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由于应力波在活立木与原木中传播过程和传播形式存在差异，在两者之间的传播机理或理论尚未完全明晰，导致尚无法实现通过检测活立木的力学性能来预测和评价相对应原木的品质等级。
 
Due to the differences in the propagation process and mode of stress waves between standing trees and logs, the underlying propagation mechanisms or theoretical frameworks connecting the two remain insufficiently understood, making it infeasible to accurately predict or assess the quality grade of logs solely based on the mechanical properties of standing trees.
 
需要注意的是，对于不同髓心、心材和边材比例的活立木模型，应力波的敲击产生输入点位于模型的左下角。
 
It is important to note that for all standing tree models with different proportions of pith, heartwood, and sapwood, the point of impact generating the stress wave is located at the lower-left corner of the model.
 
随着传播时间的增加，应力波传播距离也逐渐增大，波阵面的曲面越来越长，但倾斜程度逐渐减小，到最后波阵面变短，逐渐变成平面形状，并逐渐与活立木的长度方向垂直。
 
As the propagation time increases and the stress wave propagates farther, the curved surface of wavefront elongates, while its inclination gradually decreases. Eventually, the wavefront shortens and transitions into a planar shape, becoming more perpendicular to the lengthwise direction of the standing tree.
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