Green infrastructure and violence: Do new street trees mitigate violent crime?

Exposure to violence has been deemed as a public health epidemic due to its negative impact on mental health outcomes, especially for residents of neighborhoods where violent crime is prevalent. Access to nature has the potential to mitigate diminished mental health outcomes, such as aggression. However, current literature specifying effective and equitable green infrastructure practices is lacking. The purpose of this study was to measure the extent to which Portland's green infrastructure initiative reduced neighborhood violence by increasing the availability of new trees to residents of underserved communities as a modality for green infrastructure intervention. Lagged multilevel modeling was used to determine whether an increase in new street trees resulted in reduced violent crime counts in the years following the planting of the trees. Results indicated that there was a strong negative correlation between the number of trees planted and violent crimes in the years following the planting of trees, net of neighborhood covariates. This effect was especially pronounced in neighborhoods with lower median household income. These findings suggest that the inclusion of new street trees in underserved neighborhoods may be one solution to the endemic of violence in such neighborhoods.