 31 years, the mean annual production has been around 775 g m 2. The yearly mean litterfall amounts to 310 g m 2, including 200 g m -2 of leaves, mostly two years old. The soil surface is covered by a litter layer amounting to 3150 g m-2. Each year, following Jenny's decomposition rate and field measurements, 290 g m- 2 of the litter turns into CO2, or becomes incorporated in the soil organic matter.
Keywords: Mediterranean forests; organic matter cycling; Quercus ilex L

ORGANIC-MATTER DISTRIBUTION AND FLUXES WITHIN A HOLM OAK (QUERCUS-ILEX L) STAND IN THE ETNA VOLCANO - A SYNTHESIS - LEONARDI, S; Rapp, M; DENES, A (VEGETATIO, 1992)
Located at 1100 m above sea level, on the western site of the Etna volcano, the ecophysiology of the Mount Minardo holm oak coppice has been investigated for more then twenty years. In this stand, now 31 years old, the above ground biomass amounts to 15000 g m-2 of organic material, including leaves and perennial woody material. During these 31 years, the mean annual production has been around 775 g m-2. The yearly mean litterfall amounts to 310 g m-2, including 200 g m-2 of leaves, mostly two years old. The soil surface is covered by a litter layer amounting to 3150 g m-2. Each year, following Jenny's decomposition rate and field measurements, 290 g m-2 of the litter turns into CO2, or becomes incorporated in the soil organic matter.
Keywords: Mediterranean forests; ORGANIC MATER; QUERCUS-ILEX L

PALYNOLOGY OF A RESIN FROM AN EGYPTIAN COFFIN OF THE 2ND-CENTURY BC - MARIOTTI LIPPI, M; MERCURI, A M (REVIEW OF PALAEOBOTANY AND PALYNOLOGY, 1992)
A palynological analysis was carried out on a small amount of resin from the inside of an anthropoid Egyptian stone coffin from the second century B.C. Pinus halepensis Miller is the best represented resiniferous plant (5.3%) in the pollen spectrum and the botanical origin of the resin can be ascribed to it. The only group of pollen which is relatively abundant in the spectrum is Poaceae (29.6%). This high percentage suggests that grasses were in bloom during the period the resin was collected (late spring or summer). Pollen of Quercus ilex. Olea europaea, Ostrya carpinifolia, Castanea sativa were also found. Pollen grains of Hordeum and Avena/Triticum types together with those of Plantago, Urtica, Chenopodiaceae, Rumex and Artemisia represent anthropogenic indicators. A phytogeographical interpretation of the found pollen assemblage suggests the eastern part of the Mediterranean as the most probable area where the resin was collected. The presence of Cedrus libani pollen suggests an origin from south-eastern Turkey, north-western Syria or northern Lebanon. The flora of this area is in accordance with the pollen assemblage found in the studied resin.
APS
Keywords: Castanea sativa; Ostrya carpinifolia; palynological analysis; Pinus halepensis; Quercus ilex. Olea europaea; resin

PALYNOLOGY OF A RESIN FROM AN EGYPTIAN COFFIN OF THE 2ND-CENTURY BC - MARIOTTI LIPPI, M.; MERCURI, A. M. (REVIEW OF PALAEOBOTANY AND PALYNOLOGY, 1992)
A palynological analysis was carried out on a small amount of resin from the inside of an anthropoid Egyptian stone coffin from the second century B.C. Pinus halepensis Miller is the best represented resiniferous plant (5.3%) in the pollen spectrum and the botanical origin of the resin can be ascribed to it. The only group of pollen which is relatively abundant in the spectrum is Poaceae (29.6%). This high percentage suggests that grasses were in bloom during the period the resin was collected (late spring or summer). Pollen of Quercus ilex. Olea europaea, Ostrya carpinifolia, Castanea sativa were also found. Pollen grains of Hordeum and Avena/Triticum types together with those of Plantago, Urtica, Chenopodiaceae, Rumex and Artemisia represent anthropogenic indicators. A phytogeographical interpretation of the found pollen assemblage suggests the eastern part of the Mediterranean as the most probable area where the resin was collected. The presence of Cedrus libani pollen suggests an origin from south-eastern Turkey, north-western Syria or northern Lebanon. The flora of this area is in accordance with the pollen assemblage found in the studied resin.
APSAPSThe following values have no corresponding Zotero field: pub-location: PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS publisher: ELSEVIER SCIENCE BV
Keywords: Castanea sativa; Ostrya carpinifolia; palynological analysis; Pinus halepensis; Quercus ilex. Olea europaea; resin

Pesticide sorption on soils treated with evergreen oak biomass at different humification stages - Martinez-Iñigo, M J; Almendros, G (Communications in Soil Science and Plant Analysis, 1992)
Abstract The sorption of twelve pesticides (alachlor, atrazine, carbofuran, 2,4?D, 2,4?DB, methyl parathion, metoxuron, monuron, prometryne, propanil, silvex and spergon) was studied on two soil samples with a different carbonate content and treated with evergreen oak (Quercus ilex L. subsp. ballota) biomass at successive humification stages. The direct interaction between the above pesticides and lignocellulosic materials was also assayed independently. After the samples were suspended in 25 ppm pesticide solutions for 12 h, the concentrations in the supernatants were measured by derivatographic UV spectroscopy. The major fixations on the biomass of evergreen oak were found for spergon, prometryne and propanil. Except for atrazine, carbofuran, prometryne and silvex, composting the forest residue for 87 weeks significantly increased pesticide sorption. No correlations were found between the sorption values measured directly in the lignocellulosic materials and those in the soils amended with the latter, indicating the conspicuous influence of organo?mineral interactions in the soil. Calcium carbonate played an important role in pesticide sorption: the lowest pesticide retentions were observed for the samples of the soil with the highest pH, where the addition of organic matter led to the greatest enhancements. The fixation of silvex and carbofuran increased considerably when the organic matter was added to the soil with the lowest pH, whereas in the calcic soil samples the major fixation corresponded to chlorinated phenoxy acids. Possible mechanisms involved in pesticide sorption in the systems studied are discussed.
doi: 10.1080/00103629209368699
Keywords: humification; pesticide adsorption; Quercus ilex L. subsp. ballota; soil pH (PG)

Plant regeneration through somatic embryogenesis in Quercus suber - Bueno, M. A.; Astorga, R.; Manzanera, J. A. (Physiologia Plantarum, 1992)
Cork oak (Quercus suber L.) zygotic embryos, endosperm and ovules were treated with different concentrations of 2,4-D for induction of somatic embryos. Plant material was collected during the embryo development season, from June to September. Immature embryos proved to be the most reactive initial explant. Callus and somatic embryos developed a few weeks after the beginning of the 2,4-D treatment. For embryo development experiments, different growth regulators and cold and desiccation treatments were tested. Cold storage of somatic embryos matured in vitro at 5°C was the best treatment for breaking dormancy.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Cork oak; plant regeneration; Quercus suber; Somatic embryogenesis; tissue culture

POTENCIALIDAD DEL TERRITORI0 PARA EL ALCORNOQUE EN EXTREMADURA - González Adrados, J. R.; Elena Rosselló, R.; Tella Ferreiro, G. (Scientia gerundensis, 1992)
Most important aspects of a work titled 4ork oak Atlas of Extremaduran are presented here. A set of maps about: cork oak stands distribution; cork quality in the several zones; and ecological factors wich may limit the appearence of cork oak stands, are elaborated from the availahle thematic cartography. The Geographical Information SystemPC-ARC-IhFO ha beenused to get it. The final result is the Land Suitability for Cork Oak and Cork Quality Map of Extremadura. This map defines for the whole studied area the relative cork quaiity to be obteined and the presence of ecological factors wich may be adverse or exclusive for cork oak.
Keywords: Cork oak; Cork quality; land classification; Quercus suber; thematic cartography

POTENCIALIDAD DEL TERRITORI0 PARA EL ALCORNOQUE EN EXTREMADURA - GONZÁLEZ ADRADOS, J R; Elena Rosselló, R; Tella Ferreiro, G (Scientia gerundensis, 1992)
Most important aspects of a work titled 4ork oak Atlas of Extremaduran are presented here. A set of maps about: cork oak stands distribution; cork quality in the several zones; and ecological factors wich may limit the appearence of cork oak stands, are elaborated from the availahle thematic cartography. The Geographical Information SystemPC-ARC-IhFO ha beenused to get it. The final result is the Land Suitability for Cork Oak and Cork Quality Map of Extremadura. This map defines for the whole studied area the relative cork quaiity to be obteined and the presence of ecological factors wich may be adverse or exclusive for cork oak.
Keywords: Cork oak; Cork quality; land classification; Quercus suber; thematic cartography

PRELIMINARY ASSESSMENT OF METAL BIOAVAILABILITY TO PLANTS IN THE NEVES CORVO AREA OF PORTUGAL - FARAGO, M. E.; COLE, M.; XIAO, X. Y.; VAZ, M. C. (CHEMICAL SPECIATION AND BIOAVAILABILITY, 1992)
Cistus species and Quercus rotundifolia were collected from near the Neves Corvo copper mine and from an area 12 km from the mine. These species are widely distributed in southern Portugal. Aerial parts of the plants have been analysed and the concentrations of elements in the plants have been compared with those of the soils. There is more copper available in the soils near the mine, and this is reflected in an accumulation of copper in both Cistus and Quercus tops. Both plants can be considered to be of the following general types: accumulators of Cu in the mine area; excluders of Mo and Ni; concentration indicators of Pb and possibly Zn. We conclude that both copper and lead have migrated from the concealed orebody through geological faults. These elements in the soil resulting from the ore deposit contribute large portions ot the available metals near the mine area. It is further concluded that there is aerial contamination near to the mining activities, but copper from this source is less available to the plants.
The following values have no corresponding Zotero field: pub-location: PO BOX 314, ST ALBANS AL1 4ZG, HERTS, ENGLAND publisher: SCIENCE REVIEWS 2000 LTD
Keywords: CISTUS SPECIES; MINES; OREBODY; QUERCUS-ROTUNDIFOLIO

Preliminary results of a fertilization-irrigation experiment in a Quercus ilex L. forest in relation to leaves and twigs characteristics - Sabate, S; Calvet, S; Gracia, C A (Plant Ecology, 1992)
A multifactorial ANOVA experiment was designed for a Quercus ilex forest in the Prades mountains in Tarragona (NE Spain). The purpose of this study was to clarify the relative importance of water, ni- trogen 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 to the appropriate treatments in March 1989 with a dosage of 125 kg of P/ha and 250 kg N/ha. Irrigation was applied with a rate of 20 mm per week during the warm season. To evaluate the effects on canopy structure we measured specific leaf weight (rag/cruZ), average leaf weight (rag), average twig height and average twig length. These variables were selected as they are the most likely to manifest changes over short time periods following changes in environmental conditions. The values of these parameters before initial treatments (autumn 1988) and after treatments (summer 1990) were analyzed. The results obtained show that water and nitrogen have a greater effect than phosphorus on tree canopy structure, at least during initial development.
Keywords: fertilization experiment; Irrigation experiment; leaves and twigs characteristics

Is primary production in holm oak forests nutrient limited? - Mayor, X; Rodà, F (Plant Ecology, 1992)
Correlations between primary production and patterns of nutrient use and nutrient availability were investigated in 18 plots in closed holm oak (Quercus ilex L.) stands in the Montseny mountains (NE Spain), searching for evidence of nutrient limitation on primary production. The plots spanned a range of altitudes and slope aspects within a catchment. Nutrients considered were nitrogen (N), phospho- rus (P), potassium (K) and magnesium (Mg) in plant samples, and the above plus calcium (Ca) and sodium (Na) in the soil. Primary production was found by summing the annual aboveground biomass increment to the annual litterfall. Across plots, primary production was correlated with the annual re- turn of nutrients in litterfall, but this relationship probably arose from the common effects of the amount of litterfall on both primary production and nutrient return, and not from any nutrient limitation. Pri- mary production was not significantly correlated with nutrient concentrations in mature leaves nor leaf litterfall, nor with absolute or relative foliar retranslocation of nutrients before leaf abscission, nor with the concentration and content (kg/ha) of total N, extractable P, and exchangeable K, Mg, Ca and Na in the upper mineral soil. We conclude that there is no correlational evidence that primary production is nutrient limited in this holm oak forest.
Keywords: biomass increment; litterfall; nutrient availability; nutrient cycling; Quercus ilex

Primeros ensayos de inducción de embriones somáticos de Quercus suber L. - Bueno, A. J.; Manzanera, M. A. (Scientia gerundensis, 1992)
Susceptibility of cork oak (Quercus suber L.) embryos, endosperm and ovules to somatic embryogenesis induction has been studied. 2,4-D at different concentrations was tested. Samples were collected every two weeks, dong the fruit development period, from June till September. The embryos formed callus, from which globular and heart and torpedo-shaped structures and somatic embryos at different developing degrees were obtained.
Keywords: Cork oak; Quercus suber; Somatic embryogenesis; tissue culture; vegetative propagation

Productivity and nutrient uptake in a holm oak (Quercus ilex L.) stand and during regeneration after clearcut - Rapp, M; Derfoufi, F; Blanchard, A (Plant Ecology, 1992)
The effect of clearcutting on biomass production and nutrient consumption was examined during the two years in a clearcut and a mature Quercus ilex L. coppice. The comparison was limited to the leaf com- partment and to the annual shoots, which were the only con]parable compartments in the two situations. At the same time, the dynamics of the nutrient pool (N, P, K, Ca, Mg), monthly uptake and recycling from the foliage, were studied. The second year after cutting, the leaf production was roughly the same at the two sites. However, the photosynthates appear to be used differently: in the young stand the perennial wood production was greater than in the mature stand, where the maintenance costs are higher. This is corroborated by the patterns of nutrient use.
Keywords: biomass; Clearcut; coppice; nutrient use; production; Quercus ilex L.

