Ecological consequences of local tree interaction and individual tree sensitivity to stress events on the dynamic of beech-oak-forest stands

近年来的研究表明，干旱和霜冻等干扰事件的频率和强度会强烈影响植物群落的组成和动态。然而，我们目前对潜在的生态过程以及它们如何与其他压力源相互作用的理解非常有限，但对于预测变化的干扰和压力制度的后果至关重要。因此，拟议的项目旨在获得对森林如何对干扰制度和压力源作出反应的机制理解。为此，我们将结合树木年代学方法、点模式分析、基于个体的建模方法和现代统计技术，全面地进行模型选择。作为研究系统，我们将使用沿湿度梯度的山毛榉橡树林。树木年代学和木材解剖学分析将提供树木对环境信号的个体生长反应的信息。为了预测这种反应对林分水平的影响，将使用基于个体的模拟模型来测试关于树木如何在局部相互作用以及如何改变其形态和性能以应对竞争和干扰的替代假设。最能解释这些数据的模型将用于预测干扰和压力对林分水平树木死亡率和时空格局的累积效应。我们的结果将为森林缓冲正在进行的和预期的气候变化的潜力，特别是极端气候事件的顺序和强度，提供机制上的见解。

Recent studies show that the frequency and intensity of disturbance events, such as drought and frost, can strongly affect the composition and dynamics of plant communities. However, our current understanding of underlying ecological processes and how they interact with other stressors is very limited but crucial for predicting the consequences of changing disturbance and stress regimes. Therefore, the proposed project aims at gaining mechanistic understanding of how forests respond to disturbance regimes and stressors. For this, we will combine dendrochronological methods, point pattern analyses, individual-based modeling approaches, and modern statistical techniques for model selection in a comprehensive way. As study system, we will use beech-oak forests along a moisture gradient. Dendrochronological and wood anatomical analyses will provide information about individual growth responses of trees to environmental signals. In order to predict the consequences of such responses on forest stand level, individual-based simulation models will be used to test alternative assumptions on how trees interact locally, and modify their morphology and performance in response to competition and disturbances. The model that best explains the data will be used to predict accumulated effects of disturbances and stress on tree mortality and spatiotemporal patterns at the stand level. Our results will provide mechanistic insights into the potential of forests to buffer ongoing and expected changes in the climate regime and in particular the sequence and intensity of extreme climate events.