重庆四面山4种天然林地表的糙率系数

Surface Roughness Coefficient of Four Natural Forest Types in Simian Mountain of Chongqing,China

为探讨长江三峡库区的森林水文作用,并为三峡库区营建水土保持型森林体系提供依据,通过室内试验,用曼宁公式计算出重庆四面山4种类型天然林地坡面的糙率系数n值。对糙率系数n值的部分影响因素做出相关分析,并阐述了糙率系数n值与枯落物厚度、枯落物储量之间的关系。结果表明:①从未分解层+半分解层的整体来看,4种类型天然林枯落物的糙率系数大小顺序为阔叶林(0.103 9)>针叶林(0.088 8)>针阔混交林(0.088 0)>楠竹林(0.058 0)。②糙率系数受枯落物的厚度、储量影响很大,通过相关分析得出其相关系数分别为0.746、0.901,且在0.01水平(单侧)上显著相关。③糙率系数n值与枯落物厚度、枯落物储量均呈幂函数关系,糙率系数n值随枯落物厚度和储量的增加而增大。

The research was conducted to investigate the forest water conservation function for the construction of soil and water conservation forest system of Three Gorge Reservoir Region. The roughness coefficient （n） of four natural forest types was calculated in Simian Mountain of Chongqing by laboratory testing and the Manning Formula. The correlation analysis was conducted to elaborate the relationships between n and litter thickness as well as litter reserves. The results showed that for the undecomposed and Semi-decomposed layers, the roughness coefficients （n） of four types of natural forest litter is ranked as broad-leaved forest （0. 103 9） 〉coniferous forest （0.088 8 ） 〉broadleaf-conifer mixed forest （0.088 O） 〉bamboo forest （0.058 0）. The litter thickness and reserves have a great impact on roughness coefficient （n） with the correlation coefficients of O. 746 and 0.901, respectively, at the O. O1 level （unilateral）. The roughness coefficient （n） has the correlation of power function with the litter thickness and reserves, and the roughness coefficient （n） increases with the increase of the litter thickness and reserves.