According to a systematic review of research on the relationship between violent crime and urban green space, the presence of parks and other green space reduces urban crime. Potential causes include the role of green spaces in social interaction and recreation, their ability to affect community perception, their role in biophilic stress reduction and climate modulation, and their ability to indicate community ownership.
Shepley, Mardelle, Naomi Sachs, Hessam Sadatsafavi, Christine Fournier, and Kati Peditto. “The Impact of Green Space on Violent Crime in Urban Environments: An Evidence Synthesis.” International Journal of Environmental Research and Public Health 16, no. 24 (2019): 5119. https://doi.org/10.3390/ijerph16245119.