Large trees in urban areas are associated with lower crime rates, says a U.S. Forest Service study. Conversely, smaller trees around homes were associated with higher crime rates.
Large trees make a home seem more cared for, hence its residents seem more vigilant, researchers speculate. Smaller trees provide more places for criminals to seek cover.
From 2005-2007, researchers studied 413 reports of burglary, vandalism, and other crimes at 2,813 single-family homes in Portland, Ore. The research also considered landscaping factors, such as whether the front door was covered by vegetation. Nearby businesses, such as bars, were also considered.
Geoffrey Donovan led the research for the U.S. Forest Service’s Pacific Northwest and SouthernÂ Research Stations. The results were published in the journal Environment and Behavior.
Planting trees in high crime areas could have a positive effect on property values and reduce crime, but only if done right. Tree plantings need to avoid blocking lines of sight or providing hiding places. Proper pruning of smaller trees could also reduce crime, by removing places criminals can lurk.
One question that remains unanswered: Does the presence of large trees reduce crime, or is the lower crime rate because older, larger trees tend to grow in more-established neighborhoods?
Figuring that out could help city planners decide whether to start recruiting trees into the police force.