Full Citation: Abatzoglou, John T.; Kolden, Crystal A. 2013. Relationships between climate and macroscale area burned in the western United States. International Journal of Wildland Fire 22(7):1003-1020.
External Identifier(s): 10.1071/WF13019 Digital Object Identifier
Location: Across the eight Geographic Area Coordination Centers (GACCs) in the western U.S., including the Pacific Northwest, Northern Rockies, Northern California, Southern California, Western Great Basin, Eastern Great Basin, Rocky Mountain and the Southwest.
Ecosystem types: Forested and non-forested ecosystems
Southwest FireCLIME Keywords: None
FRAMES Keywords: fire danger rating, fire intensity, season of fire, wildfires, statistical analysis, fire management, forest management, fire danger, management, area burned, climate-fire interactions, GACC - Geographic Area Coordination Center, MTBS - Monitoring Trends in Burn Severity

Relationships between climate and macroscale area burned in the western United States

John T. Abatzoglou, Crystal A. Kolden


Summary - what did the authors do and why?

The authors looked at the relationships between a diverse set of standard (i.e. temperature and precipitation) and biophysical variables related to water balance and fire danger indices to detect their relationships with the interannual variability of area burned derived from the Monitoring Trends in Burn Severity dataset (1984 – 2010).


Publication findings:

They found variation between fire-climate relationships across the different GACCs. For the Southwest GACC specifically, temperature, precipitation, and drought indicators were strongly correlated to forested area burned. Unburned area within a fire perimeter did show a negative correlation to summer (June – Aug) temperature, however, they conclude that temperature is acting as an indirect proxy for fuel moisture stress and flammability. In general, biophysical variables that include a direct link to fuel moisture conditions performed better than any single individual variable, such as temperature or precipitation. In the Southwest GACC, reference evapotranspiration explained the greatest percentage of variance between climate and area burned for both forested and non-forested areas. Furthermore, antecedent climate factors were more important for early season wildfire activity whereas fire season conditions were consistently stronger predictors of area burned and fire potential concurrent with the fire season. Specifically, when water-balance or fire danger indices were integrated over longer periods of time, their predictive power increased meaning they were best at predicting later or end-of-season conditions. Negative relationships with increased snow-water equivalent (SWE) were also observed in montane ecosystems where late-winter/early-spring precipitation delays the onset of fire season and increases fuel moistures into the fire season.

Climate and Fire Linkages

For the Southwest GACC specifically, temperature, precipitation, and drought indicators were strongly correlated to forested area burned. Unburned area within a fire perimeter did show a negative correlation to summer (June – Aug) temperature, however, the authors conclude that temperature is acting as an indirect proxy for fuel moisture stress and flammability. In general, biophysical variables that include a direct link to fuel moisture conditions performed better than any single individual variable, such as temperature or precipitation.

In the Southwest GACC, reference evapotranspiration explained the greatest percentage of variance between climate and area burned for both forested and non-forested areas. In general, biophysical variables that include a direct link to fuel moisture conditions performed better than any single individual variable, such as temperature or precipitation.

Negative relationships with increased snow-water equivalent (SWE) were also observed in montane ecosystems where late-winter/early-spring precipitation delays the onset of fire season and increases fuel moistures into the fire season.

Antecedent climate factors were more important for early season wildfire activity whereas fire season conditions were consistently stronger predictors of area burned and fire potential concurrent with the fire season. Specifically, when water-balance or fire danger indices were integrated over longer periods of time, their predictive power increased meaning they were best at predicting later or end-of-season conditions.