对同龄林和异龄林都可以作出一个材积模式来,这与林分调查的准确性有密切关系。每个林分里每个单元类别都有一个数学公式。单元类别按同龄林、异龄林、复层林、复层异龄林来划分·按年龄(分幼、中、成)树种、层次等分类,如一个复层林上层是松,下层是松和冷杉,则就可以划为三类:上层松一类,下层松一类,下层冷杉 For the same-age and anteroposterior species, a volume-model can be made, which is closely related to the accuracy of the stand survey. There is a mathematical formula for each cell category in each forest. Unit categories by the same age forest, different age forest, multi-stratified forest, stratified heterogeneous forest to divide by age (points young, medium, into) species, level classification, such as a stratum pine is upper, the lower is pine and fir , Then you can be divided into three categories: the upper pine, a lower pine, the lower fir