Quercus ilex browse utilization by Caprini in Sierra de Cazorla and Segura (Spain) - Cuartas, P.; García-Gónzalez, R. (Plant Ecology, 1992)
The impact of domestic and wild Caprini browsing on Quercus ilex has been examined in an area of the Sierra de Cazorla. Vegetation as a herbivore food supply, herbivore feeding regime and density in the study area during six sampling periods throughout two years, has been quantified. Wild Caprini show diets similar to the available vegetation, whereas domestic Caprini tend more towards the trophic spe- cialities (browsing or grazing) of their genus. Nevertheless, this tendency was more pronounced in do- mestic goats than in sheep. A hypothetical estimate of Q. ilex intake by each species under the study conditions was carried out. It was found that domestic Caprini have a greater impact on the holm oak than wild Caprini, density and feeding-niche deviations being the main factors responsible for this sit- uation.
Keywords: Browsing; herbivore impact; quercus ilex ecosystems

QUERCUS-ILEX L LITTER DECOMPOSITION AND MINERAL EVOLUTION IN AN EVERGREEN OAK WOODLAND IN MAJORCA (BALEARIC-ISLANDS, SPAIN) - XAMENA, J; García, C; MOREY, M (RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES, 1992)
The aim of this contribution is to describe the decomposition processes of litter in an evergreen oak wood and the evolution of the four cations; calcium, magnesium, sodium and potassium.
Keywords: decomposition; litter; minerals

Recent changes in landscape structure and function in a Mediterranean region of SW Spain (1950–1984) - Ales, R. F.; Martin, Angel; Ortega, Fernando; Ales, E. E. (Landscape Ecology, 1992)
Recent economic development has altered landscape structure and function of a mediterranean region in Southwestern Spain. Intensive agricultural systems have concentrated in the more fertile areas, while margi- nal ones have been abandoned. As a result, landscape structure has changed. Consequences of this structural change on landscape processes are discussed.
Keywords: agroecology; biological conservation; dofiana national park; guadalquivir valley; sierra morena; Spain

Recrû naturel dans des taillis de chêne vert (Quercus ilex L) à la suite d'exploitations partielles - Ducrey, M.; Boisserie, M. (Ann. For. Sci., 1992)
Natural regrowth of holm oak coppice (Quercus ilex L) following partial cuts. The aim of this article was to study the influence of coppice age (4 to 57 years old) and of intensities of cleaning (light and heavy) or thinning (26-78% of removed basal area) on the appearance and growth of new stump sprouts in Quercus ilex coppice. The sprout layer at soil level can be quantified by degree of closure, biomass and Quercus ilex sprout height. This layer grew regularly for the 5 years following harvest and increased in direct proportion to increase in thinning intensities; it was found to be greater for young coppice (25 years old and less) than for old coppice. Coppice functioning was then studied at the stool level. Number and growth of new sprouts inside each stool were then related to the initial characteristics of the initial stool as well as to the degree of thinning in the stool. Sprout number was proportional to number of cut shoots, while sprout growth tended to be related to percentage of shoot or basal area removed by thinning. Finally an attempt has been made to explain the functioning of the stools by separating the effects of the mean thinning intensity of each plot and of the degree of cutting for each stool. In conclusion, hypotheses have been proposed on physiological origin of the observed phenomena.
Keywords: coppice; Quercus ilex = holm oak; stool; stump sprout; thinning

The role of Diplopoda litter grazing activity on recycling processes in a Mediterranean climate - Bertrand, M.; Lumaret, J. P. (Plant Ecology, 1992)
Variation in Diplopoda density and biomass were studied in mediterranean holm oak formations in order to estimate the impact of the feeding activity of these Arthropod s. Field and controlled experiments have shown the importance of the litter age and of the nature of leaves on the consumption rate. The con- sequences of faecal pellet restitution on microbial activity are discussed.
Keywords: diplopoda; edaphic macrofauna; faecal restitution; litter breakdown; sclerophyll formation

SOIL EVOLUTION AFTER FIRE IN QUERCUS-ILEX AND PINUS-HALEPENSIS FORESTS - FERRAN, A.; SERRASOLSAS, I.; Vallejo, V. R. (RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES, 1992)
Four contrasted burned sites in Catalonia (NE Spain) have been compared to-illustrate the diversified response to fire depending on the interaction of substrate-vegetation characteristics. Data from plant cover evolution, forest floor layers and soil chemical properties demonstrated that the garrigue on limestone is the most resilient ecosystem as a result of the resprouting capacity of Ouercus coccifera and the high soil stability. The shrubland on marls was however, the least resilient, with the poorest plant regeneration and greatest erosion rates. The plant communities on conglomerates and the holm oak forest on schists, represented intermediate situations, where the variable degree of erosion and nutrient losses were compensated by a rapid plant colonization just after the fire.
The following values have no corresponding Zotero field: periodical: RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES pub-location: BARKING ESSEX
Keywords: burned sites; ecosystem resilience; fire; Quercus coccifera; Quercus ilex; Shrubland; Spain

Spatiotemporal patterns of egg predation in forest islands: an experimental approach - Tellería, J L; Santos, T (Biological Conservation, 1992)
Thirty holm oak Quercus rotundifolia forests, ranging from 0·1 to 350 ha, were studied in central Spain to analyse the spatial and temporal patterns of predation in relation to size of forest patches. During two springs (1988 and 1989), quail Coturnix coturnix eggs were placed in these forests to evaluate predation rates. Two trials (April and June) during each year were performed to study the intraseasonal and interyear constancy of predation. Results showed that predation rate tends to increase with forest fragmentation, although forest size was poorly related to predation rate. Predation rates seemed to be constant within spring seasons and between years. These results suggest that predators concentrate their search activities in some selected forests, thus accentuating their effect on prey species.
Keywords: Forest patches; forest size; fragmentation (voyant); predation rates

Stable hydrogen and oxygen isotope studies of rainfall and streamwaters for two contrasting holm oak areas of Catalonia, northeastern Spain - Neal, C; Neal, M; Warrington, Anita; Avila, a (Journal of Hydrology, 1992)
Results are presented of a study of stable hydrogen and oxygen isotopes in rainfall and streamwaters for the Montseny and Prades areas in northeastern Spain: results cover the full year of 1991. The isotopic pattern for rainfall is similar for both areas: there is a wide range in isotopic contents and the results show a strong, near-linear trend, 62H = 7.9 x 6~80 + 9.8 (N = 59; r 2 = 0.952), the 'local meteoric line'. There is slight curvature to the data which may be related to the sources of water vapour forming the rainfall. Within the streams, the isotopic variability is much less than that of the rainfall although the data lie on, or very near to, the meteoric line. Data for detailed collections during storm events show more scatter than those collected regularly on a fortnightly basis. The event data show a linear feature that conforms to the local meteoric line. These results indicate that: (1) the main supply of water to the stream stormflow comes from water stored in the catchment prior to the event; (2) waters of more than one isotopic composition reside within the catchment and are transferable to the stream during storm events; (3) the main process of water transfer from the catchment back to the atmosphere comes from transpiration by the trees and (possibly) complete evaporation from the near-surface soil horizons and the tree canopy; (4) the isotopic technique cannot be used for quantitative hydrograph separation in this instance at least two water types can be present within the catchment at any given time.
Keywords: isotope composition (voyant); RAINFALL; stream water

Stomatal patchiness in Mediterranean evergreen sclerophylls Phenomenology and consequences for the interpretation of the midday depression in photosynthesis and transpiration - Beyschlag, Wolfram; Pfanz, Hardy; Ryel, Ronald J.; Botanik, Lehrstuhl; Universitfit, I. I.; Dallenbergweg, Mittlerer; Republic, Federal; Science, Range (Planta, 1992)
Midday depression of net photosynthesis and transpiration in the Mediterranean sclerophylls Arbutus unedo L. and Quercus suber L. occurs with a depression of mesophyll photosynthetic activity as indicated by cal- culated carboxylation efficiency (CE) and constant diur- nal calculated leaf intercellular partial pressure of CO 2 (Ci). This work examines the hypothesis that this midday depression can be explained by the distribution of patches of either wide-open or closed stomata on the leaf surface, independent of a coupling mechanism between stomata and mesophyll that results in a midday depres- sion of photosynthetic activity of the mesophyll. Pressure infiltration of four liquids differing in their surface ten- sion was used as a method to show the occurrence of stomatal patchiness and to determine the status of sto- matal aperture within the patches. Liquids were selected such that the threshold leaf conductance necessary for infiltration through the stomatal pores covered the ex- pected diurnal range of calculated leaf conductance (g) for these species. Infiltration experiments were carried out with leaves of potted plants under simulated Mediterranean summer conditions in a growth chamber. For all four liquids, leaves of both species were found to be fully infiltratable in the morning and in the late after- noon while during the periods leading up to and away from midday the leaves showed a pronounced patchy distribution of infiltratable and non-infiltratable areas. Similar linear relationships between the amount of liquid infiltrated and g (measured by porometry prior to de- tachment and infiltration) for all liquids clearly revealed the existence of pneumatically isolated patches containing only wide-open or closed stomata. The good correspon- dence between the midday depression of CE, calculated * Dedicated to Professor Otto L. Lange on the occasion of his 65th birthday ** To whom correspondence should be addressed Abbreviations: A = net photosynthesis rate; Ci = actual leaf internal CO2 partial pressure; Ci *=apparent leaf internal CO2 partial pressure; CE = actual carboxylation efficiency; CE* = apparent car- boxylation efficiency; E = transpiration rate; g = leaf conductance under the assumption of no stomatal patchiness, and the diurnal changes in non-infiltratable leaf area strongly indicates that the apparent reduction in mesophyll activ- ity results from assuming no stomatal patchiness. It is suggested that simultaneous responses of stomata and mesophyll activity reported for other species may also be attributed to the occurrence of stomatal patchiness. In Quercus coccifera L., where the lack of constant diurnal calculated C i and major depression of measured CE at noontime indicates different stomatal behavior, non- linear and dissimilar relationships between g and the infiltratable quantities of the four liquids were found. This indicates a wide distribution of stomatal aperture on the leaf surface rather than only wide-open or closed stomata.
Keywords: arbutus; Mediterranean; Quercus; Sclerophyll; stomate (control-patchiness)

