摘要
根据连续定位测定数据,应用空气动力学和生态动力学原理探讨了杉木人工林林冠层的动力效应及动能的传输规律.结果表明：密度2000株/（10^4m^2）、林分平均高度16 m、平均胸径15.5 cm、叶面积指数8、冠层厚度9 m、郁闭度0.9的杉木林,其零平面位移长度11.15-11.98 m,冠层粗糙度2.32-2.53 m,林冠上表面乱流切应力0.135 N·cm^-2,枝叶阻力系数0.367,摩擦速度0.339m·s^-1,冠内混合长度0.12 m,相对湍流强度0.7;由于林冠的存在,枝叶对气流的阻滞作用使风速廓线发生形变,在杉木林内离地面11.15 m高度上,风速随高度的变化呈对数规律,在此以下高度符合指数法则,林冠内风速削减因子1.98;乱流切应力和动能从林冠上表面传输到林冠下表面时,乱流切应力削弱70%,动能削弱90%.乱流切应力和动能在林冠内传递变化规律与林分结构特征有关,尤其与林冠内湍流性质和温度层结影响关系极大.
Based on the data collected in successive years, the dynamic effects and the law of kinetic energy transmission in the Chinese fir plantation ecosystems were discussed in detail with aerodynamic principles and ecological dynamics. The structural parameters of the plots were investigated including the stand density of 2 000 stems per 104m^2, average stand height of 16 m, average diameter breast height of 15. 5 cm, LAI of 8, the canopy height of 9 m, and crown density of 0. 9. The results demonstrate the following dataz the length of zero plane displacement of 11.15 to 11.98 m, the canopy roughness of 2. 32 to 2. 53 m, the turbulence shearing stress above the canopy surface of 0. 135 N · cm^-2, the coefficient of leaf resistance of 0. 367, the friction velocity of 0. 339 m · s^-1, the mixed length within canopy of 0. 12 m, and the relative turbulence strength of 0. 7. Owing to the delay of airflow by leaves and branches in the canopy, wind velocity profile was distorted. And the wind velocity profile was in accord with the law of logarithms above the height of 11.15 m from the ground within the canopy, and was also in accord with the law of exponent while beneath the height of 11.15 m. And the wind velocity delay factor within the canopy was of 1.98. When the turbulence shearing stress and kinetic energy were transferred from the upper canopy surface to lower canopy surface, both of them would be weakened with a decline of 70% and 90% respectively. Theses results also suggest that the laws of the transmission of turbulence shearing stress and kinetic energy were significantly correlated to canopy structures, especially influenced by characteristics of turbulence shearing stress and temperature layer sum within the canopy.
出处
《中南林业科技大学学报》
CAS
CSCD
北大核心
2007年第2期1-6,共6页
Journal of Central South University of Forestry & Technology
基金
国家科技部平台建设项目(20021220)
国家林业局重点项目(200107)
关键词
森林生态学
杉木人工林
林冠结构
动力效应
参数
动能
forest ecology
Chinese fir plantations
canopy structure
dynamic effects
parameter
kinetic energy
作者简介
康文星（1947-），男，教授，博士生导师，主要从事森林生态和城市生态的研究．
