Can trees reduce aggression, violence and crime? Multiple studies say, “Yes!” October is domestic violence awareness month. Let trees be part of the solution. Levels of aggression and violence have been shown to be significantly lower among individuals who have some nearby nature outside their apartments than among their counterparts who live in barren conditions. Surveys exploring these results show residents with green views report using reasoning more often in conflicts with their children rather than violence. They also report less use of physical violence in conflicts with partners compared to those living in buildings without trees.

There is a strong relationship between higher levels of tree canopy and lower levels of crime, regardless of socioeconomic factors. In New Haven, Connecticut a 10% increase in tree canopy was associated with a 14% decrease in property crimes and a 15% decrease in violent crime. Similar results were found in Baltimore, with a 12% drop in all outdoor crimes for each 10% increase in tree canopy. In Chicago, an old rail corridor turned tree-lined trail had the unexpected result of a rapid decrease in the local crime rate. A public housing development, also in Chicago, had 48% fewer property crimes and 56% fewer violent crimes in or around buildings with more greenspace.

Urban greening can be used to create more defensible, safer outdoor spaces. Visibility is a key factor. Areas with larger trees and more open space are generally deemed safer than areas with dense vegetation (small trees and large shrubs.) Trees equate to a potential economic value of $928 million in reduced costs of crime for victims and property owners per year. For more information and links to published research, visit public safety in the Vibrant Cities Lab and Nature’s Riches: The Health and Financial Benefits of Nearby Nature.

Article written by: Olivia Witthun, WI DNR Urban Forestry Coordinator, 414-750-8744, Olivia.Witthun@wisconsin.gov