Climate change will substantially alter native forest ecosystem dynamics. Increased storm frequencies and severities and longer summer droughts are major threats for the provision of ecosystem goods and services (EG&S) from forests. To adapt forests stands to climate change, two silvicultural measures have been proposed: (i) the promotion of mixed stands and (ii) the integration of exotic tree species that are expected to be adapted to future climatic conditions (in particular from areas with a drier and warmer climate). Non-native tree species as well as mixed stands may be better suited for the expected future climate due to a higher resistance and resilience against disturbances. The combination of mixed stands that consist of native and non-native tree species, may present a suitable compromise between the desired effects on growth and vitality of forests and potential undesired effects on the composition of native species associations and ecosystem processes such as nutrient cycling. Despite high potential benefits of mixed stands, planted forests around the globe are mainly monocultures. To foster the provision of EG&S, more knowledge about the mechanistic functioning of mixtures as well as trade-offs between the provision of different EG&S from mixed and pure stands is necessary. Interdisciplinary research projects are necessary that address effects of mixtures consisting of native and non-native tree species on the composition of various taxonomic groups, ecosystem processes and their consequences for the provision of EG&S. The interdisciplinary research training group 'RTG2300: Enrichment of European beech forests with conifers' addresses this knowledge gap by studying the mechanistic and supplying ecosystem functioning of forest stands of native European beech (Fagus sylvatica L.), Norway spruce (Picea abies L. KARST) and non-native Douglas-fir (Pseudotsuga menziesii MIRB. FRANCO) in Northern Germany. The stand types in this project include pure stands of all three species and mixed beech/spruce and beech/Douglas-fir stands. Each stand type is represented at eight locations resulting in a total of forty study plots. Twenty out of the forty research plots of 0.25 ha size are located in the southern part of the study area in the Solling and Harz mountain ranges, whereas the other twenty plots were selected in the northern part of the study area in the North German plain. The southern plots are located at higher altitudes with lower mean annual temperatures and a higher annual precipitation than those in the north. The stands on the northern plots have less favorable growing conditions than those on the southern plots, in particular due to less precipitation. Here, we provide basic datasets that were collected by the RTG2300. This includes data about location, topography and climate of the research plots, data of the tree inventories and data about the density and spatial structure of the stands that were derived from the tree inventory data.

The RTG2300 is funded by the German Research Foundation (Deutsche Forschungsgemeinschaft - DFG).