Modeling Canopy Rainfall Interception Of Dark Coniferous Ecosystem In Gongga Mountain

Influence of forest cover change on hydrological process is one of the key problems of relationship between vegetation and environment in China. Going deep into knowledge of the regulation mechanism of forest vegetation is the urgent problem. In this paper more attentions are paid to the interception capability of dark coniferous ecosystem in Gongga Mountain, thus throughfall have been observed in different types of dark coniferous forest communities at four successive stages referenced. Simulated on rainfall interception process of individual rainfall and long term rainfall with Gash model. Based on the others conclusions and datas, validated the suitable and precision of the Gash model for the study on rainfall interception in Gongga Mountain.(1) The canopy interception and the inner precipitation raises with increase of the precipitation. The variation amplitude of the canopy interception decrease with increase of the precipitation, and the canopy interception tends to saturated state. The canopy interception rates of different types of dark coniferous forest communities at four successive stages decrease with increase of the precipitation.(2) The different of stand factors and space composite lead to the different of the interception capability in the same rain magnitude. There are field layer and brushwood layer besides canopy in mature forest, so the rainfall redistribution ability is better. The layer of canopy was not perfect in young forest and the structure of canopy changed with season, so the rainfall interception ability is weak.(3) Results show that Gash model can simulate the interception process of the long term rainfall for the overmature forest of dark coniferous in Gongga Mountain. But the result of simulating the interception process of individual rainfall is not satisfactory. In addition, As the Supplement of the identification, the result of the simulating the interception process of long term rainfall for Schima superba Plantation and Chinese fir plantation in WuYi Mountain.(4) When the amount of precipitation is between 0.45mm and 5.00mm, the canopy interception is basically saturated. In a general way, coniferous forest is larger than broad leaved forest, and it increased with the age of the stand. The canopy evaporation rate of forest is different in different sites, and the amount of the canopy evaporation rate is between 0.033 and 0.223. The amount of the water-holding capacity of stem is generally between 0.110mm and 0.905mm. The stemflow coefficient is very small and basically can be neglected.