兼顾碳贮量和木材生产目标的森林经营规划研究

以吉林省汪清林业局金沟岭林场为对象,基于小班调查数据,以木材生产和碳增量净现值最大为规划目标,考虑采伐量不大于生长量、均衡采伐、生长模型等约束,建立了多目标规划模型。通过LINGO软件求解,得到了50a规划期的最优经营方案,并进行了灵敏度分析。结果表明:各个森林类型在不同分期间伐强度在1%～15%之间,择伐强度在1%～35%之间。规划期木材总采伐量为182.33万m3,规划期末地上碳贮增量为47.92万t;规划期总收益为95 434.40万元,其中木材净现值91 895.10万元,碳贮增量净现值3 539.30万元。多目标经营方案可以同时满足对木材生产和碳贮增量的需求,是一个折衷的方案。与木材生产经营方案相比,多目标经营方案和碳贮增量经营方案在规划期内的木材净现值分别减少2.67%、45.43%,但地上碳贮增量净现值分别增加29.88%、50.42%。因此增加碳贮增量要以减少木材采伐量为代价。分析了低、中、高3种碳价格对多目标经营方案的影响,表明整个规划期内木材采伐量随着碳价格的增加而减少,而碳贮增量随着碳价格的增加而增加。

Forest Management Planning Incorporating Values of Timber and Carbon

Multi-objective harvest programming model was developed based on subcompartment data in Jingouling Forest Farm,administrated by Wangqing Forestry Bureau,Jilin,China.The model set the combination of net present value(NPV) of timber production and above-ground carbon storage change as object function,and included restrictions of harvesting less than increment,even flow of timber production,and volume growth models.Optimal solution in 50 years planning horizon was attained by LINGO software.The results showed that the thinning intensity by volume was from 1% to 15%,and the selective cutting intensity varied from 1% to 35%.The total timber harvest was 1 823 300 m3.Above-ground carbon stock change during 50 years was 479 200 tons.The total NPV was 954 344 000 yuan RMB including 918 955 000 yuan for timber and 35 393 000 yuan for carbon.The management planning scenario was a compromise which could meet both timber production and carbon storage.Comparing scenarios of timber production(Scenario 1) with multipurpose forest management(Scenario 2) and carbon stock change management(Scenario 3),the results presented that the NPVs of timber harvest for scenarios 1 and 2 were 2.67%,and 45.43% lower than that of scenario 3;and the NPVs of aboveground carbon stock were 29.88%,and 50.42% larger than that of scenario 3.Therefore,there was a compromise between timber harvest and aboveground carbon stock change.We analyzed the effects of carbon price on scenarios of multipurpose forest management.It showed that timber harvest decreased with the increased carbon price,but carbon storage change was on the contrary.The study provided methodology and reference for multiple objective forest management planning with the consideration of selective cutting regime and carbon storage.