Tuesday, September 29, 2015

Mapping America's Unprecedented Vulnerability to Wildfires

In the U.S., the steadiest population growth isn’t happening in urban centers. It’s in suburbs, exurbs, and rural areas. And as we make more and more homes along the very fringes of metropolitan areas, the more we come into contact with natural habitats. And the consequences might not be obvious. Putting aside conservation concerns, higher numbers in the “wildland/urban interface” (or the “WUI,” as the U.S.D.A Forest Service calls it) means higher numbers of homes vulnerable to wildfire. As of 2010, 99 million people, or about one-third of all people in the United States, lived in the WUI. The WUI is is formally defined as any area with at least one structure per 40 acres that’s either next to (what’s called “WUI Interface”) or sprinkled within (“WUI intermix”) a certain minimum expanse of naturally vegetated land. (Urban homes adjacent to a park, for example, wouldn’t included.) A new map by the forest service shows us where the WUI lies. The agency charts the extent of WUI in the contiguous U.S. every decade, using Census housing data and the National Land Cover Dataset (that’s why this year’s map is for 2010.) An accompanying report explains that the WUI has grown since the last map was made. Setting aside questions about forest fragmentation, habitat loss, and land conservation—all mighty concerns in their own right—the map is a reminder of how the risk of wildfire is spreading beyond the forest to human settlements...more

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