Effects of Different Age of Toona sinensis on Forest Canopy Interception

A total of 17 precipitation events were positioning monitored in Zhenning County of Guizhou Province in August,October and November of 2010 to explore its mechanism and provide a theoretical basis for evaluating its water holding capacity.The results showed that: 1) When the precipitation increased within a certain range,the throughfall,stem flow and canopy interciption all increased,but the canopy interception rate decreased.2) The throughfall were 43.36 mm,39.01 mm and 34.01 mm respectively of 8~13,15~20 and 25 years old T.sinensis forest.The average precipitation rates were 64.95%,54.19% and 44.48% respectively;The stem flow were 0.29 mm,0.23 mm and 0.17 mm,the average stem flow rates were 0.15%,0.11% and 0.08% separately;The canopy interception were 26.41 mm,35.36 mm and 44.55 mm,with the average canopy interception rates of 40.09%,51.77% and 61.65%.3) Under the same condition of precipitation,the canopy interciption was the smallest,and the throughfall was the greatest of 8~13 years old T.sinensis forest;The canopy interciption and the throughfall were all intermediate of 15~20 years old T.sinensis forest;The canopy interciption was the greatest and the throughfall was the smallest of 25 years old T.sinensis forest.