Fire recurrence impacts litter flammability in oak woodlands and shrublands on acidic soils of southeastern France
La récurrence des incendies affecte l'inflammabilité des litières dans les suberaies et les maquis sur sols acides (France)
Résumé
Characterizing the flammability of litter fuels is of major importance to assess the wildland fire hazard. We present here a comparison of the flammability of litter fuels for the main ecosystems of the Maures massif (southeastern France) forming a mosaic of oak woodlands (Quercus suber, Q. ilex and Q. pubescens) and shrublands dominated by Erica arborea, Calicotome spinosa and Cistus spp. This mosaic is partly driven by the historic fire regime, and each vegetation type corresponds to a specific range of fire recurrence. We thus tested the hypothesis that, as the fire regime impacts the composition and biomass of live fuels, it may subsequently affect the characteristics and the flammability of dead fuels. We studied undisturbed litter samples (diameter 38 cm) with at least 30 replicates per vegetation type. Each sample was submitted to an experimental burning in laboratory conditions using a glowing firebrand, in order to assess the four main components of flammability (i.e. ignitibility, sustainability, combustibility, and consumability).