Wildfire Ignitions: State of the Science in the Southeast

Wildfire ignitions are caused by lightning or a variety of human-related activities. While lightning is the most prevalent ignition source across much of the western United States, human-caused ignitions start the majority of fires in the South and nationwide. The frequency of natural and human-caused wildfires varies significantly according to different biophysical, social, and fire management and prevention factors. Understanding local and regional ignition sources is a critical element in fire management, prevention, and policy. Thus, an early focus in the National Cohesive Wildland Fire Management Strategy process was to evaluate the state of the science regarding how ignitions are produced, their predictability, and how prevention efforts can affect their occurrence. The results of that extensive review and analysis of national and international literature were released in 2013 in a General Technical Report (GTR) from the U.S. Forest Service Southern Research Station. This fact sheet extracts key findings from the GTR relevant to wildfire ignitions in the southern United States and to relationships between prevention activities and human-caused ignitions. More specifically, we focus on recent trends in different ignition causes, predictors of fire cause, and prevention activity effectiveness.