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Wind and bark beetle disturbances have increased in recent decades, affecting Europe's coniferous forests with particular severity. Management fostering forest diversity and resilience is deemed to effectively mitigate disturbance impacts, yet its efficiency and interaction with other disturbance management measures remain unclear.We focused on Central Europe, which has become one of the hotspots of recent disturbance changes. We used the iLand ecosystem model to understand the interplay between species composition of the forest, forest disturbance dynamics affected by climate change, and disturbance management. The tested measures included (a) active transformation of tree species composition toward site‐matching species; (b) intensive removal of windfelled trees, which can support the buildup of bark beetle populations; and (c) reduction of mature and vulnerable trees on the landscape via modified harvesting regimes.We found that management systems aiming to sustain the dominance of Norway spruce in the forest are failing under climate change, and none of the measures applied could mitigate the disturbance impacts. Conversely, management systems fostering forest diversity substantially reduced the level of disturbance. Significant disturbance reduction has been achieved even without salvaging and rotation length reduction, which is beneficial for ecosystem recovery, carbon, and biodiversity.Synthesis and applications: We conclude that climate change amplifies the contrast in vulnerability of monospecific and species‐diverse forests to wind and bark beetle disturbance. Whereas forests dominated by Norway spruce are not likely to be sustained in Central Europe under climate change, different management strategies can be applied in species‐diverse forests to reach the desired control over the disturbance dynamic. Our findings justify some unrealistic expectations about the options to control disturbance dynamics under climate change and highlight the importance of management that fosters forest diversity. [ABSTRACT FROM AUTHOR]

Salvage logging is one of most frequently applied management responses to forest disturbances world‐wide. As forest disturbances are increasing, so too is the application of salvage logging, yet its effects on ecosystems remains incompletely understood. In the Norway spruce (Picea abies (L.) Karst.) forests of Europe, salvaging of windfelled trees is inter alia applied to reduce the risk of bark beetle outbreaks (mainly Ips typographus L.). By preventing further disturbances, salvage logging can conserve live tree carbon (C) in forest landscapes. At the same time salvage logging reduces C stocks in detrital pools via the extraction of disturbed trees, its net effect thus remains unclear.We used the forest landscape model iLand to explore the effect of a wide range of salvaging intensities on (a) subsequent bark beetle outbreaks, and (b) landscape‐scale forest C stocks in a Norway spruce‐dominated production forest in Slovakia under past and future climatic conditions.Climate change resulted in a two‐ to three‐fold increase in bark beetle disturbances throughout the 21st century in our simulations. We found that removing >95% of disturbed trees can effectively buffer the effect of increasing disturbances, dampening bark beetle infestations and increasing live tree C. Total ecosystem C followed a U‐shaped pattern over salvaging intensity, with highest values in no salvage and 100% salvage scenarios.However, realistic rates of salvaging (<95% of disturbed trees detected and removed) had no significant effect on bark beetle dynamics and live tree C, and reduced the total ecosystem C stored in the landscape. Furthermore, the effect of reduced bark beetle disturbance under intensive salvaging was partly offset by increased wind disturbance.Synthesis and applications. Clearing disturbed areas to prevent future disturbances from bark beetles and conserve live tree carbon should only be applied where very high salvaging rates are feasible (i.e. small and concentrated disturbances). Considering that changing disturbance regimes make high‐intensity salvaging increasingly challenging, alternative disturbance management approaches need to be developed. [ABSTRACT FROM AUTHOR]

• We propose an approach to optimize salvage logging operations following windstorms. • The commonly applied large-scale treatments are inefficient to control outbreaks. • Our framework outperformed non-optimized variants under current and warmer climate. • Optimized salvaging is best suited to harmonize economic and ecological goals. Outbreaks of spruce bark beetle Ips typographus have devastating effects on European forest landscapes. Salvage removal of windfelled trees is deemed effective to prevent the outbreaks, although adverse effects on ecosystem recovery, ecologically valuable legacies, and unclear economic performance raise concerns about the widespread use of this practice. Here, we formulated a novel management framework aiming for the salvaging of a limited number of windfelled stands with the highest leverage for outbreak risk, potentially replacing the current large-scale uniform treatments. We demonstrated our concept in a Central European forest landscape using the forest disturbance model iLand and a newly developed optimization tool based on graph theory. We simulated the removal of 33% and 66% of windfelled trees in (i) stands randomly distributed on the landscape and (ii) stands identified by the optimization algorithm. Moreover, we tested the effect of (iii) a no-treatment strategy and (iv) complete removal of windfelled trees. We found that the spatially optimized salvaging that aimed to remove 66% of the windfelled trees reduced the level of damage from bark beetles by 55%, whereas the non-optimized treatments, which removed the same volume of windfelled trees, reduced the damage by only 10%. In contrast to the reference treatments, the optimized approaches also retained their efficiency under elevated air temperature, which amplified the outbreaks. Although effects on deadwood retention were variable, the optimized treatments mitigated the economic impacts of the outbreak more effectively. The total loss of 7487 EUR ha−1, incurred without any treatment, was reduced by 36.7%–68.9% (range for 33 % and 66 % salvaging intensity), whereas the loss reduction under the reference treatments was only 27.6%–57.7%. We conclude that the spatially optimized salvaging proposed here can better balance multiple management objectives than the broadly applied uniform treatment, including the reduction of secondary disturbance from bark beetles, deadwood retention and economic goals. [ABSTRACT FROM AUTHOR]

