评定森林生产力是根据一公顷立木每年木材蓄积的平均生长量(以立方米表示)。为了确定全部林地平均生长量的总值,实际上可采用两种方法。Ⅰ—合计平均生长量△M_(cp)。以某个龄级的林木总数计算,其方法是用平均龄级A除以蓄积量M; The assessment of forest productivity is based on the average annual growth (in cubic meters) of timber stock per hectare of standing tree. In order to determine the total value of the average growth of all woodlands, two methods can actually be used. Ⅰ-total average growth △ M_ (cp). Calculated by the total number of trees of a certain age class, the average age class A is divided by the storage volume M;