XVI International Botanical Congess

There is a continuous fossil record of charcoal since the Late Devonian. Modern forest fires convert approximately 10% of the biomass they burn into charcoal, preferentially preserving woody tissues, it is assumed ancient fires had similar conversion rates. Thus potentially, fire could be an extremely efficient sequestration mechanism, to remove carbon from short-term cycles, and incorporate it into sediments. A number of variables would control the rates of sequestration, including whether the ancient vegetation was fire-prone, atmospheric oxygen levels, and the 'inertness' of the charcoal once it has formed. Although charcoal is usually found in the soils of modern fire-prone ecosystems, it seems noticeably absent or poorly represented in paleosols, even paleosols of ancient environments believed to be fire-prone. The implication is that within soils, the charcoal is eventually subject to oxidisation.