Extreme weather events alter leaf phenology and growth of different Fagus sylvatica provenances

Background/Question/Methods

Fagus sylvatica, the dominant forest tree of Central Europe, is sensitive to drought. With ongoing climate change the frequency and magnitude of extreme weather events such as drought increase and can lead to forest damages. Here we explore impacts of drought and warming events at continental and regional scale and test how drought and warming affects growth and leaf phenology.

Growth was quantified in May and October as well as leaf unfolding, end of leaf unfolding and leaf senescence in a common garden experiment with two years old F. sylvatica seedlings. The fully crossed three factorial design consisted of drought, warming and selected provenances (three provenances each from western Bulgaria and southern Germany).

Results/Conclusions

Drought significantly reduced and warming significantly increased height growth. Provenances differed at the regional but not on continental scale for both treatments. Drought did not affect leaf unfolding, end of leaf unfolding and leaf senescence but the provenances differed on regional scale. Warming advanced leaf unfolding significantly but did not influence end of leaf unfolding and leaf senescence significantly but the provenances differed on regional scale.

Our data suggest, that drought can influence especially the growth of F. sylvatica, and that there is a need for further research to conserve this important European tree and to find good adapted beech provenance that beech does not loose its hegemony as the dominant tree in Central Europe.