CHAMPAIGN, Ill. — A novel research project has shown that areas with greater amounts of green space have a lower prevalence of police violence. The study is the first to find a significant relationship between greenness levels and fatal police shootings, and it showed that the most socially and economically disadvantaged areas seemed to benefit the most from green spaces.
"It's a novel discovery. We don't know of anybody that's explored this question," said University of Illinois Urbana-Champaign landscape architecture professor William Sullivan , who was part of the research team. "It opens a new line of research on an outcome that hardly anybody has thought about in terms of the benefits of greener places to live."
The research team also included Bin Jiang , a landscape architecture professor at the University of Hong Kong who received his doctoral degree at Illinois; Jiali Li , a doctoral student advised by Jiang who was the project manager and main data analyst; and Matthew Browning , a former Illinois faculty member who is now the co-director of the Virtual Reality and Nature Lab at Clemson University.
The research, which was published by the journal " Environment and Behavior ," "suggests the quantity and quality of landscape matters for achieving safer neighborhoods and regions," Jiang said.
The team collected data on green space and on fatal shootings by police officers from 3,100 counties in the U.S., including 805 metropolitan counties, over a 5-year period from 2016-2021. They also looked at social deprivation measures of disadvantaged communities to provide a larger social context. The social deprivation measures include poverty, educational levels, single-parent households, rental properties, overcrowded housing units, households without a car and employment rates for individuals under age 65.
"This research was rigorous and comprehensive, with extensive controls to account for other variables," Sullivan said.
He said that he was initially skeptical that any relationship could be found between a space's greenness and police shootings. Initial findings showed a negative relationship between greenness and police shootings and, he said, "to my astonishment, as the social deprivation score got higher, the relationship between greenness and police shootings got higher. That is, the greener the county, the fewer fatal police shootings at every level of social deprivation."
The team considered hypotheses as to why this might be the case.
"We believe that higher levels of greenness can reduce violence through four major mechanisms: reduced crime, improved short-term and long-term mental health, sending a signal that a place is well-cared for and increasing the use of outdoor spaces by nearby neighbors," Li said.
Previous research indicates that green spaces contribute to faster recovery from stress, better mental health and reduced levels of crime and violence, Sullivan said.
"People who are mentally fatigued have much greater challenges controlling impulses. They are more likely to miss subtle social clues, and they are more likely to be in a bad mood or aggressive," he said.
"If a space is greener, police officers may feel a little less stressed themselves," Sullivan said. "If that's the case, they bring their better cognitive capacities to any engagement with the people that live in these communities, and they are more likely to bring their best professional skills to bear to de-escalate and avoid violence."
Previous research also has shown that more greenness contributes to stronger ties among neighbors, who may spend more time outside socializing in a greener environment. This can increase civic engagement and informal surveillance of the neighborhood and make residents more inclined to resolve conflicts non-violently, the researchers said.
"When neighborhoods are greener, there is a stronger sense that somebody cares about this place and that it's a safer place," Sullivan said.
The type of greenness matters though. The researchers noted that some studies have found that green sites can become territory for gangs, and that people fear for their safety when vegetation limits visibility or provides hiding places for people engaged in illicit activity. It is not only the number of green spaces, but also their quality, that matters, Jiang said.
The study is a basis for further research. For example, the researchers said that fatal police shootings often are undercounted and the data they used didn't include non-fatal police shootings. They said that further research is needed to understand the mechanisms behind the negative association between green spaces and police shootings, and what variables influence individuals versus groups.
The study provides additional evidence for the health-promoting effects of green spaces that city planners, real estate developers and landscape architects can use to show how investing in greener neighborhoods benefits a community, the researchers said.
"Adding green cover may be one of the least expensive interventions available to a community seeking to reduce violence. This could involve converting vacant lots into mini-parks or community gardens or implementing urban forestry programs," Li said.
The researchers said that although green spaces are beneficial, reducing violence will require communities to also address systemic issues in the criminal justice system, implement community policing practices and provide training and support for police officers.
"We acknowledge that even if the greenness level in a community is related to fatal police shootings, a great deal more needs to be done to understand the case. We also acknowledge that addressing police shootings requires considerably more than planting trees and other forms of vegetation in neighborhoods," they wrote.
