Modelling Moisture Damping for Fire Spread in a Mixture of Live and Dead Fuels

Abstract

A model, based on those of Rothermel(1972) and Wilson (1990), is developed for the effect of fuel moisture on fire spread rate in a fuel complex consisting of a mixture of live and dead fine fuel particles. Physical arguments lead to a modification of the heat sink term of Rothermel's model. A form of moisture damping is proposed which generalises that of Wilson. It uses one extra parameter, which needs to be estimated from experimental burns in a mixture of live and dead fuels. The model is fitted to a series of experimental shrubland fires. The model fits this data better than does Rothermel's original model, but is not yet recommended for use by practitioners.