From Arbor Day Site (https://www.arborday.org/trees/treefacts/) :

 

Trees help reduce crime!

In Baltimore, a 10% increase in tree canopy corresponded to a 12% decrease in crime. 
share  University of Vermont and U.S. Forest Service, 2012

Among minor crimes, there is less graffiti, vandalism and littering in outdoor spaces with trees as a part of the natural landscape than in comparable plant-less spaces. 
share  University of Washington

Chicago public housing residents with nearby trees and natural landscapes reported 25% fewer acts of domestic aggression and violence. 
share  University of Illinois, Urbana-Champaign, 2001