The Wildland-Urban Interface

The "wildland-urban interface," commonly abbreviated WUI, describes areas where houses are built within or immediately adjacent to wildland vegetation capable of carrying fire, a concept formalized in United States federal land-management policy during the 1980s and refined through mapping work jointly conducted by the U.S. Forest Service and Census Bureau researchers, most notably Volker Radeloff and colleagues. A landmark 2018 study by Radeloff's team, published in the Proceedings of the National Academy of Sciences, found that the WUI was the fastest-growing land-use type in the contiguous United States between 1990 and 2010, expanding by 41 percent in housing units even as it added comparatively little new land area, meaning new development was increasingly concentrated exactly where existing wildland already posed fire risk rather than spreading into previously unburned terrain.