不同密度马尾松林内辐射与叶面积垂直分布关系研究

Study on Relationship of Radiation and Leaf Area Vertical Distribution of P.massoniana Lamb.with Different Densities

笔者通过对3种不同密度马尾松人工林内太阳辐射与叶面积垂直分布的观测与研究,得出以下结果：①马尾松叶面积随垂直向下深度的增加而先增加后减少;②在相同时刻,3种密度的马尾松冠层平均光合有效辐射透光率Tr（0-1.5m）〉Tr（1.5-3.0m）〉Tr（3.0-4.5m）;③在3种密度中,相同高度不同时刻平均光合有效辐射透光率都表现出Tr密度Z（1.5m×2.0m）〉Tr密度X（1.0m×1.5m）〉Tr密度Y（1.5m×1.5m）,说明密度Y（1.5m×1.5m）对光的吸收效果较好;④对比3种密度,密度Y（1.5m×1.5m）为马尾松人工林林分生长较适宜密度。

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（0-1.5 m）Tr（1.5-3.0 m）Tr（3.0-4.5 m）;③ In three densities,the PAR transmittance of the average Photosynthetic Active Radiation（PAR） all showed TrZ（1.5 m×2.0 m） TrX（1.0 m×1.5 m） TrY（1.5 m×1.5 m） in the same height and different time,which meant the light-absorbing affection of the density Y（1.5 m×1.5 m） 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.