How Mediterranean Deciduous Trees Cope with Long Summer Drought? The Case of Quercus pyrenaica Forests in Western Spain.

Abstract

The functional characteristics of Mediterranean deciduous trees provide an interesting model for investigating adaptative mechanisms to drought, useful to understand future changes of northern forests in scenery of climate change. In this article we analyse how a Mediterranean deciduous oak, Quercus pyrenaica, with a short vegetative period coincident with summer drought, cope with water deficit in that period. We revised published data on temporal dynamic of soil moisture and physiological status of tree leaves of several forest stands of Central–Western Spain and discuss the significance of soil water reserve and deep rooting system on the maintenance of tree transpiration and physiological activity of the trees along summer drought. Results revealed that (i) Q. pyrenaicaoak is only slightly water-limited during summer drought, (ii) Q. pyrenaicaoaks depend on thick weathered, porous bedrocks, and (iii) Q. pyrenaicais a well-performing deciduous oak to cope with increasing summer drought.