油松株内幼龄材与成熟材材性的比较研究

本文就中条山油松株内幼龄材与成熟材材性差异的比较研究,讨论对幼龄期划分的依据。根据木材解剖特征、物理力学性质的径向变异规律,确定其幼龄期为14年。随着树干高度的增加,油松木材幼龄期逐渐缩短、株内幼龄材范围及所占断面上的比例变小。株内幼龄材与成熟材材性差异显著。幼龄材管胞长度短、直径小,胞壁薄,微纤丝角度大,生长轮较宽,晚材率低,浸提物含量高,基本密度较大。幼龄材的力学强度远远小于成熟材。

Studies on properties of juvenile wood compared with mature wood in stems of chinese pine

Five trees of Chinese pine (Pinus tabulaeformis) were collected from a stand of Zhongtiao Mountains in Shanxi Province. Based on the radial variation of the anatomy features, physical-mechanical properties of the wood, the stemwood may be divided into juvenile wood and mature wood, and the duration of the juvenile period is about 14 years old. The width of juvenile wood and the number of growth rings, decreased noticeably from the base to the top of tree. The volume of juvenile wood decreased in a similar pattern.There are significant differences(0.05Ievel)between juvenile wood and mature wood properties of the trees. Shorter traeheid lengths, smaller tracheid diameters, thinner tracheid walls, flatter fibril angle of the S_2 layer, wider growth ring, lower percent of latewood and higher extractives content, higher specific gravity, lower physical-mechanieal properties are the characteristics of the juvenile wood in comparision with the mature wood.