“WUI” (rhymes with phooey), an acronym for “wildland-urban interface” (though some call it “wildland-urban in your face”). On a map, the WUI represents the fault line between the forest and the built environment, but over the past thirty years it has also come to represent the sweet spot in North American real estate development: hiking trails out the back door and a scooter-friendly cul-de-sac in front. Today, more than a third of American homes and more than half of Canadian homes are located in the WUI. It is a beautiful place to live, until it goes feral.