A University of Pennsylvania study found that the Pennsylvania Horticultural Society program to “green” nearly 4,500 vacant lots in Philadelphia resulted in a significant reduction in gun assaults across all four sections of Philadelphia and significant reductions in vandalism in one section of the city. In addition, the program has enhanced the health of residents, created jobs and increased surrounding property values.
The PHS program began in Philadelphia in 1999 and involves clearing trash, grading the land, planting grass and trees, and installing fences around each lot to prevent illegal dumping. The Penn study was led by Charles C. Branas, PhD, associate professor of epidemiology at the Perelman School of Medicine and compared ten years of data between vacant lots and improved vacant lots. “The large number of vacant lots we studied and the design of our analysis make this study some of the strongest evidence to date that greening vacant urban land is a promising approach to improving health and safety” Branas commented. The cleaner environment eliminates hiding places for firearms and signals that the city has regained control over those areas, discouraging crime.