Permafrost thaw and wildfire: Equally important drivers of boreal tree cover changes in the Taiga Plains, Canada
Permafrost thaw and wildfire: Equally important drivers of boreal tree cover changes in the Taiga Plains, Canada
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DOI：
10.1002/2015gl067193
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发表时间：
2016-02
影响因子：
5.2
通讯作者：
M. Helbig;C. Pappas;O. Sonnentag
中科院分区：
文献类型：
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作者：
M. Helbig;C. Pappas;O. Sonnentag
北方森林覆盖了北美永久冻土区的广大地区，其组成和结构的变化可能会对区域和全球气候产生重大影响。我们将2000年至2014年间加拿大泰加平原北部地区树木覆盖变化的主要原因划分为：永久冻土融化、野火干扰和火灾后再生长。中分辨率成像光谱仪树木覆盖率(PTC)数据与历史火灾、永久冻土和排水特征地图相结合使用。我们发现，在解释PTC变化时，永久冻土融化与火灾历史同样重要。在多年冻土区南缘，由于冻土融化造成的PTC损失超过了火灾后再生的PTC。这些发现强调了多年冻土融化在控制过去十年区域北方森林变化方面的重要性，随着气温的上升和永久冻土融化的加速，这一点可能会变得更加明显。
Boreal forests cover vast areas of the permafrost zones of North America, and changes in their composition and structure can lead to pronounced impacts on the regional and global climate. We partition the variation in regional boreal tree cover changes between 2000 and 2014 across the Taiga Plains, Canada, into its main causes: permafrost thaw, wildfire disturbance, and postfire regrowth. Moderate Resolution Imaging Spectroradiometer Percent Tree Cover (PTC) data are used in combination with maps of historic fires, and permafrost and drainage characteristics. We find that permafrost thaw is equally important as fire history to explain PTC changes. At the southern margin of the permafrost zone, PTC loss due to permafrost thaw outweighs PTC gain from postfire regrowth. These findings emphasize the importance of permafrost thaw in controlling regional boreal forest changes over the last decade, which may become more pronounced with rising air temperatures and accelerated permafrost thaw.