The environmental theory posits that the location and context of the crime bring the victim of the crime and its perpetrator together.
Studies in the early 2010s showed that crimes are negatively correlated to trees in urban environments; more trees in an area are congruent with lower victimization rates or violent crime rates. This relationship was established by studies in 2010 in Portland, Oregon and in 2012 in Baltimore, Maryland. Geoffrey Donovan of the United States Forest Service (USFS), one of the researchers, said, "trees, which provide a range of other benefits, could improve quality of life in Portland by reducing crime..." because "We believe that large street trees can reduce crime by signaling to a potential criminal that a neighborhood is better cared for and, therefore, a criminal is more likely to be caught." Note that the presence of large street trees especially indicated a reduction in crime, as opposed to newer, smaller trees. In the 2012 Baltimore study, led by scientists from the University of Vermont and the United States Department of Agriculture (USDA), a "conservative spatially adjusted model indicated that a 10% increase in tree canopy was associated with a roughly 12% decrease in crime.... [and] we found that the inverse relationship continued in both contexts, but the magnitude was 40% greater for public than for private lands."