Streamwater pH, alkalinity, p CO 2 and discharge relationships in some forested Mediterranean catchments - Piñol, J; Avila, a (Journal of Hydrology, 1992)
The streamwater chemistry of four catchments at Prades and one catchment at Montseny (NE Spain) is described and the relationships between streamwater alkalinity, pH and pCO 2 with discharge and that between pH and alkalinity are highlighted. At Montseny, results from a subsurface seepage are also presented. The Prades and Montseny catchments have similar vegetation (dense forest of holm oak. Quercus ilex L.) and lithology (phyllites). However, the catchments differ strongly in their hydrological behaviour: only 8-15% of the rainfall passes to the stream from the two gauged Prades catchments, whereas the Montseny catchment provides 50% of rainfall to the stream. Hence the mineralization of streamwaters is much higher in the Prades catchments. All the streams studied show an inverse relationship between alkalinity and discharge. Although pH also decreases with discharge in the Montseny catchment. it remains high during high flows in the Prades catchments. The Prades streamwater chemistries are determined by the solubility equilibrium of calcite: at high flows alkalinity decreases and, as a result of calcite solubility controls, this change results in an increase in pH. Consequently, pH and log(alkalinity) are either negatively correlated or uncorrelated in the Prades streams. At Montseny, the relationship between pH and alkalinity is significantly positive: calcite solubility controls do not come into play. All waters analyzed show an excess pCO 2 (epC02) with respect to atmospheric concentrations. The highest epC02 values usually correspond to low flows. However, study of the variation of epCO2 during 15 individual storm events sampled at Montseny shows that epCO 2 increases with discharge. At Prades, the degassing of epCO 2 in the stream channel produces calcite precipitation.
Keywords: Catchments; montseny; prades; precipitation (voyant); Streamwater chemistry

Structure, biomass and production of a resprouted holm-oak (Quercus ilex L.) forest in NE Spain - LLEDO, M J; Sánchez, J R; Bellot, J; Boronat, J (Plant Ecology, 1992)
When considered as a compartment of nutrients (biomass) and as a flux between compartments (pro- duction) vegetation plays an important role in the biogeochemical forest research that is carried out at the Prades research station in two adjacent catchments: L'Avic (51.6 ha) and La Teula (38.5 ha). The forest density at the Prades site, considering both the tree and shrub layers, is 9182 stems ha t, with 4527 stems ha i being the tree layer. The predominant species is Quercus ilex with Arbutus unedo and Phillyrea media less common. The structure of the population, estimated by grouping the numbers of the stems in classes of 2.5 cm, shows a distribution which conforms, in both catchments, to a negative exponential equation following the Yoda law. The distribution observed at different altitudes shows great heterogeneity, the number of stems of Q. ilex increases with altitude, from 4000 stems ha ~ at 800 m, to 14000 stems ha 1 at 1000 m of altitude. The upper and the lower parts of the watershed show dif- ferences in forest production that explain this variation. In this paper the influence of human activities and physical factors on the origin of this structure is discussed. The tree and shrub biomass was cal- culated by applying allometric regressions for the three predominant species and has been estimated as 113.2 t ha 1. The tree layer accounts for 92°o. Net production was calculated from annual increases (by differences between the 1981 and 1986 basal area measures) of the woody part and the litterfall. The above-ground net production was about 6.5 t ha 1 year 1, 95.4o0 of it being from trees and shrubs and only 4.6°0 from grasses.
Keywords: Forest structure; human activities; mediterranean forest; prades; Species distribution

STRUCTURE OF MIXED HOLM-OAK (QUERCUS-ILEX) ALEPPO PINE (PINUS-HALEPENSIS) FORESTS IN NORTHEASTERN SPAIN - Espelta, J. M.; GENE, C.; Retana, J.; TERRADAS, J. (RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES, 1992)
Mixed forests of Aleppo pine (Pinus halepensis) and holm-oak (Quercus ilex) cover a great part of Northeastern Spain. Nevertheless, little is known about their structure, dynamics and regeneration. For some years, a research group in CREAF has collected data about those aspects, in order to use them to develop models that could be used as a tool for forest management. Previous results obteined about the structure of these stands are presented in the present paper.
The following values have no corresponding Zotero field: periodical: RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES pub-location: BARKING ESSEX
Keywords: mixed forests; Pinus halepensis; Quercus ilex; Spain

Técnicas de propagação aplicadas ao melhoramento do sobreiro - Romano, A; Noronha, C; Caçorino, A I; Martins-Loução, M a (2.º Encontro sobre montados de sobro e azinho, realizado 4 e 5 de Junho de 1992 em Évora, 1992)
Neste trabalho apresentam-se os resultados referentes a técnicas de propagação aplicadas ao sobreiro, nomeadamente estacaria e micropropagação. Nas condições ensaiadas a estacaria deu resultados negativos. Aparentemente o enraizamento de estacas só é possível em matéria juvenil, o que inviabiliza a utilização desta técnica no melhoramento do sobreiro. Pelo contrário, a micropropagação pode desempenhar papel relevante. No presente trabalho foram desenvolvidas metodologias que permitem propagar explantados provenientes de material adulto seleccionado. Com esta técnica, partindo de 100 explantados podemos, potencialmente, colocar 1400 plantas no campo, ao fim de 6 meses.
Keywords: Biologia; Conferências; Crescimento vegetal; Micropropagação; Sobreiro (Quercus Suber L.); vegetal (citation)

The thermochemical degradation of cork - Pereira, H (Wood Science and Technology, 1992)
. The thermochemical degradation of cork from Quercus suber L. was studied in the temperature range 150 ~ ~ in relation to mass loss, chemical composition and the influ- ence on the cellular structure. The degradation of cork is strongly dependent on temperature and mass losses become significant at 200~ (15% of initial dry weight) and increase rapidly for higher temperatures (27% at 250 ~ 49% at 300 ~ 62% at 350 ~ until ashing at 450 ~ The polysaccharides are the most heat sensitive components: at 200 ~ hemicelluloses disappear and cellulose is degraded to a considerable extent. Suberin is more resistant and degradation starts at approx. 250~ 300~ samples only contain 7% suberin. The cellular structure of cork is also significantly influenced by temperature. Upon heating, cells expand and the cell walls stretch, attaining at 250~ a maximum cell volume increase corresponding to a factor of approximately 2. Above 300 ~ the structure of cell walls is considerably changed and show profound physical damage; in the later stages of pyrolysis, a cellular structure is no longer observed.
Keywords: Cellular structure; Cork; mass loss (voyant); thermochemical degradation

Use of direct gradient analysis to study the climate-vegetation relationships in Galicia, Spain - Retuerto, Ruben; Carballeira, Alejo (Plant Ecology, 1992)
This paper reports a bioclimatic analysis of plant species in Galicia, NW Spain. A set of floristic data obtained from 150 plots located at euclimatopes (sites with monitored climate) was analysed using di- rect gradient analysis and clustering with respect to the 8 climatic variables thought to play a major role in regulating the distribution of the species considered in the study area. Principal component analysis (PCA) and hierarchical clustering were based on a matrix of species by climatic variables. Indicator taxa for the variables were identified on the basis of their Indicator values (Brisse & Grandjouan 1978) and grouped by cluster analysis. The groups produced were compatible with the results of principal com- ponent analyis and the frequential analysis of the species, which identified their phytoclimatic nature. The groups were then characterized by determining their climatic positions and indicator values with respect to the chief climatic variables. The first three PCA axes, which were associated with Oceanity, Mean minimum temperatures and the temperature range in the coldest month, together accounted for 97.2 ~o of the variance of the data.
Keywords: climatic factors; climatic position; Clustering; frequential analysis; indicator value; phytoclimatology; Principal component analysis

Variation in tissue element concentrations in Quercus ilex L. over a range of different soils - CANADELL, J.; Vilà, M. (Plant Ecology, 1992)
In order to study the variability in nutrient concentrations in four tissues of Q. ilex in relation to soil properties, we selected fifteen stands in both Q uercus ilex forests and Q. ilex-Pinus halepensis mixed forests. These stands had developed on soils derived from eight different parent materials. Three soil groups were differentiated according to their chemical properties: calcareous soils, siliceous soils, and volcanic soils. Across sites, nutrient concentrations were generally less variable in current-year tissues than in older tissues. Nitrogen and potassium showed the lowest variability among sites, their concen- trations in current-year leaves ranging from 1.17°o to 1.39°i, for N and from 0.530{, to 0.68°o for K. There were few statistically significant correlations between tissue element concentrations, the most frequent being the antagonistic relationship between calcium and magnesium. Nitrogen concentration in current-year leaves was negatively correlated with soil chemical fertility (nitrogen, phosphorus and potassium). This may reflect a nutritional imbalance between nitrogen and other nutrients, some of which may be more limiting than nitrogen to Q. ilex growth in Catalonia forests. Negative correlations were also found between plant magnesium and soil calcium, and positive correlations between plant calcium and soil calcium.}
Keywords: N/P ratio; Nutrient antagonism; Plant nutrient concentrations; Plant-soil relationships; Soil fertility

Water relations of crok-oak (Quercus suber L.) under natural conditions - Oliveira, G; Correia, O A (Plant Ecology, 1992)
Daily and annual courses of leaf transpiration, stomatal conductance and shoot water potential of four Quercus suber individuals were compared in a semi-natural stand in southwest Portugal, from spring 1989 to early summer 1990. The trees investigated showed annual patterns typical of evergreen sclerophyllous species but varied in their range of stomatal operation. This appeared to be related to differences in hydraulic conductiv- ity in the root-to-leaf pathway. Maximum stomatal conductance and transpiration rates occurred from March to June. Water stress was found to be moderate and winter cold stress due to low air and soil temperatures appeared to have an influence on plant water balance through their effects on flow resistances. Abbreviations." g ..... stomatal conductance; g ....... maximum stomatal conductance, PAR, photosyntheti- cally active radiation; RH, relative humidity of the air; T, leaf transpiration; Ta, air temperature; TL, leaf temperature; T ........ maximum leaf transpiration; AW, air-to-leaf vapor pressure difference; W, shoot water potential; tIJPD, predawn shoot water potential; ttJMIN, minimum shoot water potential.
Keywords: Mediterranean climate; montado; Quercus suber; soil-to-leaf hydraulic conductivity; Stomatal conductance; Transpiration

Water relations of crok-oak (Quercus suber L.) under natural conditions - Oliveira, G; Correia, O A (Plant Ecology, 1992)
Daily and annual courses of leaf transpiration, stomatal conductance and shoot water potential of four Quercus suber individuals were compared in a semi-natural stand in southwest Portugal, from spring 1989 to early summer 1990. The trees investigated showed annual patterns typical of evergreen sclerophyllous species but varied in their range of stomatal operation. This appeared to be related to differences in hydraulic conductiv- ity in the root-to-leaf pathway. Maximum stomatal conductance and transpiration rates occurred from March to June. Water stress was found to be moderate and winter cold stress due to low air and soil temperatures appeared to have an influence on plant water balance through their effects on flow resistances. Abbreviations." g ..... stomatal conductance; g ....... maximum stomatal conductance, PAR, photosyntheti- cally active radiation; RH, relative humidity of the air; T, leaf transpiration; Ta, air temperature; TL, leaf temperature; T ........ maximum leaf transpiration; AW, air-to-leaf vapor pressure difference; W, shoot water potential; tIJPD, predawn shoot water potential; ttJMIN, minimum shoot water potential.
Keywords: Mediterranean climate; montado; Quercus suber; soil-to-leaf hydraulic conductivity; Stomatal conductance; Transpiration

What are the consequences of being a downy oak (quercus pubescens) or a holm oak (Q. ilex) for breeding blue tits (Parus caeruleus)? - Blondel, J.; Isenmann, P.; Maistre, M.; Perret, P. (Plant Ecology, 1992)
By comparison with deciduous oaks, the lower yearly production of new leaves in sclerophyllous oaks is hypothesized to have several consequences on animal communities. In particular, the production of arthropod communities that feed upon the leaves should be lower in sclerophyllous than in deciduous oaks, this causing changes in breeding patterns and the demographic balance in insectivorous birds. Studies in both deciduous and sclerophyllous habitats in southern France have shown that: 1) the spring development of new leaves occurs later and more slowly in sclerophyllous than in deciduous oaks, 2) the biomass of caterpillars is much lower in sclerophyllous oak forests, and 3)there is a large variation in life history traits of the Blue Tit depending in which type of habitat they breed. Laying date occurs later and clutch size is lower in sclerophyllous habitats than in deciduous habitats. The evolution of life history traits is discussed according to whether poor sclerophyllous habitats are isolated (e.g. on Corsica) or are parts of landscapes including both habitat types.
Keywords: breeding traits; caterpillars; leafing phenology; Parus caeruleus; Quercus ilex; Quercus pubescens

ABUNDANCE AND FOOD-SEARCHING INTENSITY OF WOOD MICE (APODEMUS-SYLVATICUS) IN FRAGMENTED FORESTS - Tellería, J L; Santos, T; ALCANTARA, M (JOURNAL OF MAMMALOGY, 1991)
Abundance, food-searching intensity, physiological status, and population attributes of wood mice (Apodemus sylvaticus) were studied in forest islands of central Spain. Seventeen isolated woodlots (Quercus rotundifolia) ranging from 0.1 to 280 ha were studied. The results show high densities of mice and high rates of predation on acorns in the smaller forests.
Keywords: acorns predation; Apodemus sylvaticus; forest islands; Quercus rotundifolia; Spain; wood mice

