Forests fundamentally stabilize the soil beneath them. In forests with significant gaps, however, a considerable number of shallow landslides have been observed. Terrain, geology and soil characteristics are known to influence whether such landslides take place. In her Master’s thesis at SLF, Christine Moos investigated to what extent forest structure might also be responsible. ETH awarded her work the prize for its Master’s degree program in Environmental Sciences.
In her research, Moos used data from laser scans and carried out field investigations in St. Antönien (GR). In the course of these, it emerged that the danger of landslides was smaller where trees were grouped more closely together, and where forest gaps in the direction of the slope measured less than 20 meters. The experiment also demonstrated that the direct field recordings yielded more reliable evidence than the remote sensing data. In a complementary bachelor’s thesis, Josias Mattli examined to what extent roots with a spatial dependency on neighboring tree trunks reinforced the soil. Both studies allow a better quantification of how strongly the forest stabilizes the soil and protects against shallow landslides. (Martin Heggli, Diagonal 1/16)