Fire in the Wildland Urban Interface

Wildland Urban Intermix

Wildland Urban Interface

95% of fires in the Southeast potentially involve the Wildland Urban Interface (WUI). Fire in the wildland-urban interface is a unique concern because of special issues that differentiate it from other wildland fires, which, in turn, create a critical need to mitigate fire hazards and reduce risks in the WUI zone. An important current issue is the management of fire in the Souths urbanizing landscape. The growing wildland urban interface has forced new requirements for fire control.

The Wildland Urban Interface (WUI) are places where potentially flammable vegetative fuels meet or overlap with homesites (Davis 1990). Interface is the line or zone where human development meets wildland fuels or vegetation. The wildland urban intermix is an area where human development and wildland fuels are interspersed. “Interface” is the most widely used term and is commonly used to refer to the whole range of situations where wildland fuels are close to human development.

The South’s wildland areas are distinct from wildlands in other regions of the United States in ways that affect fire in the WUI. One point of distinction is that private landowners control most of the forested land in the South, while the West has more land owned by the federal government than the South. A second point is that the South has a longer history of using prescribed fire to manage fuels than other parts of the United States. Also, vegetation growth is particularly high in the South because of higher rates of rainfall and longer growing seasons which sometimes makes it difficult to keep fuels at a minimal levelin the WUI. Finally, fire return intervals tend to be shorter in the South. Because of these and other unique qualities, the Southern WUI is particularly threatened by unwanted fire.

People are the cause of the majority of wildland urban interface fires. Many WUI fires start by accident while some are caused by arson and others result from escaped prescribed fires. Lightning is another cause of many WUI fires. Urbanization and increasing human population densities result in fragmentation of the landscape and rising wildfire risks (Zhai and others 2003 ). Population growth will be the most significant social influence to shape the South’s wildland urban interface. More than 1.2 million people may be added each year to the South’s population through both births and immigration (Cordell and Macie 2002). With population increase comes pressure for urban expansion and development, oftentimes converting rural open space into developed land. The southern WUI continues to grow as the population in the South increases and development expands into natural areas. Natural areas are simultaneously changing because of increasing human influence and changes in land use. Fire suppression, along with WUI residents’ preference for “natural” landscapes can cause fuels to increase to hazardous levels.

WUI fires increase when dispersed development increases in fire-adapted landscapes. Through the 1980s and 1990s, the frequency of large fires that swept through WUI areas increased dramatically. WUI fires range from smaller incidents that damage only one home, to catastrophic events with the potential to damage hundreds of structures (Cohen 2000). More than 900 homes in the United States were destroyed annually by wildfires in the 1990s (Institute for Business and Home Safety 2004). A Selected History of WUI Fires in the United States represents a partial history of WUI fires across the U.S., revealing the scope of these fires.