A study of 9,186 U.S. nursing homes found that increased tree canopy cover is associated with fewer depressive symptoms. This association did not vary by race or socioeconomic status of nursing home residents.
Browning, Matthew H.E.M., Kangjae Lee, and Kathleen L. Wolf. “Tree cover shows an inverse relationship with depressive symptoms in elderly residents living in U.S. nursing homes.” Urban Forestry & Urban Greening 41 (2019): 23-32. https://doi.org/10.1016/j.ufug.2019.03.002