Abstract
Pyrogenic carbon (PyC), produced naturally (wildfire charcoal) and anthropogenically (biochar), is extensively studied due to its importance in several disciplines, including global climate dynamics, agronomy and paleosciences. Charcoal and biochar are commonly used as analogues for each other to infer respective carbon sequestration potentials, production conditions, and environmental roles and fates. The direct comparability of corresponding natural and anthropogenic PyC, however, has never been tested. Here we compared key physicochemical properties (elemental composition, δ13C and PAHs signatures, chemical recalcitrance, density and porosity) and carbon sequestration potentials of PyC materials formed from two identical feedstocks (pine forest floor and wood) under wildfire charring- and slow-pyrolysis conditions. Wildfire charcoals were formed under higher maximum temperatures and oxygen availabilities, but much shorter heating durations than slow-pyrolysis biochars, resulting in differing physicochemical properties. These differences are particularly relevant regarding their respective roles as carbon sinks, as even the wildfire charcoals formed at the highest temperatures had lower carbon sequestration potentials than most slow-pyrolysis biochars. Our results challenge the common notion that natural charcoal and biochar are well suited as proxies for each other, and suggest that biochar’s environmental residence time may be underestimated when based on natural charcoal as a proxy, and vice versa.
Highlights
Pyrogenic carbon (PyC) is produced both naturally and anthropogenically and comprises a whole range of pyrogenic organic materials from partially charred biomass to soot[1]
Pyle et al.[35] suggested using this instead of Highest Treatment Temperature’ (HTT) for a more accurate characterization of pyrolysis conditions, as charring intensity (CI) takes into account temperature and heating duration
Despite the higher HTTs recorded for wildfire charcoals, their CI values were over an magnitude lower than those recorded for biochar
Summary
Pyrogenic carbon (PyC) is produced both naturally (e.g. charcoal formed during vegetation fires) and anthropogenically (e.g. kiln charcoal and biochar) and comprises a whole range of pyrogenic organic materials from partially charred biomass to soot[1]. PyC materials are the focus of numerous studies which evaluate their potential as long-term atmospheric C sinks and roles in global warming[1, 4, 6,7,8,9,10]. The term biochar was coined in the early 2000s16 and the monitoring of biochar in the environment, spans a few years at most, limiting our understanding of its long-term fate and behaviour. To overcome this limitation, charcoal produced during www.nature.com/scientificreports/. The C sequestration potential of PyC materials, both natural charcoal and biochar, is mostly estimated using indexes based on different measurements of chemical recalcitrance[4, 29, 30]. Charring intensity (CI) has been suggested as a more appropriate descriptor, as this parameter integrates both heating temperature and duration[35]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
