Forests are multi-functional ecosystems, but a major function is not well taken into account: the protective function against rockfall hazards. Therefore, research institutes (dealing with mountain forest management and risk assessment) and a private company (working in the field of risk prevention) are completing a research project on this topic: the ROCKFOR project (http://rockfor.grenoble.cemagref.fr/). The main aims of this 3-year project are: firstly, to incorporate tree mechanical behaviour in a spatial rockfall model in order to assess the efficiency of forest stands against rockfall and secondly, to produce management guidelines 

for sustainable rockfall hazard mitigation by mountain forests.This article presents the framework used for realising the virtual experiments and it 

explains the advantages and limitations of such an integrated modelling tool both for researchers and practitioners.