Abstract:Based on 5-year from 2001 to 2005 located observation in different types of forests in karst mountainous area in center of Guizhou Province, China, the annual surface runoff was from 1.765 to 22.934 mm in different forest types and from 10.553 to 11.699 mm in different observed years, with an average of 11.108 mm. The forest surface runoff changed in the order of young forest returned farmland (22.934 mm)＞ coniferous forest (17.236 mm)＞needle and broad-leaved mixed forest (10.770 mm)＞evergreen and deciduous broad-leaved forest (8.876 mm), which is similar to forests in the same or another bio-climate zones. And it is the common character of karst and nonkarst mountainous forests. The karst shrub forest was different from nonkarst in surface runoff due to mother rock properties. Surface runoff of the types was Summer＞Spring＞Autumn＞Winter, coincided with seasonal distribution of precipitation. Seasonal changing rule of surface runoff coefficients in young forest returned farmland was as same as seasonal distribution of surface runoff, and the rule in coniferous forest and needle and broad-leaved mixed forest was Summer＞Spring＞Winter＞Autumn, and the rule in shrub forest and evergreen and deciduous broad-leaved forest was Spring＞Summer＞Winter＞Autumn, and this difference was made by species composition and precipitation distribution. There existed remarkable correlation, accorded to line, between surface runoff in ten days and hydrological factors include precipitation,evaporation and relative humidity, and temperature factors include Max. and Min. and average temperature in air and surface and soil deepth in 5 cm, 10 cm, 15 cm and 20 cm. Results of contribution ratio to surface runoff from multi-variances regression analyses was that temperature is higher than hydrology, and this indicated temperature affected flow of air mass near surface, and influenced further precipitation and forested surface runoff. Influence of layer characteristics in different forest types on annual surface runoff had mutual beneficent and repellency based on community component, structure and development. Annual surface runoff was affected complexly by micro-habitat and surface soil characteristics of plots, and increased by slope of plots rising, and decreased by altitude of plots rising, there had remarkable negative correlation between annual surface runoff and total porosity and capillary pore, and contribution ratio of volume weight to annual surface runoff was -96.54%, based on multi-variances regression analyses.