Chemical characteristics and temporal variations of nutrients in throughfall and stemflow of three species in Mediterranean holm oak forest - Bellot, J; Escarre, A (Forest Ecology and Management, 1991)
In this study on chemistry of throughfall and stemflow of three dominant species in a Spanish holm oak forest few significant differences were detected in the ion concentrations between Quercus ilex, Arbutus unedo and Phillyrea media. Comparison of annual average concentration of throughfall, stemflow and bulk deposition indicated nitrate and hydrogen uptake by the plants. At the same time, the data show the importance of precipitation as a source of nutrients.
Keywords: bulk deposition; Holm oak forest; nutrients (PG); stemflow; throughfall

Chemical characteristics and temporal variations of nutrients in throughfall and stemflow of three species in Mediterranean holm oak forest - Bellot, J.; Escarré, A. (Forest Ecology and Management, 1991)
In this study on chemistry of throughfall and stemflow of three dominant species in a Spanish holm oak forest few significant differences were detected in the ion concentrations between Quercus ilex, Arbutus unedo and Phillyrea media. Comparison of annual average concentration of throughfall, stemflow and bulk deposition indicated nitrate and hydrogen uptake by the plants. At the same time, the data show the importance of precipitation as a source of nutrients.
Keywords: bulk deposition; Holm oak forest; nutrients (PG); stemflow; throughfall

Chemosystematic differentiation of Quercus ilex and Q. rotundifolia based on acorn steroids - Rafii, Zara A; Zavarin, Eugene; Pelleau, Y (Biochemical Systematics and Ecology, 1991)
Acorns from 34 individual Quercus ilex and Q. rotundifolia trees from 11 locations in Italy and Spain were sampled and analysed for composition of steroids. β-Sitosterol was most abundant in all populations. Concentrations of both stigmasterol and Δ5-avenasterol varied between individual populations in both countries. Δ7-Stigmastenol was not detected in Italian populations and brassicasterol, while absent from the Spanish specimens, was present in the Italian Uccellino population. Principal component analysis showed complete separation of Q. rotundifolia (Spain) and Q. ilex (Italy).
Keywords: acorns; chemosystematics; evergreen oak; fatty acids; Quercus ilex; Quercus rotundifolia; steroids

COLOLEJEUNEA-MINUTISSIMA (SM) SCHIFFN IN THE HOLM OAK GROVE OF PORT-CROS ISLAND (ILES DHYERES, VAR, FRANCE) - Hebrard, J P; ROUX, C (NOVA HEDWIGIA, 1991)
Discovery of Cololejeunea minutissima (Sm.) Schiffn. on Quercus ilex trunks within the holm-oak forest on Port-Cros island (departement Var). Bionomic, chorological and ecological remarks on the species.
APS
Keywords: Cololejeunea minutissima; Holm oak; Quercus ilex

Comparison between antifungal and antibacterial activities of several strains of Epicoccum purpurascens from the Mediterranean area. - Mallea, M; Pesando, D; Bernard, P; Khoulalene, B (Mycopathologia, 1991)
The antimicrobial activities of seven Epicoccum purpurascens strains isolated either from evergreen oak leaves (Quercus ilex) collected over a period of one year, or from the atmosphere were compared in vitro. Two strains sporulated and conspicuously inhibited the growth of Staphylococcus aureus and Trichophyton mentagrophytes. Thin-layer chromatographic studies showed the existence of some compounds, such as flavipin, which were common to all the strains. Epicorazine B was present in the extracts of only the two most active strains.
Keywords: antimicrobial activity; cultural characteristics; Epicoccum purpurascens; intraspecies com- parison; metabolites; thin layer chromatography

Comparison of Spatial Distribution Patterns of Dung-Feeding Scarabs (Coleoptera: Scarabaeidae, Geotrupidae) in Wooded and Open Pastureland in the Mediterranean “Dehesa” Area of the Iberian Peninsula - GALANTE, E; GARCIA-ROMAN, M; BARRERA, I; GALINDO, P (Environmental Entomology, 1991)
The seasonal and spatial distributions of dung-feeding scarabs in an open pastureland and in wooded (holm oak) pastureland in a typical Mediterranean area of the western part of the Iberian Peninsula (Salamanca) were compared. Six pitfall traps baited with bovine dung were placed in each habitat according to a model by J. P. Lumaret. Only beetles in the families Scarabaeidae and Geotrupidae were studied because they are the most important agents in the elimination of cattle dung from the soil surface. Weekly trapping for 1 yr produced 6,909 specimens. Of the 18 species found, the largest beetles and biomass were concentrated mainly in the wooded habitat, especially in the summer. This constitutes a problem for dung removal because large amounts of dung remain in open pasturelands, possibly resulting in the impoverishment of such areas.
Keywords: dung beetles; Geotrupidae; Insecta; Scarabaeidae

Constituents of cupuliferae, XIII: New and revised structures of acylated flavonoids from Quercus Suber L. - Romussi, Giovanni; Bignardi, Gaetano; Pizza, Cosimo; De Tommasi, Nunziatina (Archiv der Pharmazie, 1991)
From leaves of Quercus suber L. in addition to ten known glycosides, two new acylated flavonoids have been isolated and identified as 3-O-kaempferol 2-O-(trans-p-coumaroyl)-β-D-glucopyranoside (1) and 3-O-kaempferol 2,3-di-O-acetyl-4-O-(cis-p-coumaroyl)-6-O-(trans-p-coumaroyl)-β-D-glucopyranoside (3). The structures of the previously described 3-O-kaempferol 2,4-di-O-(trans-p-coumaroyl)-β-D-glucopyranoside2) and 3-O-kaempferol 3,6-di-O-acetyl-2,4-di-O-(trans-p-coumaroyl)-β-D-glucopyranoside3) were revised to 3-O-kaempferol 2,6-di-O-(trans-p-coumaroyl)-β-D-glucopyranoside (4) and 3-O-kaempferol 3,4-di-O-acetyl-2,6-di-O-(trans-p-coumaroyl)-β-D-glu-copyranoside (5).
APS
Keywords: acylated flavonoids; glycosides; Quercus suber

DESICCATION TOLERANCE AND OSMOTIC PARAMETERS IN DETACHED LEAVES OF QUERCUS-ILEX L - KYRIAKOPOULOS, E; RICHTER, H (ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY, 1991)
Batches of detached Quercus ilex leaves from a natural site were desiccated to different relative water contents. The percentage of necrotic leaf area was evaluated after resaturation, and necrosis of 1-2% defined as ``incipient injury{''}. The relative water content at incipient injury was higher in the dry summer than in the humid winter. Osmotic potentials of young leaves decline rapidly during leaf maturation; the values are not closely coupled to desiccation tolerance. The results are discussed with reference to the evolutionary origins of Quercus ilex, an Arcto-Tertiary element of the Mediterranean flora.
Keywords: DESICCATION TOLERANCE; OSMOTIC PARAMETERS; QUERCUS-ILEX

Distribution of condensed tannins (proanthocyanidins) in various fibre fractions in young and mature leaves of some oak species - Makkar, H P S; Singh, B (Animal Feed Science and Technology, 1991)
The distribution of proanthocyanidins (PAs), using HCl-butanol reagent, was studied in various fractions in young and mature leaves of five oak species, Quercus incana, Quercus semecarpifolia, Quercus serrata, Quercus ilex and Quercus glauca. In leaves of all the oak species studied, PAs expressed as A550 nm g−1 whole leaf, neutral detergent fibre (NDF) or acid detergent fibre (ADF) were higher in mature leaves. When the PAs were expressed as a percentage of the total PAs, the PAs in NDF were lower in mature leaves except for Q. ilex, and in ADF were lower in young leaves. Significant proportions of total PAs were present in NDF and ADF; the values ranged from ∼ 7 to 28% in NDF and from 3 to 21% in ADF. Similarly, PAs which could not be extracted using 50% aqueous methanol varied from 10 to 55% of the total PAs. These observations suggest that there is a need to recognise the importance of these tannins as well as those which are extractable. The PAs in both NDF and ADF had a significantly positive correlation with total and unextracted PAs and NDF, and with ADF, hemicellulose, cellulose and lignin their correlations were positive but not significant. The results are discussed in relation to maturity of the leaves and their likely contribution towards producing artefacts or errors when using the detergent system of feed analysis.

EFFECTS OF REAFFORESTATION BY EUCALYPTUS-GLOBULUS ON THE EDAPHIC COLLEMBOLA - DaGama, M M; NOGUEIRA, A; DOSSANTOS, AFAM (REVUE D ECOLOGIE ET DE BIOLOGIE DU SOL, 1991)
The authors studied the effects of reafforestation by Eucalyptus globulus on the edaphic Collembola, by means of factorial analysis of correspondences applied to the study of Collembola populations, occurring in coppices of Quercus suber and in Eucalyptus globulus plantations.
Keywords: Collembola; EUCALYPTUS; FACTORIAL; REAFFORESTATION

EFFECTS OF USNIC ACID ON THE OXYGEN-EXCHANGE PROPERTIES OF MESOPHYLL CELL PROTOPLASTS FROM COMMELINA-COMMUNIS L - VAVASSEUR, A; GAUTIER, H; THIBAUD, M C; LASCEVE, G (JOURNAL OF PLANT PHYSIOLOGY, 1991)
Usnic acid, a phenolic compound synthesised by Usnea sp. totally inhibits oxygen evolution of illuminated mesophyll cell protoplasts from Commelina communis L. at a concentration of 4-mu-M. This inhibition was not reversed by manganese ions, as previously observed with chloroplasts extracted from leaves of Quercus rotundifolia treated with usnic acid. At 10-mu-M usnic acid, dark respiration was 59% inhibited within 10 min and eliminated after 200 min. Usnic acid rapidly affects the oxidative phosphorylation pathway and later the alternative oxidase pathway. The different responses of isolated chloroplasts, protoplasts and whole plant to usnic acid are discussed.
Keywords: COMMELINA-COMMUNIS L; LICHENIC ACIDS; MESOPHYLL PROTOPLAST

Évolution du potentiel hydrique foliaire et de la conductance stomatique de quatre chênes méditerranéens lors d'une période de dessèchement - Acherar, M; Rambal, S; Lepart, J (Ann. For. Sci., 1991)
Influence of soil drying on leaf water potential and stomatal conductance in four Mediterranean oak species. The water relations and the responses of 2 evergreen Quercus species (Quercus ilex L and Q suber L) and 2 deciduous species (Q afares Pomel and Q faginea Willd) were studied under experimental conditions. Two-yr old seedlings grown in 30-1 pots were subjected to a drying period where stomatal conductance, pre-dawn leaf water potential and minimum leaf water potential were measured. The results show that, for all species, the daily course of stomatal conductance agrees with the patterns proposed by Hinckley et al (1978, 1983). Concurrent with the species responses to short-term variation in water availability, it was found that pre-dawn leaf water potential controlled the maximum daily leaf conductance. There was a strong correlation between pre-dawn leaf potential and maximum daily conductance (gsr max) as described by the reciprocal function gsr max = (-0.47 + 2.61 ψb)-1 for the evergreen oaks and gsr max = (-1.94 + 7.39 ψb)-1 for the deciduous ones. The differences between the 2 groups may partially explain their geographic distributions, and also lead to general questions concerning the mechanisms of water use in the Mediterranean oak species.
Keywords: deciduous; evergreen; mediterranean species; Quercus; Stomatal conductance; water potential; water stress

Hydrological balance of two Mediterranean forested catchments (Prades, northeast Spain) - Piñol, J; LLEDO, M J; Escarre, A (Hydrological Sciences Journal, 1991)
Abstract Precipitation and discharge have been measured for several years in two small forested catchments located in the Mediterranean area of Spain. Actual evapotranspiration has been calculated as the difference between annual precipitation and discharge. Results show that: (a) most of the precipitation is evaporated rather than lost by streamflow, even in the most humid years; (b) there is a high inter-annual variability both in discharge and evapotranspiration; and (c) annual evapotranspiration correlates significantly with annual precipitation, in contrast to the constancy of annual evaporation in catchments of wet, colder climates. Finally, a simple expression is proposed in order to calculate annual actual evaporation from the ratio of precipitation to potential evapotranspiration. This expression uses a derived exponent, k, which takes into account the characteristics of individual catchments.
doi: 10.1080/02626669109492492
Keywords: Catchments; evapotranspiration (voyant); hydrological response; Precipitation

