Thursday, September 20, 2012
On this morning’s edition of National Public Radio’s “Marketplace,” Jeff Horwich interviewed Tim DeChant on the correlation between income equality and trees. The spot coincided with the release of aggregate data by the Census Bureau indicating that income equality is on the rise in twenty states.
DeChant, the host of the blog persquaremile.com, recently reported on a 2008 study conducted by forestry scholar Yaoqi Zhang (Auburn) and planning scholar Pengyu Wu (Boise State). Assessing data from 210 urban areas, the study found a strong correlation between income inequality and tree cover. Motivated by the study, DeChant turned to GoogleEarth to see just how evident the tree cover disparity might be, and posted a host of comparative photos here. Describing his reaction when he first glimpsed the aerial images below, DeChant explained in today’s NPR interview that West Oakland looked like “a concrete jungle,” while neighboring Piedmont looked “like a real jungle.”
As he explained to Horwich, DeChant attributes the comparative lack of trees in lower-income areas to wealthy individuals and cities having the economic resources and real property to plant and maintain more trees. He suggests that this reality is disconcerting in light of trees’ direct economic impacts (e.g., trees increase property values, ease cooling costs, alleviate air pollution, reduce stress, etc.).
Today's NPR interview obviously did not---and could not have in the brief time allotted---address all of the many pressing issues associated with urban forestry. For instance, it did not raise the point that, beyond the noted economic impacts, trees can have significant “existence value;” that is, people might feel a lost sense of well-being by virtue of the fact that natural features of the land are depleted in areas outside their own daily surroundings. In addition, it did not highlight the important distinction between wild and human-planted trees. And perhaps most significantly, as an empirical matter the 2007 study that served as the initial trigger for DeChant's blog posts did not seem to offer any causal link between tree cover and income inequality, though the interview could have been interpreted to suggest that it did. Still, the story calls attention to the advantages and challenges of incorporating green space into local planning and development models.