Just ran across this article, which describes a statistically significant correlation between the presence (or absence) of trees and human health. In urban areas of the upper midwest most heavily affected by the Emerald Ash Borer—which has in the past 10 years killed over 100 million ash trees—human mortality rates from cardiovascular and respiratory illnesses have risen significantly. In another study, patients in post-operative recovery have been found to heal more quickly, and with less need for pain medications, when there is even a single tree visible through the window of their room. Correlations have also been found between reduced feelings of anger, sadness, depression, and chronic physical pain of all types with regular exposure to forested landscapes. Immune response has been shown to be increased (and stress hormones reduced) simply by walking in a woodland, leading to the practice of forest bathing.
Good article, but it’s unfortunate that the author (or editor) chose to focus on the negative, half-empty cup (“When Trees Die, People Die”); the title should have been “Regular Exposure to Trees found to be Tremendously Beneficial to Human Physical and Mental Health.”