Le classement de l'inflammabilité des espèces ornementales peut-il être utilisé dans l'évaluation du risque d'incendie dans les interfaces habitat-forêt? | Can ranking the flammability of ornamental species be used for the fire risk assessment in WUI ?

In WUI, the ornamental vegetation is an efficient vector of fire propagation towards the housings. One way to assess the fire risk around housing is the ranking of the flammability of the ornamental species. The objective of this work was to show if the ranking of the flammability of the species varied between live and dead fuels of the main ornamental species in SE France. Flammability variables were recorded during burning experiments using a fire bench for litters and an epiradiator for live leaves. For both types of fuel, the different species were ranked from the least flammable to the most flammable according to these variables. The rankings were compared together as well as to the “total” ranking obtained using the variables of live and dead fuels. The main results showed that a few species presented the same ranking regardless of the type of fuel. However, for most species, the ranking of litter flammability differed from that of live leaf flammability; the litter of some species being ranked more flammable than their live leaves or the opposite. For the “total” ranking of these species, the most flammable species corresponded to the species presenting the most flammable litters and the moderately flammable ones to those of moderately flammable live leaves. However, the poorly flammable species corresponded to species either with highly flammable litters or moderately flammable live leaves. Among the least flammable species, Ligustrum japonicum presented litters ranked as highly flammable. The underestimation of the flammability of some species in the “total” ranking can be an issue in the fire risk assessment.