Abstract. The seasonal and longer-term dynamics of fuel accumulation affect fire seasonality and the occurrence of extreme wildfires. Failure to account for their influence may help to explain why state-of-the-art fire models do not simulate the length and timing of the fire season or interannual variability in burnt area well. We investigated the impact of accounting for different timescales of fuel production and accumulation on burnt area using a suite of random forest regression models that included the immediate impact of climate, vegetation, and human influences in a given month, and tested the impact of various combinations of antecedent conditions in four productivity-related vegetation indices and in antecedent moisture conditions. Analyses were conducted for the period from 2010 to 2015 inclusive. We showed that the inclusion of antecedent vegetation conditions on timescales > 1 yr had no impact on burnt area, but inclusion of antecedent vegetation conditions representing fuel build-up led to an improvement of the global, climatological out-of-sample R² from 0.567 to 0.686. The inclusion of antecedent moisture conditions also improved the simulation of burnt area through its influence on fuel build-up, which is additional to the influence of current moisture levels on fuel drying. The length of the period which needs to be considered to account for fuel build-up varies across biomes; fuel-limited regions are sensitive to antecedent conditions over longer time periods (~4 months) and moisture-limited regions are more sensitive to current conditions.

中文翻译：

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量化使用随机森林的燃烧区域之前与燃料相关的植被属性的重要性

摘要。燃料积聚的季节性和长期动态会影响火灾的季节性和极端野火的发生。不考虑其影响可能有助于解释为什么最新的火灾模型不能很好地模拟火灾季节的长度和时间或燃烧区域的年际变化。我们使用一套随机森林回归模型调查了考虑不同时间尺度的燃料生产和累积对燃烧面积的影响，该模型包括给定月份的气候，植被和人类影响的直接影响，并测试了各种组合的影响四个与生产力相关的植被指数和前期水分条件中的前期条件。进行了从2010年到2015年（含）的分析。²从0.567到0.686。之前的水分条件的加入还通过其对燃料积聚的影响，改善了燃烧区域的模拟，这是当前水分含量对燃料干燥的影响的补充。生物群落需要考虑到燃料堆积的时期长短有所不同；燃料限制区域对较长时间段（〜4个月）内的先前条件敏感，而水分限制区域对当前条件更敏感。