"The longtime Chicago mayor has vowed to make his city the greenest in the nation," begins an article in Metropolis magazine.
More than 40,000 trees have been planted in the city during his tenure; 63 miles of "median strips with planters were built into city streets and filled like cornucopias with flowers, plants, shrubs, and of course, more trees."
“It’s not just about beautification. And he gets that," Lisa Roberts, director of the Garfield Park Conservatory ("one of the nation’s largest and oldest—which was on the verge of total collapse when Daley put her in charge of a complete renovation") told Metropolis. "One of the smart things he did was to bring in some researchers to address city council members who showed that the presence of greening in people’s lives has a direct link to lowering crime rates, improving test scores, boosting real estate values, et cetera."
I would add: a greener city is also likely to be a more walker-friendly community.
(If you'd like to see what planting trees can do for a moribund business district, do take a look at this Flash presentation from Urban Advantage).