Forest management decision support for evaluating forest protection effects against rockfall

Despite the fact, that much practical experience exists in managing rockfall protection forests, there is so far only limited quantitative knowledge available in evaluating the effect of rockfall impact on forests and, vice versa, in quantifying the effect of forest cover on single rockfall activity. For that reason GIS-based tools have been developed to support resource managers in evaluating the protection capacity of rockfall-influenced forests. These tools can be applied at the local to regional scale and consist of the following main model components: (i) a model, which quantitatively evaluates the protection effect by calculating the energy dissipation potential due to boulder/tree collisions, and (ii) the re-calibrated forest growth simulator PROGNAUS which allows to extent the evaluation in the time domain. In this contribution we focus on the quantitative estimation of rockfall protection efficiency. The models are compared to rockfall event data and to results from a stochastic rockfall trajectory simulation. Findings indicate that the presented approach can be employed to quantify the protection effect of homogeneous forest stands.