Experimental study on the flammability and burning behaviour of live and dead Eucalyptus saligna foliage

Abstract

Wildland fires are frequent catastrophic events that lead to the loss of life and economic devastation. Wildfires can involve dead and live fuels; however, only limited research has studied the combustion characteristics of those fuel conditions. This paper studies the burning behaviour of live and dead Eucalyptus saligna leaves using the Mass Loss Calorimeter. Tests were carried out using different indicent radiant heat flux and wide range of fuel moisture content (4-120% on dry weight for live leaves and 3-14% on dry weight for dead leaves). This study includes the proximate analysis and thermogravimetric analysis to observe the impact of chemical composition. Flammability parameters (i.e. ignition delay time, time to peak mass loss rate, burnout time, peak mass loss rate, and residual mass fraction) were analysed to identify the differences between live and dead leaves. The results show that ignition delay time of dead leaves are eight times faster than live leaves, thus the regression model derived from dead leaves cannot be used well to predict the ignition delay time of live leaves, and vice versa. From all parameters, it is concluded that live and dead leaves will not behave the same in fire condition; dead leaves are shown to be more flammable than live leaves, even though the leaves are in the same oven-dried condition. This confirms that the live fuels can no longer be assumed as wet dead fuels, and should be considered explicitly in assessing wildland fire risk.