黄河流域森林植被碳储量分布特征及动态变化

根据四次全国森林资源清查数据，结合生物量估算模型及植被含碳系数，研究了黄河流域森林植被碳储量、碳密度的分布特征及动态变化。结果表明:（1）1989-2008年期间黄河流域森林植被总碳储量由131.15 Tg C增加到265.63 Tg C，且占全国森林植被碳储量的比例从2.83%增加到4.18%；期间森林植被的平均碳密度为34.47~39.00 Mg/hm²。（2）从林龄来看，2004-2008年期间黄河流域森林植被碳储量在各林龄组的分布差异不大，介于46.64~68.31 Tg C之间；天然林碳储量主要分布在中龄林、过熟林、成熟林、近熟林；人工林碳储量主要集中在幼龄林和中龄林。流域内森林植被、天然林及人工林平均碳密度均随着林龄增加而表现出上升趋势。（3）从森林起源来看，黄河流域天然林碳储量是人工林的3.5~4.5倍，且随着时间推移，天然林和人工林的碳储量均表现出增加趋势。（4）从不同河段来看，黄河流域森林植被碳储量主要集中于黄河上中游地区，占全流域的97%以上；2004-2008年期间黄河流域上、中、下游的森林植被碳储量比1999-2003年期间分别增加了7.61%，13.13%和136.98%。研究表明黄河流域森林植被碳储量占同期全国碳储量的比例呈增加趋势，且未来固碳潜力巨大，将在全国森林碳汇中发挥重要作用。

Carbon Storage of Forest Vegetation and Its Dynamic Changes in Yellow River Basin Based on Continuous Forest Resources Inventory

Based on the forest inventory data of China, the carbon storage and carbon density of forest vegetation in Yellow River Basin were assessed by means of the regression equation between vegetation biomass and volume, and with the carbon fraction of dry matter. The results showed that during the period 1989-2008, total carbon storage of forest vegetation increased from 131.15 Tg C to 265.63 Tg C in the Yellow River, the percentage increased from 2.83% to 4.18% of carbon storage of the national forest vegetation; and the average carbon density of forest vegetation was 34.47~39.00 Mg/hm² during the period; the distribution of the carbon storage in the Yellow River Basin was not significantly different among all forest age groups from 2004 to 2008, ranging from 46.64 to 68.31 Tg C; the carbon storage of natural forests mainly distributed in middle-aged and over-mature forest, mature forest, near-mature forest; and carbon storage of planted forest mainly concentrated in young and middle-aged forests; the average carbon densities of forest vegetation, natural forest and planted forest in the basin all showed the increasing trend with the increase of forest ages. The carbon storage of natural forest in the Yellow River Basin was 3.5 to 4.5 times higher than that of planted forests; the carbon storages of both natural forests and planted forest showed an increasing trend over time; the carbon storage of forest vegetation in the Yellow River Basin mainly concentrated in the upper and middle reaches of the Yellow River, accounting for more than 97% of the whole basin; the carbon storage of forest vegetation in the upper, middle and lower reaches of the Yellow River Basin from 2004 to 2008 increased by 7.61%, 13.13% and 136.98%, respectively, compared to those in the period 1999-2003. Furthermore, the results also showed that the forest in the Yellow River Basin would play an important role in enhancing national forest carbon sequestration due to higher carbon sequestration in the forest in comparison with national level, and the huge potential for carbon sequestration in the future.