湖北林业科技

Abstract：The study on the radiation and leaf area vertical distribution in relation to the P. massoniana Lamb. plantations of three densities was observed and studied by authors. The result showed that① As the increasing of the downward depth from the top of the tree, the leaf area of P. massoniana Lamb. was declined after increasing first; ②In the same time, the PAR transmittance(Tr) of P. massoniana Lamb. of the three densities showed Tr(0～1.5m)＞Tr(1.5～3.0m)＞Tr(3.0～4.5m); ③ In three densities, the PAR transmittance of the average Photosynthetic Active Radiation(PAR) all showed TrZ(1.5m×2.0m) ＞TrX（1.0m×1.5m) ＞TrY(1.5m×1.5m) in the same height and different time, which meant the light-absorbing affection of the density Y(1.5m×1.5m) was the best; ④ Comparing the three densities, the density of 1.5m×1.5m was the best one for the growth of P. massoniana Lamb. plantations.