In the summer of 2015, hundreds of wildfires burned across the state of Alaska, and consumed more than 1.6 million ha of boreal forest and wetlands in the Yukon–Koyukuk region. Mapping of 113 large wildfires using Landsat satellite images from before and after 2015 indicated that nearly 60% of this area was burned at moderate-to-high severity levels. Field measurements near the town of Tanana on the Yukon River were carried out in July of 2017 in both unburned and 2015 burned forested areas (nearly adjacent to one-another) to visually verify locations of different Landsat burn severity classes (low, moderate, or high; LBS, MBS, HBS). Field measurements indicated that the loss of surface organic layers in boreal ecosystem fires is a major factor determining post-fire soil temperature changes, depth of thawing, and carbon losses from the mineral topsoil layer. Measurements in forest sites showed that soil temperature profiles to 30 cm depth at burned forest sites were higher by an average of 8–10 °C compared to unburned forest sites. Sampling and laboratory analysis indicated a 65% reduction in soil carbon content and a 58% reduction in soil nitrogen content in severely burned sample sites compared to soil mineral samples from nearby unburned spruce forests. Combined with nearly unprecedented forest areas severely burned in the Interior region of Alaska in 2015, total ecosystem fire-related losses of carbon to the atmosphere exceeded most previous estimates for the state, owing mainly to inclusion of potential “mass wasting” and decomposition in the mineral soil carbon layer in the 2 years following these forest fires.

中文翻译：

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阿拉斯加内部2015年森林大火造成的生态系统碳排放量。

2015年夏天，阿拉斯加州数百场野火燃烧，在育空地区-尤库克地区消耗了超过160万公顷的北方森林和湿地。使用2015年之前和之后的Landsat卫星图像绘制的113起大型野火的地图显示，该地区近60％的烈度为中度至高度。2017年7月，在育空河上塔纳纳镇附近的野外测量在未燃烧和2015年燃烧的森林地区（几乎彼此相邻）中进行，以目视验证不同Landsat燃烧严重程度等级（低，中或高）的位置高； LBS，MBS，HBS）。野外测量表明，北方生态系统火灾中地表有机层的损失是决定火灾后土壤温度变化，融化深度，和矿物表土层的碳损失。森林站点的测量表明，与未燃烧的森林相比，被燃烧的森林站点的土壤温度剖面至30厘米深度平均高8–10°C。采样和实验室分析表明，与附近未燃烧的云杉林的土壤矿物样品相比，严重燃烧的样品点的土壤碳含量降低了65％，土壤氮含量降低了58％。加上2015年阿拉斯加内陆地区严重烧毁的近乎前所未有的森林地区，与生态系统火灾相关的大气中碳的总损失超过了该州以前的大多数估计，这主要是由于潜在的“质量浪费”和分解所致。这些森林大火发生后的2年内，矿物土壤的碳层增加。森林站点的测量表明，与未燃烧的森林相比，被燃烧的森林站点的土壤温度剖面至30厘米深度平均高8–10°C。采样和实验室分析表明，与附近未燃烧的云杉林的土壤矿物样品相比，严重燃烧的样品点的土壤碳含量降低了65％，土壤氮含量降低了58％。加上2015年阿拉斯加内陆地区严重烧毁的近乎前所未有的森林地区，与生态系统火灾相关的大气中碳的总损失超过了该州以前的大多数估计，这主要是由于潜在的“质量浪费”和分解所致。这些森林大火发生后的2年内，矿物土壤的碳层增加。森林站点的测量表明，与未燃烧的森林相比，被燃烧的森林站点的土壤温度剖面至30厘米深度平均高8–10°C。采样和实验室分析表明，与附近未燃烧的云杉林的土壤矿物样品相比，严重燃烧的样品点的土壤碳含量降低了65％，土壤氮含量降低了58％。加上2015年阿拉斯加内陆地区严重烧毁的近乎前所未有的森林地区，与生态系统火灾相关的大气中碳的总损失超过了该州以前的大多数估计，这主要是由于潜在的“质量浪费”和分解所致。这些森林大火发生后的2年内，矿物土壤的碳层增加。