Abstract ID: 3.13176 | Accepted as Poster | Talk | TBA | TBA

Mountain forests play a crucial role as nature-based solutions (NbS) in mitigating natural hazard risks in Alpine regions. Despite their importance, the economic value of these forests in risk reduction is rarely quantified in detailed analyses. Large-scale risk assessments have been conducted for snow avalanche and rockfall hazards regarding damage on buildings and infrastructure, yet a detailed, spatially explicit and large-scale direct economic valuation of the protective function of forests considering rockfall and avalanches remains lacking. To address this gap, we developed a framework to spatially quantify the economic value of forests in mitigating snow avalanche and rockfall risks within a 1,700km² region in Switzerland, where 32% of the area is forested and 60% of these forests serve a protective function. This framework includes: 1.) Deriving relevant forest parameters from high-resolution LiDAR data and stand maps. 2.) Computing avalanche and rockfall intensities using the corresponding physical models within the RAMMS suite, both with and without the effect of the forest cover. 3.) Assessing related risks under both scenarios using the EconoMe framework. Risk is the product of hazard, exposure and vulnerability, whereby hazard intensities are derived from RAMMS simulations, exposure considers the monetary value of buildings, roads, and human life, and vulnerability is assessed using damage functions. 4.) Calculating the risk difference between the two scenarios (with and without forest cover) which correspond to the benefit of the forest as risk reduction. We then assign the benefit value to the specific stand contributing considerably to the risk reduction. Our results highlight the crucial role of mountain forests as NbS for disaster risk reduction, revealing substantial variations in protective effects even within small areas. Our framework represents an important step toward an objective decision-support system (DSS) for identifying protective forests and assessing their economic value. The results are integrated into an interactive, cartographic web application (www.wsl.ch/de/projekte/mountex/), which facilitates knowledge transfer and supports practical decision-making. The framework provides a valuable basis for prioritizing management interventions, developing post as well as pre-management strategies for large-scale disturbances, and for planning additional technical measures to protect human life and infrastructure.