Wildland fire reburning trends across the US West suggest only short-term negative feedback and differing climatic effects
Wildland fire reburning trends across the US West suggest only short-term negative feedback and differing climatic effects
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DOI：
10.1088/1748-9326/ab6c70
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发表时间：
2020-03-01
影响因子：
6.7
通讯作者：
Lucash, M.
中科院分区：
文献类型：
--
作者：
Buma, B.;Weiss, S.;Lucash, M.
野火是森林干扰的重要因素，对气候变化高度敏感。特别是间隔时间短的火灾和严重程度高（造成死亡）的火灾，可能通过消灭木本物种和引发从森林到灌木或草地生态系统的转变，催化生态系统的迅速和重大变化。建模和精细尺度的观察表明，火灾和燃料之间的负反馈应限制再烧的患病率整体火灾频率上升。然而，尽管我们有关于个别火灾或小区域再燃烧模式的良好信息，但将这些结论扩展到美国西部等广泛地区的有效性仍然未知。在区域范围内，再燃的普遍程度和在不同时间尺度上对再燃可能性的反馈强度都没有记录。在这里，我们表明，虽然有很强的负反馈非常短的再燃间隔整个美国西部的荒地森林，反馈减弱后10-20年。再燃烧间隔与干旱之间的关系因地点而异，沿海系统在潮湿条件下再燃烧更快（例如火灾间隔更短），而内陆森林则更干燥。这支持了这样一种观点，即植被生产力--主要是快速积累的精细燃料（
Wildfires are a significant agent of disturbance in forests and highly sensitive to climate change. Short-interval fires and high severity (mortality-causing) fires in particular, may catalyze rapid and substantial ecosystem shifts by eliminating woody species and triggering conversions from forest to shrub or grassland ecosystems. Modeling and fine-scale observations suggest negative feedbacks between fire and fuels should limit reburn prevalence as overall fire frequency rises. However, while we have good information on reburning patterns for individual fires or small regions, the validity of scaling these conclusions to broad regions like the US West remains unknown. Both the prevalence of reburning and the strength of feedbacks on likelihood of reburning over differing timescales have not been documented at the regional scale. Here we show that while there is a strong negative feedback for very short reburning intervals throughout wildland forests of the Western US, that feedback weakens after 10-20 years. The relationship between reburning intervals and drought diverges depending on location, with coastal systems reburning quicker (e.g. shorter interval between fires) in wetter conditions and interior forests in drier. This supports the idea that vegetation productivity-primarily fine fuels that accumulate rapidly (