Assessment of physiological plasticity and genetic variability of pine (Pinus sylvestris L.) at its western range limit under climate change conditions.

For no other main tree species is the potential for climate adaptation discussed as controversially as for the Scots pine. The evaluation of forest condition data shows that pines have a high drought stress tolerance with comparatively low needle losses in the northeast, but that mortality rates increase at the southern limit of distribution, especially after dry years. As pine is the second most common tree species in Germany, the contradictory assessment causes uncertainty in forestry practice. Despite the activities to convert pure pine stands into mixed stands rich in hardwoods, pine continues to have a high forestry relevance due to its age structure alone. Against this background, the project aims to investigate the phenotypic, physiological plasticity of pine populations along a northeast-southwest gradient and in comparison between pine forests and unmanaged pine forests. Field typing of 8 pine level 2 monitoring plots and 3 pine natural forests will be performed using genetic and physiological markers. In a second step, seed orchards will be evaluated with respect to their potential climate adaptation using these markers. In the final evaluation, correlations between current forest damage and other phenotypic characteristics (crown condition, dendrochronologies) of the pines, their site conditions and the results of physiological phenotyping and genotyping will be investigated. The project builds on long-standing findings in stress physiology, population genetics and forest environmental control on pine. The results allow the hypothesis that, as a result of different selection conditions at the border of the natural range, diverse ecotypes have evolved, which have a different adaptive capacity to biotic and abiotic stress factors.