Evaluating wind damage vulnerability in the Alps: A new wind risk model parametrisation

Abstract

The risk of wind damage to European forests is expected to increase due to the changed climate. Research efforts in forestry have been focussing on the development of analytical and modelling tools to aid with the evaluation and the prediction of forests' vulnerability to wind damage, and ultimately to inform forest management decisions aimed at promoting wind-resistance in forest stands. Recent catastrophic wind damage to European forests has shown that wind damage risk applies also to montane forests. These are of particular importance for the various ecosystem services they provide, including protection from gravitational hazards and defence against soil erosion. At present, the available forest wind risk models have been tested and used mainly on production or planted forests in different countries, but never in the complexity of mountainous terrains. The aim of this study is to introduce a methodology for the validation of a new parametrisation of the ForestGALES wind risk model, specifically designed for the alpine scenario. To do so, we used parameters from pulling tests in the field, and laboratory mechanical tests. We also developed a workflow that, starting from data obtained by LiDAR, aims at producing wind damage vulnerability maps. After validating this new parameterisation, we investigated the variations in wind vulnerability for a case study in the Italian Alps by introducing the Difference of Vulnerability (DoV) raster. Among our results, the DoV proves to be an innovative tool whose future use can increase understanding of the factors predisposing a forest stand to wind instability.