According to Joseph Murray, biology instructor at Blue Ridge Community College in Weyers Cave, Virginia, it's the latter:
Police tend to believe more vegetation means less visibility. A study in 2001 looked at subsidized housing units with varying amounts of vegetation around them. The most calls to the police came from the building with the least vegetation. Those with more vegetation tended to draw residents who demanded benches and well-maintained playground equipment. Then, people were out there watching.We need to internalize more sophisticated models of the impact greening and gardening can have on urban communities. It's much more than "neighborhood beautification"; at least, when it's done well, it is. People need green growing things around them to be healthy, to reduce stress, to connect with neighbors, and to feel positively about belonging where they live. Gardening builds and supports community resiliency to respond creatively and constructively to internal and external crises and pressures. Gardening builds community. As it should.
- Urban Forestry Has Crime Prevention Role, Patricia R. McCoy, Alliance for Community Trees, January 22, 2008