Cardiovascular Disease

• In 15 states infected with emerald ash borer, an additional 15,000 people died from cardiovascular disease and 6,000 more from lower respiratory disease compared with uninfected areas of the country.Donovan, G.H. et al. (2013). The relationship between trees and human health: Evidence from the spread of the emerald ash borer. American Journal of Preventative Medicine, 44(2), 139-145.

Asthma

• Levels of asthma are highest where tree density is the lowest but the rate of childhood asthma is 29% lower for every 343 trees per square kilometer.Lovasi, G.S., Quinn, J.W., Neckerman, K.M., Perzanowski, M.S., and Rundle, A. (2008). Children living in areas with more street trees have lower prevalence of asthma. J Epidemiol Community Health, 62(7), 647-649.

Obesity

• Accounting for socioeconomic factors, residents of areas with the highest levels of greenery were three times as likely to be physically active and 40% less likely to be overweight or obese than residents living in the least green settings.Ellaway, A., Macintyre, S., and Bonnefoy, X. (2005). Graffiti, greenery, and obesity in adults: secondary analysis of European cross sectional survey. The BMJ, 331(7517), 611-612.

Skin Cancer

• Urban trees reduce ultraviolet (UV) radiation, especially UV-B radiation, which is known to cause skin cancer. A person standing in direct sunlight takes 20 minutes to burn. Under a tree providing 50% coverage, it takes 50 minutes to burn. Under full shade it takes 100 minutes for one to get a sunburn.Grant, R.H., Heisler, G.M., and Gao, W. (2002). Estimation of pedestrian level UV exposure under trees. Photochemistry and Photobiology, 75(4), 369-376.