Systematic Search for Drought-Resilient Provenances in Bavaria, Germany

Repeated droughts have led to a decline in vitality and the death of entire populations of European beech (Fagus sylvatica L.), particularly in Lower Franconia, over the last decade. In order to identify suitable seed sources for future forest conversion measures, seed stands are being sought that remain resistant even under hot and dry conditions. This article presents a concept for a systematic method for identifying climate-resilient beech populations in Bavaria. Data from forest damage surveys, climate models, and site data have been merged for the first time in this context. The pilot study demonstrated a significant correlation between the modelled climatic marginality and the reported drought damage. The method of stratification using niche models and forest damage survey data thus proved to be a good starting point for identifying endangered forest sites and stands. The approach enables a targeted search for phenotypically healthy trees and forest stand that show little drought symptoms even under high site-related vulnerability (e.g., marginal sites, low plant available water capacity [AWC]). These stands, showing an apparently high phenotypic plasticity, are observational classified and hypothesised as particularly drought-resilient. Hence, carrying out these data analyses for the identification of more drought resilient beech in a first step effectively narrows the search area for field work and genetically analysis of potential seed stands.