中国森林碳动态及其对全球碳平衡的贡献

Carbon dynamics of Chinese forests and its contribution to global carbon balance

利用我国第一次 ( 1 973～ 1 976年 )至第四次 ( 1 989～ 1 993年 )森林资源清查资料 ,依据建立的不同森林类型生物量和蓄积量之间的回归方程 ,对我国近 2 0 a来森林的碳储量进行了推算。结果表明 :我国 4次森林资源清查中森林的总碳储量分别是 3 .75、4 .1 2、4 .0 6和 4 .2 0 Pg C,虽然存在一定的波动现象 ,但总体呈增加的趋势 ,自第 1次森林资源清查末期至第 4次清查结束的 1 7a间 ,我国森林共增加 0 .4 5Pg C,平均每年以 2 6.5Tg C的速率递增 ,这说明我国的森林起着一个轻微的CO2 “汇”的作用。然而 ,进一步对我国森林的平均碳密度分析发现 ,它们不仅呈逐渐下降的趋势 (分别是 3 9.1、4 3 .1、3 9.7和 3 8.7Mg C/hm2 ) ,而且也远低于世界的平均水平 ,这充分说明我国的森林质量比较差 ,幼龄林和残次林较多 ,但从另一个侧面也反映也如果对现有森林加以更好的抚育和管理 ,作为 CO2 的“汇”,我国森林还有很大的潜力。因此 ,需要指出的是虽然植树造林至关重要 ,但对现有森林的抚育管理也是不容忽视的。

Using the national foreset inventory data that surveyed by the Forestry Ministry of P.R.China from 1973 to 1993,carbon storage of Chinese forest are estimated with the method of regression equation between stand biomass and volume in different forest types.The results show that total carbon storage of Chinese forest in the four periods(1973～1976,1977～1981,1985～1988,1989～1993)were 3.75,4.12, 4.06 and 4.20 Pg C,respectively.Although the results of different periods are fluctuating,their trends are increasing with the time.From 1977 to 1993,the total carbon of Chinese forests had increased 0.45 Pg C and accumulated about 26.5 Tg C per year.It means that Chinese forests played a role as a little sink of atmospheric carbon dioxide in that period.However,mean forest carbon density is decreased with time(The four periods are 39.1、43 1、39 7 and 38.7 Mg C/hm 2,respectively)and far below to the average of global forest.This means that the quality of Chinese forests is very poor,the young forests make up large proportion of Chiese forests.On the other hand,it also reflects that Chinese forests is a huge potential carbon sink in the future if current forests is fostered and managed well.Therefore,foster and management of current forests is very important.