As human populations grow, city boundaries expand and neighborhoods develop into wildland areas, now called the wildland urban interface (WUI). WUIs have a greater chance of being affected by fire because they contain large amounts of plant landscaping, fuel sources, and structures that could sustain a fire. NPS fire experts educate neighboring communities how to reduce the risks of wildfires by creating defensible space around structures. NPS firefighters conduct and assist partners with prescribed burns to create fire-resilient ecosystems. They may practice extinguishing structure, vehicle, and dumpster fires and extracting victims from car accidents and burning buildings.