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采伐后保留的老树使次生林分的生长不整齐。在澳大利亚,林场经理十分需要知道这种林分的生长和产量信息。在新南威尔士州东南台地的高桉(E.fastigata)异龄次生林分中随机收集了30块样地资料,推导出了与老树密度有关的次生林分收获量方程。收获量方程的预测结果是,如果没有任何老树,在最好的立地条件上,异龄次生椿分蓄积量从20年时的253m~3/hm~2能长到80年时的623m~3/hm~2;在一般立地条件下,可从253m~3/hm~2长到339m~3/hm~2;而在较差的立地条件下则可从84m~2/hm~2长到206m~3/hm~2。如果保留的老树密度从0～100株/hm~2,次生林分的蓄积量的百分比则减少0～66％。由于过去的森林大火和采伐的影响,老树的树冠大小范围较大,许多树冠较小而且稀少,但又不是原来的健康树冠。在应用本收获量方程之前,必须对老树的含义有一个清楚的了解,否则次生林分的蓄积量的预测会出现误差。
The old trees preserved after harvesting made the growth of the secondary forest irregular. In Australia, forest managers are in great need of information on the growth and yield of this stand. Thirty plots were randomly collected from secondary forest stands of E.fastigata in the southeastern South New South Wales, and the secondary forest standoff yield equation was derived. The result of the yield equation is that in the best condition of the site without any old trees, the stock volume of secondary seedlings can grow from 253m ~ 3 / hm ~ 2 at 20 years to 623m at 80 years ~ 3 / hm ~ 2, and from 253m ~ 3 / hm ~ 2 to 339m ~ 3 / hm ~ 2 under normal site conditions and from 84m ~ 2 / hm ~ 2 under poor site conditions Grow to 206m ~ 3 / hm ~ 2. If the density of preserved old trees is from 0 to 100 plants / hm ~ 2, the percentage of secondary forest volume will decrease by 0 ~ 66%. Due to the effects of past forest fires and logging, the canopy size of older trees is larger and many are smaller and sparse, but not the original crown of health. Before applying this yield equation, you must have a clear understanding of the meaning of the old tree, otherwise the prediction of the stock volume of the secondary forest will be in error.