Wildfire Behavior Study in a Mediterranean Pine Stand Using a Physically Based Model

Abstract

The aim of this article is to study the propagation of a wildfire, propagating through two eco-systems characteristics of the Mediterranean region located in south of France: the garrigue and the aleppo pines forest. The behavior of a line fire is analysed using a physical model based on the resolution of conservation equations (mass, momentum, energy) governing the coupled system formed by the vegetation and the surrounding atmosphere. The effects of wind (ranged from 3 to 30 m/s) and slope of the terrain (ranged from 0 to 40°) have been studied for surface fires propagating through shrubs (quercus coccifera) composing the surface vegetation of a garrigue and the understorey vegetation of a young pines stand (pinus halepensis). Then the configuration has been generalized, in adding a solid fuel layer above the first one, representing the canopy of a young pines stand. The numerical results have highlighted the strong connection between the surface fire and the canopy. In all cases (on flat terrain) the active crown fire regime has never been reached, and the behaviour of fires, predicted with the model, was more representative of passive crown fires (torching).

Keywords:

• Crown fire
• Forest fire spread
• Physically modelling

Acknowledgments

The authors thank INRA-PIF team (Avignon, France), for providing quantitative data concerning the fuel distribution.