Characterizing wildfire regimes in the United States

Area of Science:

• Ecology
• Geoscience
• Forestry

Background:

• Wildfires are a significant ecological phenomenon in the United States.
• Understanding wildfire dynamics is crucial for effective land management and hazard assessment.

Purpose of the Study:

• To analyze wildfire statistics across the conterminous United States in a spatially and temporally explicit manner.
• To investigate wildfire occurrence as a function of ecoregion, ignition source, and decade.
• To classify wildfire regimes for probabilistic hazard estimation.

Main Methods:

• Utilized a high-resolution dataset of 88,916 wildfires from 1970-2000.
• Examined frequency-area power-law behavior in 18 different ecoregions.
• Compared scaling of burned areas using normalized power-law exponents.
• Calculated recurrence intervals for wildfires of specific burned areas.

Main Results:

• Wildfires exhibit robust frequency-area power-law behavior across diverse U.S. ecoregions.
• A systematic east-to-west gradient in wildfire-burned area scaling was identified.
• Eastern U.S. wildfires showed higher power-law exponents for anthropogenic versus lightning ignition sources.
• Recurrence intervals were calculated for probabilistic hazard estimation.

Conclusions:

• Wildfire behavior exhibits predictable scaling laws that vary geographically and by ignition source.
• The findings provide a framework for classifying wildfire regimes and improving hazard assessment.
• This research offers a novel approach to wildfire risk management, analogous to earthquake hazard estimation.