Fire Technology

, Volume 47, Issue 2, pp 421–436 | Cite as

Fuel Moisture Thresholds in the Flammability of Calluna vulgaris

  • G. Matt DaviesEmail author
  • Colin J. Legg


Managed and wild fires play a significant role in the ecology of heathlands in the UK but we currently have little ability to forecast fire behaviour or the likelihood of accidental wildfires. Like many shrubland fuel types, heathlands display significant structural complexity and the role of different fuel components in governing flammability has not been clear. Using a series of small, field-based ignition tests, we demonstrate the critical importance of the moisture content of dead fine fuels in the lower canopy for determining when sustaining fires in the vegetation canopy can develop. At moisture contents above c. 70% both spot and line ignitions failed but where moisture contents were less than c. 60% fires developed rapidly. The initial rate of spread of successful ignitions was primarily controlled by the moisture content of the lower canopy and the moss/litter layer. Models that predict the moisture content of elevated dead fuels and the moss litter layer are urgently needed in order to protect heathlands from wildfire and to allow forecasts of the suitability of conditions for prescribed burning to be developed.


Fire behaviour Fire sustainability Heathland Ignition Logistic regression Managed burning Rate of spread Wildfire 



We wish to express our thanks to the landowners and managers that allowed us access to their property for our research: the Ministry of Defence, the Scottish Agricultural College and Ralia Enterprises. The Game and Wildlife Conservation Trust kindly provided us with field logistical support. Teresa Valor-Ivars assisted with the fieldwork. This project forms part of the FireBeaters project ( and was funded by the Scottish Government through the Scottish Wildfire Forum and by Scottish Natural Heritage. We are grateful to Wendy Anderson for her advice and to Michael Bruce, the chairman, and the other members of the FireBeaters Scottish Wildfire Forum steering group.


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Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  1. 1.Centre for the Study of Environmental Change and Sustainability, School of GeoSciencesThe University of EdinburghEdinburghUK
  2. 2.School of Forest ResourcesUniversity of WashingtonSeattleUSA

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