International Journal of Wildland Fire International Journal of Wildland Fire Society
Journal of the International Association of Wildland Fire

Flammability descriptors of fine dead fuels resulting from two mechanical treatments in shrubland: a comparative laboratory study

Eva Marino A C , Javier Madrigal A , Mercedes Guijarro A , Carmen Hernando A , Carmen Díez A and Cristina Fernández B
+ Author Affiliations
- Author Affiliations

A Centro de Investigación Forestal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Ministerio de Ciencia e Innovación, E-28040 Madrid, Spain.

B Centro de Investigación Forestal de Lourizán, Consellería de Medio Rural, Xunta de Galicia, E-36080 Pontevedra, Spain.

C Corresponding author. Email:

International Journal of Wildland Fire 19(3) 314-324
Submitted: 14 July 2008  Accepted: 23 September 2009   Published: 13 May 2010


Mechanical treatments are traditionally used to modify the fuel complex in shrubland, but information about their actual effectiveness in reducing the risk of wildfire initiation is scarce. The effects of two mechanical fuel treatments (shrub clearing with crushing and manual removal) on flammability in a shrubland community in north-western Spain were compared. Three months after treatment, laboratory tests using a point-ignition source were conducted on the fine dead fuels to analyse the effect of type of treatment and fuel moisture content (FMC) under two conditions: (1) flaming; or (2) glowing+wind ignition source. Fuel load effect within each treatment was also studied. Time-to-ignition, flaming duration, number of burnt sides of the sample and fuel consumption ratio were assessed. Logistic models were developed to assess ignition and sustained combustion probabilities. Type of treatment and FMC significantly affected flammability under both experimental conditions tested. Slow smouldering was observed in fuels subjected to shrub clearing and removal, whereas crushing fuels were rapidly burnt with flaming phase combustion. In general, shrub clearing and removal appeared to be more effective in reducing wildfire hazard in these shrubland communities.

Additional keywords: fuel management, Galicia (north-western Spain), ignition, mixed heathland, shrub clearing, sustained combustion.


This study was supported by the National Institute for Agricultural Research (INIA) from the Spanish Ministry of Science and Innovation and co-funded by FEDER funds through Project RTA05–00244-C02–02, and by the European Commission, through the Integrated Project FIRE PARADOX FP6–018505. Eva Marino’s participation in this research was possible through a PhD scholarship funded by INIA. We are grateful to Antonio Arellano from the Departamento de Protección Ambiental, CIF-Lourizán, for field assistance. We sincerely acknowledge the critical reviews of three anonymous referees who helped improve an early version of the manuscript.


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