天然同龄林的林龄转移滞后现象及林龄公式的修正

The Phenomenon of Forest Age Retardation and the Amending of Forest Age Formulas for Natural Even-aged Forest

从分析法正林的永续的林学假设出发 ,研究天然林的林龄转移滞后现象。通过固定小班的基础假设 ,由黑龙江省两次独立的、间隔近 40a、总面积达 3 0 0万hm2 的森林经理资料 ,成功地获得天然同龄林 2 153个“固定小班”的林龄转移资料。经林龄转移资料归一化处理 ,构造出三类天然林林龄转移概率矩阵。发现天然同龄林普遍存在林龄转移滞后现象。林龄转移滞后的概率为 0 .15～ 0 .3 5,且略有随着林龄增大而增大的趋势。林龄转移滞后的概率也与林分的优势树种有关 ,生长速度快的软阔林龄转移滞后的概率略高一些。分析产生林龄转移滞后现象的林学机理是 ,组成林分的林木枯损率会随着林木年龄的加大而增大。根据上述分析对第一、二林龄公式作了相应的修正 ,并对森林的成熟龄作出新的解释。

Proceeded from the Normal forest assumption, the phenomenon of forest age transf er and retardation for natural forest was studied. According to the basic assump tion of permanent sub-compartments and the two forest management inventories of Heilongjiang Province (Total area 3×10 6 hm 2 from 1950 to 1990), the forest age transfer data of 2153 permanent sub-compartments for natural even-aged fore st were successfully acquired. Through processing these data, the transfer proba bility matrixes of three kinds of natural forest age were constructed. The pheno menon of forest age retardation was discovered. The probability of forest age re tardation was 0.15～0.35, and it increased with forest age and was related to th e dominant forest type. The probability of forest age transfer and retardation fo r soft broad-leaved forests was a little higher. The forestry mechanism of this phenomenon is that forest morality increases with forest age. Based on these ana lyses, the first and second forest age formulas were amended and forest mature a ge was re-explained. The above demonstrations would provide a reference for fore st fall and fell period.