Characterization and mapping of dwelling types for forest fire prevention

In a context of risk of forest fire, the development of actions concerning wildfire prevention and land management is necessary and essential particularly in wildland urban interfaces (WUI). The term ‘WUI’ always includes components such as human presence and wildland vegetation. Both the hazard (probability of fire outbreak, distribution) and the vulnerability of urban areas can be characterized through the spatial organization of houses and vegetation. The first step required is to characterize and map WUI in large areas and at a large scale, which, in turn requires qualifying different types of dwellings and mapping them. With this goal in view, the paper presents a brief synthesis of results coming from an exploratory process for the characterization of dwelling types (Lampin et al., 2007), and develops a method based on GISgeo treatments to characterize different types of dwelling with regard to fire risk. Three types of dwellings were classified: isolated dwellings, scattered dwellings and clustered dwellings, using criteria based on the distance between houses, the size of clusters of houses and housing density, which can be mapped automatically. Within dwelling types, the density value of forest fire ignition changed and was twice as high for isolated dwellings as for clustered dwellings. The spatial organization of dwellings seems to have a real impact on fire occurrence. Thus maps of different dwelling types can be interpreted for use in developing fire fighting strategies or prevention actions concerning end-users such as forest and land planning managers or firefighters.