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以一种单的可变干形树干尖削度曲线为基础,建立了一个给出树干纵剖面(树干上部带皮直径),总林木材积、商品材材积(从地面到某树高限或直径限)的材积估算系统。这一树干尖削度曲线由指示圆锥干形和抛物线干形的系数值所确定。对于给定的树高,小径木确定为抛物线干形,大径木确定为圆锥干形。林木在这一干形系列中的位置由其总树高与胸径的比值来确定。利用大湖区北部美国赤松、斑克松、白云杉的树干解析资料,对本材积估算系统的性能进行了评价。
On the basis of a single, variable dry trunk taper curve, a model was established that gave the longitudinal section of the trunk (skin diameter at the top of the tree trunk), the total forest volume, the commodity timber volume (from the ground to a tree height limit or diameter Limited) volume estimation system. This trunk taper curve is determined by the coefficient values that indicate the dryness of the cone and the dryness of the parabola. For a given tree height, footpath wood is determined to be a parabolic dry, and woodwood is identified as a conical stem. The location of trees in this dry series is determined by their ratio of total tree height to DBH. Based on the analytical data of the stems of American red pine, northern pine and white spruce in the Great Lakes region, the performance of this estimation system was evaluated.