Caractéristiques de la litière et de la biomasse de certains combustibles de sous-étage marocains dominants dans cinq régions forestières sujettes au feu

In Morocco, efforts have been made to prevent wildfires, although with limited results because the pyric properties of forest fuels have not been adequately quantified. In order to remedy this gap, the bulk densities of litter and individual shrubs and biomass per size class were assessed in five fire-prone forest regions. The study covered a total of 35 sites, on both north and south-facing slopes in the Central Plateau, the Middle Atlas (Western and Eastern), the Western Rif and the Pre-Rif regions. Litter depths ranged from 1.1 ( Ononis natrix L.) to 7.5 cm ( Daphne laureola L.), and the bulk density of individual shrubs varied from 0.35 ( D. laureola ) to 4.64 mg/cm 3 ( Thymelaea tartonraira L.). The lowest fine fuel bulk density was found for D. laureola (0.22 kg/m 3 ), and the highest for T. tartonraira (4.05 kg/m 3 ). As for the bulk density of individual shrubs, no significant intra-species differences were found between the sampled regions, except for Arbutus unedo L., while the effect of the region on fine fuel biomass was not significant in all species. Linear functions were used to adjust the fine fuel biomass for the effect of individual shrub volume. Such adjustments will be very useful for forest managers, since they will make it possible to estimate the fine fuel biomass contained in a shrub using simple, independent measurements of the shrub size. Integrating data on the structural traits of fuels into fire behaviour prediction systems will facilitate estimations of fuel hazards in the regions studied and thus guide decision-makers in their task of protecting both humans and natural resources.