Vegetation structure and fire weather influence variation in burn severity and fuel consumption during peatland wildfires

Davies, G.M., Domenech-Jardi, R., Gray, A. and Johnson, P.C.D. (2016) Vegetation structure and fire weather influence variation in burn severity and fuel consumption during peatland wildfires. Biogeosciences, 13(2), pp. 389-398. (doi: 10.5194/bg-13-389-2016)

Abstract

Temperate peatland wildfires are of significant environmental concern but information on their environmental effects is lacking. We assessed variation in burn severity and fuel consumption within and between wildfires that burnt British moorlands in 2011 and 2012. We adapted the Composite Burn Index (pCBI) to provide semi-quantitative estimates of burn severity. Pre- and post-fire surface (shrubs and graminoids) and ground (litter, moss, duff) fuel loads associated with large wildfires were assessed using destructive sampling and analysed using a Generalised Linear Mixed Model (GLMM). Consumption during wildfires was compared with published estimates of consumption during prescribed burns. Burn severity and fuel consumption were related to fire weather, assessed using the Canadian Fire Weather Index System (FWI System), and pre-fire fuel structure. pCBI varied 1.6 fold between, and up to 1.7 fold within, wildfires. pCBI was higher where moisture codes of the FWI System indicated drier fuels. Spatial variation in pre- and post-fire fuel load accounted for a substantial proportion of the variance in fuel loads. Average surface fuel consumption was a linear function of pre-fire fuel load. Average ground fuel combustion completeness could be predicted by the Buildup Index. Carbon release ranged between 0.36 and 1.00 kg C m−2. The flammability of ground fuel layers may explain the higher C release-rates seen for wildfires in comparison to prescribed burns. Drier moorland community types appear to be at greater risk of severe burns than blanket-bog communities.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Domenech-Jardi, Miss Ruth and Davies, Dr Gwilym and Johnson, Dr Paul
• Authors: Davies, G.M., Domenech-Jardi, R., Gray, A., and Johnson, P.C.D.
• College/School: College of Social Sciences > School of Education > Interdisciplinary Science Education Technologies and Learning; College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Biogeosciences
• Publisher: Copernicus Publications
• ISSN: 1726-4170
• ISSN (Online): 1726-4189
• Copyright Holders: Copyright © 2016 The Authors
• First Published: First published in Biogeosciences 13(2): 389-398
• Publisher Policy: Reproduced under a Creative Commons License

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
58192	1	Understanding the impact of severe wildfires on ecosystem carbon dynamics	Gwilym Davies	Natural Environment Research Council (NERC)	NE/J006289/1	IS - INTERDISCIPLINARY STUDIES