Characteristics of Rainfall Redistribution under the Canopy of Larix Principis-rupprechtii Forest in Diediegou watershed of Liupanshan Mountains

Though a field investigation during growing season from May to October in 2006 and 2007 the partitioning of gross rainfall into throughfall,stemflow and canopy interception in the Larix principis-rupprechtii forest was studied in the small watershed of Diediegou located at the north part of Liupan Mountains,Ningxia.And the influence of meteorological factors was evaluated based on the simultaneous weather observation.An obviously spatial variation of throughfall ratio was observed,and this spatial variation declined with rising rainfall depth.The results also showed that throughfall,stemflow,and canopy interception accounted for(74.94±2.4)%,(0.16±0.03)%,and(25.08±2.41)% of the total rainfall,respectively.The amount of throughfall,stemflow and canopy interception was significantly(p0.01) and positively correlated with rainfall depth.As rainfall depth and intensity increased,the throughfall ratio in gross rainfall increased,but will gradually stabilized when the rainfall depth was higher than 20 mm and the rainfall intensity was higher than 5 mm/h.The stemflow began to appear when the rainfall depth arrived at 6.44 mm.The canopy interception ratio in gross rainfall decreased significantly(p0.05) and hyperbolically with increasing rainfall depth,rainfall duration,and air humidity.