Back when Mitt Romney was campaigning in Michigan, he had this weird phrase about his one-time home state that he kept robotically repeating: "The trees are the right height." Well, I can't say for sure what "the right height" is to Mitt Romney. And Michiganders -- who, yes, were polled as to their trees' height -- came back with mixed reviews on how their trees measure up. But as it turns out, the height of trees -- and how many of them you can see from space -- reveals a lot about the health and wealth of an urban community. And when the trees are wrong, that's actually an indicator of a larger problem.
Over at Per Square Mile, Tim de Chant has done yeoman's work in studying the trees and what they mean, and he's found that if you want to measure income inquality in an urban neighborhood, you should look for the available shade:
Research published a few years ago shows a tight relationship between per capita income and forest cover. The study’s authors tallied total forest cover for 210 cities over 100,000 people in the contiguous United States using the U.S. Department of Agriculture’s natural resource inventory and satellite imagery. They also gathered economic data, including income, land prices, and disposable income.
They found that for every 1 percent increase in per capita income, demand for forest cover increased by 1.76 percent. But when income dropped by the same amount, demand decreased by 1.26 percent. That’s a pretty tight correlation. The researchers reason that wealthier cities can afford more trees, both on private and public property. The well-to-do can afford larger lots, which in turn can support more trees.
De Chant subsequently found that this phenomenon comes to life when you look at various communities using Google Earth. A fine example is seen in comparing Chicago's Woodlawn neighborhood (predominantly African American, with median income of about $13,000) to the more tony Hyde Park, just to the north (more racially diverse, with median income about $44,000):
According to de Chant, trees provide unsung benefits to urbanites: "They shade houses in the summer, reducing cooling bills. They scrub the air of pollution, especially of the particulate variety, which in many poor neighborhoods is responsible for increased asthma rates and other health problems." He also noted that the trees-to-affluence ratio correlates to economic conditions all over the world.
[Hat tip: Boing Boing]
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