Greening Land to Improve Public Health

Imagine making a significant improvement in the mental health of entire communities at a cost of just a couple hundred dollars per year. That is the conclusion of a study published on the JAMA Network entitled: Effect of Greening Vacant Land on Mental Health of Community-Dwelling Adults (by Eugenia C. South, MD, MS; Bernadette C. Hohl, PhD; Michelle C. Kondo, PhD; John M. MacDonald, PhD; Charles C. Branas, PhD). Funding and support for the study was provided by the National Institutes of Health and the Centers for Disease Control.

I wanted this study to be the subject of my first blog post. The trials conducted in their study were completed between 2011 and 2014 in Philadelphia, PA. I came across their results shortly later and have kept this filed away due to the significant impact of their results and conclusion. If the experiment can be replicated in other cities with similar conclusions, their strategies can be an effective (and low-cost) way to improve lives.

The study was arranged to test the physical conditions of neighborhoods to determine how those conditions impact the mental health of the residents living there. Specifically, they wanted to test how “greening” vacant land would have an impact. For the study, vacant lots across the city were selected if they exhibited “blight” such as unmanaged vegetation growth, abandoned cars, or material illegally dumped on the site. Also, the focus of the study was on small vacant lots so only lots <5,500 square feet were eligible.

Their “greening” interventions would include removing garbage from the side, re-grading land areas if needed, planting new grass and small trees, installing low wooden fences, and, finally, hiring services for regular monthly maintenance of the sites. I thought the “low wooden fences” might have actually been one of the keys to the success of these interventions. Fences can be an excellent way to define an area and demonstrate it is cared for. In a northern climate like Philadelphia, much of the grass and trees will become barren for significant parts of the winter months, but the fences will remain visible and purposeful to the site.

The study randomly picked vacant sites to receive the greening interventions and other sites were chosen to remain the same and serve as the control group for the study. Residents within 0.25 miles of the sites were interviewed in the 18 months leading up to the lot interventions. They were not told of any connection between the surveys and the modification of vacant lots in their neighborhood. The residents were then again surveyed in waves in the 18 months after the greening interventions were completed.

The results of the study were impressive, if not staggering, given the low-cost and simplicity of these interventions. Participants living near the greened lots had a 41% decrease in reporting “feeling depressed” versus the control group. And those reporting “feeling worthless” saw a 51% drop in the greening group versus the control. In regards to the cost of the greening efforts, the study estimated each lot under the greening application had an initial cost of $1,597 per lot and $180/year to maintain that.

Obviously this isn’t something that would improve the health lives of everyone in the neighbordhood, but as a whole this type of effort and work can have very positive population-level effects that shouldn’t be overlooked. Making physical / structural changes to areas with blight is a real way to improve mental health.

Similar work to what has been described in this study is actively taking place over at Better Way Detroit (betterwaydetroit.org). BWD is a nonprofit organization working to engage, feed, counsel and even pay homeless persons through employment opportunities around the city. Especially in the summer months, the organization is paying to employ workers to clean Detroit parks and neighborhoods of trash, and remove the overgrowth – to make them safer and, according to the JAMA Network Effect of Greening study, improving the mental health of all residents with the vicinity of their efforts!