Just published, The Health Benefits of Parks: How Parks Help Keep Americans and Their Communities Fit and Healthy draws from the latest research to outline the ways in which parks, open space, greenways, and trails support and promote healthy lifestyles, potentially decreasing health care costs. The second in Trust for Public Land’s planned series of white papers on park benefits, the 24-page report is intended to help park professionals and volunteers make the case for parks as a wise community investment.
The first in the series about the health benefits of trees, published July 2005, generally laid out how green space in urban areas provides substantial environmental benefits. Trees reduce air pollution and water pollution, they help keep cities cooler, and they are a more effective and less expensive way to manage stormwater runoff than building systems of concrete sewers and drainage ditches.
Trees in New York City removed an estimated 1,821 metric tons of air pollutants in 1994. In an area with 100 percent tree cover (such as contiguous forests stands within parks), trees can remove from the air as much as 15 percent of the ozone, 14 percent of the sulfur dioxide, 13 percent of the particulate matter, 8 percent of the nitrogen dioxide, and 0.05 percent of the carbon monoxide.
Trees also act as natural air conditioners to help keep cities cooler, mitigating the effects of concrete and glass that can turn cities into ovens under the summer sun. The evaporation from a single large tree can produce the cooling effect of ten room-size air conditioners operating 24 hours a day.
The City of Garland used an innovative method to encourage private-property owners to plant more trees. It mapped all the impervious surfaces in the city and then changed the formula for charging stormwater fees to property owners. Instead of tying the fee to property value or charging a flat fee, the city now bases the fees on the property’s impervious surface and the volume of stormwater the property generates. An analysis showed that Garland’s tree cover saves it from having to handle an additional 19 million cubic feet of stormwater. Building facilities to handle that stormwater would cost $3.8 million.
Exposure to Nature and Greenery Makes People Healthier
Beyond the recreational opportunities offered by parks, a growing body of research shows that contact with the natural world improves physical and psychological health. One important study reviewed the recoveries of surgical patients in a Pennsylvania hospital. The rooms of some patients overlooked a stand of trees, while others faced a brown brick wall. A review of ten years of medical records showed that patients with tree views had shorter hospitalizations, less need for painkillers, and fewer negative comments in the nurses’ notes, compared with patients with brick-wall views.
The Excellent City Park System
Another related study delves into what makes city parks great and how aspiring cities can get there. A notable case study from the report is the Phoenix Department of Parks and Recreation, which maintains a staff that includes more than 40 foresters, horticulturalists, and landscape architects. The heart of the study recommends seven measures of an excellent city park system, and three have a direct correlation to urban trees.
#1: A Clear Expression of Purpose notes that, in the urban setting, trees must be planned. They don’t always instinctively grow in a pleasing and usable fashion.
#3: Sufficient Assets in Land, Staffing, and Equipment to Meet the System’s Goals asks how many natural resources professionals- horticulturalists, foresters, and landscape architects- are on staff.
#7: Benefits for the City Beyond the Boundaries of the Parks highlights that the city will benefit from cleaner air as trees and vegetation filter out pollutants by day and produce oxygen by night, and improved learning opportunities from outdoor classrooms in forests,
Trust for Public Lands- Health Benefits of Parks white paper
New York Times- Thinking Outside the Sandbox
The Benefits of Parks- Parks for People (PDF)
The Benefits of Parks- Health (PDF)
The Excellent City Park System (PDF)
City Parks Foundation