Increases in burned area across the western United States (US) since the mid‐1980s have been widely documented and linked partially to climate factors, yet evaluations of trends in fire severity are lacking. Here we evaluate fire severity trends and their interannual relationships to climate for western US forests from 1985 to 2017. Significant increases in annual area burned at high severity (AAB_hs) were observed across most ecoregions, with an overall eightfold increase in AAB_hs across western US forests. The relationships we identified between the annual fire severity metrics and climate, as well as the observed and projected trend toward warmer and drier fire seasons, suggest that climate change will contribute to increased fire severity in future decades where fuels remain abundant. The growing prevalence of high‐severity fire in western US forests has important implications to forest ecosystems, including an increased probability of fire‐catalyzed conversions from forest to alternative vegetation types.

中文翻译：

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从1985年到2017年，温暖和干燥的火灾季节导致美国西部森林高烈度烧毁面积的增加

自1980年代中期以来，美国西部的烧伤面积增加已得到广泛记录，并与气候因素有部分联系，但尚缺乏对火灾严重性趋势的评估。在这里，我们评估火灾的严重性趋势及其对气候的美国西部森林1985年度区2017年显着增加，在烧伤程度高际关系（AAB _HS）在大多数生态区进行了观察，在AAB整体增加了八倍_HS横跨美国西部的森林。我们确定的年度火灾严重性指标与气候之间的关系，以及观测到的和预计的趋势，即炎热季节更加干燥和干燥，表明气候变化将在未来数十年燃料仍然充足的情况下加剧火灾严重性。美国西部森林中高烈度火灾的日益流行对森林生态系统产生重要影响，包括由火催化将森林转化为其他植被类型的可能性增加。