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“优势木高度”是指每公顷100株胸径最大的林木平均高,这个平均高通常可从林分的树高一直径曲线图查得。在南非共和国的西南部地区,从171个林班的调查获得如下数据(见右表) 方程式的调配都是以优势木高度作因变量,年龄、每公顷株数,胸径、平均高等因子作为自变量。全部自变量的显著性水平都是99%。获得最合意的比较简单的方程式是: TH-H=0.02901578log(SPH-99)A TH为优势木高度(米);H为平均高(米),SPH为每公顷株数,A为年龄该方程式的自变量极显著,其F值为612,约为显著性水平99%所要求的最小F值的90倍。
The “dominance wood height” means the average height of 100 trees per hectare with the highest DBH. The average height can usually be obtained from the height-diameter curve of the stand. In the southwestern region of the Republic of South Africa, the following data were obtained from surveys of 171 forest classes (see the table on the right). All the equations were allotted based on the height of the dominant wood as the dependent variable, the age, the number of trees per hectare, the diameter at breast height, and the average higher factor . The significance level of all independent variables was 99%. The simplest formula for obtaining the most desirable is: TH-H = 0.02901578log (SPH-99) A TH is the dominant wood height (m); H is the average height (m); SPH is the number of trees per hectare; A is the age The independent variable was significantly significant, with an F value of 612, about 90 times the minimum F value required for a 99% significance level.