The long-term pattern of population deconcentration in the United States has resulted in rapid development in the outlying fringe of metropolitan areas and in more remote, rural areas with attractive recreational and aesthetic amenities, especially forests. This demographic change is increasing the wildland-urban interface (WUI), defined by the Federal government as the area where structures and other human development meet or intermingle with undeveloped wildland.

When a record 8.4 million acres of forest burned in the U.S. in 2000 and wildland fire suppression costs reached $1.66 billion, the WUI became a primary focus of Federal fire management policy, especially with the Healthy Forest Restoration Act, which authorizes hazardous fuels reduction. The WUI creates an environment in which fire can move readily between structural and vegetation fuels. Therefore, its expansion has exacerbated wildfire threats to structures and people, especially in the Western U.S. Last year over 3,000 houses in the U.S. were destroyed by wildland fires, resulting in estimated damages of more than $2 billion. Even in states like Wisconsin, with relatively low forest fire risk (except in a few areas like the Pine Barrens in Bayfield, Douglas, Burnett, and Washburn Counties) the WUI is a focal arena for conflicts between humans and the environment.

Using U.S. Census data and the National Land Cover Dataset (NLCD), a team of University of Wisconsin and USDA Forest Service researchers, have analyzed and summarized the size and extent of the WUI in the contiguous 48 states for the years 1990 and 2000. Areas with at least one housing unit per 40 acres were included in the WUI if 50% or more of its land area was comprised of coniferous, deciduous and mixed forest; shrubs; native grasslands; and wetlands or if the area was located within 1.5 miles of an area with 50% or more of its land area comprised of these same "wildland" vegetation types (Figure 1). In Wisconsin WUI areas are prominent in the northern part of the state, as well as in more forested areas such as the Wisconsin River Valley.

Although the "farmland-urban interface" has not been defined by the Federal government, nor has it become the focus of public policy to the same extent, for much of Wisconsin it may serve as an equally important indicator of emergent environmental and social conflicts. Using the same housing density categories but selecting only areas in which 50% or more of their land area was comprised of pasture/hay, row crops, and small grains delineates the area where structures and other human development meet or intermingle with farmland, the Farmland-Urban Interface (FUI). As would be expected, the FUI is concentrated in southern Wisconsin (Figure 2). An article in the next Land Use Tracker will explore housing growth during the 1990�s in agricultural areas across Wisconsin.

Farmland-Urban Interface maps for each UWEX district are available at:
www.drs.wisc.edu/personnel/faculty/hammer/Hammer_Extension.htm.

Roger B. Hammer is an Assistant Professor in the Department of Rural Sociology at the University of Wisconsin-Madison.