<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>3</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">COTILLAS, M</style></author><author><style face="normal" font="default" size="100%">ESPELTA, J M</style></author><author><style face="normal" font="default" size="100%">Sabate, S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">¿Puede la gestión forestal mitigar los efectos de un incremento de sequía en los montes mediterráneos? El caso de los bosques de encina y roble en el contexto del cambio climático.</style></title><secondary-title><style face="normal" font="default" size="100%">V Congreso Forestal Español</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">cambio climático</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus cerrioides</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">resalveo</style></keyword><keyword><style  face="normal" font="default" size="100%">sequía</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><pub-location><style face="normal" font="default" size="100%">Avila</style></pub-location><pages><style face="normal" font="default" size="100%">1-13</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Uno de los grandes retos para la conservación de los ecosistemas forestales a lo largo del presente siglo es el cambio climático, del que se esperan importantes repercusiones en la cuenca mediterránea. Los modelos climáticos proyectan para esta área un descenso en la precipitación que, unido a un aumento de las temperaturas, acrecentará la ya de por sí característica sequía estacional que caracteriza esta zona. Dadas estas proyecciones, se hace necesario determinar los efectos que tendría una reducción de la precipitación en las diferentes especies que componen nuestros bosques, para poder así estimar posibles cambios en la estructura y composición de los mismos e identificar estrategias de gestión adecuadas para mitigar su efecto. En este contexto, el objetivo de nuestro estudio es analizar los efectos de una reducción de la precipitación en el monte bajo de encina (Quercus ilex L.) y roble (Quercus cerrioides Willk &amp; Costa), así como evaluar los efectos de la gestión (resalveo) en su respuesta a este. Para ello, se combinan en un bosque mixto dos niveles de precipitación (precipitación natural vs. reducción de la precipitación de un 15%) y gestión (no gestión vs. gestión) en cuatro tratamientos. Se analiza la mortalidad, crecimiento, nueva rebrotada y dinámica foliar. Tras cuatro años de seguimiento el experimento sigue en curso, y hasta ahora se han obtenido los resultados definitivos de mortalidad, crecimiento y nueva rebrotada, que muestran que: i) La gestión reduce fuertemente la mortalidad, ii) El crecimiento de los robles se ve notablemente afectado por la reducción de precipitación, mientras que el de las encinas permanece constante, iii) La gestión incrementa fuertemente el crecimiento en ambas especies, especialmente en condiciones de precipitación natural. Actualmente se están comenzando a analizar los datos de dinámica foliar, y los resultados preliminares muestran que iv) Las parcelas sometidas a reducción de precipitación presentan un número menor de hojas, una menor longevidad de las mismas, y una mayor tasa de caída de hojarasca que las no sometidas a este tratamiento, v) La gestión atenúa la caída de hojas en todas las parcelas, mitigando los efectos de la reducción de precipitación en las parcelas sometidas a este tratamiento. De estos resultados se extrae la conclusión de que el cambio climático puede tener consecuencias negativas sobre los bosques de Quercus mediterráneos, siendo más acusados los efectos en robles caducifolios. Sin embargo, la gestión forestal puede ser una potente herramienta para mitigar estos efectos y conservar nuestros bosques de cara al futuro.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">López, B</style></author><author><style face="normal" font="default" size="100%">Sabate, S</style></author><author><style face="normal" font="default" size="100%">Gracia, C A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Fine-root longevity of Quercus ilex</style></title><secondary-title><style face="normal" font="default" size="100%">New Phytologist</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Fine root longevity</style></keyword><keyword><style  face="normal" font="default" size="100%">Holm oak</style></keyword><keyword><style  face="normal" font="default" size="100%">minirhizotron</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">vertical longevity pattern</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2001</style></year></dates><publisher><style face="normal" font="default" size="100%">Blackwell Science Ltd</style></publisher><volume><style face="normal" font="default" size="100%">151</style></volume><pages><style face="normal" font="default" size="100%">437-441</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">* • Fine-root longevity and phenology were studied in a Quercus ilex (holm oak) forest in Prades (NE Spain). Differences were investigated among roots that had appeared in different seasons and at different depth intervals, differentiating between white and brown roots. * • Using minirhizotrons