While we at Ostvig Tree Care might seem biased on the benefits of planting trees on your property – whether it’s a private or shared space within your community – you’d be hard-pressed to argue with independent studies that support the fight for foliage.
Studies in Baltimore and Philadelphia, both published in the journal Landscape and Urban Planning, have linked areas with increased forestry to low crime rates in both urban and rural areas. A few other studies with similar findings were conducted in Pennsylvania, in faraway UK, and in a closer proximity here in Minnesota. Here is a summary of the studies and what it means to us in Minnesota.
Researchers from the University of Vermont and USDA Forest Service were able to compare the crime rates and tree canopy of geographical locations throughout the greater Baltimore area to determine their relationship. They found that areas with a 10% increase in tree coverage had a 12% decrease in crime. The study also cites suggestions that having vegetation in neighborhood areas encourages the community to enjoy their environment. The safety of the neighborhood is therefore strengthened by the number of onlookers to detect and report suspicious activity. Download the full study paper here.
A study at Temple University had very similar results. Researchers found that crime, specifically assaults and robberies, was lower in areas of high vegetation. The authors concluded that such greenery encourages interaction within the community and a higher level of supervision of the shared spaces. They also cited the “window box theory” – neighborhoods with a well-maintained indicate a “stable, healthy community” – as well as the suggestion that trees have a calming effect on humans. You can read more about the study here.
The results of these studies aren’t exclusive for the areas mentioned above. In fact, researchers, Geoffrey H. Donovan and Jeffrey P. Prestemon, conducted a study in Portland, Oregon with the same outcome.
A few other studies show similar observations on the relationship of urban trees and crime rates. Here’s a similar study in UK, The Benefits of Urban Trees. “Two mechanisms are suggested by which crime rates might be reduced by trees. The first is through an increase in surveillance, essentially because public open space with trees tends to be used much more than space without trees. The second mechanism relates particularly to violent crime and relates to evidence that vegetation has a mitigating effect on mental fatigue, itself often a precursor of outbursts of anger and violence.“
A closer study, entitled Understanding the Relationship between Tree Canopy and Crime in Minneapolis, Minnesota using Geographically Weighted Regression was done by Andrew W. Eckerson in Saint Mary’s University of Minnesota, in Winona, MN. “These findings
support the conclusions of previous literature that the relationship between tree canopy and
crime is inverse.” More trees in Minnesota bring about lesser crime rates.
The Department of Criminology in the University of Pennsylvania conducted a working paper in 2015, The Effect of Trees on Urban Crime: Evidence from the Spread of the Emerald Ash Borer in Cincinnati. They conducted experiments by removing Ash Tree in certain areas. The study did not provide any insights into the mechanisms linking tree loss to shifts in crime. However, the working paper results are consistent with criminology theories suggesting that trees may reduce crime by making the built environment less attractive to potential offenders. On the other hand, tree loss may be a sign of neighborhood blight, which signal to a potential offender that a neighborhood is not well cared for. If trees indeed encourage more pedestrians on a street, which deters potential offenders, the loss of trees could serve the opposite purpose.
Overall, the results broadcast a key message: make it known that your community is cared for. A healthy, mature tree is a positive reflection on the care of the community and saplings indicate growth within the area. Including forestry in your landscape and your community’s landscape will signify a warm, welcoming neighborhood – making yours a destination. While there are large cities across the U.S. with higher crime rates than those of Minneapolis and the Twin City area, we can all take steps in ensuring that our communities stay safe for ourselves and our neighbors.