Understanding the role of vegetation root systems in the initiation of rainfall-induced shallow landslides: scaling perspectives

The contribution of root systems, defined as the arrangement of belowground structures formed within plant communities through both individual plant root systems and their interactions, to the stability of forested hillslopes can be assessed at individual root and plant levels. Root systems influence both vertical and lateral flow by creating preferential flow pathways or bypassing flow and influencing pore-water development and slope stability. Root systems development differs depending on stand density (i.e. tree spacing) and species composition, which are also associated with resource competition among individual plants. Forest stand conditions related to plant density and resultant root system development possibly alter frequency and size of landslides. Scaling effect, defined as translation of insights of individual root system into entire hillslopes or watersheds, poses challenges due to the heterogeneity of forest stand conditions, soil properties, topography, and hydrological processes. The primary goal of this review is to explore how forest root systems and forest stand conditions influence landslide dynamics through hydrological and mechanical processes, thereby providing insights for further research to address sustainable forest management and disaster risk reduction.