摘要
利用３６块落叶松一样树混交林标准地调查资料，研究其幼龄期林分Ⅰ级木单位面积株数与林分密度之间的关系，结果表明：Ⅰ级木的株数并非随密度的增加而直线递增，而是趋向“二阶常数”分布，且在同一年龄阶段，在较低的密度范围（２３２５～４８００株／ｈｍ２）或较高的密度范围（４８０１～６７５０株／ｈｍ２）．Ⅰ级木的株数变动幅度不太大。
Based on the data from 36 sample plots ofmixed forests of larch and birch,the rela-tionship between the tree numbers of the first grade per unit area in juvenile stage and treedensity is studied.The results show that the increment of tree density does not result in linearincrement of the first grade trees．Its distribution is of quadratic constant distribution.And,no significant differences for the tree numbers of the first grade between low and high treedensities are found when the growing stage is fixed.
