相同投入不同产出水平下桉树生产周期的确定

Decission of Eucalyptus Production Cycle under Same Imput in Different Output

根据桉树的实际培育和利用过程，对广西东门林场种植的白桉（Ｅｕｃａｌｙｐｔｕｓａｌｂａ）、巨桉（Ｅ．ｇｒａｎｄｉｓ）和尾叶桉（Ｅ．ｕｒｏｐｈｙｌｌａ）三个树种进行投入产出的边际分析，通过计算每公顷林地的利润，每绝干吨木片成本，增量收入与增量成本的对比关系研究其生产周期。结果是三种桉树的合理生产周期是１０年，即第９年进入主伐，主伐后一年开始下一次更新。只有这样才能获得最佳的经济效益。

Based on the actual cultivation and its utilization process of Eucalyptus, this article deals with the marginal analysis of the imput-output for the three spp. of Eucalyptus (Eucalyptus alba, E. grandis and E. urophglla) and the research on their production period by calculating the profits of each hm￣2 tree land, the cost of every BDMT wood chip and the contrast relation between the increment output value and the increment cost. It shows that the production period of these three spp. of Eucalyptus planted in Dongmen Forestry Farm is ten years long, i. e. in the ninth year they come to their final felling. After a year of that they go in for the next reforestation. Only in such way could the best economic interests are obtained.