不同林龄杉木实生林物理力学性质变异研究

以湖南省金洞林场同一立地条件、不同林龄的杉木实生林木材为研究对象,按照国家标准测定其物理力学性质的气干密度、基本密度、横纹弦向全部抗压、横纹径向全部抗压等10个性状指标.方差分析发现,杉木实生林木材的10个性状指标均随林龄的增大而增加,且各指标差异显著.对其进行相关性分析,发现木材物理与力学性质间表现为正相关,其中与横纹弦向局部抗压、横纹径向局部抗压、顺纹抗弯模量、顺纹抗拉强度表现出极显著相关性,相关系数为0.207～0.680.变异系数计算结果表明,各性状的变异系数变化范围为3.57％ ～11.40％,30年生时,气干密度、基本密度、横纹弦向全部抗压、横纹径向局部抗压、顺纹抗弯强度、顺纹抗压强度、顺纹抗拉强度的变异系数小于其他2个林龄.全部性状的变异系数均处于10％左右,说明实生林各性状总体稳定.综上可知,实生林的物理力学性质具有密切的相关性,随着林龄的增加,表现出受环境因素影响越来越小,受遗传因素影响越来越大.

Study on the variation of physical and mechanical properties of Chinese fir seedling forest in different stand ages

Taken Chinese fir seedlings from different stand stages in the same site condition of Jindong forest farm in Hunan Province as the research objects, 10 characters of the physical and mechanical properties of Chinese fir were determined, such as air-dry density, basic density, compression resistance of all stripes(flat) and compression resistance of all stripes(radial) according to the national standard. The analysis of variance showed that the 10 characters of Chinese fir seedlings increased with the increase of the stand age, and the difference in each index was significant. The correlation analysis showed that the physical and mechanical properties of wood were positively correlated with the compression resistance of all stripes(flat), the compression resistance of local(radial), the modulus of elasticity to grain, and the tensile strength parallel to grain with the correlation coefficient of 0.207 - 0.680. The results showed that the variation coefficients of each character varied from 3.57% - 11.40%. At 30 years of age, the variation coefficients of air-dried density, basic density, compression resistance of all stripes(flat), compression resistance of local(radial), bending strength to grain, compressive strength parallel to grain, and tensile strength parallel to grain were lower than those of the other two stand ages. However, the variation coefficients of all the characters were about 10%, which indicated that all the characters of the seedling forests were stable on the whole. In conclusion, the physical and mechanical properties of Chinese fir seedling forests are closely related, and which are less affected by environmental factors, more affected by genetic factors with the increase of stand age.