Abstract:

Global warming is one of the most important environmental problems today, mainly due to the increasing concentrations of greenhouse gases such as carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) in the atmosphere. High-latitude permafrost regions are the most sensitive areas affected by climate change, and also the areas most affected by forest fires. Over the years, the intensified thawing of permafrost after forest fire disturbance has led to increased release of soil carbon deposited, which in turn threatens the regional carbon balance. Combined with relevant research literature, this paper summarized the effects of soil carbon release laws in permafrost regions and forest fire disturbances (fire intensity, fire frequency, and post-fire recovery) on soil carbon release in permafrost regions, and the influences of forest fire disturbance on the release of soil carbon from newly-born wetlands in permafrost areas. Relatively systematic research results concerning these issues are available in the literature. This review found that forest fire might increase the rate of permafrost degradation, leading to the release of a large amount of organic carbon in the form of CH₄ and CO₂ in the permafrost layer, thereby changing the carbon balance of regional ecosystems. At the same time, the permafrost thawed under the disturbance of forest fires to form newly-born wetlands, which changed the way of soil carbon release. Based on the existing literature, this paper summarized the research status of soil carbon release in permafrost regions. The following research prospects were proposed for examining the influences of forest fire disturbance on soil carbon release in high-latitude permafrost regions: (1) strengthening the monitoring research on the release of soil carbon from the burned areas in the permafrost area; (2) strengthening the research on the influences of permafrost fire on the release of soil carbon under the background of wetlandization; and (3) revealing the long-term variation law of soil carbon released from burned areas in permafrost regions. This study provides important information for maintaining the carbon balance of the permafrost region and the protection of the ecological environment, and also has ecological significance for exerting the carbon sink function of the forest ecosystem in the high-latitude permafrost region.

Key words: forest fire disturbance, forest fire and ecosystem, soil carbon release, impact mechanism, High-latitude permafrost regions, Newly-born wetland

摘要：

全球变暖是当今最重要的环境问题之一,其主要原因是大气中二氧化碳（CO₂）、甲烷（CH₄）和氧化亚氮（N₂O）等温室气体浓度不断增加。高纬度冻土区是受气候变化影响最敏感的区域,同时又是受森林火灾干扰最严重的区域。林火干扰后多年冻土融化,导致多年沉积的土壤碳释放加剧,威胁区域碳平衡。因此,各国对林火干扰下冻土区土壤碳释放研究给予了高度重视。结合相关研究文献,文章在冻土区土壤碳释放规律、林火干扰（火烧强度、火烧频率、火后恢复）对冻土区土壤碳释放的影响,以及林火干扰对冻土区新生湿地土壤碳释放影响等方面进行较系统地综述。综述发现林火可能会增加冻土退化速率,从而迫使冻土层大量的有机碳以CH₄和CO₂形式释放出来,进而改变区域生态系统碳平衡。同时由于林火干扰下冻土融化形成新生湿地,从而改变了土壤碳释放方式。文章在基于现有文献的基础上,总结冻土区土壤碳释放的研究现状,针对高纬度冻土区林火干扰对土壤碳释放的影响从以下3个方面作了研究展望：（1）加强冻土区火烧迹地土壤碳释放的监测研究;（2）加强多年冻土火烧后湿地化背景下对土壤碳释放的影响研究;（3）揭示冻土区火烧迹地土壤碳释放的长期变化规律。这些研究对维持多年冻土区生态系统碳平衡及生态环境的保护具有重要借鉴意义,对发挥高纬度冻土区森林生态系统碳汇功能具有重要生态学意义。

关键词: 林火干扰, 林火与生态系统, 土壤碳释放, 影响机制, 高纬度冻土区, 新生湿地