17年生邓恩桉两个种源木材密度与干缩性研究

Studies on Wood Density and Shrinkage of Two Provenances of 17-year-old Eucalyptus dunnii

通过对邓恩桉两个种源木材基本密度和在湿、气、全干状态下的径、弦向尺寸的测定,研究了不同树干位置的基本密度和干缩率的变异规律,并运用加工工艺中减小木材皱缩和开裂措施(蒸汽调湿处理方法)探索皱缩开裂缺陷的恢复性能。结果表明:1)邓恩桉种源100(0.5265 g/cm3)的木材基本密度小于种源98(0.5360 g/cm3);2)木材基本密度在树干纵向呈波浪式变化,在横向边材显著大于心材;3)木材干缩率在纵向随高度的增加而减小,在横向边材大于心材,且弦向干缩率均为径向的1～3倍;4)经喷蒸调湿处理后,木材开裂程度减轻,且径向和弦向皱缩恢复率分别为0.4%、3.3%;5)木材基本密度与气干弦向干缩率存在极显著负相关(r=-0.313),并建立了气干干缩率与全干干缩率的回归模型。

Based on two provenances of Eucalyptus dunnii for measuring wood basic density,and checking radial and tangential dimension in green,air-dry and oven-dry states,the variation regulation of wood basic density and shrinkage ratio in different place of tree stem was studied,and the processing technology of reducing shrinkage and splitting measures（reconditioning treatment） was took to explore the restoration performance of shrinkage and splitting defects.The results indicated that： firstly,wood basic density of number 100 provenance（0.5265 g/cm3） was bigger than number 98 provenance（0.5360 g/cm3）;Secondly,wood basic density showed corr change in longitudinal direction of tree stem,and sapwood density was significant higher than heartwood in traverse direction;Thirdly,wood shrinkage become smaller with the height of tree stem increasing,and sapwood shrinkage was remarkably higher than heartwood in traverse direction.Besides,tangential shrinkage ratio was 1 to 3 times more than of radial,both in longitudinal and traverse direction;Fourthly,wood splitting severity declined by reconditioning treatment,and the shrinkage recovery ratio of radial and tangential direction were 0.4% and 3.3% respectively;Eventually,wood basic density had extra significant correlation with tangential shrinkage of air-dry,and its correlation coefficient was-0.313,and linear regression models between shrinkage ratio of air-dry and oven-dry was also established.