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, 12(18), pp. 15737-15762. (doi:10.5194/bgd-12-15737-2015)

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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 Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
College of Social Sciences > School of Education > Interdisciplinary Science Education Technologies and Learning
Journal Name:Biogeosciences
Publisher:Copernicus Publications
ISSN:1726-4170
ISSN (Online):1726-4189
Copyright Holders:Copyright © 2015 The Authors
First Published:First published in Biogeosciences 12(18):15737-15762
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
581921Understanding the impact of severe wildfires on ecosystem carbon dynamicsGwilym DaviesNatural Environment Research Council (NERC)NE/J006289/1IS - INTERDISCIPLINARY STUDIES