May 8, 2013, 11am PDT
Recent analysis shows that Louisville, Ky. suffers from the worst 'heat island' conditions among America's 50 largest cities. The city is also one of the few without a tree ordinance. Coincidence? Sarah Goodyear investigates.
January 11, 2011, 7am PST
A study of tree cover and pregnant women suggests that women living in areas with more trees are less likely to give birth to undersized babies.