Holocene fire history: can evidence of peat burning be found in the palaeo-archive?

Abstract

Smouldering wildfires in peatlands have the potential to release substantial amounts of the carbon currently sequestered in these ecosystems. However, past studies of Holocene fire history in peatlands have given little consideration to the identification of evidence left behind after peat burning, or to charring of the peat matrix. In this study, modern peat samples from peatlands across the globe were charred in order to assess the identifiable characteristics of charred peat. On this basis we believe that charred aggregates of partially decayed organics which can be identified in cores provide clear evidence that the peat matrix itself burned. A range of charred morphotypes could be found throughout a 2 m peat core from All Saints Bog in County Offaly, Ireland, and we are able to identify charred partially decayed aggregates that appeared to correspond with peaks in fire activity on the bog. These may reflect periods when surface fires ignited the peat surface below, or when the radiant heat from surface fires was sufficient to pyrolyse the surface peat. We conclude that it is possible to find evidence of peat burning in the palaeo-archive, and that future studies should begin to document the occurrence of charred particles so that the discipline can begin to build a picture of possible past peat fire activity.

Keywords

• charcoal
• charred aggregates
• peat matrix
• smouldering wildfire