There to remain? Pyrogenic carbon production of savanna fires

Abstract

Southern African savanna fires account for ~30% of the annual global carbon (C) emissions from vegetation fires, but their impact on the global C cycle extends beyond direct emissions During fire, part of the C burnt is converted to pyrogenic carbon (PyC), which is more resistant to degradation than original biomass and acts as a buffer to global fire C emissions when stored in soils or sediments. Despite its recognized importance for the C cycle, how much PyC is produced and how much of it stays in savanna ecosystems is still not well known, with no information yet for Southern African savannas. To address this research gap, we quantified how much PyC was produced during four fires in Kruger National Park (South Africa) and how much PyC was stored in surface soils. We also characterized the chemical and thermal recalcitrance of this PyC. Our results will be discussed in the broader context of C emissions from savanna fires as well as the role PyC plays as a C sequestration mechanism through its accumulation in soils, redistribution and ex-situ transport.