The study looked at how different types of vegetation affect how water moves through soil in hilly areas. They collected soil samples from forests and shrub areas in Nanjing Purple Mountain and analyzed their physical properties. The results showed that soil under pure Quercus acutissima forests had the highest water infiltration rates compared to mixed forests and shrub areas. The researchers found that soil properties like silt content and porosity were linked to how fast water could soak into the ground. This suggests that planting more Quercus acutissima forests could help improve soil water retention in the study area.