Zone where structures and other human developments meet, or intermingle with, undeveloped wildlands (SKCNP). The [WUI] fire interface is any point where the fuel feeding a wildfire changes from natural (wildland) fuel to man-made (urban) fuel. ...For this to happen, wildland fire must be close enough for its flying brands or flames to contact the flammable parts of the structure (Butler, 1974, p. 3). The WUI has been variously defined as any area designated by the agencies that includes an interface/intermix community. The Inslee Amendment to a U.S. House of Representatives Bills for expediting fuel reduction projects defined the wildlandurban interface as limited to land in high fire-risk areas within ½ mile of communities. The McInnis-Miller Amendment to these House bills regarding fuel reduction projects does not include a distance limitation. Speaking at a public lecture fire researcher Jack Cohen said that often the radiant heat from a fire, not the fire itself, will ignite a home or other structure. This “ignitability zone” lies within 100 feet of the house. Cohen also addressed crown fires and demonstrated that crown fires did not ignite homes and urban structures at distances greater than 65 feet, which means that home ignitions from flames occur within distances of about 30 to 40 feet (Colonna, 2000).