The physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing): evidence from field experiments in 24 forests across Japan.

Park BJ, Tsunetsugu Y, Kasetani T, Kagawa T, Miyazaki Y.
Environ Health Prev Med. 2010 Jan;15(1):18-26

https://www.ncbi.nlm.nih.gov/pubmed/19568835