杉木无性系与实生苗木材物理力学性能差异研究

Comparison on the Physical and Mechanical Properties Between Clone and Seedling from Cunninghamia lanceolata

  • 摘要: 为揭示杉木无性系与实生苗木材物理力学性能的差异,以26年生杉木无性系和实生苗人工林木材为研究对象,对其不同圆周方位(南北向)、不同高度位置的主要物理力学性能进行测定,考察木材强度品质系数,综合评定杉木无性系和实生苗木材的材质等级。结果表明:除冲击韧性外,杉木无性系木材的密度、干缩率、差异干缩、湿胀率(全干−气干)、硬度、抗弯强度、抗弯弹性模量、顺纹抗压强度和横纹抗压强度均高于实生苗木材;圆周方位对杉木无性系与实生苗木材物理力学强度影响不显著;树高对杉木无性系木材气干密度、吸水率,实生苗木材基本密度、气干密度、吸水率、横纹抗压强度、硬度影响极显著,对无性系木材基本密度、全干密度、体积湿胀率,实生苗木材全干密度、体积湿胀率影响显著,对2种木材其他物理力学强度影响不显著;2种木材的气干密度、端面硬度、横纹抗压强度和顺纹抗压强度随树高增加呈现先降低后升高的趋势;除干缩性外,2种木材各物理力学性质指标均在国产材中属低等级;2种杉木木材综合品质系数较高,均为高等级材。

     

    Abstract: In order to reveal the differences in the physical and mechanical properties of wood from Cunninghamia lanceolata clones and seedling plantations, the main physical and mechanical properties of wood from 26-year-old C. lanceolata clones and seedling plantations at different circumferential orientations(north-south orientation) and different height positions were measured, and the wood strength and quality coefficients were investigated to comprehensively evaluate the material grades of wood from C. lanceolata clones and seedling plantations. The results showed that in addition to impact toughness, the density, shrinkage, difference shrinkage, swelling rate(all dry−air dry), hardness, flexural strength, flexural modulus of elasticity, compressive strength parallel to grain, and transverse compressive strength of C. lanceolata clones were higher than those of seedlings; the influence of circumferential orientation on the physical and mechanical strength of C. lanceolata clones and seedlings was not significant; tree height had a significant impact on the air dry density and water absorption of C. lanceolata clones wood, the basic density, air dry density, water absorption, transverse compressive strength, and hardness of seedling wood, while it had a significant impact on the basic density, total dry density, and volume moisture expansion of clone wood, the total dry density, and volume moisture expansion of seedling wood, and had no significant impact on other physical and mechanical strength of the 2 types of wood; the air dried density, end hardness, transverse compressive strength, and longitudinal compressive strength of the 2 types of wood showed a trend of first decreasing and then increasing with the increase of tree height; in addition to the shrinkage, the physical and mechanical properties of the 2 types of wood were in the low-grade of domestic wood; the comprehensive quality coefficient of the 2 types of C. lanceolata wood was relatively high, and they were both high-grade wood.

     

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