Trees: Stockton’s stoic crime fighters

Stockton has a lot of crime; this is no secret. Stockton also benefits from a tremendous tree canopy and was once named “Best Tree City.” Is there a correlation between crime and trees? Yes, but maybe not the kind you were thinking of. While Stockton suffers from soaring crime rates, evidence shows the presence of trees can have a positive effect on public safety. Obviously, planting trees won’t magically stop crime, but it’s important to understand that there is a relationship between public safety and good tree coverage.

In the past there have been conflicting theories on the relationship between crime and greenery. Some studies have suggested more vegetation provides criminals more places to hide, increasing crime rates. On the other hand, some have suggested that the presence of trees and landscaping has something of a “broken windows” effect, deterring crime by showing criminals that people care about the neighborhood. Turns out, both of these theories may hold some weight, according to a new study of the relationship between trees and crime.

In a recent report in Landscape and Urban Planning, researchers studying Baltimore, Maryland found a clear inverse relationship between tree coverage and crime. Specifically, the study concluded that overall, a 10% increase in tree coverage was associated with a roughly 12% decrease in robberies, burglaries, thefts, and shootings. Baltimore, setting for the best TV show in history, The Wire, suffers from a bad crime reputation just like Stockton, so these results are somewhat telling for our community, especially since our city’s trees are suffering from a lack of maintenance.

But not all types of vegetation are associated with lower crime rates. Within the study area, the researchers found that areas with more unkempt and overgrown vegetation experienced an increase in crime rates, showing that not all crime fighting flora are created equal. Clearly, healthy trees are better at deterring criminal activity than overgrown bushes and shrubs.These findings are consistent with other studies done on trees and crime, as noted by the Atlantic Cities.

A recent study in Baltimore found a 10% increase in tree coverage led to a 12% decrease in crime

Just to be clear, the argument here is not that places with trees are simply safer than those without trees. Many will read this and argue that older neighborhoods with mature trees are not nearly as safe as newer suburbs with no tree coverage. This argument may be true, but misses the point of this kind of study. The research controls for other factors affecting crime rates such as income level and race by using regression analysis, meaning that the researchers are able to isolate the effects of trees on crime when all other factors are equal. It is best to interpret the study’s findings in the following way: a neighborhood that has 10% more tree coverage than another neighborhood with the same socioeconomic demographics will experience 12% less crime than the comparable neighborhood. I have written before about the positive correlation between property values and trees, and we now have proof that trees can also fight crime.

While Stockton is not Baltimore, the information provided by this study is still relevant, especially since the city’s trees face dwindling maintenance budgets. The big takeaway here is not that we need to plant more trees to help stop crime. Instead, the study shows that we cannot afford to let our existing trees fall into a further state of disrepair. On top of policing shortages and stagnant economic conditions, allowing our tree canopy to decrease could compound our already difficult crime problem.

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Categories: Community Commentary

Author:David A. Garcia

David A. Garcia created SCL in March of 2012. Garcia is a Stockton native with a background in urban policy and planning, holding a Bachelor's Degree from UCLA as well as a Master's Degree in Public Policy from the Johns Hopkins Institute for Policy Studies. He currently serves as the Policy Director at the UC Berkeley Terner Center for Housing Innovation. David was also COO at Ten Space, a real estate development firm focused exclusively on Downtown Stockton, and continues to advise on their projects. Prior to that, he worked three years as a researcher/analyst for a Congressional research agency in Washington, DC. The views expressed on this site are entirely of the author's

5 Comments on “Trees: Stockton’s stoic crime fighters”

  1. Ned Leiba
    June 7, 2012 at 9:03 pm #

    The benefits of urban and rural trees are well studied, well supported and fundamental to the health of human community. As you observe, crime is related to the community and neighborhood environment. Holding all other factors the same, a nicer, greener, more tree populated neighborhood, will be a neighborhood with less crime. For many reasons, enhanced tree planing and landscaping should be at the top of our list of essential environmental goals for our City. I am alarmed that other weakly justified proposals seem to top the official list, e.g., solar photo voltaic (SPV) may become mandated for new and even older remodel structures, which means (1) trees will need to be removed or cut back to increase the extremely modest efficiency of SPV, (2) the enormous funds spent on SPV and other such measures, could much more wisely and economically be used to support trees and landscaping.

  2. LW
    June 11, 2012 at 7:28 pm #

    I like Stockton City Limits very much and I look forward to each new article. This blog illustrates the value of planning to communities.

    I wonder about the issue of water consumption and trees. As the Upper Central Valley has experienced water stress, perhaps the water usage for various types of trees to be planted could be taken into account.

  3. Ned Leiba
    June 11, 2012 at 9:00 pm #

    Water stress is a problem, but paradoxically, the higher the ambient co2 content, the better trees and other plants do in the face of water shortage or increased temperature. I believe there are many well controlled, scientific studies that support this conclusion, e.g., the Idsos have a long list of such scientific studies reported at their website Co2 Science.

  4. Stockton City Limits
    June 13, 2012 at 1:50 pm #

    Thanks for the comments, LW and Ned.

    There have been studies done recently that show higher temperatures, ironically brought on by the urban heat island effect, increase the rate of growth for trees. The study is detailed here:

    With respects to the question regarding water stress and trees, the city does have an approved tree planting list which can be found here.

    As you can see, many of the trees that are permitted are “drought resistant” species, particularly larger trees. Trees that traditionally looked nice but were water-guzzlers are no longer approved for residential planting (eg palm trees). Many cities have taken into account water scarcity as well as tree diseases and vulnerability to pests and are attempting to diversify their urban forests to protect against these types of problems.


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