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Long lead statistical forecasts of area burned in western U.S. wildfires by ecosystem province

Anthony Leroy Westerling, Alexander Gershunov, Daniel R. Cayan, Tim P. Barnett
Summary - what did the authors do and why?

The authors model the relationship between seasonal area burned aggregated by Bailey’s ecosystem provinces and monthly U.S. Climatological Division Palmer Drought Severity Index (PDSI) to forecast area burned a season in advance.

Publication findings:

The authors found that, generally, in shrub- and grassland-dominated ecosystems, there was a strong relationship between area burned and increased moisture in the year before the fire season, suggesting these systems are fuel limited and only burn after moisture (inferred from PDSI) increases fuel production. For open-canopy forests, they found a strong relationship between area burned and decreased moisture immediately prior or during the fire season, suggesting that the moisture conditions of the heavier fuels drive fire activity.

Climate and Fire Linkages

How does drought relate to annual area burned and fire size?

The authors found that, generally, in shrub- and grassland-dominated ecosystems, there was a strong relationship between area burned and increased moisture in the year before the fire season, suggesting these systems are fuel limited and only burn after moisture (inferred from PDSI) increases fuel production. For open-canopy forests, they found a strong relationship between area burned and decreased moisture immediately prior or during the fire season, suggesting that the moisture conditions of the heavier fuels drive fire activity.