Research has shown city dwelling is associated with a higher risk of depression and anxiety. Could a lack of greenery be contributing to this issue? A recent study provides urban planning food for thought, as researchers found even the smallest of intentional urban green space—such as street trees—can greatly benefit mental health. Follow Now : Apple Podcasts / Spotify / Google Podcasts
The Study
By analyzing data from nearly 100,000 individuals, researchers in Leipzig, Germany, established a connection between the presence of individual trees planted on city streets and the instance of prescription antidepressants. The data on antidepressant medication prescriptions came from an adult health study run by the University of Leipzig on individuals aged 18-79. With these numbers in mind, researchers compiled data on the number and species type of trees planted throughout Leipzig’s streets, as well as their distance from people’s homes. They then combined the datasets to identify any sort of association. It’s important to note that the focus on street trees, rather than parks or other types of green space, was intentional. Whereas visiting a park often requires conscious intention, trees planted on city streets induce a more passive consumption of nature. They are observed unintentionally on walks through the neighborhood or through the windows of a home. This makes for more easily accessible daily contact with nature. Study researchers concluded that a greater presence of trees around the home was associated with a decreased risk of being prescribed antidepressant medication, most notably for individuals living at a lower socio-economic status. And as a small-scale, public green space, street trees could act as a nature-based solution to the health inequity experienced by these individuals.
Spaces for Healing
Lead study author Melissa Marselle, PhD, points out that her findings support past studies’ discoveries that green space surrounding the home reduces social inequalities in health. “Some of the pathways through which low socio-economic status might lead to worse mental health are possibly modified by exposure to nearby nature,” Marselle says. “These pathways are psychological restoration—attention restoration, stress reduction. Stress and poor attentional functioning are risk factors for depression, and these risk factors are experienced more in individuals with low socio-economic status.” However, focused efforts to plant a high number of trees near homes in these areas could effectively reduce risk factors that jeopardize mental health. And these benefits have been on the radar of certain mindful experts for some time. Chicago architect Paul Alt specializes in the design and planning of healing environments. His studio, Alt Architecture + Research Associates, has produced a series of healing sanctuaries in cities across the country for military veterans returning to civilian life. He points to sunlight and views of nature as design attributes that facilitate healing. “What this means is if the individual is exposed to nature, the individual’s heart rate and blood pressure reduces, allowing for the body to restore quicker,” Alt says. “If you are in a traffic jam on a boulevard full of trees and flowers, your anxiety levels will be less than an individual caught on a four-lane expressway.” This study provides concrete data to show greenery in even the smallest capacity can greatly benefit community members. This specificity is important. Marselle criticizes much of past research on urban nature for being too broad. “This generic information is not specific enough to guide decisions by city planners or urban foresters,” Marselle says. “In order to better design cities with nature, we need to know what types of urban nature are important for mental health—parks, forests, grass fields, street trees—and where they should be located in the city.”
Improved Urban Planning
By ensuring trees are planted equally across a city’s neighborhoods, regardless of the socio-economic status of the individuals living there, city planners can play a part in leveling the playing field of access to health benefits. At the same time, Marselle hopes her findings can help city planners address other global dilemmas without having to embark on large-scale, expensive projects. “Cities are stressful environments,” she says. “Our study suggests that trees planted in residential streets in cities can serve as a nature-based solution to reduce the risk of depression, and the burden on the NHS while having the added benefits of addressing climate change and biodiversity loss.” As urban populations continue to increase, planting trees along neighborhood streets could be a small and simple step toward improving quality of life for city dwellers.
