Urban Trees for Changing Climates: Insights for Bavarian Cities

Abstract. Urban trees have the capability to enhance ecological city resilience. By providing vital ecosystem services mitigation of urban heat island effects, management of stormwater, or support of biodiversity can be improved. Climate change, however, poses challenges to urban trees in general, and in particular for Bavarian cities. This study uses the climate envelope approach to assess the future climatic suitability of native and non-native tree species in 21 Bavarian cities (Germany). Using climate projections from the CHELSA dataset under the SSP5-RCP8.5 scenario, we evaluate temperature and precipitation thresholds for 12 tree species over three periods (2011–2040, 2041–2070, and 2071–2100). The results were compared with the land cover share of the respective cities. The results show distinct variations in climatic suitability across cities and time periods. Several species remain climatically suitable over time, especially Black locust, London plane, and European hornbeam. However, tree species, like European beech, Norway maple, and Silver birch, experience a marked decline. These findings underscore the urgent need for a paradigm shift in urban green space management. Although the study employs climate envelope methodologies that have inherent limitations, it provides a proof-of-concept for integrating climate projections with urban data such as tree inventories and land use patterns. Overall, the research contributes to our understanding of urban tree adaptation strategies and highlights the importance of prioritizing heat-tolerant species to preserve urban biodiversity and ecosystem services.