Douglas fir in Central Europe and South America: A cross-continental solution for integrative forest management or a potential threat for natural communities?

• Applicants: Professorin Dr. Steffi Heinrichs; Professor Dr. Dominik Seidel
• Subject Area: Forestry ; Ecology of Land Use
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 546312213

Climate change poses a major challenge for the integrity of forest ecosystems. To maintain the provision of different forest ecosystem goods and services, forests need to be adapted to potential future environmental conditions. One adaptation strategy is the promotion of non-native tree species that are presumably better adapted to novel climatic conditions. However, cultivation of non-native tree species is seen critical and is controversially discussed as it is difficult to predict how the dynamics of forest ecosystems are altered by an alien species. A tree species that has been introduced in many different parts of the world due to its good growth performance is Douglas-fir (Pseudotsuga menziesii), native of North America. Even though largely grown in monospecific plantations, there is experience of cultivating Douglas-fir in mixture with native tree species both in Central Europe (Fagus sylvatica) and in South America (Nothofagus spec.). Thus, similar preconditions in Central Europe and Chile provide a perfect setting to test general hypotheses regarding mixing effects between native and non-native tree species. In addition, such cross-continental approach opens the opportunity to study main driving patterns of invasion in different environmental settings in Central Europe and Chile, an important topic regarding the establishment of non-native tree species. The three general objectives of this project are (1) to analyze and contrast the invasive potential of Douglas fir in Chile and Central Europe to identify drivers and barriers of Douglas fir establishment, (2) to contrast and compare plant species diversity and trait composition in pure and mixed native-broadleaved/Douglas fir stands across countries to detect universally valid patterns or local dependencies, and (3) to contribute to the mechanistical understanding of mixing effects of non-native Douglas fir with native broadleaved tree species on the complex relationship between forest structure and tree and stand growth. We previously established a network of study sites in Central Europe (8 sites in Germany and 8 sites in Switzerland) and Chile (9 sites) in regions with presence of Douglas-fir and native broad-leaved species. We propose a project consisting of two subprojects studying the effects of Douglas fir in pure and mixed stands at the stand and landscape level focusing on invasiveness (subproject 1), stand structures (subproject 2) and effects on biodiversity and trait composition (subproject 1). The subprojects will be tightly interlinked by studying the stand level and the effect of Douglas fir in pure and mixed stands on biodiversity mediated by forest growth and structure. By increasing our understanding of mixing effects between non-native and native species on different forest functions, this project will contribute to the development of adaptive forest management strategies across continents in light of climate change.

• DFG Programme: Research Grants
• International Connection: Switzerland
• Partner Organisation: Schweizerischer Nationalfonds (SNF)
• Cooperation Partner: Dr. Jonas Glatthorn