The beech (Fagus sylvatica) is generally considered to be less tolerant of drought. Therefore, the increasing summer drought with climate change poses a potential threat to this important deciduous tree species. In order to better assess this risk, local adaptations of beech provenances to drought must be taken into account. Little is known about the occurrence of such provenances in Switzerland, although there are beech populations in the inner-alpine valleys of the Rhone and the Rhine that grow on very dry locations.
The Project BuKlim should clarify whether these populations have adapted to the local site conditions and thus react more tolerantly to drought than populations of humid sites. For this purpose, 64 young plants were removed from 16 mother trees each in 12 of these beech populations and transplanted into the WSL model ecosystem system (MODOEK). There they are subjected to a controlled dry treatment in order to assess their drought tolerance based on their morphological and physiological reactions.
These experimental investigations on young plants are supplemented by a dendroecological field study in order to also record the reaction of the mother trees to natural drought. The results of the project provide important information about the adaptability of the beech to drought and its vulnerability to climate change.