April 1 (UPI) -- When researchers analyzed healthcare expenditures and environmental data in 3,086 of the 3,103 counties in the continental United States, they found counties with more trees and shrubs have lower Medicare costs.
The correlation persisted even after researchers accounted for socioeconomic factors that influence health care costs. Researchers found healthcare costs in the poorest counties, both rural and urban, benefited the most from a higher density of trees and shrubs.
"At first, I was surprised by this," Douglas A. Becker, a graduate student at the University of Illinois at Urbana-Champaign, said in a news release. "But then it occurred to me that low-income communities are getting the biggest bang for their buck because they probably have the most to gain."
The latest findings -- published this week in the journal Urban Forestry and Urban Greening -- confirm the conclusions of a number of other studies linking green spaces and exposure to nature with improved health and wellness outcomes.
Several studies have identified correlations between urban green spaces and improved mental health -- less depression and anxiety. One study even showed patients in intensive care recover more quickly if their hospital room looks out at trees and green space instead of a parking lot.
Scientists have also linked trees, parks and green space with improved childhood eating habits and lower crime rates. Unfortunately, in the United States, wealthier citizens have greater access to green space than those living in poorer communities.
Becker and his research partner, Matt Browning, a professor of recreation, sport and tourism at the University of Illinois, used the National Land Cover Database to measure the density of trees and shrubs in each county. The database divides the nation into 30-meter-square plots and classifies each as either open space, forest, grassland, shrubs or agricultural cover.
"We took the average of different types of land cover and the per capita Medicare spending in a county and compared these two while controlling for several socioeconomic and demographic factors like age, sex, race, median household income, health care access and health behaviors," Becker said.
Becker and Browning determined that for every 1 percent of land that is covered in forest, a county saves $4.32 per person per year in Medicare costs.
"If you multiply that by the number of Medicare fee-for-service users in a county and by the average forest cover and by the number of counties in the U.S., it amounts to about $6 billion in reduced Medicare spending every year nationally," Becker said.
The savings are closer to $9 billion when the cost savings of scrublands are accounted for.