Joni Mitchell sang about "paving paradise" in the 1970s, but some U.S. cities like Portland, Ore., are now making parks from parking lots and creating urban forests that cut pollution and save energy. Which are the nation's 10 best for greenery?
For a top 10 list, released Tuesday, a federally funded survey looked at the 50 most populous U.S. cities to see which have the most parkland per capita as well as which do the most to create green spaces and make them accessible to the public.
Portland, which has also turned a freeway into a riverfront park, made the cut, according to the survey by American Forests, a non-profit group that restores and protects forests. Also on the list, in alphabetical order: Austin, Charlotte, Denver, Milwaukee, Minneapolis, New York City, Sacramento, Seattle and Washington, D.C.
"As communities across the country manage more and more for the impact of climate change and other critical environmental and social challenges, their urban forests become even more important to the health of their city," Scott Steen, the head of American Forests, said in announcing the findings.
Steen said the project's judges, which included federal and private forest experts, found that urban green spaces also help manage stormwater runoff, promote tourism, boost property values and reduce crime.
The survey says parkland covers 18% of Austin and 19.5% of New York City, where Mayor Michael Bloomberg has set a goal of planting one million trees by 2017. It says Charlotte has a public-private initiative, Trees Charlotte, to plant trees on public property.
Minneapolis has a park every six blocks while the nation's capital has 7,000 acres of parkland and Sacramento has a 33-mile bike trail, according to the survey. The Denver Botanical Garden has more than 32,000 species of plants and Milwaukee's Lakeshore State Park has a 40-acre sculpture garden. Seattle, which has an old-growth forest, turned the site of an oil plant into a park.