The Hydrological and Mechanical Effects of Forests on Hillslope Soil Moisture Changes and Stability Dynamics

Abstract

Vegetation can play a crucial role in stabilizing slopes through their hydrological and mechanical properties, yet few studies have systematically compared their effects on soil moisture resistance and slope stability. To investigate this, four steep slopes covered by different forests were analyzed in terms of climatic conditions, soil moisture dynamics, root strength and soil physical properties. The results revealed that the roots of Phyllostachys pubescens forests had a higher number and were deeper than the main plant species in the other three forests. Although the root tensile strength of Phyllostachys pubescens was not the strongest, its additional cohesion contributed more to hillslope stability. In the other three forests, suction stress was the main factor contributing to hillslope stability. The soil moisture change rate in Phyllostachys pubescens was found to be the smallest among the four forests studied, indicating that it had the greatest rainfall interception ability. The stability of the slope land covered by shrub forest was found to be more variable than the other three lands in high temperature conditions. Through its soil moisture reducing ability, root characteristics and magnitude of safety factor, Phyllostachys pubescens was identified as a suitable species for slope stabilization in the study area. The findings of this work may provide useful insights for local forest management in terms of selecting suitable plant species to reduce shallow landslides.