Multi-objective Management Planning At Forest Landscape Level

The study developed volume growth models of six major forest types based on subcompartment data in Jingouling forest farm of Wangqing Forestry Bureau, Jilin Province. Multi-objective management planning at landscape level was studied with timber production and above-ground carbon stock as objectives. The optimal management scenario was obtained. The results were as follows:(1) Sub-compartment investigation data were used for model calibration of volume growth of main forest types in Jingouling forest farm. Richards, logistic, single molecule, Gompertz, and Korf growth equations were tested,and model performance was evaluated by fitting statistics, errors and residual distribution. The results showed that Richards model was the best for volume growth estimation of birch forest, mixed plantation and natural mixed conifer-broad-leaved forest, and logistic model was the best volume growth model for larch plantation, mixed broad-leaved forest and natural mixed coniferous forest.(2) Multi-objective programming model was established with six major forest types as subjects and the maximum of net present value of timber harvest and aboveground carbon stock change as object function. The planning period was 50 years. The model could be resolved by LINGO software under the constraints of an even flow of timber production. We got thinning and selective cutting intensity and the corresponding volume of various forest types in different planning horizons. The thinning intensity by volume was from 7% to 15%, and the selective cutting intesity varied from 8% to 35%. The total timber harvest was 3,675,310m3 and the harvest volume of each year was 73,506 m3 . Above-ground carbon stock change after 50 years was 4,963,590 tons, and annual increase was 99,270tons. .The total net present value (NPV) was 691,518,400 Yuan including timber NPV 553,613,300 Yuan and carbon NPV 137,905,100yuan.The management planning scenario was an optimal one which could meet both timber production and carbon storage.(3) We compared two scenarios for multipurpose forest management (Scenario 1 and 2) with only timber production scenario (Scenario 3). The results showed that there was no significant difference in the total NPV for these three scenarios in 50 planning period with the NPVs of 691,518,400Yuan, 690,751,100Yuan and 689,548,100Yuan, respectively, however, the NPVs of timber harvest for scenarios 1 and 2 were 6.75% and 2.54% lower than that of scenario 3; and the NPVs of aboveground carbon stock were 14.44% and 25.45%larger than that of scenario 3.Therefore, there was a compromise between timber harvest and aboveground carbon stock change.(4) We analyzed the effects of carbon price on the multipurpose forest management (Scenario 1 with the same weight ). The results showed that timber harvest volume in the whole planning period decreased with the increased carbon price, but net carbon storage was on the contrary.The study provided methody and reference for multiple objective forest management planning with the consideration of selective cutting and carbon storage.