关键词: 碳储量；蓄积量；森林碳汇潜力；GM（1, 1）灰色模型；森林城市；北京市

Abstract: 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 m³/hm² over four decades, far below the nation's average of 73.56 m³/hm², leaving room for increment. The total carbon storage increases to 34 765.1 kt from 5 718.0 kt with a yearly rising rate 691.6 kt, of which forest carbon storage increases to 11 577.5 kt from 1 018.8 kt with a yearly rising rate 251.4 kt. Forest carbon  density increases to 16.12 t/hm² from 5.09 t/hm², far below the nation's average of 41.50 t/hm². Forest carbon storage value increases to 1 430.886 1 million Yuan in 2018 from 67.066 6 million Yuan in 1976 by a yearly rising rate 32.471 9 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 22 556.9 kt by GM(1, 1), carbon sink to 915 kt/a from 2018 to 2030, forest stock volume to 47 488.3 km³ in 2030. Forest storage is forecasted to be 29 318.2 kt in 2030 by power function,  carbon sink to 1 478.4 kt/a from 2018 to 2030, forest stock volume to 61 722.6 km³ 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.

Key words: carbon storage, stock volume, forest carbon sink potential, GM(1, 1) grey model, forest city, Beijing city