Canadian Forest Service Publications

The effect of fire front width on surface fire behaviour. 1999. Wotton, B.M.; McAlpine, R.S.; Hobbs, M.W. International Journal of Wildland Fire 9(4):247-253.

Year: 1999

Issued by: Great Lakes Forestry Centre

Catalog ID: 36061

Language: English

Availability: PDF (request by e-mail)

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To determine the effect of fire front width on surface lire spread rates, a series of simultaneously ignited experimental fires was carried out in a pine plantation. Fires were ignited in plots with widths ranging from 0.5 m to 10 m and were burned in low wind conditions. Flame lengths were small in all fires, ranging from 20 cm to 60 cm. Since pre-heating of the forest floor litter from flame radiation is assumed to be an important mechanism in the spread of low intensity, low wind surface fires, it then follows that the width of a flaming front should have a strong effect on the heating of the fuel to ignition temperatures. Total flame radiation was also mea sured at a point 50 cm ahead of the advancing flame front for a number of the fires. Experimental results indicate that a flame radiation measured ahead of the fire stays fairly con stant once the flame width is between 2 and 5 m. Theoretical flame radiation calculations confirm this trend. Rates of spread between the 5 and 10 metre width fires also appear to be similar; this indicates that, for the type of fires studied, once flame width is greater than about 2 m, radiation from any extra width of fire front has little effect on spread rate.