The association between urban trees and crime: Evidence from the spread of the emerald ash borer in Cincinnati
Loss of trees in urban neighborhoods is associated with an increase in crime
This study used a natural experiment approach to investigate the association between urban trees and crime. The setting for this study was Cincinnati, Ohio where the emerald ash borer (EAB) started killing trees in 2007. The EAB is one of the most invasive tree pests, killing over 100 million trees in North America since it was first discovered in Detroit in 2002. Cincinnati was chosen as the setting for this study because the city kept detailed records of where and when they removed a diseased ash tree.
For this study, city block groups with ash tree removals served as the treatment group while city block groups without ash tree removals served as the control. Pre-treatment data included tree canopy measures from the year 2000 and demographic data from the U.S. Census American Community Survey for the years 2005-2009. The Cincinnati Police Department provided crime data (including date, location, and type of crime) for the years 2005-2014.
Crimes in the EAB infested areas were then compared with crimes in the non-infested areas. Results indicated more crime in the infested areas than in the non-infested areas. Calculations indicated that the loss of each additional tree was associated with significant increases in theft, breaking and entering, property crime, assaults, and violent crimes.
The results of this study suggest that the loss of ash trees in urban areas due to EAB infestation may be associated with an increase in crime. These findings also suggest that planting trees in urban areas might be used as an effective crime-prevention measure.
Kondo, M.C., Han, S.H., Donovan, G.H., MacDonald, J.M., (2017). The association between urban trees and crime: Evidence from the spread of the emerald ash borer in Cincinnati. Landscape and Urban Planning, 157,