13种杨树木材物理力学性质的研究

A Study on wood Physical and mechanical properties of thirteen Poplar varieties

采集I- 69杨等 10种黑杨的 9年生试材、易县毛白杨等 3种白杨的 13年生试材 ,测试木材物理力学性能 ,分析心边材、不同树高位置、株间的变化规律 ,比较品种间木材性质的差异。试验结果表明 ,13种杨树全树木材心材率在 14.6%～ 34 .1%之间 ,生材含水率在 86.2 %～ 148.5%之间 ,由生材干燥至含水率为12 %所产生的干缩率在 8.66%～ 11.96%之间 ,气干密度属低类或很低类 ,强度属弱类 ,硬度属软类或甚软类 ,冲击韧性中等 ;黑杨心材颜色深、心边材性质差异大 ,白杨心材颜色淡 ,心边材性质差异小 ;品种间木材物理力学性质差异较大 ,按其主要特点可将 13个品种的木材分为 4类。

Nine-year wood samples of 10 varieties of black poplar(Populus nigra), and Thirteen-year wood samples of 3 varieties of white poplar P.tomentosa were collected. Their physical and mechanical properties, the variation of heartwood and sapwood in different heights and trees were measured and analyzed. The results indicate: the heartwood ratio of entire tree wood of 13 poplar varieties is between 14.6% and 34.1%, moisture content in green condition is between 86.2 and 148.5%. Shrinkage rate from green condition to air-dry condition (a wood moisture content of 12 percent) is between 8.66% and 11.96%. Proof- density, strength, hardness, and shock resistance are light or very light, low, soft or very soft, and medium respectively. Black poplar varieties have dark color heartwood, and large difference of properties between heartwood and sapwood. White poplar varieties have bright color heartwood, and less difference of properties between heartwood and sapwood. The physical and mechanical properties among different varieties are significant. The thirteen varieties can be divided into 4 classes based on the main characteristics.