碳达峰碳中和目标下北京市森林碳汇潜力分析

CARBON SINK POTENTIAL OF BEIJING’S FOREST UNDER CARBON PEAK AND CARBON NEUTRALITY

核算北京市森林资源碳储量和价值量,预测北京市森林碳储量及碳汇潜力,为北京市国家森林城市建设和林业碳汇减排及碳达峰碳中和目标实现提供参考。利用1973—2018年9次中国森林资源清查数据中北京部分数据,采用森林蓄积量法核算北京市森林资源总的碳储量及其变化情况,并按照不同林种分类核算森林资源的碳储量和价值量。采用GM(1,1)灰色预测模型和幂函数模型联合预测北京市森林资源碳汇发展潜力。研究表明:(1)40多年来,北京市森林资源单位面积蓄积量平均为29.98 m^(3)/hm^(2),远低于全国平均水平73.56 m^(3)/hm^(2),有较大的增长空间。森林资源总碳储量从571.80万t增加到3476.51万t,年均增加碳汇量69.16万t。其中,森林碳储量从101.88万t增加到1157.75万t,年均增加碳汇量25.14万t。森林平均碳密度从5.09 t/hm^(2)增长到16.12 t/hm^(2),但与全国森林平均碳密度41.50 t/hm^(2)相比,还有较大增长空间。(2)北京市林木碳储量价值从1976年的6706.66万元增加到2018年的143088.61万元,年均增加3247.19万元,年复合增长率达7.56%,其中,人工林碳储量价值量年均增长13.70%。(3)GM(1,1)灰色模型预测,2030年北京市森林碳储量可达到2255.69万t,2018—2030年年均碳汇量为91.50万t,预计2030年北京市森林蓄积量可达到4748.83万m^(3);幂函数模型预测,2030年北京市森林碳储量达到2931.82万t,2018—2030年年均碳汇量为147.84万t,预计2030年森林蓄积量可达到6172.26万m^(3),森林覆盖率达到61.77%,可以实现北京市森林城市规划目标,也可以实现北京市碳达峰碳中和的目标。在不考虑经济、政策等外部因素的影响下,基于森林生物量和蓄积量的变化,北京市森林碳储量和价值量都是增加的,北京市森林碳汇潜力较大,能够为北京市碳达峰碳中和目标的实现发挥较大的作用。

This paper estimates the carbon stock and values of Beijing’s forest resources,and forecasts forest carbon stock and carbon sink potential,and provides references for Beijing national forest city construction,realization of carbon neutrality goal.This paper,based on Beijing’s forest survey data from 1973 to 2018,uses forest volume method to estimate the total carbon storage and changes of Beijing’s forest resources,measures the carbon storage and value of different forest types,and applies GM(1,1)grey model and power function model to forecast the carbon sink potential of Beijing’s forest resources.Beijing’s unit forest stock volume has been 29.98 m^(3)/hm^(2) over four decades,far below the nation’s average of 73.56 m^(3)/hm^(2),leaving room for increment.The total carbon storage increases to 34765.1 kt from 5718.0 kt with a yearly rising rate 691.6 kt,of which forest carbon storage increases to 11577.5 kt from 1018.8 kt with a yearly rising rate 251.4 kt.Forest carbon density increases to 16.12 t/hm^(2) from 5.09 t/hm^(2),far below the nation’s average of 41.50 t/hm^(2).Forest carbon storage value increases to 1430.8861 million Yuan in 2018 from 67.0666 million Yuan in 1976 by a yearly rising rate 32.4719 million Yuan,amounting to a compound yearly rising rate 7.56%,of which artificial forest carbon storage value has a yearly rising rate 13.70%.Beijing’s forest carbon storage is forecasted to be 22556.9 kt by GM(1,1),carbon sink to 915 kt/a from 2018 to 2030,forest stock volume to 47488.3 km^(3) in 2030.Forest storage is forecasted to be 29318.2 kt in 2030 by power function,carbon sink to 1478.4 kt/a from 2018 to 2030,forest stock volume to 61722.6 km^(3) in 2030,and forest coverage to 61.77%.Forecast results indicate that Beijing’s forest city planning objectives,carbon peak and carbon neutrality can be realized.This paper concludes that Beijing’s forest storage and value have increased since 1976 based on forest biomass and stock volume changes without considering economic and political factors.Beijing has a big forest carbon sink potential which may largely contribute to Beijing’s carbon peak and carbon neutrality.