Genomic basis of fitness relevant traits in F. sylvatica

European beech (Fagus sylvatica L.) is the dominant tree species in Germany. Beech forests harbour more than 6000 species and are a significant source of timber and recreational space for humans. As an effect of global climate change, droughts are intensifying in frequency and severity. In Germany, the severe droughts of 2018 and 2019 caused damage and local mortality in beech populations of up to 7%. However, mortality after a drought event may occur even years later, hence the final impact of the two drought events isn't fathomable yet. Nevertheless, some individuals showed remarkable resilience as they were seemingly unaffected by the extreme drought. The genomic basis of drought susceptibility, or its resistance, in European beech is currently being investigated and the alleles responsible were previously identified. Selection for resistant individuals after extreme drought events causes the respective alleles in populations to increase in frequency. Hence, an adaptation of beech populations to the changing climate seems possible. Assumptions about the adaptive response of beech populations under intensifying drought conditions require knowledge of the current level of selection in different age classes of beech. In order to quantify this current level of selection in beech populations in Hessen, Germany, we genotyped pool-sequences of three age classes of beech trees by alignment to a reference genome and determined the allele frequencies of the genotypes. This will allow predictions about the trajectory of the species' persistence in Germany in the face of climate change.