Sure, a park is nicer to look at than a trash-filled vacant lot. But according to a new study from the University of Pennsylvania, greening abandoned urban space might also save lives.
In 1999, the Pennsylvania Horticultural Society began a program of cleaning vacant lots in Philadelphia. They cleared them of trash, leveled the land, planted grass, and built low fences to make the lots feel like parks. Each one got maintenance checkups several times a year.
Dr. Charles C. Branas, associate professor of Epidemiology at the Perelman School of Medicine, University of Pennsylvania, decided to see if those greened lots improved the health and safety of residents living nearby. His research, published online in the American Journal of Epidemiology, is striking.
Branas and his team looked at the period from 1999 to 2008. They got dates and locations for various crimes and arrests from the Philadelphia Police Department and health survey data from the Philadelphia Health Management Corporation. They then looked at how those metrics changed around the 4,436 lots that had been greened during the decade. To make sure they were isolating the effects of the greening program, they also tracked “control” lots that hadn’t been greened but were in comparable neighborhoods to those that had.
The results? Greening vacant lots was “associated with consistent reductions in gun assaults” across the entire city. In some parts of the city, the greened lots were also associated with consistent reductions in vandalism, lower stress levels, and even higher rates of exercise.
Why exactly the greened lots had these positive effects isn’t entirely clear. It might be due to what’s called a “broken windows” effect, where tidy, well-maintained public spaces discourage crime across the board. Another factor could be the well-documented psychological and physiological benefits of being near nature.
Regardless, this is just another reason for cities (or, you know, guerrilla gardeners) to make crumbling urban spaces greener and more hospitable. A little time and money invested in an abandoned lot could forestall a shooting.