Regional Mountain Conference

Windstorms are the principal cause of disturbance to forests, and due to climate change their frequency and magnitude are expected to increase by the end of the century. Different studies assessed the risk of forest wind disturbances but most of them were mainly limited by forest vulnerability accuracy or climate data especially in complex terrain like the Alps. In this study, we assessed and mapped at high resolution scale (20×20 m) the forest wind risk under the historical (1996-2005) and the future (2090-2099, Representative Concentration Pathway 8.5) reference periods. The study took advantage of high-resolution remotely sensed data to derive individual tree and stand characteristics for calculating forest vulnerability with ForestGALES, a hybrid mechanistic-empirical forest wind risk model. Wind intensities were derived from an ensemble of high temporal and spatial resolution of Convection-Permitting Models. Combining these two datasets, we derived high resolution mapping of the forest wind risk for the Agordino study, in the Dolomites in North-east Italy (extent of 477 km²). This study firstly assess the forest wind vulnerability and then classifies the forest area into three levels of risk. Thanks to the forest metrics the study quantitatively assesses the relative amount of growing stock at risk for each class. Results show that the relative area at risk respect the total forest area is equal to 5.3% and increasing to 6.3 % under the historical and future reference periods, respectively. The risk maps clearly identified the stands at higher risk, mainly composed of pure Norway spruce trees (11.5% and 13.3% at risk respect the total stand spruce forest area), and provide fundamental insights for management prioritization for improving the forest resistance to wind at the regional scale.