Spatial and temporal patterns in the climate-growth relationships of Fagus sylvatica across Western Europe, and the effects on competition in mixed species forest

1. The effect of extreme climate events on ecosystems is an important driver of the bioticresponse to climate change. For forests, extreme drought has been linked to negativeeffects such as large scale mortality and reduced primary production. However, theresponse of plant communities to extreme drought events remains poorly understood. 2. We used mortality data from a long term monitoring programme in the core of the focalspecies’ ranges, in combination with annual growth data from tree-rings, to study theeffect of, and recovery from, an extreme drought event. We examined both theintraspecific and interspecific drought response and explored how differential responsesaffect competitive dominance between the dominant species Fagus sylvatica and Quercuspetraea. 3. Mortality for the most drought-susceptible species, F. sylvatica, occurred alongside atemporary reduction in competition-induced mortality of Q. petraea, resulting in the long-term alteration of the relative abundance of the two species. 4. Significant intraspecific variation occurred in post-drought recovery in surviving F.sylvatica, with two distinct cohorts identified. A prolonged recovery period was coupled