Modelling cork oak production in Portugal - Ferreira, M C; Oliveira, A M Carvalho (Agroforestry systems, 1991)
The layout of 32 permanent plots in the most important cork production regions of Portugal and the measurement of the most representative tree parameters were performed for statistically sound cork weight modelling. The establishment of cork weight equations is presented for the different cork oak study areas considered alone or grouped according to the most representative tree parameters. For the presented cork weight models was chosen independent variable the total stripping surface (artmax). For the selection criteria five statistic were used, including PRESS, APRESS and Mallows's statistic. The crossvalidation of the best classified models was performed and to discuss the importance of the "study area" factor, a regression analysis with "dummy" variables was performed.
Keywords: cork weight models; Quercus suber; validation

Nest-site selection and nesting success in the Azure-winged Magpie in Central Spain - Alonso, J A; Muñoz-Pulido, R; Bautista, L M; Alonso, J C (Bird Study, 1991)
Nest-site selection and nesting success in Azure-winged Magpies Cyanopica cyana were studied in 1986 in central Spain. Preferred nest sites were a nonrandom subset of the available habitat. Nests built on evergreen trees had significantly earlier clutch initiation dates than those built on deciduous trees. Birds selected larger trees of each species for nesting, but nests built on very high trees had significantly lower nesting success. Birds tended to locate their nests in a central position relative to the canopy height and as far from the main trunk as possible, without being of the periphery. This may minimize nest accessibility and maximize concealment. Nesting success was higher in the preferred regions of the tree canopy. Predation and inclement weather were probably the factors selecting for the observed patterns in nest-site distribution.
doi: 10.1080/00063659109477066
Keywords: Canopy; Cyanopica cyana; Evergreen and deciduous species (voyant); Nest site selection; Nesting success

POSTFIRE RESPROUTING OF SHRUBBY SPECIES IN MEDITERRANEAN MAQUIS - Gratani, L; AMADORI, M (VEGETATIO, 1991)
The vegetative resprouting of mediterranean maquis shrubby species was examined eight years after fire. Post-fire regeneration occurs through the resprouting of stumps. All species (Quercus ilex L., Phillyrea latifolia L., Arbutus unedo L., Erica arborea L., Pistacia lentiscus L.) show a rapid growth in the first years after fire, and a decrease already from 4th-5th year. All the species survived the fire and reconstituted a community similar to that unburned in a relatively short time span.
Keywords: fire; Mediterranean maquis; VEGETATIVE RESPROUTING

PREDICTION OF BOTANICAL COMPOSITION IN GRASSLAND HERBAGE SAMPLES BY NEAR-INFRARED REFLECTANCE SPECTROSCOPY - GARCIACRIADO, B; GARCIACIUDAD, A; PEREZCORONA, M E (JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, 1991)
Near infrared reflectance spectroscopy (NIRS) was evaluated as a method to predict the botanical composition of seminatural grassland in `dehesa' systems. Samples of herbaceous biomass were harvested over four consecutive years, determining in each-by manual separation-the proportion by weight of the following taxonomic groups: grasses, legumes and the rest of the families in a single block ('others'). After reconstructing the natural samples they were analysed by NIRS. One set of samples (calibration set) was selected for the development of the equations, assaying different mathematical treatments (log 1/R, first derivative and second derivative). The ranges of coefficients of multiple determination and standard errors of calibration, respectively, for the various components were: grasses, 0.86 to 0.92 and 6.66 to 9.14; legumes, 0.77 to 0.81 and 6.82 to 7.43; and `others', 0.85 to 0.88 and 8.17 to 9.54. The remaining samples not included in the development of the NIRS equations (prediction set) were used for the purposes of validating the best equations. Standard errors of performance were: grasses, 6.12; legumes, 7.56 and `others', 7.70.
Keywords: BOTANICAL COMPOSITION; grassland; NEAR; prediction

Relationship between temperature and the timing of breeding of the blue tit (Parus caeruleus) in two Mediterranean oakwoods - Bellot, M D; Dervieux, Alain; Isenmann, Paul (Journal of Ornithology, 1991)
They think that these temperatures have an influence on the timing of breeding but it remains unclear if this influence is direct or indirect. In this study, we present the results of an investigation of the effect of temperature on the timing of breeding of a population of Blue Tits (Parus caeruleus) breeding in two neighbouring oakwoods, one dominated by evergreen Holm Oaks, the other by deciduous Downy Oaks in Mediterranean France. Though experiencing the same climate, this population shows marked variation between individuals for laying time (BLoNDEL et al. 1987, CLAMENS & ISENMANN 1989, DERVIEUX et al. 1990). In this con- text, two questions are considered: 1) is there a relationship between temperature and laying date in the two oakwoods and, 2) how may temperature cause such variation?
Keywords: breeding; egg laying; Parus caeruleus (voyant); Temperature

RESPONSE OF MEDITERRANEAN GRASSLAND SPECIES TO CHANGING RAINFALL. - Figueroa, M. E.; Davy, A. J. (Journal of Ecology, 1991)
Investigates the long-term changes in the composition of a species-rich Mediterranean grassland in south-western Spain. Determination of the frequency of every species of herbaceous vascular plants annually; Domination of winter annual vegetation; Correlations between the logit of the total annual frequency of each species and rainfall totals; Link between species abundance and rainfall.
Keywords: BOTANY; Grasslands; MEDITERRANEAN Coast (Spain); RAINFALL frequencies; SPAIN (citation)

RESPONSE OF MEDITERRANEAN GRASSLAND SPECIES TO CHANGING RAINFALL. - Figueroa, M E; Davy, A J (Journal of Ecology, 1991)
Investigates the long-term changes in the composition of a species-rich Mediterranean grassland in south-western Spain. Determination of the frequency of every species of herbaceous vascular plants annually; Domination of winter annual vegetation; Correlations between the logit of the total annual frequency of each species and rainfall totals; Link between species abundance and rainfall.
Keywords: BOTANY; Grasslands; MEDITERRANEAN Coast (Spain); RAINFALL frequencies; SPAIN (citation)

Root biomass of Quercusilex in a montane Mediterranean forest - Canadell, Josep; Rodà, Ferran (Canadian Journal of Forest Research, 1991)
Biomass allocation to roots was studied in holm oak (Quercusilex L.), a dominant evergreen tree in broad-leaved sclerophyllous Mediterranean forests. The root systems of 32 single-stemmed holm oaks growing in shallow soils on largely unfissured bedrock were excavated in a mesic site and a xeric site in the Montseny Mountains (northeast Spain). Individual root:shoot biomass ratios (roots with diameter <1 cm not included) of single-stemmed trees were significantly higher in the xeric site (mean 0.45) than in the mesic site (mean 0.37), probably reflecting the lower water availability and higher light availability in the xeric site. It is concluded that single-stemmed holm oaks have higher root:shoot ratios than most temperate forest trees, particularly so when growing on a xeric site. Root:shoot ratios of single-stemmed trees were not linearly correlated with dbh. Allometric regressions of root biomass on dbh did significantly differ between sites. Roots <1 cm in diameter were sampled with soil cores in the mesic site. Holm oaks ≥5 cm dbh in a stand dominated by single-stemmed trees on the mesic site had an aboveground biomass of 160 t/ha and a belowground biomass of 63 t/ha. The belowground biomass was composed of 30 t/ha of root crowns plus roots >5 cm in diameter, 17 t/ha of roots 1–5 cm in diameter, and 16 t/ha of roots <1 cm in diameter. The xeric stand was dominated by multistemmed holm oaks with massive root crowns developed after repeated coppicing. Three multistemmed trees were excavated, yielding a mean root:shoot ratio of 1.2. Through resprouting from root crowns, managed or disturbed holm oak forests can accumulate a belowground biomass greater than that displayed aboveground: 91 t/ha (excluding roots <1 cm in diameter) and 79 t/ha, respectively, in our xeric stand.
doi: 10.1139/x91-245

SEED STORAGE PROTEINS IN FAGACEAE - SIMILARITY BETWEEN CASTANEA GLOBULINS AND QUERCUS GLUTELINS - COLLADA, C; CABALLERO, R G; CASADO, R; ARAGONCILLO, C (PLANT SCIENCE, 1991)
Castanea sativa Mill. and C. crenata Lieb. and Zucc. store 11S globulins as major seed proteins while Quercus ilex L. and Q. robur L., also members of the Fagaceae family, accumulate glutelins. The structure of the 11S Castanea globulins, which is similar to the accepted model for this class of proteins, has been studied by different two-dimensional electrophoretic methods. The oligomer has a M(r) of 240 000-260 000, and the pairs of acidic-basic subunits, which form it, show great heterogeneity. The Quercus glutelins are made up of dimers linked by disulphide bridges, and their characteristics indicate a similarity to the subunits of 11S Castanea globulins. We suggest that, as in the case of rice glutelins, Quercus glutelins can also be considered legumin-like proteins.
Keywords: 11S GLOBULINS; Castanea; GLUTELINS; Quercus

The stomata of the cork-oak, Quercus suber. An ultrastructural approach - Molinas, M L (Nordic Journal of Botany, 1991)
In the evergreen leaves of Quercus suber, stomata play a major role in adaptation to drought and temperature stress. The leaf is of zygostomic type and has about 430 stomata per square milimeter of abaxial leaf surface. The stomatal complex is of the anomocytic type. The guard cells protrude from the epidermal plane. The guard cell nucleus contains heterochromatin in small granules. The guard cell cytoplasm is characterised by a large number of well developed mitochondria, amyloplasts with stroma and grana, and a well developed cytoskeleton with a cortical array of microtubules oriented pa railed to the slit axis that persist even in mature cells. Guard cell walls are asymmetrically thickened and devoid of plasmodesmata. No area of cell walls was free of cuticle or covered by a thin cuticular layer and apparently no area of limited cuticular development provides evaporation when the stomata are closed.
Keywords: Quercus suber; stomata; ultrastructure (PG)

TANNIN LEVELS IN LEAVES OF SOME OAK SPECIES AT DIFFERENT STAGES OF MATURITY - Makkar, H P S; DAWRA, R K; Singh, B (JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, 1991)
Total phenolics, condensed tannins, degree of polymerisation, protein precipitation capacity, protein precipitable phenolics and specific activity (protein bound per unit tannins) were determined in the leaves of four oak species at different stages of maturation (4 days old to 1 year old). The content of total extractable phenols was higher in younger leaves in Quercus ilex Linn, Quercus semecarpifolia Sm and Quercus serrata Roxb, whereas in Quercus glauca Thunb the content was higher in the mature leaves. In all species studied, condensed tannins increased with maturation. Protein precipitation capacity had a trend similar to that of total phenols. In Q serrate and Q semecarpifolia the apparent degree of polymerisation increased, and the content of protein precipitable phenolics and specific activity decreased as the leaves matured. The decrease in protein precipitation capacity with maturation in these two species may be explained by both the decrease in the content and the change in the nature of phenols capable of binding proteins. Protein precipitation capacity was not detectable in Q ilex leaves. Protein precipitation capacity in the mature leaves decreased in the order of Q serrata > Q semecarpifolia > Q glauca > Q ilex.
Keywords: CONDENSED TANNINS; Tannins; TOTAL PHENOLS

Thermal decomposition of wood in oxidizing atmosphere. A kinetic study from non-isothermal TG experiments - Cordero, T; Rodriguez-Maroto, J M (Thermochimica acta, 1991)
The kinetics of thermal decomposition of four wood species in oxygen-bearing atmo- spheres of 5, 10 and 20% molar Oz concentrations have been studied from temperature-pro- grammed experiments carried out at 5, 10 and 20 K mm ’ -* heating rate. Devolatihzation as weII as combustion of the reaminin g solid have been considered to analyze the weight loss curves. The homogeneous volume reaction (VR) model has been used to describe devolatihza- tion, whereas for solid combustion the grain model has been also checked. A two-stage approach has been used to fit the conversion-time curves and to derive the corresponding apparent kinetic parameters. The VR/VR (pyrolysis/combustion) combination provided a better description of the experimental (~-1 curves than the VR/grain combination. Hohn oak and cork oak showed very close reactivities, whereas some differences were observed for aleppo pine and eucalyptus.
Keywords: Aleppo pine; combustion (voyant); Cork oak; EUCALYPTUS; Holm oak; Kinetic model; pyrolysis; Wood

