As forests have always been my favourite place for leisure time, I should have known. Forests, and other natural, green settings, can reduce stress, improve moods, reduce anger and aggressiveness and increase overall happiness. And it can be measured objectively according to Dr. Eeva Karjalainen of the Finnish Forest Research Institute, Metla in ScienceDaily of 27 July 2010. Blood pressure, heart rate, muscle tension and the level of stress hormones all decrease faster in natural settings. That is a big relief after all the worrisome news lately about all the threats to human health that forests harbour. Like ticks that can transmit Borrelia burgdorferi, the bacteria that causes Lyme disease, or voles that can transmit Hanta virus, of which some can be mortal for humans.
Another benefit of forests is the compounds they provide us with to make therapeutic drugs. So, perhaps it is possible that there is enough scientific evidence to proof that forests' health benefits outweigh their risks. And perhaps this will lead to physicians prescribing forest visits as a cure. The fundaments are being explored already with the drafting of the Health Impact Assessments in forest context by the 'forHealth' task force. More about the task force to be found here.So far for my ignorance on the healing effects of forests.
Just recently some additional proof has been published in the American Journal of Preventive Medicine. In a study of the USDA Forest Service the presence of trees was associated with human health. In an analysis of 18 years of data from 1,296 counties in 15 states, researchers found that Americans living in areas infested by the emerald ash borer, a beetle that kills ash trees, suffered from an additional 15,000 deaths from cardiovascular disease and 6,000 more deaths from lower respiratory disease when compared to uninfected areas. When emerald ash borer comes into a community, city streets lined with ash trees become treeless. Although the study shows the association between loss of trees and human mortality from cardiovascular and lower respiratory disease, it did not prove a causal link. The reason for the association is yet to be determined.