Abstract: As a typical representative in the gorges and deep valleys in the upper-reaches of the Yangtze River, SW China, the Hutiaoxia Gorge Area has a serious environmental problem of soil erosion. To tackle the erosion problem, a large area of suitable mountains has been reforested. Yunnan pine is one of the most wildly used tree species for reforestation. This study is trying to investigate the hydrological effect and its potential of the pine forest on soil erosion control, taking the Hutiaoxia Gorge Area as an example. The study has found that the dense pine forest was able to intercept up to 31.1% of total rainfall throughout the rainy season in 1993. The total splash detachment in the forest (4.9kg·m-2)was 19.7% lower than the one on the bare land(6.1kg·m-2). The total soil loss in the forest was considerably decreased to 32.9g·m-2, as compared with 57.9g·m-2 on the bare land, showing a soil erosion reduction by 43.19%. As experiments indicated, rain intensity here was the most affecting factor on soil erosion and the hydrological effect of the forest as well. On the other hand, the dense forest was also found to cause drip splash detachment by producing large leaf drips; and it did not actually reduce surface runoff. Considering the comprehensive role, however, the dense forest has a net positive effect on erosion limitation. Compared with dense grasses, the forest seems to be less effective on soil erosion control.

Key words: Pine forest, Potential, Erosion control, Alpine gorges