installed in March 1994, 1211 roots were monitored every 3 wk from June 1994 to March 1997. * • Mean and median fine-root longevity were 125 ± 4 d and 67 d, respectively. Longevity of summer and winter roots was greater than that of spring and autumn roots. Although roots appeared and disappeared throughout the year, the rate of appearance was greatest in spring. Maximum longevity occurred at a soil depth of 20–30 cm. Differences among 10-cm depth intervals were due to the number of days that roots were brown, since roots remained white for a similar number of days, independent of soil depth. * • Temperate soil temperatures and lignotubers permitted the appearance of roots throughout the year. Holm oak fine roots might be more efficient during the first 50 d of their life before the white roots become less efficient brown roots.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>3</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">López, B</style></author><author><style face="normal" font="default" size="100%">Sabate, S</style></author><author><style face="normal" font="default" size="100%">Ruiz, I</style></author><author><style face="normal" font="default" size="100%">Gracia, C</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Mohren, GMJ and Kramer, K and Sabate, S</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Effects of elevated CO2 and decreased water availability on holm-oak seedlings in controlled environment chambers</style></title><secondary-title><style face="normal" font="default" size="100%">IMPACTS OF GLOBAL CHANGE ON TREE PHYSIOLOGY AND FOREST ECOSYSTEMS</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">CO2</style></keyword><keyword><style  face="normal" font="default" size="100%">controlled environment chambers</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1998</style></year></dates><publisher><style face="normal" font="default" size="100%">SPRINGER</style></publisher><pub-location><style face="normal" font="default" size="100%">PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS</style></pub-location><volume><style face="normal" font="default" size="100%">52</style></volume><pages><style face="normal" font="default" size="100%">125-133</style></pages><isbn><style face="normal" font="default" size="100%">0-7923-4921-0</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In Mediterranean ecosystems, water is an important limiting factor for&lt;br/&gt;plant growth. In addition to the increase in atmospheric CO2, some&lt;br/&gt;models predict increased drought in Mediterranean areas as a consequence&lt;br/&gt;of global change. Thus, to determine how increased atmospheric CO2&lt;br/&gt;interacts with increased water stress and affects Mediterranean plant&lt;br/&gt;growth is an important achievement. The present study analyses how helm&lt;br/&gt;oak (Quercus ilex L.) seedlings are affected by both elevated CO2 and&lt;br/&gt;increased water stress. The CO2 concentrations were supplied in&lt;br/&gt;controlled environment chambers (350 and 500 ppm CO2), and water stress&lt;br/&gt;was performed according to a Mediterranean pattern (Potential&lt;br/&gt;Evapotranspiration to Rainfall ratio). The increased water stress was&lt;br/&gt;attained by watering half of the Mediterranean reference pattern.&lt;br/&gt;Results show that the positive effects of elevated CO2 on photosynthesis&lt;br/&gt;and growth are counteracted by increased water stress.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sabate, S</style></author><author><style face="normal" font="default" size="100%">Sala, Anna</style></author><author><style face="normal" font="default" size="100%">Gracia, C A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Nutrient content in Quercus ilex canopies: seasonal and spatial variation within a catchment</style></title><secondary-title><style face="normal" font="default" size="100%">Plant and Soil</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Canopy</style></keyword><keyword><style  face="normal" font="default" size="100%">nutrient content and dynamics</style></keyword><keyword><style  face="normal" font="default" size="100%">nutrient resorption</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1995</style></year></dates><volume><style face="normal" font="default" size="100%">168-169</style></volume><pages><style face="normal" font="default" size="100%">297-304</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Spatial and temporal changes in canopy nutrient content were studied in 1988 and 1989 in a Mediterranean Quercus ilex ssp. ilex L. forest in north-eastern Spain. Sampling was conducted in parallel at two sites which represent endpoints along a slope gradient within a small catchment (ridge top at 975 m and valley bottom at 700 m). Deeper soils resulted in significantly higher N and P concentrations, and N content on a leaf area basis at the valley bottom site. In contrast, K concentration in leaves was significantly higher at the ridge top site, where soil K concentration was also higher. At both sites, N and P content on a leaf area basis was highest at the top of the canopy, where leaf area is highest. N resorption efficiency decreased from top to bottom of the canopy. Results suggested a minor role of shaded leaves as nutrient storage sites. Lower P resorption efficiency was found at the ridge top site. Seasonal changes of P and N concentration on a leaf area basis suggest P replenishment, and to a lesser degree N, during periods of lower growth activity due to low temperatures, but coinciding with higher water availability (autumn-early spring period). Thus, N and P resorption from the remaining foliage in the canopy took place, and to a larger degree at the valley bottom site, coinciding with a slightly higher leaf area index and productivity at this site.