Being able to take a walk in the park should be as easy as, well, a walk in the park. Research published in the September 2015 issue of Frontiers in Ecology and Environment has confirmed what many may have already suspected: A breath of fresh air in the middle of a large city can do a body good.
Researchers analyzed case studies of nine major international cities and found that high-density cities with large parks, such as Golden Gate Park in San Francisco and Table Mountain National Park in South Africa, provide the most benefits to humans and the environment.
"Large parks are essential to provide some ecosystem services that indirectly benefit people, like pollination, carbon storage and water filtration," says Iain Stott, PhD, lead author and associate research fellow at the University of Exeter's Environment and Sustainability Institute.
While previous studies have shown that urban green spaces are crucial for the good health of both people and the environment, there has been some debate over the best approach: Should cities build compact housing developments with large parks or create smaller gardens and green spaces that are interspersed within sprawling suburbs?
"Our research finds that compact developments that include large green spaces are essential for the delivery of ecosystem services," Dr. Stott says. "For humans to get the most benefit, however, combining this approach with… street trees and some small parks and gardens is the best method."
But it can be unrealistic for denser cities to try to provide large parks, says Peter Harnik, director of The Trust for Public Land's Center for City Park Excellence. "The reality is, in a place like San Francisco or New York, I can't just say, 'Can we have a small park or a large park?' It's not realistic... You can't just uproot people to build a park."
That doesn't mean cities can't get creative, however: Many are now building "railroad trails," or narrow green spaces that run along old tracks. The spaces provide long stretches of green without taking up a lot of prime urban real estate. Chicago's new 606 park, for example, stretches for almost three miles but takes up only 24 acres of total space. (For reference, Golden Gate Park is more than 1,000 acres.)
"Hundreds of thousands of people will get to get their hearts pounding and lungs breathing on this trail," Harnik says.
Stott suggests that cities looking to provide more urban housing build compact, high-rise style housing that leaves larger areas open for green space. Small parks are good, he says, but city expansion without proper parks is a problem that ultimately limits city-dwellers' ability to reap the health benefits of the great outdoors.