[Effects of fire recurrence on fire behaviour in cork oak woodlands (Quercus suber L.) and Mediterranean shrublands over the last fifty years]

C R Biol. 2015 Dec;338(12):812-24. doi: 10.1016/j.crvi.2015.10.001. Epub 2015 Nov 29.
[Article in French]

Abstract

Past fire recurrence impacts the vegetation structure, and it is consequently hypothesized to alter its future fire behaviour. We examined the fire behaviour in shrubland-forest mosaics of southeastern France, which were organized along a range of fire frequency (0 to 3-4 fires along the past 50 years) and had different time intervals between fires. The mosaic was dominated by Quercus suber L. and Erica-Cistus shrubland communities. We described the vegetation structure through measurements of tree height, base of tree crown or shrub layer, mean diameter, cover, plant water content and bulk density. We used the physical model Firetec to simulate the fire behaviour. Fire intensity, fire spread, plant water content and biomass loss varied significantly according to fire recurrence and vegetation structure, mainly linked to the time since the last fire, then the number of fires. These results confirm that past fire recurrence affects future fire behaviour, with multi-layered vegetation (particularly high shrublands) producing more intense fires, contrary to submature Quercus woodlands that have not burnt since 1959 and that are unlikely to reburn. Further simulations, with more vegetation scenes according to shrub and canopy covers, will complete this study in order to discuss the fire propagation risk in heterogeneous vegetation, particularly in the Mediterranean area, with a view to a local management of these ecosystems.

Keywords: Comportement du feu; Cork-oak woodland (Quercus suber L.); Fire behaviour; Fire recurrence; Maquis (Erica arborea, Cistus); Massif des Maures (Var, France); Modèle physique Firetec; Physically-based model Firetec; Récurrence de feu; Shrubland (Erica arborea, Cistus); Structure de végétation; Suberaie (Quercus suber); Vegetation structure.

MeSH terms

  • Ecosystem
  • Fires*
  • Forests*
  • France
  • Quercus*
  • Time Factors