Résumé
The increasing duration and intensity of drought is precipitating widespread episodes of forest decline around the world, possibly in combination with other climatic (e.g. soil water logging) and land-use (e.g. fire and coppicing suppression) changes that have been occurring through the last century. A meta-analysis of physiological data compiled from recent data bases indicates that, comparatively to other species, oaks are mostly tolerant to drought and anisohydric, although also relatively vulnerable to severe water stress. The succession of droughts in unmanaged overcrowded stands is affecting many physiological processes associated with water transport and carbon metabolism and making trees more susceptible to further abiotic and biotic stresses. Although oaks maintain large reserves of nonstructural carbohydrates (NSC) in comparison with other tree species, water restrictions to net carbon gain in declining trees can reduce NSC reserves and favor the sudden or more progressive death of trees. In view of correlative and process-based vegetation model simulations, oaks in the southern-most part of their range can undergo extinctions in the future due to increases in temperature and drought. Hence, managing forests so as to increase acorn production and seedling recruitment is a necessary task to increase adaptability of oak forests to Global Change. Different silvicultural alternatives can improve the physiological status of residual trees and be employed to mitigate the sensitivity of oak forests to drought in the short and long run. However, more studies are needed to understand and mitigate oak decline.