Characteristics of Runoff on Forest Vegetation Slopes in Three Gorges Area

Four different vegetation stand slopes in Jinyun Mountain in Chongqing city were studied.By contrasting the rainfall and the surface runoff in 2002,the results showed that,with the same precipitation,the amount of runoff in the mixed forest was the maximum（65.18 mm）,the second was the Phyllostachys pubescens forest（64.72 mm）,the third was the shrub forest（30.52 mm）,the fourth was the broad-leaved forest（18.71 mm）.The amount of runoff concent rated mainly from April to September.In this period the amount of runoff in the broad-leaved forest was the minimum in all the vegetation stand slope.The results showed that effects of the broad-leaved forest on the regulation of slopes runoff were the maximum.Between all the surface conditions and the amount of runoff grey relation of soil thickness was the maximum,the second was litter amount,the third was canopy closure extent,the fourth was slope.Effects of all the surface conditions on the amount of runoff were all great.Effects of soil thickness on the amount of runoff were the maximum,and effects of slope were the minimum.The correlativity between the amount of rainfall and the amount of runoff was remarkable,and soil thickness directly affected the amount of rainfall of initiative runoff.