Street trees can reduce non-accidental and cardiovascular mortality. In a study of street trees planted in Portland over 30 years, planting 11.7 trees annually in each census tract was associated with 15.6 fewer non-accidental deaths and 5 cardiovascular deaths per year when controlling for race, education, income, and age. Older, larger trees were more connected to reduced mortality than saplings.
Donovan, Geoffrey H., Jeffrey P. Prestemon, Demetrios Gatziolis, Yvonne L. Michael, Abigail R. Kaminski, and Payam Dadvand. “The association between tree planting and mortality: A natural experiment and cost-benefit analysis.” Environment International 170 (2022). https://doi.org/10.1016/j.envint.2022.107609.