Scott, Joe H. and Elizabeth D. Reinhardt. 2001.
Assessing crown fire potential by linking models of surface and crown
fire behavior. Res. Pap. RMRS-RP-29. Fort Collins, CO: U.S. Department
of Agriculture, Forest Service, Rocky Mountain Research Station. 59 p.
ABSTRACT -- Fire managers are
increasingly concerned about the threat of crown fires, yet only now are
quantitative methods for assessing crown fire hazard being developed.
Links among existing mathematical models of fire behavior are used to
develop two indices of crown fire hazard-the Torching Index and Crowning
Index. These indices can be used to ordinate different forest stands by
their relative susceptibility to crown fire and to compare the effectiveness
of crown fire mitigation treatments. The coupled model was used to simulate
the wide range of fire behavior possible in a forest stand, from a low-intensity
surface fire to a high-intensity active crown fire, for the purpose of
comparing potential fire behavior. The hazard indices and behavior simulations
incorporate the effects of surface fuel characteristics, dead and live
fuel moistures (surface and crown), slope steepness, canopy base height,
canopy bulk density, and wind reduction by the canopy. Example simulations
are for western Montana Pinus ponderosa and Pinus contorta stands. Although
some of the models presented here have had limited testing or restricted
geographic applicability, the concepts will apply to models for other
regions and new models with greater geographic applicability.