Quality of lower trees in compound storied forests of Sugi(Cryptomeria japonica D.DON)

对13个不同类型的复合层状林、1个群选林、5个二叉林和7个选树林的树体性状和木材质量进行了调查，结果如下：1)形成率(树高/胸径)受光照条件的影响。在均匀林分中，各林分间光照条件基本相同，形成率变化较小。另一方面，复层林分各林分的光照条件不同，形成率也有波动。下部树种形成率在良好光照条件下较大，在较好光照条件下较小。2)下部树干的变细受人工修剪的影响，而不是林型。3)积雪和积雪运动造成的下部树干倒伏。因此，在雪域森林和没有上层树木的均匀林中，树干扫掠变得更大，从而阻止了积雪的移动。4)复合林下部乔木的树干扫掠比均匀林大。然而，频繁的密集修剪可以防止树干横扫，而且随着树龄的增长，主干横扫变小。5)两株林分中矮小的树种表现出很好的强度特性。这是由于光照条件的控制和密集的修剪造成的。

Tree character and wood quality of lower trees were investigated in thirteen various compound storied forests,one group-selection stand, five two-stried stands and seven tree-selection stands.The obtained results are as follows.1)The form ratio(tree height/stem diameter at breast height) was afected by light condition. Since in uniform stands,the light condition was much the same among each stand, the variation of form ratio was small. On the other hand, the light condition of compound storied stands was varied with each stand, therfore there was a fluctuation in form ratio. Form ratio of lower trees in favorable light condition was large, while that in inforior light condition was small.2) The tapering of lower bole was affected by artificial pruning rather than forest type.3) The butt-sweep in caused by snow deposit and snow moving. Therefore the butt-sweep became larger in forest of snowy areas and in uniform stands without upper trees which prevent a movement of snow deposit.4) The stem-sweep was larger in lower trees of compound stried forests than uniform stands. However frequent intensive pruning can prevent the stem-sweep and it was recognized that stem-sweep became smaller as tree grows older.5) The lower trees in two-stried stands exhibited an excellent strength properties. It is due to the control of light condition and intensive pruning.