Deriving from original work under the National Cohesive Wildland Fire Management Strategy completed in 2011, this report summarizes the state of knowledge regarding the underlying causes and the role of wildfire prevention efforts on all major categories of wildfires, including findings from research that have sought to model wildfire occurrences over fine and broad spatial and temporal scales. The report also describes a conceptual model of wildfire ignitions, which is designed to provide a modeling framework for analysts who seek to better understand wildfire ignition processes or develop statistical models that can predict wildfire occurrences across any spatial or temporal scale.