中国森林面积变化及其温室气体储量模拟研究

陆地生态系统承载的温室气体对全球碳循环及气候调节服务意义重大,森林生态系统是陆地生态系统的重要组成部分,量化森林对温室气体的储量有利于从生物地球化学角度研究全球变化问题。针对中国森林生态系统承载的温室气体在大尺度上无法有效量化的问题,基于2000与2010年两期土地利用数据和前人的相关研究,通过一个生态系统温室气体值模型,模拟得到中国森林生态系统承载的三大主要温室气体(CO_2,CH_4,N_2O)的量。结果表明:(1)中国森林生态系统的面积从2000年的224.3×10~6 hm~2略增到2010的224.6×10~6 hm~2;其中落叶阔叶林、常绿阔叶林和针叶林的面积减少,而混交林与灌木林的面积增加;(2)对应地,2000和2010年中国森林的温室气体储量分别为154.03和154.37 Pg CO_2当量,10年间增加了0.34 Pg CO_2当量。其中,常绿针叶林、常绿阔叶林、落叶阔叶林在研究时段内的GHG储量减少,而混交林和灌木林增加。分区来看,温室气体储量增长较多的区域有华北、西北与西南地区,分别增长了0.13 Pg CO_2、0.12 Pg CO_2与0.15 Pg CO_2当量。温室气体储量减少较明显的是东北地区,减少了约0.1 Pg CO_2当量。本研究分别用本地化参数和模型自带参数,首次尝试对中国森林生态系统的GHG储量进行了模拟研究,并与他人的研究做了对比分析。研究同时发现,当前的相关研究存在很多不确定性,未来需要多源数据和方法提升精度,而模型模拟是一个重要的手段。

Modeling greenhouse gas sequestration potential of forest change in China

Greenhouse gases carried by terrestrial ecosystems are of great significance to the global carbon cycle and climate regulation services. Forests are an important part of terrestrial ecosystems and quantifying the greenhouse gas sequestration potential of forests can analyze global change directly from a biogeochemical perspective. However, greenhouse gases carried by China''s forests have not currently be effectively quantified on a large scale. In this study, based on land use data of 2000 and 2010, and previous studies on forest carbon storage, we simulated the sequestration potentials of three main greenhouse gases (CO₂, CH₄, N₂O) in forests in China through a greenhouse gas value model. The results showed that:(1) China''s forest area increased slightly from 2.243 million km² in 2000 to 2.246 million km² in 2010; among them, areas of deciduous broad-leaved, evergreen broad-leaved, and coniferous forests all decreased, whereas the areas of mixed and shrub forests increased; (2) correspondingly, the sequestration potential of greenhouse gas for China''s forests was equivalent to 154.03 and 154.37 Pg CO₂ in 2000 and 2010, respectively, increasing by about 0.34 Pg CO₂ during our study period. The sequestration potential in evergreen coniferous, evergreen broad-leaved, and deciduous broad-leaved forests decreased during 2000-2010, whereas the sequestration potential in mixed and shrub forests increased. Regarding spatial patterns, sequestration potentials in North, Northwest, and Southwest China all increased largely, with an increase of 0.13, 0.12, and 0.15 Pg CO₂, respectively. The sequestration potential in Northeast China was obviously decreased, with a reduction of about 0.1 Pg CO₂. This study used the localization parameters and model''s own parameters to simulate the sequestration potential of greenhouse gases in China''s forests for the first time, and compared our simulated results with those from others research. This study also found that various definitions and data sources on forests had many problems. In the future, it is necessary to refine the model parameters within ecosystems under a unified framework and consider using multi-resource data to improve the accuracy of sequestration potential. Model simulation should be used as an important and effective study method.