Large wildfires are increasing in the eastern United States; however, what factors are heightening large wildfire risk remains unclear. Increases in fuel loads from woody encroachment and canopy infilling have been associated with increasing wildfire risk in other US regions. Understanding if and where woody cover increases wildfire risk can help direct proactive fuels management. We characterize multi-scale changes in woody cover through time and assess the relationship between woody cover and large wildfire (>200 ha) occurrence in the eastern US between 1990 and 2020. We found a 37% increase in woody cover across the eastern US, with increases occurring in every ecoregion. The odds of large wildfire increased as woody cover increased in most central and southern ecoregions, where large wildfires were typically more likely in areas with high woody cover (70%–100% cover). Our findings suggest fuels management will be an important tool for reducing large wildfire risk.

中文翻译：

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木质覆盖加剧了美国东部的巨大野火风险


美国东部的大型野火正在增加;然而，哪些因素加剧了大型野火风险仍不清楚。木本侵占和树冠填充造成的燃料负荷增加与美国其他地区野火风险的增加有关。了解木本覆盖是否以及在何处会增加野火风险有助于指导主动的燃料管理。我们描述了木本覆盖随时间的多尺度变化，并评估了 1990 年至 2020 年间美国东部木本覆盖与大型野火 （x3E200 ha） 发生之间的关系。我们发现，美国东部的木本覆盖率增加了 37%，每个生态区都有所增加。随着大多数中部和南部生态区木质覆盖率的增加，发生大型野火的几率增加，在这些生态区，木质覆盖率高（70%-100% 覆盖率）的地区通常更容易发生大型野火。我们的研究结果表明，燃料管理将成为降低大型野火风险的重要工具。