Modelling of the wind effect on the rate of spread of a flame in a forest fire usually employs a wind velocity measured at mid-flame height. An alternative formulation is proposed in this paper, based on the wall shear-stress produced by the wind on the fuelbed in the absence of combustion. Some tests performed on a laboratory scale are described and the results obtained together with those from other sources confirm the possibility of using wall shear-stress to correlate the rate of spread of a flame front. © IAWF. Reproduced from the International Journal of Wildland Fire (Viegas, D.X. and L.P.C. Neto, 1991) with the kind permission of CSIRO PUBLISHING on behalf of the International Association of Wildland Fire. (http://www.publish.csiro.au/journals/ijwf/).