Excerpts: Between 1990 and 2020, the United States added 179,000 square kilometers of wildland-urban interface (WUI), an area equivalent in size to the state of Washington. During the same period, the number of homes in WUI areas of the United States increased by 47 percent. National forests are hotspots for WUI growth, with a 38 percent increase in WUI area and 46 percent growth in WUI houses from 1990 to 2010 for the area around national forests. Growth within national forests was higher than the surrounding area. Most houses exposed to wildland fire are in WUI areas. WUI expansion increases the number of houses at risk from wildland fire and makes it more likely that wildland fires will occur.