Variations de la croissance radiale de Quercus ilex L en fonction du climat - Zhang, S H; Romane, F (Ann. For. Sci., 1991)
Diameter growth of Quercus ilex L and the interannual variability of climatic characteristics. Diameter growth of Quercus ilex L, the dominant sclerophyllous species in much of the Mediterranean basin vegetation, was studied in relation to precipitation and temperature. The study site in Montpellier (Southern France) has a Mediterranean climate. Eleven trees, grown from acorns in 1963, were cut in 1984 and the rings studied at 3 levels (ground, 0.5 and 1 m above the ground). The data were analyzed by the ARMA procedure which gives the part of the total variation due to the autocorrelation processes. A multiple regression between the factors of a principal component analysis (PCA) of the monthly climatic data (rainfall and temperature) and the residuals issuing from the ARMA procedure then suggested that the large annual rings were due to a particular rainfall distribution during the year, the late summer precipitation promoting a large annual growth diameter (table II). The presence or absence of false rings (table I) was also analyzed by PCA (figs 2 and 3). The false rings were positively correlated to a large annual growth diameter corresponding to a high summer rainfall (fig 4), while the relationship with the temperature preceding the growing season was negative. It therefore appears that this species is relatively unaffected by spring climatic conditions, ie which generally indicate the main growth phase, but that it is able to take advantage of the interannual climatic variations of the region.
Keywords: diameter growth; Mediterranean climate; Precipitation; Quercus ilex L; ring; Temperature

WINTER DIET OF RED DEER STAG (CERVUS-ELAPHUS L) AND ITS RELATIONSHIP TO MORPHOLOGY AND HABITAT IN CENTRAL SPAIN - ALVAREZ, G; MARTINEZ, T; MARTINEZ, E (FOLIA ZOOLOGICA, 1991)
The winter diet of red deer stags in a mediterranean environment of Central Spain is studied. Tree foliage and shrubs made up 95.5% of the diet, particularly Quercus rotundifolia (35.4%). Arbutus unedo (19.7%), Rosmarinus officinalis (9.4%), Phillyrea angustifolia (7%), Erica spp. and Cistus ladanifer. Herbaceous species formed 4% of the diet, mainly in a dry condition. There was a high similarity between the diets in the two periods studied, December and the end of January, with greater diversity in December. In January, the dominance of Quercus rotundifolia and Arbutus unedo increased. A relationship was detected of diet with body weight and antler growth. The largest animals consumed Arbutus unedo heavily, indicating a preference for forest understories with dense developed shrubs in mountain areas, while the smaller individuals associated with Erica umbellata, Phillyrea angustifolia and herbaceous species, had a wider diet niche and occupied less sheltered zones.
APS
Keywords: diet; Mediterranean; red deer; Spain

Aspectos fisiológicos do descortiçamento em Querqus suber - Correia, O A; Oliveira, G; Martins-Loução, M a; Catarino, F M (I Congresso Ibérico de Ciências Hortícolas, 18 a 21 de Junho de 1990 em Lisboa, 1990)
Quercus suber is the primary source of industrial cork, and can produce cork every 9-10 years. The main objective of the present work was to investigate the influence of the bark stripping of the cork-oak on the stomacal activity and water relations. For this purpose, diurnal variations on transpiration, stomacal conductance and water potencial were studied before and after bark stripping during July and August 1989. The stripping on the trees had been done at various levels. The water loss by the stripping surface was also measured. These preliminary results show that the stress caused by stripping on these trees is different according to the stripping area. The transpiration is immediatly reduced after stripping, under the conditions of these investigations and high stripping coeficients. Sendo o sobreiro uma espécie que proporciona sucessivas tiradas de cortiça, um dos aspectos que importa salientar é o dos exagerados descortiçamentos, que poderão ser um factor de decréscimo de produtividade. Neste trabalho foi estudada a reacção de plantas submetidas a diferentes coeficientes de descortiçamento no que respeita aos parâmetros fisiológicos relacionados com o balanço hídrico e economia de água. Foram efectuados estudos ecofisiológicos em árvores descortiçadas nos meses de Julho 89/Agosto 89, tendo sido estudada a variação diurna da transpiração, condutância estomática e condutividade hidráulica. Foi igualmente determinada a perda de água, por evaporação, através do tronco até à formação de nova periderme. São apresentados resultados preliminares que põem em evidência o stress que o descortiçamento provoca nestas plantas e que é tanto mais grave quanto maior for o coeficiente de descortiçamento aplicado.
Keywords: Descortiçamento; Fisiologia vegetal; Sobreiro (Quercus Suber L.)

Aspectos fisiológicos do descortiçamento em Querqus suber - Correia, O A; Oliveira, G; Martins-Loução, M a; Catarino, F M (I Congresso Ibérico de Ciências Hortícolas, 18 a 21 de Junho de 1990 em Lisboa, 1990)
Quercus suber is the primary source of industrial cork, and can produce cork every 9-10 years. The main objective of the present work was to investigate the influence of the bark stripping of the cork-oak on the stomacal activity and water relations. For this purpose, diurnal variations on transpiration, stomacal conductance and water potencial were studied before and after bark stripping during July and August 1989. The stripping on the trees had been done at various levels. The water loss by the stripping surface was also measured. These preliminary results show that the stress caused by stripping on these trees is different according to the stripping area. The transpiration is immediatly reduced after stripping, under the conditions of these investigations and high stripping coeficients. Sendo o sobreiro uma espécie que proporciona sucessivas tiradas de cortiça, um dos aspectos que importa salientar é o dos exagerados descortiçamentos, que poderão ser um factor de decréscimo de produtividade. Neste trabalho foi estudada a reacção de plantas submetidas a diferentes coeficientes de descortiçamento no que respeita aos parâmetros fisiológicos relacionados com o balanço hídrico e economia de água. Foram efectuados estudos ecofisiológicos em árvores descortiçadas nos meses de Julho 89/Agosto 89, tendo sido estudada a variação diurna da transpiração, condutância estomática e condutividade hidráulica. Foi igualmente determinada a perda de água, por evaporação, através do tronco até à formação de nova periderme. São apresentados resultados preliminares que põem em evidência o stress que o descortiçamento provoca nestas plantas e que é tanto mais grave quanto maior for o coeficiente de descortiçamento aplicado.
Keywords: Descortiçamento; Fisiologia vegetal; Sobreiro (Quercus Suber L.)

BIOMASS PRODUCTION AND NUTRIENT REQUIREMENT DURING RESTORATION OF A HOLM OAK COPPICE - LEONARDI, S; Rapp, M (ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY, 1990)
The restoration of a holm oak (Quercus ilex L.) coppice was studied during three years following a clear-cut. Leaf area rebuilding, above-ground biomass production and nutrient requirement are especially studied. The new produced above-ground biomass amounts respectively to 151, 913 and 2 161 g m-2, one, two and three years after clear-cut. Leaf area index, at the same ages, amounts respectively to 0,3-1,9 and 4,4 m2/m2. The last value is nearly the same as those of the 30 year old coppice stand (4,4 m2/m2). The biomass increment corresponds to a current yearly above-ground productivity of 165, 748 and 1 248 g m-2 of fresh material during these three years. The mean annual above-ground production, calculated over thirty years, only amounts to 800 g m-2. Concerning nutrients, it seems that the early years are characterized by a higher requirement of nitrogen, phosphorus and potassium in comparison to the mature stand. The needs for calcium start to be important only after the third year, with the reappearance of ``stems{''} and later trunks.
Keywords: biomass; coppice; NUTRIENT REQUIREMENT; STAND RESTORATION

Caractérisation de la résistance au froid de deux espèces sclérophylles méditerranéennes par la fluorescence de la chlorophylle - Méthy, M; Trabaud, L (Ann. For. Sci., 1990)
Frost resistance characterisation of two mediterranean sclerophyllous species by chlorophyll fluorescence. Frost resistance of the photosynthetic system of 2 sclerophyllous species of the mediterranean region, Quercus ilex and Quercus coccifera, has been analysed. Measurements were made on 1 year and 1 month old leaves by the chlorophyll fluorescence induction method. Photosynthetic activity is inhibited very quickly for both the 2 species at the development stages studied. The photosynthetic system of Q ilex seems to be the most resistant but is destroyed after half an hour of exposure to cold at -20 °C, without any recovery after treatment. The effect of winter temperatures on the distribution areas of Q ilex and Q coccifera is discussed.
Keywords: chlorophyll fluorescence; Freezing; Quercus coccifera; Quercus ilex; Sclerophyll

Características y producción de los pastos de las dehesas del SO de la Península Ibérica - Olea, L; Verdasco, M P; Paredes, J (Pastos, 1990)
La producción de los pastos naturales de zonas semiáridas del S. O. de la Península Ibérica (DEHESA) es limitada tanto en cantidad como en calidad, siendo sus valores medios anuales de 1.440 kg/ha de M. S. con 10,3 % de Vroteina Bruta (P. B.) y 55,2 % de Digestibilidad de la Materia Orgánica (D.M.O.). Cuando se mejoran los pastos, con fertilizaciones fosfóricas o con introducción de especies más fertilizaciones fosfóricas, las producciones aumentan llegando a alcanzar los 2.500 kg/ha de M.S., con 12,6 % de P.B. y 60,7 % de D.M.O. La calidad de los pastos mejorados, aun estando secos, y su gran producción de semillas permite aprovecharlos en verano, consiguiendo sistemas de producción que duplican, al menos, la carga ganadera
Keywords: fertilización; leguminosas anuales; mejora de pastos; pastos

Changes and disturbances of forest ecosystems caused by human activities in the western part of the Mediterranean basin - Barbero, M; Bonin, G; Loisel, R; Quezel, P (Plant Ecology, 1990)
The development of socio-economic activity over the past ten years in the Mediterranean region has induced severe changes in the main natural forest ecosystems. In the northern Mediterranean, rural depopulation has accelerated since the end of the second World War, particularly since the establishment of Common Market agricultural policies, and led to an under-utilization of species causing a strong biological resurgence of the forest, even at high altitudes. This means that, at the present time, the extension of expansion model coniferous forests is favored by their capacities for spatial, biological and ecological selection. Along with this, the under-utilization of sclero- phyllous (resistance model) and deciduous (stabilization model) oak coppices has led to the establishment of new forest structures and architectures which are notably different from the main climatic groups defined up to now by phytosociological and synchronic methods. Two new forms of disturbances have appeared: - increasingly important wild fires have replaced disturbances caused by burn beating and are at the origin of the very strong spatial and temporal heterogeneity of current forest species. - In addition, the geographical continuity of the main groups of same-aged sclerophyllous and deciduous species, due to their non-use over the past ten years, has accelerated a phytosanitary imbalance by an increase in the action of pests. In the southern Mediterranean, particularly in North Africa, demographic pressure and grazing have widely disturbed the main forest ecosystems which show a continual regression of their surface. Many forest tree species with a low spatial and biological selection, such as Mediterranean firs and black pines (Pinus nigra subsp, mauritanica), are threatened with extinction, as are the deciduous oak forests which, considering the climatic stress and edaphic constraints, are permanently in a state of imbalance. Human disturbances induce a complete modification of structures and architectures tending towards the instal- lation of simplified forest models (trees-grasses) where tree regeneration is nearly impossible. The sclero- phyllous coppices well-adapted to stress are also threatened by shorter and shorter cutting cycles and by the high usage of tree canopies for grazing. - The forest understory structures have witnessed a decrease in their characteristic sylvatic species and the matorralization of most of the forests can be seen by the replacement of typical forest groups by preforest groups (Tetraclinis forests, Aleppo pine forests). - New geopedological constraints linked to the removal of the surface soil layer combined with regular climatic stress (duration of drought periods) strongly decrease the resilience of these ecosystems which are under continual pressure (unbalanced models). - In diverse regions, particulary in semi-arid bioclimates, hyperdegradation affects the shrub cover which disappears for a time in favor of perennial grasses (forest steppization): Andropogon div. sp., Ampelodesmos, Stipa div. sp. In all bioclimatic groups, the increase in grazing pressure throughout the southern Mediterranean ecosystems can even lead to the total disappearance of perennial species from the ecosystem with the exception of the dominant tree. Regardless of the altitude or ecosystem, invasive therophytes are then the only plants to occupy the understory and indicate hyperdegradation (forest therophytization).
Keywords: changes; disturbances; dynamic models; human activities; Mediterranean forests

