Some neighborhoods could use more of both—more cops, that is, as well as a greener environment. Since the former is discussed often, let's talk about the latter.
Greening a city can lower its crime rate, research increasingly suggests, and can make poor, segregated areas not only safer but generally more livable.
It's long been assumed that vegetation abetted crime in urban areas, because it makes it easier for offenders to hide and escape. But a study in the November-December issue of the journal Landscape and Urban Planning, focusing on the relationship between trees and crime in Philadelphia, found that the more vegetation in an area, the lower the rate of aggravated assaults, robberies, and burglaries. It wasn't merely because wealthier areas have more trees; the researchers controlled for poverty and the educational attainment of residents.
This followed a study in the same journal in June that looked at Baltimore, and found a "strong inverse relationship" between tree canopy and robbery, burglary, theft, and shooting. An increase of 10 percent in tree canopy was associated with at least a 12 percent decrease in crime. The researchers controlled for income, race, and other socioeconomic factors.
In 2011, a study in the American Journal of Epidemiology reported intriguing findings about an ambitious program to green vacant lots, again in Philadelphia. From 1999 to 2008, nearly 4,500 of the city's vacant lots were greened—trash was removed, the land was graded, grass and trees were planted, and low fences were installed around the lots. The researchers found "consistent, statistically significant" reductions in gun assaults in the areas near the greened lots, compared with areas near lots that were left alone.
The authors of the most recent study, Jeremy Mennis and Mary K. Wolfe of Temple University, wrote that vegetation may deter crime in two ways. A more pleasant setting draws people outside, and the more eyes on the street, the less likely offending is. Vegetation may also have a "mentally restorative effect" that suppresses crime, the authors observed. Their data on vegetation abundance came from satellite imagery, which couldn't show how well-maintained the vegetation was. The authors speculated that "an abundance of unmanaged vegetation in abandoned lots" could signal "that there is little or no social authority exerting control over an area, and that consequently deviant behavior may be tolerated"—whereas well-maintained vegetation would send the opposite signal.
The authors of the vacant-lot study—researchers from the Perelman School of Medicine at the University of Pennsylvania—also presumed that maintenance was key. "Violent crime may have simply been discouraged in the presence of greened and tended vacant lots which signaled that someone in the community cared and was potentially watching over the space in question," they wrote.
Alex Kotlowitz, writing in Mother Jones last summer about urban farming in poor Chicago neighborhoods, observed that such enterprises "have less to do with providing healthy food than they do with a reclamation of sorts"—of urban farmers "taking ownership of their community and their daily lives."
Chicago has supported community farming, and is considering greater support, with a Green Healthy Neighborhoods project in the works for Englewood, Washington Park, and Woodlawn that, among other things, would increase farming on vacant lots. Given the variety of ways in which urban farming seems to help—supplying healthy food, teaching skills to participants, providing a handful of jobs, leading occasionally to the "reclamation" Kotlowitz noted, and reducing crime as the studies suggest—backing it makes sense.
There already are some laudable farming enterprises in depressed or border areas of Chicago—in the far-south-side Riverdale neighborhood, for example, and near the Cabrini-Green rowhouses, and in North Lawndale. But Chicago still has plenty of room for growth, literally, in its poorer neighborhoods. A recent mapping of gardens here by University of Illinois researchers showed that the vast majority of Chicago residents—2.4 million out of 2.7 million—live in census tracts with no community gardens; that nearly half of these tracts have a poverty rate above the city average of 21 percent; and that most of these low-income tracts are on the south and west sides. These are areas with many sprawling vacant lots that would benefit from farming or at least better tending. Community gardens set up near racial borders in the city, and designed to encourage farming by racially and economically mixed groups, would be especially helpful.
Urban farming isn't a panacea—and if the goal is to try to make poor, segregated neighborhoods sustainable, this is a wrongheaded campaign. Chicago shouldn't continue to ignore the culprit chiefly responsible for its violence: the decades of racial segregation, and the bitter fruit those years have borne—concentrated poverty on the south and west sides. Racial and economic integration need to be fostered, in housing and in schools, throughout the city and the metro area.
But segregation's roots are deep and dense, eradicating them is a long-term job, and there's been little evidence that any leaders—here or in Washington—are ambitious enough to take on that project. Efforts that treat symptoms in the meantime are welcome. Urban greening is one of these.