Effects of vegetation description parameters on forest fire behavior simulated with

This study focuses on the effects of vegetation characteristics on fire propagation, with the coupled atmosphere-wildfire behaviour model HIGRAD/FIRETEC. On the basis of an idealized Pinus pinaster ecosystem, the sensitivity of the model to fuel load, cover fraction in a stand and horizontal tree dimensions was investigated. The results are discussed in terms of influence on rate of spread, torching or crowning activities, and damage to canopies. The vegetation distribution can affect very seriously fire propagation and damage to crown. Propagation characteristics depend on some thresholds on vegetation descriptors. However, this first part of the study was done with wind profiles that did not reproduce accurately the turbulence due to the canopy itself. The use of the code with cyclic boundary conditions can help to compute more accurately wind-flows in canopies. A validation of FIRETEC’s wind prediction based on experimental data has been done. These accurate wind-flows will be used in a close future to simulate ambient wind during fire propagation to investigate the influence of resolved fluctuations in a heterogeneous landscape. Résumé: Cette étude s’appuie sur le modèle physique de propagation HIGRAD/FIRETEC, pour évaluer les effet