西南地区乔木林碳储量及木材生产潜力预测

Prediction of Forest Carbon Storage and Timber Yield Potential in Southwestern China

定量评价森林碳储量及其碳汇潜力,有助于科学评估森林减缓气候变化的潜在贡献,对国际气候变化谈判和国内应对气候变化的决策均具有重要意义。然而,如何对森林进行可持续经营管理以确保木材产量和森林碳汇量间的平衡是一个十分重要的问题。为准确评估西南地区乔木林碳储量及木材产量供应潜力,利用西南各省(市、区)第七次(2004—2008年)和第八次(2009—2013年)森林资源连续清查数据,结合森林经营规划目标设定采伐与非采伐两种情景,采用蓄积-生物量转换因子法,估算了乔木林生物量碳储量和碳密度,模拟预测了2010—2050年间的乔木林生物量碳汇潜力及木材产量。结果表明,(1)2010年西南地区乔木林碳储量为2 449.06 Tg,碳密度为57.64 Mg·hm^(-2)。碳储量大小顺序为:西藏>云南>四川>贵州>重庆,碳密度大小顺序为:西藏>四川>云南>重庆>贵州。(2)采伐和非采伐情景下,2050年西南地区乔木林碳储量分别为3 829.18 Tg和4 057.29 Tg,碳密度分别为81.60 Mg·hm^(-2)和85.08 Mg·hm^(-2)。(3)与非采伐情景相比,2050年时采伐情景下碳储量下降了228.11 Tg,碳密度下降了3.48 Mg·hm^(-2);但是采伐情景下2010—2050年间累计提供木材产量7.86×10~8m^3。西南地区幼、中龄林比例较高,随着生长成熟以及抚育经营管理使森林质量提高,该地区森林碳汇潜力巨大。制定合理的乔木林更新采伐比例,有助于在有效发挥森林碳汇效益的同时实现森林质量的提升和木材产量的增加。

Quantifying forest carbon storage and carbon sequestration potential provides scientific support to evaluating the potential contribution of forest to climate change mitigation,which is of great significance to international negotiations and domestic decision support to climate change.How to manage the forests with a sustainable method to ensure the balance between timber yield and carbon sink is a very important issue.In order to accurately evaluate the carbon storage and potential timber production of forests in Southwest China,based on the seventh(2004-2008)and eighth(2009-2013)forest inventory data of five provinces in Southwest China,we used IPCC volume-biomass methods to estimate the carbon storage and carbon density in southwest provinces.Combined with growth target of the forest area and accumulation in forestry management plan of Southwest provinces and to predict carbon sequestration potential and timber yield during 2010-2050.The main conclusions are as follows:The total carbon storage in forest biomass in SW China is 2 449.06 Tg,and the average carbon density is 57.64 Mg·hm-2 in 2010.The order of forest carbon storage in each province is:Tibet>Yunnan>Sichuan>Guizhou>Chongqing,and the order of carbon density is:Tibet>Sichuan>Yunnan>Chongqing>Guizhou.By 2050,the forest carbon storage under logging and non-logging scenarios in SW China is 3 829.18 Tg and 4 057.29 Tg,respectively,while the forest carbon density is 81.60 Mg·hm-2 and 85.08 Mg·hm-2 respectively.Compared with non-logging scenario,logging decreased forest carbon storage and carbon density by 228.11 Tg and 3.48 Mg·hm-2 by 2050,respectively.However,logging can provide more than 786 million cubic meters of timber during 2010-2050.Since the high proportion of the area of young and middle-aged forests in SW China,there is enormous potential of increasing forest carbon storage and carbon density in the future if with forest growing and maturity.Reasonable proportion of forest harvesting and regeneration will serve the purpose of increasing forest carbon sequestration,forest quality and timber production simultaneously.