The relevance of pyrogenic carbon for carbon budgets from fires: Insights from the FIREX experiment

Santin, Cristina, Doerr, Stefan H., Jones, Matthew W., Merino, Agustin, Warneke, Carsten and Roberts, James M. (2020) The relevance of pyrogenic carbon for carbon budgets from fires: Insights from the FIREX experiment. Global Biogeochemical Cycles, 34 (9). ISSN 0886-6236

[img]
Preview
PDF (GBC_Santin_etal_2020) - Published Version
Download (7MB) | Preview

Abstract

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.

Item Type: Article
Uncontrolled Keywords: ash,carbon accounting,carbon emissions,charcoal,prescribed fire,wildfire,global and planetary change,environmental chemistry,environmental science(all),atmospheric science ,/dk/atira/pure/subjectarea/asjc/2300/2306
Faculty \ School: University of East Anglia > Faculty of Science > Research Centres > Tyndall Centre for Climate Change Research
Faculty of Science > School of Environmental Sciences
Related URLs:
Depositing User: LivePure Connector
Date Deposited: 15 Dec 2020 00:50
Last Modified: 21 Jul 2021 01:42
URI: https://ueaeprints.uea.ac.uk/id/eprint/77965
DOI: 10.1029/2020GB006647

Actions (login required)

View Item View Item