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sala, A</style></author><author><style face="normal" font="default" size="100%">Sabate, S</style></author><author><style face="normal" font="default" size="100%">Gracia, Carlos</style></author><author><style face="normal" font="default" size="100%">Tenhunen, J D</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Canopy structure within a Quercus ilex forested watershed: variations due to location, phenological development, and water availability</style></title><secondary-title><style face="normal" font="default" size="100%">Trees-Structure and Function</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Canopy structure</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf area index</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean sclerophylls</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">water deficit</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1994</style></year></dates><pages><style face="normal" font="default" size="100%">254-261</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Spatial and temporal changes in canopy structure were studied in 1988 and 1989 in a Mediterranean Q u e r c u s ilex forest in north-eastern Spain. Due to differences in precipitation patterns the 1989 growing season was drier than the 1988 growing season. Sampling was conducted in parallel at two sites which represent endpoints along a slope gradient within a watershed (ridge top at 975 m, and valley bottom at 700 m). At both sites, similar inter-annual changes in canopy structure were observed in response to differences in water availability. Samples harvested in the upper 50 cm of the canopy during 1989 exhibited a de- crease in both average leaf size and the ratio of young to old leaf and stem biomass relative to samples obtained in 1988. At the whole canopy level, a decrease in leaf pro- duction efficiency and an increase in the stem to leaf bio- mass ratio was observed in 1989. Temporal changes in canopy leaf area index (LAI) were not statistically sig- nificant. Average LAI values of Q. ilex at the two sites were not significantly different despite differences in tree stature and density (4.6 m 2 m -2 at the ridge top, and 5.3 m 2 m -2 at the valley bottom). Vertical distribution of leaves and stems within the canopy was very similar at the two locations, with more than 60% of the total LAI in the uppermost metre of the canopy. The possible significance of such an LAI distribution on the canopy carbon budget is discussed.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>3</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Gracia, C A</style></author><author><style face="normal" font="default" size="100%">Sala, A</style></author><author><style face="normal" font="default" size="100%">Sabate, S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">ASPECTOS ECOFISIOLOGICOS RELACIONADOS CON LA PRODUCCION DE LOS ENCINARES MEDITERRANEOS</style></title><secondary-title><style face="normal" font="default" size="100%">Congreso Forestal Español, Lourizán - Pontevedra. 1993</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">ecophysiology</style></keyword><keyword><style  face="normal" font="default" size="100%">L.A.I.</style></keyword><keyword><style  face="normal" font="default" size="100%">productivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1993</style></year></dates><pub-location><style face="normal" font="default" size="100%">Pontevedra</style></pub-location><pages><style face="normal" font="default" size="100%">209-218</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The productivity of Quercus ilex forests is low in relation to other tree species. Waterand nutrients are often the most important limiting factors. Nevertheless the ecophysiological traits of this specie could help to explain the observed patterns of productivity. Leaf area index of european evergreen-oak forests is rather constant with values about 5. The energetic cost of formation and maintenance of the leaves of Quercus ilex accounts for more than 50 per cent of total carbon fixed by the trees. The resproutig ability of evergreen oaks could explain the high density and low mean diameter of these populations. The high proportion of living tissues in this type of structuni increases the respiration costs of the stems and branches. As a consequence, an important fraction of carhon fixed by leaves is used to maintain the structure of the community which contribute to explain the low observed net primary production of Quercus ilex forests</style></abstract></record></records></xml>