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Rapid Wildland-Urban Interface Growth Increases Wildfire Challenges

Housing development adjacent to undeveloped wildlands outside Reno, Nevada. Photo by Miranda Mockrin, USDA Forest Service

The wildland-urban interface (WUI), where homes meet or intermingle with undeveloped forests and grasslands, is a critical area for wildfire and natural resource management. Both the number of homes in the WUI and total footprint of the WUI grew rapidly from 1990 to 2010, with broad implications for wildfire management and other natural resource management issues.

Homes and forests intersect in the WUI, a geography that now includes one-third of all homes in the United States within just 10 percent of the nation?s land area. For the first time, scientists with the USDA Forest Service and the University of Wisconsin-Madison have been able to track change in the nation?s WUI over a 20-year period, revealing that new WUI area expanded by more than 46 million acres, an area that is larger than Washington State. Wildland-urban interface is an area close to or intermingled with forests and grasslands, with at least one home per 40 acres. Scientists distinguish between ?intermix? WUI, in which housing and vegetation intermingle, and ?interface? WUI, where housing is near a large area of wildland vegetation. From 1990 to 2010, both types of WUI grew rapidly, increasing from 30.8 to 43.4 million homes (41 percent growth) and expanding in area from 143,568,227 acres to 190,271,144 acres (33 percent growth). Ninety-seven percent of new WUI areas were created by housing development, not an increase in wildland vegetation. The greatest expansion of WUI area occurred in the East, with the highest gains in houses and people in the South and Southwest.



External Partners

  • Volker C. Radeloff, David P. Helmers, Anu H. Kramer, Patricia M. Alexandre, Susan Stewart, and Sebastian Martinuzzi of the University of Wisconsin-Madison
  • Avi Bar-Massada, University of Haifa
  • Van Butsic, University of California ? Berkeley
  • Todd J. Hawbaker, U.S. Geological Survey
  • Alexandra D. Syphard, Conservation Biology Institute