Increases in the number of urban trees could make people feel healthier and reduce instances of cardio-metabolic conditions according to research in Scientific Reports this week.

Marc Berman and colleagues investigated the relationship between neighbourhood greenspace, specifically trees besides streets and in other areas such as parks and domestic gardens, and people’s perceived level of health. Using self-reported data from 31,109 residents in Toronto via an online questionnaire, the authors found that people who live in areas with a higher street tree density reported having a better perception of their health. They also reported fewer cardio-metabolic conditions such as hypertension and obesity compared to those participants living in areas with fewer trees on the street.

The authors found that an increase of ten street trees per block, equivalent to a four percent increase in tree density, increased health perceptions comparably to increasing each household’s income by $10,200, or being seven years younger. Increasing the number of trees to 11 led to a decrease in cardio-metabolic conditions comparable to an increase in personal income of $20,000 a year or being 1.4 years younger.

Although the study does not identify the mechanisms by which the benefits may occur, the authors suggest that improving air quality, relieving stress and promoting physical activity could all be contributing factors to improved reported health.