An intriguing new study makes an association between the loss of trees and impaired health.
The study, by researchers with the U.S. Forest Service, found an increase in deaths from cardiovascular disease and lower respiratory disease in areas of the United States where the emerald ash borer has devastated ash tree populations.
The researchers looked at 18 years' worth of data from 1,296 counties in 15 states affected by the ash borer. It found an additional 15,000 deaths from cardiovascular disease and 6,000 deaths from lower respiratory deaths when compared with uninfected areas. The researchers took into account demographic differences such as race, income and education.
"There's a natural tendency to see our findings and conclude that, surely, the higher mortality rates are because of some confounding variable, like income or education, and not the loss of trees," researcher Geoffrey Donovan said in a news release from the Forest Service. "But we saw the same pattern repeated over and over in counties with very different demographic makeups."
Nevertheless, the study did not prove a causal link between tree loss and the increase in deaths.
The findings are published in the current issue of the American Journal of Preventive Medicine.