Tree-lined residential streets are nice places to live and now, according to a new study by the University of Miami, we know they are also healthier places for residents. Larchmont area neighborhoods are already among the greenest in the city, and many residents are strong advocates of tree plantings to replace old or diseased trees. For many, it’s because trees make neighborhoods more beautiful, but now there’s evidence that a healthy tree canopy promotes greater health among the residents too.
According to the new study:
Growing evidence supports greater health benefits for people who live in ‘green’ neighborhoods – those with more tree canopy and street level vegetation specifically on the block where they live. A new study from researchers at the University of Miami Miller School of Medicine and the School of Architecture adds to this emerging recognition– finding a 28 percent lower risk for depression and 18 percent decreased risk for Alzheimer’s disease compared with residents of blocks low in greenness.
Interestingly, the association was even more pronounced in low-income areas. An increase from one standard deviation below to one standard deviation above the mean greenness level was associated with 37 percent lower odds of depression. In contrast, the risk decreased by 27 percent in medium-income neighborhoods and by 21 percent in high-income neighborhoods. The difference between low- and high-income neighborhoods was statistically significant for depression and trended toward significance for Alzheimer’s disease risk.
The findings were published online March 1 in the International Journal of Environmental Research & Public Health.
Of particular interest is the mental health benefit, which suggests that environment is more important to health outcomes:
Even though some initial research suggested improvements in cognitive function associated with more neighborhood vegetation, “to our knowledge no one has looked at block-level greenness in relation to either of these two mental health outcomes,” said lead study author Scott Brown, Ph.D., research assistant professor of public health sciences and architecture, and project director of the UM Built Environment, Behavior, and Health Research Team.
Investigators focused on depression and Alzheimer’s disease because of their critical public health importance. “The World Health Organization considers depression one of the chronic conditions most likely to lead to disability in the world,” Brown said. “Also, Alzheimer’s disease is currently in the No. 6 position for leading causes of death in the United States.”
The findings of the study could help physicians counsel at-risk patients with more specific recommendations based on where they live. “Oftentimes in the doctor-patient encounter there is a recommendation to exercise more in addition to the other recommendations,” Brown said. “But it may be important to know about the environment where the person lives.” Miami-Dade Parks offers programs at low cost or no cost for low-income populations, for example. “So there may be ways the physician can help the patient discover where it is they can engage in physical activity.”
So efforts to green our neighborhoods can now claim another reason for their importance and another reason to be deserving of our support. Also, officials from the City of Los Angeles Department of Urban Forestry recently told the members of the Hancock Park Garden Club that the leading cause of death among new trees is lack of water and weed whackers. To protect these young trees, they recommend clearing a large well around the trees to keep grass from growing next to the trunk, and consistently deep watering…especially in our current drought conditions. They also advised against removing any mature tress, unless they are dead or dying, because mature trees in front yards or parkways are extremely valuable and worth saving, not to mention very expensive to replace.