雪岭云杉林分结构密度图的编制

<正>本文根据日本安腾贵的基本理论,以林分密度控制图为基础编制雪岭云杉天然林分结构密度图。它由Y-N曲线、等限界直径线和最大密度线组成。Y-N曲线由累积株数和累积材积间关系导出,模型为Y=AWN+BN,由此得出三参数β型分布函数。使用该图不仅知道林分总量,而且知道各材种量,它比密度图好,实践中最好与密度图结合使用。

A STAND STRUCTURE DENSITY DIAGRAM FOR SCHRENK SPRUCE IN XINGJIANG

A structure density diagram is devised for natural schrenk spruce stands in Xingjiang, China, on the basis of the stand density control diagram in accordance with the theory used in Japan. The diagram consists of Y-N curves, equivalent boundary diameter curves and a full density curve. A Y-N curve is derived from the relation between cumulative summation (Y) of individual tree volume, and number (N) of these trees, and expressed by Y=AwN+BN from which we obtain the three-parameter Beta-type distribution function of individual tree volume. With this diagram, not only the total number and volume of a stand, but also the number and volume of trees of the selected diameter can be found. In this respect, it is better than the stand control diagram, but the best way is to use both simultaneously.