Although lacustrine sedimentary charcoal has long been used to infer paleofires, their quantitative reconstructions require improvements of the calibration of their links with fire regimes (i.e. occurrence, area, and severity) and the taphonomic processes that affect charcoal particles between the production and the deposition in lake sediments. Charcoal particles >150 µm were monitored yearly from 2011 to 2016 using traps submerged in seven head lakes situated in flat-to-rolling boreal forest landscapes in eastern Canada. The burned area was measured, and the above-ground fire severity was assessed using the differentiated normalized burn ratio (dNBR) index, derived from LANDSAT images, and measurements taken within zones radiating 3, 15, and 30 km from the lakes. In order to evaluate potential lag effects in the charcoal record, fire metrics were assessed for the year of recorded charcoal recording (lag 0) and up to 5 years before charcoal deposition (lag 5). A total of 92 variables were generated and sorted using a Random Forest-based methodology. The most explanatory variables for annual charcoal particle presence, expressed as the median surface area, were selected. Results show that, temporally, sedimentary charcoal accurately recorded fire events without a temporal lag; spatially, fires were recorded up to 30 km from the lakes. Selected variables highlighted the importance of burned area and fire severity in explaining lacustrine charcoal. The charcoal influx was thus driven by fire area and severity during the production process. The dispersion process of particles resulted mostly of wind transportation within the regional (<30 km) source area. Overall, charcoal median surface area represents a reliable proxy for reconstructing past burned areas and fire severities.

中文翻译：

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利用北方湖泊沉积物木炭重建烧毁面积和火灾严重程度

尽管湖相沉积木炭长期以来一直被用于推断古火灾，但它们的定量重建需要改进它们与火灾状况（即发生、面积和严重程度）的联系以及影响木炭颗粒在生产和沉积之间的埋藏过程的校准。湖泊沉积物。从 2011 年到 2016 年，每年使用位于加拿大东部平坦到滚动的北方森林景观中的七个水头湖中的陷阱对大于 150 µm 的木炭颗粒进行监测。测量了燃烧面积，并使用差异归一化燃烧比 (dNBR) 指数评估了地上火灾的严重程度，该指数源自 LANDSAT 图像，并在距离湖泊 3、15 和 30 公里的区域内进行测量。为了评估木炭记录中的潜在滞后效应，对记录木炭记录的年份（滞后 0）和木炭沉积前长达 5 年（滞后 5）的火灾指标进行了评估。使用基于随机森林的方法生成和排序了总共 92 个变量。选择了年度木炭颗粒存在的最具解释性的变量，表示为中值表面积。结果表明，在时间上，沉积木炭准确地记录了火灾事件，没有时间滞后；在空间上，距离湖泊 30 公里远的地方记录了火灾。选定的变量强调了燃烧面积和火灾严重程度在解释湖泊木炭方面的重要性。因此，木炭流入是由生产过程中的火灾面积和严重程度驱动的。粒子的弥散过程主要是由区域（<30 km）源区内的风传播造成的。全面的，