CO2 and steam gasification reactions of a charcoal from holm-oak wood. KINETIC AND TEXTURAL CHARACTERIZATION - Valenzuela Calahorro, C; Bernalte García, M J; Serrano Gómez, V; Bernalte García, A (BIOMASS FOR ENERGY AND INDUSTRY: 5th E.C. Conference, 1990)
In this work are shown the kinetic results of carbon dioxide and steam gasification reactions of a charcoal from holm-oak wood and the evolution of some textural parameters (BET surface area, micropore and mesopore volume) of several activated carbons prepared by such reactions
APS
Keywords: activated carbon; Carbon dioxide; charcoal; Holm oak; kinetic; steam gasification

Contributo alla conoscenza dei boschi a Quercus ilex della Sicilia - Bartolo, Giuseppina; Brullo, Salvatore; Minissale, Pietro; Spampinato, Giovanni (Acta Botanica Malacitana, 1990)
In this paper the Quercus ilex woods occurring in Sicily were examined. Apart from the associations previosly observed in this territory, the presence of Ostryo-Quercetum ilicis is reported for the first time; besides some new subassociations of the Querco-Teucrietum siculi and of the Aceri obtusati-Ostryetum curpinifoliae are described. Syntaxonomic, ecological and syndynamic considerations are given for every associations.
Keywords: phytosociology; Quercus ilex woods; Sicily

Datos sobre la vegetación silicícola de Andalucia I. - Caldera, J M Nieto; Latorre, A V Pérez; Cabezudo, B (Acta botánica malacitana, 1990)
: The phytocenologic study about climatophilous vegetation series, which inhibat on siliceous soils in Málaga, Cádiz, Sevilla and Granada (Spain), has produced the identification of six vegetation series. It is described the following new syntaxa: Smilaco mauritanicae-Quercetum rotundifOliae quercetosum suberis,Teucrio baetici-Querceturn suberis quercetosum rotundifoliae and Cytiso baetici-Arbutetum unedonis.
Keywords: Cádiz; Cork oak forests; Granada; holm oak forests; Málaga; phytosociology; Sevilla; siliceous soils; Spain; strawbwerry tree copses; vegetation series

Degradation stages of the oak forests in the area of Algiers - Wojterski, Teofil W (Vegetatio, 1990)
Long lasting human impact on the natural Mediterranean vegetation is the reason for its degradation. Uncontrolled felling of trees, fire and overgrazing are the most important ecological causes of this process. Geobotanical investigations made in the area of Algiers facilitated the characterization of degradation changes in the structure of vegetation and in the floristic composition in all the degradation stages. Under the influence of the degradation factors, mentioned above, the oak forests, growing on different, more or less calcareous substrates, are transformed into various shrub formations, mainly into many types of 'maquis' and 'garrigue'. The floristic composition of these communities is given in Table 2. Further degradation leads to widespread Cistus-formations and then to 'palmitto', a formation created by the dwarf palm (Chamaerops humilis). When the anthropopressure becomes stronger even this dwarf palm retreats. Loose swards, replacing the 'palmitto' formation, often cannot stop the subsequent degradation. Bare rock is the extreme, relatively rare stage of forest degradation in this area. The most common form of natural regeneration is the invasion of Pinus halepensis, observed in all degradation stages identified. This pine is also one of trees, most commonly planted on mountain slopes to prevent their erosion.
Keywords: anthropic influence; degradation; Mediterranean vegetation; Vegetation dynamics; vegetation structure

Encinares luso-extremadurenses y sus etapes preclimácicas - Ladero, Miguel; PÉREZ-CHISCANO, J L (Acta botánica malacitana, 1990)
We comment several faciations holm-oak wood's of the Luso-Extremadurense province belonging to the mesomediterranean series Pyro-Querceto rotundifoliae S.
Keywords: Holm-oak woods; Luso-Extremadurense province (Spain); Pyro-Querceto rotundifoliae S.

Fluorescence Parameters Measured Concurrently with Net Photosynthesis to Investigate Chloroplastic CO2 Concentration in Leaves of Quercus ilex L. - Di Marco, Giorgio; Manes, Fausto; Tricoli, Domenico; Vitale, Elisabetta (Journal of Plant Physiology, 1990)
Summary The relationship between net carbon assimilation and non-photochemical quenching (qN) was studied in Q. ilex. In leaf discs, in saturating C02 at various irradiances, qN responded linearly in a 1:1 relationship to 1-A/Ap, which represents the proportion of light energy that is not used in photosynthesis. In calculating Ap, a measured, maximal quantum yield for CO2 fixation of 0.080 for 1-year-oldleaves and 0.085 for young leaveswas used. In attached leaves, under natural conditions, this 1: 1 relation was found when a quantum yield of 0.020 and 0.031 was adopted respectively. According to a model of leaf photosynthesis these quantum yields correspond to stromal CO2 concentrations of 90 and 120μLL L-1, in contrast to an average value of substomatal CO2 concentration of 280μLL L-1 found through gas exchange measurements. Similar results were obtained when the relative increase of fluorescence, observed after a saturating flash given during steady photosynthesis at different irradiances, was plotted against the quantum yield of CO2 fixation. The slope of this relation in attached leaves differed from the slope obtained in saturating CO2 in the leaf discs to such an extent as to indicate stromal CO2 concentrations slightly lower compared with the above values obtained by using qE. The marked difference between stromal and substomatal CO2 concentration could be explained by the highly sclerophyllous character of Q. ilex leaves.
Keywords: carbon assimilation; fluorescence; fluorescence quenching; quantum yield; Quercus ilex; stromal CO2

Germination of Quercus ilex and Q. pubescens in a Q. ilex coppice - Bran, D; Lobreaux, O; Maistre, M; Perret, P; Romane, F (Plant Ecology, 1990)
Quercus ilex L. (holm oak) coppices, widespread around the Mediterranean basin, are probably the result of 5 000 years of prolonged human disturbance of the original Quercus pubescens Willd. (downy oak) forests. Since disturbance has almost ceased in recent years, a question arises as to the development of these coppices: will the Q. pubescens forests return, or will Q. ilex remain the dominant species? To investigate the phenomenon, we analyzed the first stages, i.e. germination of the two species in holm oak coppices. Our experiments show that both species germinated better in coppices than in clearings or clear-cuts. Moreover, Q. pubescens appears to be slightly favored above Q. ilex and it is suggested auto-allelopathy is involved, at least partially inhibiting the germination of Q. ilex.
Keywords: dynamics; Mediterranean climate; Southern France; succession

Histology of Callogenesis and Somatic Embryogenesis Induced in Stem Fragments of Cork Oak (Quercus suber) Cultured In Vitro - MAÂTAOUI, M E L; Espagnac, H; MICHAUX-FERRIÈRE, N (Annals of Botany, 1990)
Calluses able to produce somatic embryos were formed during in vitro culture of shoot fragments of cork oak (Quercus suber L.).Histological monitoring of these fragments during culture showed that it was the cortical parenchyma cells which underwent dedifferentiation before calluses were formed by repeated divisions. The calluses consisted of parenchyma cells surrounded by a few layers of meristematic cells. Proembryos formed in groups around the edge of some calluses. Histological examination showed that they were produced by the evolution of two different categories of cell: one category had the appearance of ‘embryogenic’ cells with very thick walls, a small vacuole rich in starch and a well-developed nucleus with a prominent nucleolus. The other cells were very bulky with large vacuoles; their morphology was similar to that of suspensor cells encountered in embryogenesis in gymnosperms. The ontogenic stages were similar to those described in zygotic embryos of the genus Quercus. Nevertheless, most of the embryonic structures deviated from normal development and at all stages produced secondary proembryos.
Keywords: callogenesis; cork-oak; embryogenic cells; histology; Quercus suber L.; secondary embryogenesis; Somatic embryogenesis; starch

A kinetic study on chemical activation of holm oak wood - Blasco, J. M.; Cordero, T. (Journal of Analytical and …, 1990)
Activation energy distribution functions for thermal decomposition of untreated and chemically treated holm oak wood have been obtained from temperature-programmed TG experiments. H,SO,, H,PO, and ZnCl, have been used as pretreating agents. When using HaSO, the results obtained become quite comparable with those corresponding to the original untreated wood whereas in the cases of H,PO, and ZnCl, significant differences are evident in the distribution functions. Using the activation energy distribution functions, a very good reproduction of the experimental weight-loss curves has been achieved.
Keywords: Activation energy distribution functions; chemically treated wood; pyrolysis.

Land abandonment : Changes in the land use patterns around the Mediterranean basin - Correia, T Pinto (Options Méditerranéennes, 1990)
This paper focuses on land abandonmenitn the EEC Mediterranean regions, where the phenomenon, in its actual extension and its trends towards aggravation, demands urgent monitoring and management. The causes and processes of land abandonment are analyzed, as well as the consequences at landscape and ecological level. Depending also on the socio-economic context, new strategies for land management are outlined.
Keywords: extensification; Land abandonment; landscape; marginalization; Mediterranean

Life forms variability of mediterranean sclerophyllous forests - Blasi, C; Mazzoleni, S; Spada, F; Stanisci, A (Plant Ecology, 1990)
Variations in Raunkiaer's life-forms spectra for mature Quercus ilex forest stands in N-Mediterranean basin were examined in order to assess their predictability in local vegetation analysis. Physiognomic variations in Quercus ilex communities appear to be mainly determined by structural variations due to intrinsic characteristics (long-term human disturbance all over their range) and to different dynamical status of the stands, without any geographical pattern.
Keywords: Mediterranean basin; raunkiaer's life-forms; sclerophyllous forests

L'impact du déboisement sur l'azote minéral susceptible d'être absorbé par un taillis de chêne vert (Quercus ilex L) en reconstitution - Merzouki, A; Lossaint, P; Billes, G; Rapp, M (Ann. For. Sci., 1990)
The impact of deforestation on the mineral nitrogen available during restoration of the holm oak (Quercus ilex L) coppice. The impact of deforestation on the biological activity of a mediterranean red soil was studied from January 1984 to April 1986 within a holm oak (Quercus ilex L) stand after clearcut. Part of the study involved the estimation of the amount of nitrogen available for vegetation both in the mature holm oak coppice and in the 1-2-yr-old recovery stand. The study indicates that the new shoots essentially took up nitrate nitrogen; however, the mature site used both nitrate and ammonium nitrogen as nitrogen source. The availability of mineral nitrogen, essentially nitrate, ranged from 47.4 to 118.6 kg·ha -1·yr-1 in the rebuilding site and 25.6 to 63.9 kg·ha-1·yr-1 in the mature stand. At the control site, ammonium nitrogen represented 43% of the total nitrogen available.
Keywords: Deforestation; holm oak coppice; nitrate; nitrogen availability; Quercus ilex L; shoots

Micronutrients in biomass fractions of holm oak, beech and fir forests of the Montseny massif (Catalonia, NE Spain) - Caritat, A; Terradas, J (Ann. For. Sci., 1990)
This study is part of a larger research programme on different forest ecosystems in the Montseny massif (Barcelona, NE Spain). The contents of 4 micronutrients (Mn, Fe, Zn and Cu) are given for some biomass fractions in individual monospecific stands of holm oak (Quercus ilex L), beech (Fagus sylvatica L) and fir (Abies alba). The behaviour of different micronutrients is related to relative mobility. Mn, Fe and Zn concentrations increase with leaf age. Nutrient levels of the Montseny stands are compared with those found in other forests of the same species. We have observed relatively high Mn concentrations in different biomass fractions of the holm oak forest studied. This can be related to the low soil pH values. Our 3 forests show different micronutrient allocational patterns. Total quantities of the micronutrients in the biomass are only calculated for Q ilex forest. Values found are 33.6 kg Mn/ha, 15.0 kg Fe/ha, 2.8 kg Zn/ha and 0.17 kg Cu/ha.
Keywords: Abies alba; biomass fraction; Fagus sylvatica; micronutrient; Quercus ilex

Micropropagation of juvenile and adult Quercus suber L. - Manzanera, J A; Pardos, J A (Plant Cell, Tissue and Organ Culture, 1990)
This paper describes research on the application of tissue culture techniques to the micropropagation of cork oak (Quercus suber L.), a forest species of ecological and industrial importance in the Mediterranean area. Apical buds and nodal stem segments were employed as initial explants. Their origins were young seedlings, stump sprouts and sprouts formed on cuttings collected from old trees. The action of the mineral medium and growth regulators was studied in the multiplication stage. Media with low concentrations of ions, such as Sommer's or Heller's, are more suitable for growth and proliferation of explants than other media richer in salts. It was also observed that cytokinin (BA) must be present for the culture development. Adding low concentrations of auxin (NAA) to the medium improves the multi- plication rate, especially in vegetative material of adult origin. The auxin type is the most important factor in the promotion of rhizogenesis. The method of application determines the quality of the root system. Treatment with low concentrations of IBA added to the rooting medium gives the best results. High sucrose concentration also improves rooting. Diluting the mineral rooting medium is slightly favourable, although there is no significant difference between it and the standard mineral concentration.
Keywords: Cork oak; micropropagation; Quercus suber; rooting; tissue culture

