Vegetation fires play an important role in global and regional carbon cycles. Due to climate warming and land use shifts, fire patterns are changing and fire impacts increasing in many of the world's regions. Reducing uncertainties in carbon budgeting calculations from fires is therefore fundamental to advance our current understanding and forecasting capabilities. Here we study 20 chamber burns from the FIREX FireLab experiment, which burnt a representative set of North American wildland fuels, to assess the following: (i) differences in carbon emission estimations between the commonly used “consumed biomass” approach and the “burnt carbon” approach; (ii) pyrogenic carbon (PyC) production rates; and (iii) thermal and chemical recalcitrance of the PyC produced, as proxies of its biogeochemical stability. We find that the “consumed biomass” approach leads to overestimation of carbon emissions by 2–27% (most values between 2% and 10%). This accounting error arises largely from not considering PyC production and, even if relatively small, can therefore have important implications for medium‐ and long‐term carbon budgeting. A large fraction (34–100%) of this PyC was contained in the charred fine residue, a postfire material frequently overlooked in fire carbon research. However, the most recalcitrant PyC was in the form of woody charcoal, with estimated half‐lives for most samples exceeding 1,000 years. Combustion efficiency was relatively high in these laboratory burns compared to actual wildland fire conditions, likely leading to lower PyC production rates. We therefore argue that the PyC production values obtained here, and associated overestimation of carbon emissions, should be taken as low‐end estimates for wildland fire conditions.

中文翻译：

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火热碳与大火碳收支的相关性：FIREX实验的见解

植被大火在全球和区域碳循环中起着重要作用。由于气候变暖和土地用途的变化，世界许多地区的火灾模式正在改变，火灾影响也在增加。因此，减少火灾造成的碳预算计算中的不确定性对于提高我们目前的理解和预测能力至关重要。在这里，我们研究了FIREX FireLab实验产生的20个燃烧室，燃烧了一组代表性的北美野地燃料，以评估以下内容：（i）常用“消耗生物量”方法与“燃烧碳”之间的碳排放估算差异”方法；（ii）热解碳（PyC）的生产率；（iii）产生的PyC的热化学耐受性，作为其生物地球化学稳定性的代表。我们发现“消耗生物量”方法导致碳排放量高​​估2–27％（大多数值在2％至10％之间）。这种会计错误主要是由于不考虑PyC生产而引起的，即使相对较小，也可能对中长期碳预算产生重要影响。这种PyC的很大一部分（34–100％）包含在烧焦的细残留物中，这是在火炭研究中经常被忽视的一种后燃材料。但是，最顽强的PyC是木炭形式，大多数样品的半衰期估计超过1000年。与实际的野外火灾条件相比，这些实验室燃烧中的燃烧效率相对较高，可能导致PyC生产率降低。因此，我们认为这里获得的PyC产值，