Historical trends of forest fires and carbon emissions in China from 1988 to 2012

A larger amount of carbon is stored in forest ecosystems than in the entire atmosphere. Thus, relatively small changes in forest carbon stocks can significantly impact net carbon exchange between the biosphere and atmosphere. Changes in forest stocks can result from various disturbances, such as insect pests, windstorms, flooding, and especially forest fires. Globally, the impact of forest fires has been enhanced due to ongoing warming of the climate. The current study reported an evaluation of carbon emissions from historical forest fires in China during 1988-2012 with observational data collected from national agriculture statistics. Historical fire trends and fire-induced carbon emissions were described over space and time at both national and regional levels. The results indicated that no significant increases in fire occurrence and carbon emissions were observed during the study period at the national level. However, at the regional level, there was a significant increasing trend in fire occurrence, and drought severity was a major driver of fire activity. Most carbon emissions were from north and northeast China, and these emissions contributed significantly to total carbon emissions. The results also showed that annual fire-induced emissions ranged from 0.04TgC to 7.22TgC, with an average of 1.03TgC. Large interannual and spatial variabilities of carbon emissions were also indicated, and these were attributed to spatial and temporal variations in fire regimes. The results improve understanding of fire characteristics and provide significant information for reducing model-related uncertainty of fire-induced carbon emissions.