One school of thought has it that inner-city trees and shrubs make convenient hiding places for criminals. Another, argues that urban foliage may actually reduce crime. Where previous studies have tended to focus on individual housing blocks or neighborhoods, new research out of Temple is among the first to examine the issue at the city-scale. Jeremy Mennis, associate professor of geography and urban studies at Temple, analyzed the relationship between vegetation concentration and crime for all of Philadelphia. "As vegetation increases, aggravated assaults, robberies, and burglaries decrease," he said.