Fire-Southern Oscillation relations in the Southwestern United States. Needle-fire in ponderosa pine. Photograph courtesy of Rocky Mountain Research Station, Flagstaff, Arizona.
Wildfires are a fundamental ecological process.
Sophisticated models have been developed to evaluate the influence of daily weather on fire behavior but the role of seasonal or longer term climate is less certain. The structure and diversity of such communities, which are regulated by fire frequency, extent, and intensity, may have nonequilibrial properties associated with variations in global climate. Successful prediction of vegetation change hinges on a better understanding of climatically driven disturbance regimes and the relative contributions of regional versus local processes to community dynamics. The southwestern United States is an ideal area for assessment of regional fire-climate patterns. Detailed meteorological records and fire statistics are available for extensive areas, and centuries-long climate and fire history proxies have been obtained from tree rings at many sites.