Canopy interception effects of Acacia magium plantation

Through-fall,stem flow and rainfall of Acacia mangium plantation in Gaoyao Forest Farm were measured from 2006 to 2007,and the characteristics of canopy interception were analyzed.The results indicate that the annual rainfall of Gaoyao Forest Farm was 1 767.1 mm in 2006,and 1 692.7 mm in 2007.The rainfall mainly occurred in April to September,with its proportion of 81.7% to annual rainfall of 2006,and 84.5% to annual rainfall of 2007 respectively.The through-fall and stem flow had a linear relationship to rainfall.But the canopy interception,through-fall rate and stem flow rate had a logarithm relationship to rainfall.The relationship between interception rate and rainfall was a power curve function.Annual mean through-fall rate,stem flow rate and interception rate were 84.2%,7.3%,and 8.5% respectively.Canopy interception effect had notable season changes due to the difference of rainfall and canopy characteristic,with the canopy interception rate of 8.5% in rain season,and 17.9% in dry season.Compared to the adjacent evergreen broad-leaved forest of Dinghushan,A.mangium plantation had higher through-fall rate and lower canopy interception rate,which was beneficial to increase net rain and water resources of forest system.