6个杨树无性系木材密度及干缩性能差异

The difference of density and shrinkage properties of six cloned poplar trees

以6个杨树无性系木材为研究对象,对杨树的密度及干缩性能进行了分析研究,为杨树木材的加工利用提供依据。结果表明:6个杨树无性系木材基本密度为0.33~0.43 g/cm 3,气干密度为0.39~0.51 g/cm 3,全干密度为0.37~0.49 g/cm 3,密度在不同无性系间差异极显著。50号杨、中林46杨、南杨木材密度沿径向呈逐渐增加的变化趋势,而108杨、N179杨和桑巨杨木材密度呈现先降低后逐渐增加的趋势。杨树无性系木材气干和全干干缩差异均值分别为2.53和2.22,不同无性系间气干干缩率(径向、弦向、体积、干缩差异)和全干干缩率(径向、弦向、体积、干缩差异)差异均极显著。50号杨、N179杨和桑巨杨木材干缩差异沿髓心向外呈现先增加后减小的趋势,中林46杨呈现逐渐增加的趋势,108杨和南杨则是呈现先减小后增加的趋势。相关性分析表明:木材密度与不同状态下干缩差异呈极显著负相关;木材基本密度除与弦向和体积气干干缩率不相关,与其他干缩指标均呈极显著正相关;不同干缩指标之间呈极显著正相关。

The density and drying shrinkage properties of six cloned poplar trees were compared and analyzed,which provided some references for the processing and utilization of poplar wood.Density and shrinkage characteristics of wood are important parameters to determine wood quality.There are many cultivars and great differences in wood quality of poplar trees,so it is particularly urgent and important to study the wood properties of poplar trees and the law of variation to improve the wood quality,especially to select the best clones based on this study and carry out directional cultivation to improve the wood quality of poplar trees in plantation forests.The basic densities of six clones were 0.33-0.43 g/cm 3,the air-dried densities were 0.39-0.51 g/cm 3,and the oven-dried densities were 0.37-0.49 g/cm 3.The difference of wood densities between different clones was very significant.The wood densities of Populus deltoides‘55/65’,P.euramericana‘Zhonglin46’and P.deltoides‘Nanyang’gradually increased along the radial direction,and the wood densities of P.euramericana‘Guariento’,P.nigra‘N179’and P.euramericana‘Sangju’showed a trend of decreasing firstly and then gradually increasing.In the air-dried state,the tangential shrinkage,radial shrinkage and volume shrinkage rate were 4.61%-6.08%,1.82%-2.35%and 6.64%-8.81%,respectively.The air-dried differential drying shrinkages were 2.28-2.71.In the oven-dried state,the tangential shrinkage,radial shrinkage and volume shrinkage rate were 7.29%-8.63%,3.26%-4.01%and 10.79%-12.77%,respectively.The oven-dried differential drying shrinkages were 2.04-2.35.The mean air-dried and oven-dried differential drying shrinkage of cloned poplars were 2.53 and 2.22,respectively.The difference of air-dried shrinkage rate(radial,tangential,volume,differential dry shrinkage)and oven-dried shrinkage rate(radial,tangential,volume,differential dry shrinkage)among different clones were very significant.The differential drying shrinkage of P.deltoides‘55/65’,P.nigra‘N179’and P.euramericana‘Sangju’showed a trend of firstly increasing and then decreasing along the pith outward,P.euramericana‘Zhonglin46’showed a trend of increasing all the time,while P.euramericana‘Guariento’and P.deltoides‘Nanyang’showed a trend of firstly decreasing and then increasing.According to the correlation analysis,the wood density was significantly negatively correlated with the differential drying shrinkage under different conditions.Except for the wood basic density that was not correlated with the tangential and volume air-dried shrinkage rate,the wood density was positively correlated with other dry shrinkage indexes.There was a significant positive correlation between different dry shrinkage indexes.