Modelling landslide–forest dynamics with controlled tree breakage

Field observations have shown that forests can serve as natural barriers to reduce landslide runout distance by dissipating energy during impact and enhancing resistance through tree entrainment. While recent physical modelling studies indicated how forest spatial configurations enhance energy dissipation, they oversimplified trees as rigid, unbreakable elements, neglecting the critical role of tree failure in landslide dynamics. This study presents a novel physical model of landslide–forest interaction with an explicit consideration of tree failures. The flume utilizes tree elements that are designed to fail at calibrated bending moments to model the mechanical behaviour of forests during landslide impact. A new dimensionless number is introduced to characterize the ratio of landslide impact-induced bending moment to the bending resistance of tree elements. The performance of this dimensionless number is validated through a series of flume tests. Preliminary findings on the tree mechanical properties in controlling landslide mobility and new insights into nature-based landslide mitigation strategies will be discussed.