山杨木材性状及个体内变异的研究

Study on Wood Quality Characteristics of Populus davidiana and Its Variation of Intra-tree

在山杨主要分布区６省内，各抽样１个天然林分，每个林分随机抽样２０株。其中５株伐倒木作标准材性试验；另１５株钻取木芯条测试。试验结果：（１）胸径处木芯条的木材密度与纤维长度等与伐倒木测定结果具有一致性；（２）株内髓心向外水平方向年轮组之间，木材密度及纤维长度的差异都极显著（α＝０．０１），两性状随年龄增大而增长，符合“Ｓ曲线”与“Ｓａｎｉｏ规律”，木材密度与纤维长度的相对增长率的最高值分别在１１～２０ａ与６～１５ａ；（３）材性幼一成龄相关，在木材密度与纤维长度性状方面表现不同，主要性状在１０～１５ａ进行早期选择具有合理性。

natural stands were selected respectively from 6 provinces in the main dis-tributing regions of P. davidiana Dode and 20 trees were sampled randomly from each plot.5among the 20 trees were cut for standard test of wood quality characteristics and the other 15trees with the increment cores drilled out increment cores at DBH, which are used for con-trast and supplemental test. The results of the analysis are as follows:(l)Both wood specificgravity and fiber length of cores agree with those dataum attained by the test of the felledtrees. (2)Wood specific gravity and fiber length among annual ring groups of intra-tree areincreasing with the increase of tree age,and conform to S curving line and Sanio regularity,whose variations are significant at 0.0l level. The maximum point of relative increasing rateof wood specific gravity and fiber length appear between 11 a and 20 a,6a and l5a,respec-tively.(3)Correlation of wood specific gravity of junenil-eadult is slightly different from thatof fiber length.It is suggested that early selection of main wood quality characteristics shouldbe carried out during 10～15a.