Even if the fire is formally regulated, violations are rarely sanctioned, as this punitive approach is considered by public authorities and the justice system as a lower priority in our societal context, which explains the numerous ignitions. Customary and neighborhood fire management rules and sanctions exist in some places and sometimes implemented, however hindered by the numerous fire ignitions, fueling tensions and conflicts driving to fatalism. Moreover, the regular awareness-raising campaigns, essentially based on a moralizing approach (“fire is bad”), are considered to be ineffective or even inappropriate (Toussaint, 2018). In some occasions, local communities undertake reforestation projects to “repair the damage”, hoping for a reduction in fire use; these actions rarely take into account the fire regime nor the flammability of planted species. On the 10 sites where the Northern Province has supported local community tree planting over the past 12 years, 39% of the planted areas have been burned at least once (Conservation International, 2021). Innovative mitigation approaches are therefore needed.

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The mobilization of traditional knowledge associated with fire retardant vegetation offers an important potential. From an informal spontaneous conversation, numerous traditional communities throughout the territory have confirmed the traditional empirical knowledge that “Bourao does not burn well; the fire hardly goes through; often the fire stops at its foot; other species have similar fire-retardant characteristic, etc.”.

The fire-retardant attribute of the vegetation is mostly related to a lower flammability than its environment, reducing direct fire propagation risk. Indirect effects of these species are important on local vegetation composition and environment conditions such as lower temperature and higher humidity on the ground (Murray et al 2020).

The vegetation flammability can be assessed through its ability to ignite and propagate fire. Specific flammability depends on the leaf morphological features, the dead fuel proportion in the plant, the leaf chemical content (water and other organic components) and the litter density, for instance (Ganteaume et al. 2011; Ganteaume et al. 2013; Romero et al. 2019).

The Bourao can therefore be described as fire-retardant (Fig. 2):

• Empirical observations systematically demonstrate that Bourao’s leaves and twigs may desiccate during a grassland fire (which are low intensity and rapid fires) but hardly burn. This low flammability significantly reduces the risk of direct fire propagation.

• Its wide and dense canopy reduces the soil dryness and prevents the formation of herbaceous vegetation creating a ground fuel break mitigating surface fire propagation.

• Its dense and relatively high canopy (frequently more than 4 meters, and up to 8 meters) reduces heat radiation and intercepts glowing or flaming vegetation particles that are generated during a fire (i.e. barrier effect on firebrands; Ganteaume 2018). Its smooth bark does not desquamate, avoiding firebrand generation during a fire. These characteristics further reduce the risk of fire propagation.