Integrated methodology to assess windthrow impacts on forest stands under climate change

Storms have a high potential to cause severe ecological and economic losses in forests. We performed a logistic regression analysis to create a storm damage sensitivity index for North Rhine-Westphalia, Germany, based on damage data of the storm event “Kyrill”. Future storm conditions were derived from two regional climate models. We combined these measures to an impact metric, which is embedded in a broader vulnerability framework and quantifies the impacts of winter storms under climate change until 2060. Sensitivity of forest stands to windthrow was mainly driven by a high proportion of coniferous trees, a complex orography and poor quality soils. Both climate models simulated an increase in the frequency of severe storms, whereby differences between regions and models were substantial. Potential impacts will increase although they will vary among regions with the highest impacts in the mountainous regions. Our results emphasise the need for combining storm damage sensitivity with climate change signals in order to develop forest protection measures.