The relative importance of fuels and weather on fire behavior in subalpine forests
The authors used Rothermel’s 1972 and Van Wagner’s 1977 fire models to predict surface fire intensity and crown fire initiation using fuel data from upland subalpine conifer forest stands using daily weather variables. They used this information to determine the relative importance of fuel components versus weather components on fire behavior.
The authors found that surface fire intensity and crown fire initiation were both strongly related to weather factors (temperature, precipitation, wind speed, and relative humidity) significantly more so than fuel components. Subalpine forests historically only burned during extreme weather events, such as prolonged drought. The authors suggest that during extreme weather events, fuels become increasingly less important in determining fire behavior as forest stands pass a threshold that permits crown fire initiation. They also found a significant correlation between annual area burned and fire intensity directly related to the weather variable frequency. Years where large area burned were associated with extreme fire weather and subsequent high intensity fire.