• Reduced forest rotation length can reduce wind and bark beetle disturbance. • Efficiency of this measure decreases under climate change. • Short-term collateral effects on forest carbon and biodiversity are severe. Forest disturbance regimes are intensifying in many parts of the globe. In order to mitigate disturbance impacts a number of management responses have been proposed, yet their effectiveness in addressing changing disturbance regimes remains largely unknown. The strong positive relationship between forest age and the vulnerability to disturbances such as windthrows and bark beetle infestations suggests that a reduced rotation length can be a potent means for mitigating the impacts of natural disturbances. However, disturbance mitigation measures such as shortened rotation lengths (SRL) can also have undesired consequences on ecosystem services and biodiversity, which need to be considered in their application. Here, we used the process-based landscape and disturbance model iLand to investigate the effects of SRL on the vulnerability of a 16,000 ha forest landscape in Central Europe to wind and bark beetle disturbances. We experimentally reduced the current rotation length (between 100 and 115 years) by up to −40% in 10% increments, and studied effects on disturbance dynamics under current and future climate conditions over a 200-year simulation period. Simultaneously, we quantified the collateral effects of SRL on forest carbon stocks and indicators of biodiversity. Shortening the rotation length by 40% decreased disturbances by 14%. This effect was strongly diminished under future climate change, reducing the mitigating effect of shortened rotation to <6%. Collateral effects were severe in the initial decades after implementation: Reducing the rotation length by 40% caused a spike in harvested timber volume (+92%), decreased total forest carbon storage by 6% and reduced the number of large trees on the landscape by 20%. The long-term effects of SRL were less pronounced. At the same time, SRL caused an increase in tree species diversity. Shortening rotation length can reduce the impact of wind and bark beetle disturbances, but the overall efficiency of the measure is limited and decreases under climate change. Given the potential for undesired collateral effects we conclude that a reduction of the rotation length is no panacea for managing increasing disturbances, and should be applied in combination with other management measures reducing risks and fostering resilience. [ABSTRACT FROM AUTHOR]

Windfelled Norway spruce (Picea abies) trees play a crucial role in triggering large-scale outbreaks of the European spruce bark beetle Ips typographus. Outbreak management therefore strives to remove windfelled trees to reduce the risk of outbreaks, a measure referred to as sanitation logging (SL). Although this practice has been traditionally applied, its efficiency in preventing outbreaks remains poorly understood. We used the landscape simulation model iLand to investigate the effects of different spatial configurations and intensities of SL of windfelled trees on the subsequent disturbance by bark beetles. We studied differences between SL applied evenly across the landscape, focused on the vicinity of roads (scenario of limited logging resources) and concentrated in a contiguous block (scenario of spatially diversified management objectives). We focused on a 16 050 ha forest landscape in Central Europe. The removal of >80% of all windfelled trees is required to substantially reduce bark beetle disturbances. Focusing SL on the vicinity of roads created a "fire break effect" on bark beetle spread, and was moderately efficient in reducing landscape-scale bark beetle disturbance. Block treatments substantially reduced outbreaks in treated areas. Leaving parts of the landscape untreated (e.g., conservation areas) had no significant amplifying effect on outbreaks in managed areas. Climate change increased bark beetle disturbances and reduced the effect of SL. Our results suggest that past outbreak management methods will not be sufficient to counteract climate-mediated increases in bark beetle disturbance. • Removal of windfelled trees is often applied in Europe to prevent the build-up of bark beetle populations. • Low-to medium-intensity removal has no effect on bark beetle outbreaks. • Different spatial configurations of removal have different effects on bark beetle dynamics. • Climate change critically reduces the efficiency of removal. [ABSTRACT FROM AUTHOR]