Forests are an important cover type in the Alpine landscape. In the Swiss Alps, they cover 23-43% of the landscape (Brassel and Brändli 1999), depending on the region. At least 10-30% (Brassel and Brändli 1999) of those forests are considered as protection forests, the primary function of which is the protection of people or assets against the impacts of natural hazards such as snow avalanches and rockfall (Brang et al. 2001). Many villages in the Alps depend on protection forests. They would become uninhabitable, or at least temporarily inaccessible, if the protection offered by forests were insufficient. In the Swiss National Forest Inventory, evidence of moving snow was recorded on 37% of the plots in mountain forests, evidence of rockfall on 31%, and evidence of erosion on 16% (Mahrer et al. 1988).