西南地区退耕还林工程主要林分50年碳汇潜力

Abstract

为评估西南地区退耕还林工程主要林分未来50a碳汇潜力，调查收集该地区2011年以前退耕还林工程主要造林树种及其造林面积等相关数据资料，利用国家森林资源清查资料中人工林历史数据建立生长模型，结合文献调研获得的相关林分碳计量参数，预测出本区域退耕还林工程7种主要林分碳储量和年碳储量未来变化。结果表明：西南地区退耕还林工程主要林分总碳储量在2020、2030、2040、2050和2060年分别为52.98、73.88-80.57、73.62-102.16、88.41-115.17和77.15-123.36TgC，年总碳储量则分别为3.15、-1.11-2.45、-3.92-1.95、2.08-0.96和0.25-0.73TgC，到2060年华山松、马尾松、柳杉、杉木、柏树、杨树和桉树7种林分碳汇潜力在无采伐情景下分别达到：13.01、15.01、13.44、24.13、28.05、15.63和14.09TgC，可对本地区森林碳汇功能产生明显影响。;Vegetation growth, through photosynthesis, takes up carbon dioxide from the atmosphere and converts to organic carbon into biomass thereby forms a carbon sink. Research on carbon sequestration potential of forests has become a key content to slow down global warming by forestry. To assess carbon sequestration potential in stands under the Grain for Green Program (GGP) in Southwest China, the carbon storages and their annual changes in the GGP-stands in the region were estimated based on: (1) collected data on annual planted area of each tree species under the GGP in Southwest China from 1999 to 2010; (2) empirical growth curves developed for each species of the GGP-stands using growth data about plantation from the National Forest Inventory; (3) parameters associated with stand such as wood density, biomass expansion factor, carbon fraction, the change rate in soil organic carbon content. Two scenarios for forest management option were schemed: scenario A for no harvesting and scenario B for logging at the time of maturity followed by replanting. The results showed that there are seven tree species with over 100,000 hm²of planted area in Southwest- China throughout the recent goal period of strategic planning for the GGP, and their total acreage account for 40.7% of that of all species of the GGP-stands. The expected carbon stocks in these major stands under the Grain for Green Project in Southwest China are52.98TgC, 73.88-80.57TgC, 73.63-102.16TgC, 88.41-115.17TgC and 77.15-123.36TgC(T=10¹²) by the year of 2020, 2030, 2040, 2050 and 2060, and the estimated relevant annual carbon stock changes are 3.15TgC, -1.11-2.45TgC, -3.92-1.95TgC, 2.08-0.96TgC and 0.25-0.73TgC, respectively. In 2060, the carbon stocks in forests of <em>Pinus armandii</em>, <em>Pinus massoniara</em>,<em> Cryptomeria fortunei</em>,<em> Cunninghamia laceolata</em>,<em> Cupressus </em>spp., <em>Populus deltoides</em> and <em>Eucalyptus</em> spp.under the Grain for Green Project in Southwest China will be 13.01TgC, 15.01TgC, 13.44TgC, 24.13TgC, 28.05TgC, 15.63TgC和14.09TgC, respectively, indicating a significant contribute to forest carbon sinks in this region. The <em>Cupressus </em>spp. species play a leading role in carbon sequestration potential in stands under the Grain for Green Project due to highest area proportion in Sichuan province, Chongqing municipality and even Southwest China. The <em>Cryptomeria fortune</em> and<em> Cunninghamia laceolata</em> species play a leading role in Guizhou province; the <em>Eucalyptus</em> spp. and <em>Pinus armandii</em> species in Yunnan province; the <em>Populus deltoides</em> species in Tibet autonomous region.