Emerald Ash Boer (EAB) is devastating urban forest tree populations all over the Midwest. Cities commonly talk about how expensive it is to remove infested trees. Sometimes progressive cities with excellent urban forestry programs plan to replace the trees. No one has really talked about the other costs associated with losing so much canopy cover.
We know that the way a place is designed and cared for can directly impact crime. The presence of trees is generally believed to deter crime. However, when trees are too low or overgrown they can provide cover for criminals. But what about when an invasive species like EAB causes widespread destruction of the urban forest?
To gain insights into how the loss of trees affects crime rates, a group of USDA foresters and University of Pennsylvania researchers studied nine years of crime data from Cincinnati, OH in areas hard hit by EAB.
They took a look at crime as defined by the Cincinnati Police Department, simple assault, felony assault, rape, theft, burglary, robbery, breaking and entering and criminal damage or endangerment. They also looked at index crimes: Violent crimes (murder, rape, simple and felony assault and robbery) and property crimes (burglary, theft, criminal damage and endangerment).
EAB was associated with higher crime in all categories except damage/endangerment, burglary, robbery and rape. “…the loss of each additional tree was associated with a significant increase in theft, breaking and entering and property crime incidents (p <0.001) and in simple assaults, felony assaults and violent crimes (p <0.001) at EAB-infected block groups compared to in non-EAB infected block groups.” Crime jumped between 1-2% per block group. Property crimes rose the most.
There are limitations on the data. The study did not determine whether or not losing trees to EAB increased crime in Cincinnati or whether crime simply moved from one part of the city to another. The study also aggregated data by census block, so it cannot be generalized. Trees lost on private property were not included, nor was the effect of removing trees over time.
Even though there are limitations, it was clear: Losing trees “was associated with a relative increase in crime rates in Cincinnati” from 2007 to 2014. Their results suggest that when healthy trees are present, crime may be deterred.
Add planting trees to city crime fighting plans in addition to street lights, neighborhood watch groups and police patrols.
January 3, 2017 NewTerrain.