检测角对健康立木中应力波传播速度的影响

Effect of Different Detection Angle on Propagation Velocity of Stress Wave in Health Standing Trees

以东北林业大学实验林场中水曲柳、白桦、落叶松等3种含水率为饱和状态的活立木为研究对象,利用Arbotom应力波测试仪研究了不同检测角度(0°、15°、45°和75°)对应力波传播速度的影响。利用Excel和SPSS软件包,对所得实验数据进行含水率、胸径等因素与应力波传播速度的相关性分析。结果表明,当只有含水率对应力波传播速度影响较大时,检测角为45°可大幅减少含水率对应力波传播速度的影响;当只有胸径对应力波传播速度影响较大时,检测角为75°可大幅减少胸径对应力波传播速度的影响。当含水率和胸径对应力波影响都较大时,根据不同树种采用不同的检测角度来减小含水率和胸径对应力波传播速度的影响;白桦选取检测角为75°,水曲柳和落叶松选取检测角为45°。

The experiment was conducted to study the effect of different detection angles （0°, 15°, 45° and 75° ） on propagation velocity of stress wave in standing trees （Fraxinus mandshurica Rupr. , Betula platyphyUa Suk and Larix gmelinii Rupr） with saturated water content. With stress wave testing equipment, the detection angle should be limited according to the variance of the trees＇ diameter at the breast height （DBH） and wood moisture content. When the wood moisture contents of trees influence the propogation velocity of stress wave greatly, the detection angle of 45 ° is the optimal angle, and it can reduce the influence of wood moisture content on stress wave velocity in trees. When the influence of trees＇ DBH is great, the detection angle of 75° is the best angle that can reduce the influence of DBH on stress wave velocity in trees. When DBH and wood moisture contents of trees have a great influence on stress wave velosity, the optimal detection angle depends on tree species. The best detection angle for B. platyphylla Suk is 75°, and 45° for F. mandshurica Rupr. and L. gmelinii Rupr.