Recent studies projecting future climate change impacts on forests mainly consider either the effects of climate change on productivity or on disturbances. However, productivity and disturbances are intrinsically linked because 1) disturbances directly affect forest productivity (e.g. via a reduction in leaf area, growing stock or resource-use efficiency), and 2) disturbance susceptibility is often coupled to a certain development phase of the forest with productivity determining the time a forest is in this specific phase of susceptibility. The objective of this paper is to provide an overview of forest productivity changes in different forest regions in Europe under climate change, and partition these changes into effects induced by climate change alone and by climate change and disturbances. We present projections of climate change impacts on forest productivity from state-of-the-art forest models that dynamically simulate forest productivity and the effects of the main European disturbance agents (fire, storm, insects), driven by the same climate scenario in seven forest case studies along a large climatic gradient throughout Europe. Our study shows that, in most cases, including disturbances in the simulations exaggerate ongoing productivity declines or cancel out productivity gains in response to climate change. In fewer cases, disturbances also increase productivity or buffer climate-change induced productivity losses, e.g. because low severity fires can alleviate resource competition and increase fertilization. Even though our results cannot simply be extrapolated to other types of forests and disturbances, we argue that it is necessary to interpret climate change-induced productivity and disturbance changes jointly to capture the full range of climate change impacts on forests and to plan adaptation measures.

Bark beetles are a key forest disturbance agent worldwide, with their impact shaped by climate, forest susceptibility, and interactions with other disturbances such as windthrow and fire. There is ample evidence of the interactions among these factors at small spatial and temporal scales, but projecting their long‐term and landscape‐scale impacts remains a challenge.We developed a spatially explicit model of European spruce bark beetle (Ips typographus) dynamics that incorporates beetle phenology and forest susceptibility and integrated it in a climate‐sensitive landscape model (LandClim). We first corroborated model outputs at various spatial and temporal scales and then applied the model in three case studies (in the Black Forest, Germany, and Davos, Switzerland) that cover an extended climatic gradient. We used this model and case study framework to examine the mechanisms and feedbacks that are driving short‐term and long‐term interactions among beetle disturbance, climate change, and windthrow, and how they may shift in the future.At the current cold‐wet end of the Norway spruce (Picea abies) distribution, climate change is projected to increase temperature and drought, such that beetles become a more dominant disturbance agent. At the warm‐dry end of the spruce distribution, where, under current climate, beetle outbreaks are confined to the simultaneous occurrence of drought and windthrow, the simulated level of drought alone sufficed for triggering beetle outbreaks, such that elevated drought‐ and beetle‐induced spruce mortality would negatively feed back on beetle disturbance in the long term. This would lead to receding beetle populations due to the local extinction of Norway spruce.These results suggest that, depending on initial environmental conditions, climate change may shift the importance of direct and indirect drivers of disturbances. These shifts may affect the sign and strength of cross‐scale disturbance interactions and may impact the cost–benefit trade‐off between beetle suppression and preventive management strategies.

Developing adaptive forest management strategies is essential to maintain the provisioning of forest goods and services (FGS) under future climate change. We assessed how climate change and forest management affect forest development and FGS for a diverse case‐study landscape in Central Europe. Using a process‐based forest model (LandClim) we simulated forest dynamics and FGS under a range of climate change and management scenarios in the Black Forest, Germany, which is shaped by various management practices. We focused on the interdependencies between timber production and forest diversity, the most valued FGS in this region.We found that the conversion to more drought‐adapted forest types is required to prevent climate change‐induced forest dieback and that this conversion must be the target of any adaptive management, especially in areas where monocultures of drought‐sensitive Norway spruce (Picea abies) were promoted in the past. Forest conversion takes up to 120 years, however, with past and future adaptive management being the key drivers of timber and forest diversity provision. The conversion of drought‐sensitive conifer monocultures maintains timber production in the short term and enhances a range of forest diversity indices. Using uneven‐aged forest management that targets a drought‐adapted, diverse, and resilient species mixture, high species diversity can be combined with timber production in the long term. Yet, the promotion of mature‐stand attributes requires management restrictions. Selecting future adaptive management options thus implies the consideration of trade‐offs between forest resource use and environmental objectives, but also the exploitation of synergies between FGS that occur during forest conversion. Lastly, the large impact of past management practices on the spatial heterogeneity of forest dynamics underpins the need to assess FGS provisioning at the landscape scale.

Yousefpour, R., C. Temperli, J. B. Jacobsen, B. J. Thorsen, H. Meilby, M. J. Lexer, M. Lindner, H. Bugmann, J. G. Borges, J. H. N. Palma, D. Ray, N. E. Zimmermann, S. Delzon, A. Kremer, K. Kramer, C. P. O. Reyer, P. Lasch-Born, J. Garcia-Gonzalo, and M. Hanewinkel. 2017. A framework for modeling adaptive forest management and decision making under climate change. Ecology and Society 22(4):40. https://doi.org/10.5751/ES-09614-220440