A new technique to classify the compatibility of wood with cement - Hachmi, M; Moslemi, A A; Campbell, A G (Wood science and technology, 1990)
Wood-cement panels have commanded renewed interest during the last decade be- cause of their potential application in the building industry. Several methods to classify wood of various species regarding its compatibility with cement have been established in the literature based on hydration measurements in Dewar flasks. These ranking methods lack consistency in the classification of species because the hydration conditions vary among laboratories. Three techniques for evaluating wood-cement compatibility were established and compared. The best technique is based on a wood-cement compatibility factor which is the ratio of the area under the wood-cement hydration heat rate curve to that of neat cement. The area is calculated on 24-h basis starting from the initial cement set time. This area ratio method ranks species over a 100% scale and accounts well for species that are totally incompatible.
Keywords: cement; hydration; Wood; wood-cement compatibility (voyant); wood-cement panels

OVIPOSITIONAL HOST PLANT PREFERENCE OF SEPIA-OFFICINALIS - DENUCE, J M (ZEITSCHRIFT FUR NATURFORSCHUNG C-A JOURNAL OF BIOSCIENCES, 1990)
The present study was undertaken to verify ancient data in the literature on ovipositional preference of the cuttlefish Sepia officinalis for the terrestrial plant Pistacia lentiscus (mastic tree). - Adult specimens of Sepia were placed in basins together with aerial parts not only of P. lentiscus, but also of Artemisia arborescens, Centaurea alba var. deusta, Quercus ilex and Laurus nobilis. The egg masses deposited on the plants quantified on a daily basis during the 16 day observation period. By far the largest amounts of eggs were found attached to the stems and petioles of P. lentiscus (51.8%), but Q. ilex and A. arborescens also scored high as ovipositional host plants (23.1 and 20.2% respectively). L. nobilis and C. alba var. deusta ranked very low (3.6 and 1.3% respectively). Considering the extremely divergent shape of the three preferred oviposition substrates, which excludes affinity for a uniform type of plant, the possibility of chemical attraction cannot be ruled out.
Keywords: HOST PLANT PREFERENCE; oviposition; SEPIA-OFFICINA

Perspectives on research into spanish open woodlands (dehesa): some recent ecological experiences - Pineda, F D (Giornale botanico italiano, 1990)
Abstract Dehesa (open savanna-like woodland) is a Mediterranean ecosystem covering some two million hectares in the central, western and southeast parts of the Iberian Peninsula. Its importance as an ecosystem is seen from the perspective of food and energy production, scientific study and cultural traditions (Balcells et al., 1982 a, b; Humbert, 1980; Montoya, 1983; Ruiz, 1986; Vacher et al., 1985). Scientists have been carrying out studies from all of these perspectives for many years. Their conclusions have nevertheless had little influence on Spanish agricultural policy. While the information has been relevant and applicable to the ecosystem's management, policy has always been conditioned by controls on marketing channels, international stock-feed and agricultural machinery markets etc. This has led to a lamentable situation involving the destruction of landscapes, ancestral cultures and extensive grazing in large areas of the Iberian Peninsul (Balabanian, 1980; Campos Palicin, 1983; Fourneau Vacher et al., 1985). Some significant aspects of Spanish research in recent decades is summarized below, covering both the theoretical and the applied aspects of work done, particularly by the Ecology Department of Madrid's two Universities. Research on the dehesa in recent years has covered several phenomena: ? The conditioning factors imposed by climate and meteoroligical fluctuations in Mediterranean environments ? Types of herbivore grazing and pasture management ? Woodland-herbaceous vegetation interaction ? The perception and interpretation of landscapa by both its traditional users as well as others not involved in dehesa management ? Spatial plants organization observable on different scales of detail. Other aspects givin rise to several important studies include changes in land use and historic, institutional, economic, social and conservation question (Elena Rosellò, 1984; Garcia Sanz, 1978; Groome, 1985).
doi: 10.1080/11263509009428151
Keywords: conservation; Dehesa; Ecological succession; Mediterranean pastures; spatial organisation of plant communities

Plant and soil nitrogen dynamics in mediterranean grasslands: a comparison of annual and perennial grasses - Joffre, R (Oecologia, 1990)
The predominance of annual species in the rangelands of southwestern Spain is not due only to climatic factors but is also strongly influenced by grazing management. Manipulating the grazing system in an experimental plot gave a vegetation structure with patches of annual grasses (mainly Vulpia ssp. and Bromus hordeaceus) and patches of perennial grasses (mainly Phalaris aquatica). This vegetation change allowed us to test the hypothesis that life-cycle differences between annual and perennial grasses affect soil nitrogen availability and plant uptake. Nitrogen availability, measured by in situ incubation, and nitrogen uptake were measured through the growing period (October to June). Amounts of in situ mineralized nitrogen over the whole growth phase were more important for soils supporting perennials (37 ppm) than for soils supporting annuals (27 ppm). The difference between the mineral nitrogen produced in situ and the mineral nitrogen accumulated during the same time in the soil allowed an estimation of the maximum mineral nitrogen quantity which can be taken up by the vegetation during each incubation period. The quantities accumulated over the year were 47 and 38 ppm (or 103 and 83 kg/ha) for soils supporting perennials and annuals respectively. For the same period, amounts of nitrogen immobilized in biomass production were 90 and 70 kg/ha for perennials and annuals respectively. During the autumn, a large proportion of mineral nitrogen was leached from soils supporting annual plants which had only just commenced germination. By contrast, the ability to use mineral nitrogen as soon as autumn rains occurred gave a competitive advantage to the perennial species, but only if they were protected from grazing during this period. The higher mineralization and use of this nitrogen reserve by perennials indicates that they made more efficient use of nitrogen resources than annuals, and validate the initial hypothesis.
Keywords: Annual; grassland; Nitrogen mineralization; nitrogen uptake; Perennial

Precipitation, throughfall, soil solution and streamwater chemistry in a holm-oak (Quercus ilex) forest - Rodà, Ferran; Avila, Anna; Bonilla, David; Rodà, Ferran (Journal of Hydrology, 1990)
Bulk precipitation, throughfall, soil solution at 20 and 40 cm depths, and stream water were monitored for 2–4 years in a holm-oak forest on schists in the Montseny Mountains (NE Spain). Bulk precipitation was mildly acidic, with Ca2+ and SO2−4 as dominant ions. Canopy interactions produced a throughfall less acidic than bulk precipitation and enriched in all other ions. Large amounts of K+ were leached from the canopy. Magnesium in net throughfall behaved similarly to K+, and it is concluded that leaching makes a major contribution to Mg2+ enrichment beneath the canopy. Judging from the moderate increase of Na+ and Ca2+ in throughfall, dry deposition rates for both marine and continental aerosols were low in the studied stand, probably because of its sheltered topographic position within a well-vegetated massif, coupled with moderate tree height and low canopy roughness. Soil solution in the mineral soil was less acidic than throughfall. In common with most temperate forests, SO2−4 was the dominant mobile anion in the soil water, being largely accompanied by Ca2+. Potassium and NO−3 were depleted within the soil water with respect to throughfall, probably owing to biological uptake and cation exchange, and incorporation of K+ into clay lattices. Subsurface flow dominated the hydrology of the small forested catchment studied. Stream water was basic and rich in bicarbonate. Its chemistry revealed fast rates of weathering of sodium- and magnesium-bearing silicates (mainly albite and chlorite, respectively). Soil respiration and silicate hydrolysis resulted in HCO−3 being the dominant mobile anion in stream water. Calcium to chloride ratios were similar in bulk precipitation and in stream water, indicating that Ca2+ release from weathering has been counteracted by plant uptake. Nutrient uptake by this aggrading forest strongly influences the solution dynamics of K+, NO3 and Ca2+. It is concluded that: (1) this forest does not currently receive acidic atmospheric deposition; (2) the neutralization capacity of the soil-bedrock system is quite high; (3) biotic regulation and silicate weathering are the major processes shaping the solution biogeochemistry in this Mediterranean forest ecosystem.
Keywords: Canopy; chemistry (voyant); Holm oak; Montseny mountains; Precipitation; soil solution; stream water; throughfall

Ribosomal RNA genes inQuercus spp.(Fagaceae) - Bellarosa, R; Delre, V; Schirone, B; Maggini, F (Plant Systematics and …, 1990)
The taxonomy of the genus Quercus is still unclear. In order to elucidate the taxonomy of Mediterranean oaks we have analyzed ribosomal RNA genes of Quercus cerris, Q. coccifera, Q. trojana, Q. ilex, Q. suber, and Q. macrolepis by means of Southern blot hybridization. Oak nuclear DNA was extracted from root tips of 300 acorns and from catkins of single plants. EcoRI and BamHI restriction endonucleases were used. DNA electrophoresis and rRNA/DNA hybridization were performed using Vicia faba rRNA 18 S and 25 S as probes. The rRNA genes of all the species studied have an identical restriction mapping in the 18 S and 25 S regions, while differences in length are present in the intergenic regions. Q. cerris possesses at least four types of genes of 12.1, 11.5, 8.5, and 8.3 kb; Q. coccifera at least three types of 12.4, 10.4, and 10.1 kb; Q. trojana possesses the same rRNA genes as Q. cerris plus another gene type 12.0 kb long, with EcoRI and BamHI restriction sites in the intergenic spacer; Q. ilex at least three types of 12.4, 10.85, and 9.5 kb; Q. suber at least five types of 11.5, 11.0, 8.6, 8.5, and 8.3 kb; Q. macrolepis, finally, at least seven types of 11.5, 11.0, 10.2, 8.6, 8.5, 8.3, and 8.15kb. Q. coccifera and Q. ilex rDNA appears quite different respect to other species examined, while high similarity seems to exist between Q. cerris, Q. trojana, Q. suber, and Q. macrolepis. These results are in agreement with the taxonomic model proposed by SCnWARZ for the genus Quercus.
Keywords: Angiosperms; Fagaceae; Gene mapping; Quercus; ribosomal RNA genes; rRNA/DNA hybridization; taxonomy

Ribosomal RNA genes inQuercus spp.(Fagaceae) - Bellarosa, R.; Delre, V.; Schirone, B.; Maggini, F. (Plant Systematics and …, 1990)
The taxonomy of the genus Quercus is still unclear. In order to elucidate the taxonomy of Mediterranean oaks we have analyzed ribosomal RNA genes of Quercus cerris, Q. coccifera, Q. trojana, Q. ilex, Q. suber, and Q. macrolepis by means of Southern blot hybridization. Oak nuclear DNA was extracted from root tips of 300 acorns and from catkins of single plants. EcoRI and BamHI restriction endonucleases were used. DNA electrophoresis and rRNA/DNA hybridization were performed using Vicia faba rRNA 18 S and 25 S as probes. The rRNA genes of all the species studied have an identical restriction mapping in the 18 S and 25 S regions, while differences in length are present in the intergenic regions. Q. cerris possesses at least four types of genes of 12.1, 11.5, 8.5, and 8.3 kb; Q. coccifera at least three types of 12.4, 10.4, and 10.1 kb; Q. trojana possesses the same rRNA genes as Q. cerris plus another gene type 12.0 kb long, with EcoRI and BamHI restriction sites in the intergenic spacer; Q. ilex at least three types of 12.4, 10.85, and 9.5 kb; Q. suber at least five types of 11.5, 11.0, 8.6, 8.5, and 8.3 kb; Q. macrolepis, finally, at least seven types of 11.5, 11.0, 10.2, 8.6, 8.5, 8.3, and 8.15kb. Q. coccifera and Q. ilex rDNA appears quite different respect to other species examined, while high similarity seems to exist between Q. cerris, Q. trojana, Q. suber, and Q. macrolepis. These results are in agreement with the taxonomic model proposed by SCnWARZ for the genus Quercus.
Keywords: Angiosperms; Fagaceae; Gene mapping; Quercus; ribosomal RNA genes; rRNA/DNA hybridization; taxonomy