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Although the modelling of the spreading of a forest fire has made considerable progress recently, there remains a lack of reliable field measurements of thermodynamic quantities. We propose in this paper a method and a set of measuring structures built in order to improve the knowledge on the fundamental physical mechanisms that control the propagation of wildland fires. These experimental apparatus are designed to determine: the fire front shape, its rate of spread, the amount of energy impinging ahead of it, the vertical distribution of the temperature within the fire plume as well as the wind velocity and direction. The methodology proposed was applied to a fire spreading across the Corsican scrub on a test site.The recorded data allowed us to reconstruct the fire behaviour and provide its main properties. Wind and vegetation effects on fire behaviour were particularly addressed.

One of the objectives of the present study is to gain a deeper understanding of the heat transfer mechanisms that control the spread of wildfires. Five experimental fires were conducted in the field across plots of living vegetation. This study focussed on characterising heat transfer ahead of the flame front. The temperature and heat flux were measured at the top of the vegetation as the fire spread. The results showed the existence of two different fire spread regimes that were either dominated by radiation or governed by mixed radiant–convective heat transfer. For plume‐dominated fires, the flow strongly responds to the great buoyancy forces generated by the fire; this guides the fire plume upward. For wind‐driven fires, the flow is governed by inertial forces due to the wind, and the fire plume is greatly tilted towards unburned vegetation. The correlations of the temperature (ahead of the flame front) and wind velocity fluctuations change according to the fire regime. The longitudinal distributions of the radiant heat flux ahead of the fire front are also discussed. The data showed that neither the convective Froude number nor the Nelson convection number – used in the literature to predict fire spread regimes – reflect the observed behaviour of wind‐driven fires.