Fires initiated in wildland areas can spread to populated areas where structures can be ignited (UWI fires). The onset of burning structures introduces fire intensities and durations different from that produced by vegetation. Community fire spread and the risk of ignition for homes exposed to both burning vegetation and other structures are complex. As the geometry and types of fuels are dictated by landscaping instead of larger scale wildland fuel beds, fire models need to be constructed to account for the ignition and burning characteristics of individual fuel elements, such as trees, shrubs, decks, building siding, windows, and roofs. Quantifying the benefits and hazards associated with urban vegetation and its placement on property is part of the research program of the Forest Service Pacific Southwest Station, Center for Urban Forest Research. The Center and its partners are developing a Web-based quantitative tool for use by property owners to make informed decisions about landscape design and management relative to energy conservation, hydrology, and fire safety.