Climate-Driven Range Shifts Limit the Role of Non-Native Trees for Adaptation Processes of European Forests

Climate change threatens biodiversity and ecosystem services by reducing the suitability of many native tree species in Europe. As the ranges of native species contract, non-native tree species (NNTs) are increasingly considered as potential alternatives in forest management. We analyzed published ensemble species distribution models (SDMs) for 15 non-native and 13 native tree species at 1-km resolution to estimate range shifts of the NNTs and compared range shift patterns of NNTs and native species to identify alternative species under climate change. Most coniferous NNTs are expected to lose suitability in southern and southeastern Europe while expanding northward under climate change. In contrast, broadleaved NNTs such as Juglans nigra, Fraxinus pennsylvanica, and Robinia pseudoacacia are likely to retain southern suitability and expand into central and northern regions. Although NNTs are projected to experience a 50%-70% increase in climatic suitability, their role remains limited, as they can replace native species as the most suitable option in only 17%-21% of Europe's forested areas by 2061-2080. Native species are expected to remain dominant across most of Europe, while a limited subset of NNTs may provide complementary options in specific regions. Integrating NNTs into climate adaptation strategies, therefore, requires careful, site-specific evaluation of ecological risks and benefits.