流体静力称衡法测定生长锥取样木材密度的改进方法

An Improved Method for Determining the Density of Increment Core Wood Samples Using Hydrostatic Weighing Techniques

利用生长锥取样观测树木密度指标是评价林木培育措施和效果的一种常用技术手段,但由于生长锥表面形貌不规则导致采用常规手段无法进行密度测试.本文在考虑木材作为多孔材料吸水影响的基础上,基于阿基米德定律提出了利用试验室常用天平采用流体静力称衡法和助沉法相结合确定生长锥取样密度测算的改进方法.为了验证改进方法的可靠性,分别按照国家标准(GB1993-2009)木材密度测定方法和改进方法对形状规则的杉木Cunninghamia lanceolata、樟木Cinnamomum camphora、印茄Intsia bijuga和铁樟木Eusideroxylon zwageri试件进行了密度测算,结果表明对于具有规则形状的试件,改进方法测试的密度值与GB1993-2009方法测试的密度值具有非常好的一致性.对采自广东省乐昌市龙山林场的不同植株杉木的东南西北向13个生长锥取样,按照改进方法进行密度测试,结果表明,考虑木材作为多孔吸水材料的方法操作更为简单,测试结果分布更合理.

A common and effective technique to evaluate wood quality and the effects of forest cultivation is by determining wood density using increment core sample sections, however, it is difficult to measure the density due to irregular surface of the increment core sample sections. An improved method for determining the density of the increment core sample sections was proposed considering the porous properties of wood based on the Archimedes Law. A series of regular samples made of Chinese fir（ Cunninghamia lanceolata ）, Camphor （ Cinnamomum camphora ）, Intsia （ Intsia bijuga ） , and Belian （ Eusideroxylon zwageri ） were used to verify the robust and effectiveness of the proposed system in comparison with the standard testing method of GB1993--2009. The results showed that the densities determined by the proposed method were very close to those determined by the standard testing method. The 13 increment sections,which were sampled from the Longshan Forest Farm, Lechang, Guangdong Province, were also tested using the proposed methods. The results demonstrated that density determination by Formula（6） ,which considered the effects of the porous properties of the sample, are more operable and reasonable as compared with those determined by Formula （7）.