Forest dynamics, management and ecosystem services: the future of European mountain forests in an era of climate change


In an era characterized by rapid changes of environmental, particularly climatic, and socio-economic conditions, there is a growing need to better understand the influence of these changes on forests and their capacity to provide key ecosystem services (ES) to human communities. Since climate change is particularly pronounced in mountain regions, mountain forests deserve particular attention to assess the impacts of these changes. Moreover, as forests develop slowly over decades to many centuries, possible adaptation measures must be planned in the long term as well, and they should be based on thorough scientific knowledge.Dynamic vegetation models (DVMs) are often used to investigate climatic influences on long-term forest dynamics, and more recently also to explore management impacts. Among the many types of DVMs, forest gap models are flexible tools to analyze future forest development, but management regimes have received little attention to date. Although these models include the inter-specific sensitivity to the environment, intra-specific local adaptation and intra-annual varia-tions in the environmental responses are not considered. This is especially important for capturing drought effects on growth and limits the reliability of gap models in drought-prone forests. The overall objective of this thesis was to evaluate the potentials and limitations of current and alternative forest management strategies on the provision of multiple ES in European mountain forests under climate change. To this end, I improved the gap model ForClim in two respects (1) the modeling of harvesting, and (2) the growth response to drought. I then applied the improved model in four mountain regions across central and southern Europe. I recommend that future studies that aim to assess the impacts of climate change under different management strategies should i) assess stand vulnerability to disturbance using a set of models that operate on different spatial scales; ii) expand the analysis to more stands and evaluate additional management strategies iii) quantify ecosystem services using multiple indicators or region-specific trait-based approaches iv) explore other assessment meth-odologies that consider non-linear interactions between ES. I demonstrated that DVMs are important and useful tools to assess the impacts of anthropogenic climate change on forest dynamics. As these impacts are likely to vary strongly among and within mountain regions, future studies should consider local and regional differences in environmental conditions and in stand structure. The role of small-scale forest management is especially crucial in these assessments, since its impact is likely to be more pronounced than the impact of climate change per se.