Crown fire hazard assessment tool for Catalonia region forests (North-East Spain)

There are different forest fire types depending on the layer involved in its spread: a) ground
fires, in which duff, organic soils and roots are consumed (Frandsen, 1987), b) surface fires,
where needles, leaves, grass, dead and down branch wood and logs, low brush and short
trees are implicated in the combustion, and c) crown fires, in which canopy fuels are
involved (Van Wagner, 1977). Furthermore, crown fires are divided into three categories: a)
passive crown fires (individual or small groups of trees torch out but flame is not maintained
in canopy), b) active crown fires (surface and canopy fuel stratum burn and crown fire
spread depends on the heat released by the surface fuel layers), and c) independent crown
fire (fire spreads in the canopy independently of the heat released from the surface fire),
which occur rarely and under extreme conditions (Van Wagner, 1993). [...]