落叶松人工林径阶分布与经济轮伐期的研究

根据人工用材林培育目标和对木材分级利用的观念，以黑龙江省佳木斯市孟家岗林场的落叶松人工林为研究对象．运用Weibull分布函数对林分的直径分布规律进行研究，通过模型预估得到各个径阶的详细收获量和各材种的出材量。由此得到不同利用方式的经营收入，结合生产投入，运用经济效果评价动态分析法中的效益成本比、净现值指标对落叶松人工林进行研究。结果显示：落叶松人工林的经济轮伐期为：13～18a。林分密度为1000株／hm^2时，效益成本比RBG最大值为3．8653，净现值胛矿最大值为9574．3元；l500株／hm^2时，RBC为4．2486，NPV为14408．6元；2000株/hm^2时，RBC为4．4937，NPV为16705．9元；2500株／hm^2时，RBC为4．685，NPV为19256．3元；3000株／hm^2时，RBC为4．8671，NPV为21749．7元；具有较好的经济效益。研究结果还表明落叶松人工林林分密度越大，经济轮伐期越大。

Study on Diameter Class Distribution and Economic Rotation of Larix gmelini Plantation

According to the goal of plantation cultivation and the concept of wood grading use, taking the Larix gmelini plantation in Mengjiagang forest farm of Heilongjiang province as study case, the diameter distribution law of forest stand was stud-ied with Weibull function. Detailed output volume of each diameter class and merchantable volume of different woods could be ob-tained by using prediction model and the operation income was calculated. The economic rotation period was determined according to the radio of benefit and cost (RBC) as well as the net present value (NPV) using economic appraisal dynamic analysis meth-od, which was 13～18 years. When stand density was 1000 per hm2, the maximum of RBC and NPV was 3.865 3 and 9 574.3 yuan respectively; when stand density was 1500 per hm2, the maximum of RBC and NPV was 4.248 6 and 14 408.6 yuan respec-tively; when stand density was 2000 per hm2, the maximum of RBC and NPV was 4.493 7 and 16 705.9 yuan respectively; when stand density was 2 500 per hm2, the maximum of RBC and NPV was 4.685 and 19 256.3 yuan respectively; when stand density was 3000 per hm2, the maximum of RBC and NPV was 4.867 1 and 21 749.7 yuan respectively. The economic benefits were rela-tively remarkable, and the result also indicated that the economic rotation got longer as the stand density of Larch plantation in-creased.