天然常绿阔叶异龄幼林胸径的Weibull分布及动态预测

 常绿阔叶林是我国亚热带东部地区的地带性自然植被。本次在浙江西北部研究的44块常绿阔叶林样地的主要树种是青冈(Cyclobalanopsis glauca)、石栎(Lithocarpus glaber)、甜槠(Castanopsis eyrei)、木荷(Schima superba)和苦槠(Castanopsis sclerophylla)等。Weibull函数能够较灵活地用来表达常绿阔叶异龄林的这种具有不同偏度和峭度变化的直径分布。随着林分平均胸径(D)的增大，常绿阔叶异龄林的胸径分布表现出由指数形转向倒J形至正态形。偏度由正偏趋于负偏．峭度逐渐变小．多数相应增大的动态分布规律。采用参数预估法研究建立了以D为自变量的天然常绿阔叶异龄林直径分布动态模型及其预测数表．可供合理经营等参考使用。

WEIBULL D.B.H. DISTRIBUTIONS AND THEIR DYNAMIC PREDIC-TIONS IN THE NATURAL UNEVEN-AGED EVERGREEN BROAD-LEAF JUVENILE FOREST

Evergreen forest is the natural vegetation in the eastern part of subtro-pical zone of China, This study area was in the northwestern part of Zhe-jiang Province where the dominant tree species based on 44 sample plotswere Cyclobalanopsis glauca, Lithocarpus glaber, Castanopsis eyrei,Schimasuperba,Castanopsis scleophylla and so on. The Weibull fuctiion couldflexibly express the D.B,H. distributions of the evergreen broan-leaf forestwith varied skew and kurtosis distributions.With the increase of standdiameter(D),the D.B.H. distributions of the evergreen broad-leaf forestcould be expressed by curves that changed from exponential to inverse-J,and finally to normal skapes. The skew degrees tended to change frompositive to negative,and kurtosis degreased gradually with an accompanyingincrease in the modes.Using parameter estimation methods,the models andschedules,in which D was used as independent variable,of the dynamic D.B.H. distributions of the natural uneven-aged evergreen broad-leaf forestwere established.These models can be used for tke reasonable managementof forest resources.