Effects of Vegetation Exclusion on Rainfall Redistribution Characteristics of Shrubs Under Different Rainfall Types

[Objective] In order to explore the effects of canopy structure changes on rainfall distribution characteristics under different seasons and rainfall types. [Methods] Taking karst typical shrub forest as the research object, three 10 m×10 m plots were selected to remove 30% (TC30) and 10% (TC10) vegetation, respectively, and no exclusion (TC0) was used as the control to monitor the throughfall and stemflow of each sample plot after removal in the dry and rainy seasons. [Results] The throughfall rate of each sample plot was 72.3%~96.6% under different rainfall types in the dry and rainy season, and there was no significant difference in the throughfall rate of each sample plot under different rainfall types or exclusion ratios. However, the stemflow rate was TC0 (5.6%~13.9%)> TC10 (4.8%~8.1%)> TC30 (2.1%~6.1%) in both dry and rainy seasons, and there were significant differences under moderate rainfall in dry season, heavy rain in rainy season and heavy rain in rainy season (p<0.05). In addition, compared with TC0 and TC10, TC30 had the highest rainfall input (throughfall + stemflow) in both the dry and rainy seasons (98.9% and 94.8%, respectively). [Conclusion] The removal of vegetation has no obvious effect on the throughfall rate, but can significantly reduce the stemflow rate, and appropriate forest thinning can increase rainfall input, increase soil and vegetation water availability, and improve the rainfall-soil water conversion efficiency, which can provide a reference for improving the rainfall resource use efficiency in karst areas.