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Protection against falling rock
04 August 2011
Irstea (formerly Cemagref)
In the mountains, rock falls occur at the end of fall and beginning of spring, when thermal variation is the greatest. Rockfall nets and other types of structures can be installed to protect the buildings and roads below. However, field observations have revealed that mountain forests play a protective role. They slow and can even stop the downward progression of rocks, thus constituting an ecological and economic alternative to man-made structures.
Simulation models developed by Cemagref enable forest managers to determine the types of forest stands that best resist against falling rocks. The ideal protective configuration is a forest with a mix of tree species and comprising both younger and older trees, in order to constitute the most effective, natural net possible.
Because coppice comprises a large number of stems, it offers a higher probability of collision between a rock and a tree and thus serves as an effective barrier to rock propagation.