Study Finds Proximity To Trees Associated With Healthier Newborn Outcomes

A recent study by Drexel University's Dornsife School of Public Health highlights the significant health benefits of increasing urban tree cover, particularly in underserved communities. The research indicates that enhancing green spaces can reduce stress, improve mental health, and lower mortality rates. 

Using a unique dataset - the planting of more than 36,000 trees between 1990 and 2020 in Portland, Oregon, by the nonprofit group Friends of Trees - the researchers measured the number of new trees planted within 100 meters of a mother's address for the first 10 years after their child's birth (using Jan. 1, 2015 - December 31, 2020, birth data from the Oregon Health Authority), existing tree cover and road coverage in that area.

"Although there is benefit from well-established trees, we're finding that newly planted trees are also associated with healthy birth weight," said senior author Yvonne Michael, ScD, a professor and interim chair in the Dornsife School of Public Health. "This is another data point showing that planting trees is a relatively easy and low-cost way to improve public health from the earliest stages of a life."

Living within 100 metres of at least 10 trees was associated with about a 50-gram increase in birth weight, according to the researchers. The birthweight benefit from trees generally tops out at about 10 trees, the researchers found.

"Fifty grams may not seem like a lot, but if every baby in our sample gained 50 grams at birth, that means 642 fewer babies considered small for gestational age and at higher risk for worse development later in life," said Michael, who noted that there were 2,879 babies with that diagnosis in the study.

Notably, the study estimates that achieving a 30% tree canopy in Philadelphia could prevent approximately 400 premature deaths annually, with the most substantial benefits observed in lower-income neighbourhoods. These findings underscore the importance of equitable urban greening initiatives as a cost-effective strategy to address health disparities and promote environmental justice.