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.

Briner, S., R. Huber, P. Bebi, C. Elkin, D. R. Schmatz, and A. Grêt-Regamey. 2013. Trade-offs between ecosystem services in a mountain region. Ecology and Society 18(3): 35.http://dx.doi.org/10.5751/ES-05576-180335

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.

In many regions of the world, drought is projected to increase under climate change, with potential negative consequences for forests and their ecosystem services (ES). Forest thinning has been proposed as a method for at least temporarily mitigating drought impacts, but its general applicability and longer‐term impacts are unclear. We use a process‐based forest model to upscale experimental data for evaluating the impacts of forest thinning in a drought‐susceptible valley in the interior of the European Alps, with the specific aim of assessing (1) when and where thinning may be most effective and (2) the longer‐term implications for forest dynamics.Simulations indicate that forests will be impacted by climate‐induced increases in drought across a broad elevation range. At lower elevations, where drought is currently prevalent, thinning is projected to temporarily reduce tree mortality, but to have minor impacts on forest dynamics in the longer term. Thinning may be particularly useful at intermediate and higher elevations as a means of temporarily reducing mortality in drought‐sensitive species such as Norway spruce and larch, which currently dominate these elevations. However, in the longer term, even intense thinning will likely not be sufficient to prevent a climate change induced dieback of these species, which is projected to occur under even moderate climate change. Thinning is also projected to have the largest impact on long‐term forest dynamics at intermediate elevations, with the magnitude of the impact depending on the timing and intensity of thinning. More intense thinning that is done later is projected to more strongly promote a transition to more drought‐tolerant species.We conclude that thinning is a viable option for temporarily reducing the negative drought impacts on forests, but that efficient implementation of thinning should be contingent on a site‐specific evaluation of the near term risk of significant drought, and how thinning will impact the rate and direction of climate driven forest conversion.