Disaster Mitigation of Debris Flows , Slope Failures and Landslides 229 Rockfor . NET : A New Efficient Tool for Quantifying the Residual Rockfall Hazard of a Forested Slope

To provide a tool that quantifies rapidly the protective capacity of a forest stand against rockfall, which takes into account general characteristics of the slope, the forest stand and the dominating falling rock, we developed Rockfor (http://www.rockfor.net). The underlying calculation is formalised in a user-friendly tool and uses only a small amount of input data. These data give a global representation of reality and are easy to acquire at the scale of a slope or a forest stand. Presently, there are no clear quantitative rules for determining the optimal combination of stand density and mean stem diameter for a protection forest, depending on the dominating rock size, its kinetic energy and the tree species present. Rockfor fills this gap. This paper explains the underlying principles of the tool.