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

对13个不同复层林分、1个群择林分、5个二层林分和7个择树林分的下部树种的树木性状和木材品质进行了调查，结果表明：1）形比（树高/胸径）受光照条件的影响;均匀林分中，各林分的光照条件基本相同，形状比的变异较小。复层林分的光照条件因林分而异，形比存在波动。2）人工修剪对下部树干的削尖影响较大，而非林分类型; 3）雪存款和雪的移动造成的拱起。因此，积雪区的林分和无阻碍积雪移动的上层树木的均匀林分的树干后掠角增大。4）复层林的下层树木的树干后掠角大于均匀林分。但频繁的密集修枝可以防止树干弯曲，随着年龄的增长，树干弯曲逐渐变小。5）二层林分中的下层树表现出优良的强度特性。这是由于对光照条件的控制和密集的修剪。

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.