This study investigates the pore water pressure and water content on a forested slope, focusing on the impact of canopy interception across various rainfall intensities. The study was performed on slopes in the Sukajaya Sub District of West Bogor, West Java, Indonesia, a region that encountered landslides in 2020. Soil hydraulic characteristics, soil textures, saturated water content, and soil moisture content at different pressures, were assessed at different slope locations and depths. The pore water pressure and water content change were simulated using the one-dimensional uniform (equilibrium) finite element model of water movement using the modified Richards and were executed with the HYDRUS 1D model across six scenarios of a combination of three rainfall events at two initial conditions of water content, contrasting bare and vegetated slopes of Maesopsis eminii, which exhibited 35% canopy interception. Findings demonstrate that bare soil attains saturation more rapidly, resulting in elevated pore water pressure and increased susceptibility to slope instability. Conversely, vegetated slopes have delayed saturation owing to canopy interception, which diminishes the volume of rainfall that reaches the soil. The results highlight the crucial function of vegetation in preserving slope stability by regulating soil water pressure and water content, particularly during intense rainfall events. This research enhances comprehension of how vegetated areas might reduce landslide hazards in high-rainfall environments.

The assessment of landslide susceptibility often overlooks the influence of forests on shallow landslide mobility, despite its significance. This study delved into the impact of forest presence on shallow landslide mobility during intense rainfall in Mengdong, China. Field investigations were coupled with the analysis of pre- and post-rainfall remote sensing (RS) images to delineate landslides. The ratio of landslide height (H) to travel distance (L) from a digital elevation model (DEM) were used to calculate landslides mobility. Preceding the event, forest coverage was evaluated using the normalized difference vegetation index (NDVI) derived from multiband RS image. The research identified 1531 shallow landslides in the area, revealing a higher concentration of landslides on slopes with elevated NDVI. Results indicated that disparities in soil permeability and cohesion, generating pore water pressure (PWP), triggered clusters of shallow landslides. Shallow landslides exhibit a higher propensity on slopes with elevated NDVI. The dimensions (height and area) of these identified shallow landslides typically exhibit a positive correlation with NDVI, consequently resulting in longer travel distances for landslides occurring on higher NDVI slopes. The average H/L ratio of all identified landslides was about 0.63. H/L generally increases with NDVI and decreases with landslide area. However, due to river channel restrictions, the H/L increases with slope gradient. The findings suggest that the high permeability of areas with tree roots poses a risk to the shallow stability of slopes, yet trees contribute to mitigating landslide mobility.