所谓后伐,就是二次渐伐最后一次采伐。二次渐伐适用的林分条件:天然更新容易或林冠下已有幼树幼苗更新良好,土层浅薄人工更新困难的成熟单层林。落叶松、白桦均为阳性喜光树种,所以无论是纯林或混交林,均难以形成复层异龄林。复层异龄林的标准是:主副林层平均树高相差15%以上;各林层每公顷蓄积量不少于三十立方米;各林 The so-called after-cut, is the second time the last cut logging. The second sub-cut suitable for the stand conditions: natural regeneration is easy or under the canopy seedlings have been updated well under the tree, shallow artificial regeneration difficult mature monolayer. Larch, birch are positive hi-tree species, so whether it is pure or mixed forest, are difficult to form stratified heterogeneous forest. Stratospheric anaerobic forest is the standard: the average difference between the main forest and the stratum of more than 15%; forest per hectare of not less than thirty cubic meters of accumulation; each forest