Spatial Patterns of Wildfire along Climatic, Ecological, and Social Gradients

Wildfire is an essential natural process in certain locations playing a key ecological role. Yet wildfire is also destructive and costly to human lives and property. Understanding drivers of broad-scale spatial patterns of wildfire is necessary to achieve a balance between vital ecological processes and detrimental hazards. This research aims to explain how coarse-scale spatial patterns of wildfire are influenced by climatic, ecological, and human activity gradients in United States national forests from 1970-2014. Wildfire occurrence data was obtained from the National Interagency Fire Management Integrated Database (NIFMID) for individual national forests. Climatic data was obtained from the National Center for Environmental Information (NCEI) and used to calculate a number of statistics for analysis with wildfire data. Lastly, county population data retrieved from the US Census Bureau were collected for each county within the boundary of each national forest. The climate and population metrics were then used in correlation and regression analyses against the wildfire data to reveal possible relationships. Spatial patterns uncovered suggest that the western US has a greater amount of fire when compared to the eastern US. However, some national forests in the Southeast possess equally high levels of fire activity, particularly in terms of ignition density. Both mean moisture conditions and the variability in those conditions were associated with wildfire activity. Daily precipitation variability revealed the importance of not just the amount of precipitation an area receives but also the timing of precipitation. Ultimately, national forests with warm temperatures, dry conditions, and more variable precipitation regimes are most prone to burning. Metrics pertaining to social gradients did not reveal conclusive results and more research is warranted.