Tree-lined streets boost a community's overall health, new research suggests

How different types of green space affect mental health.

Tree-lined streets boost a community's overall health, new research suggests
Photo credit: Vladimir Kudinov on Unsplash
  • Increasing tree canopy cover increases residents' mental wellbeing.
  • Research suggests that trees give greater benefits than low-lying grasslands.
  • Adults with 30 percent or more tree coverage in their neighborhood had 31 percent lower odds of developing poor general health.

A deluge of studies, personal anecdotes, and some plain old common earthly sense, has found that living near green spaces leads to an overall healthier life. People live longer, have stronger cognitive functions, and possess greater peace of mind.

A new study dug a little deeper into this phenomenon and found that different types of greenery affect health benefits. The research suggests that urban residents' mental health correlated more positively when they lived near tree-lined streets or higher density vegetative spaces.

Authors Thomas Astell-Burt and Xiaoqi Feng of the University of Wollongong in New South Wales write, "Our findings suggest that urban greening strategies with a remit for supporting community mental health should prioritize the protection and restoration of urban tree canopy. In addition, the promotion of equal access to tree canopy may provide greater equity in mental health."

The evidence suggests that urban reforestation projects should be at the forefront of future urban greening projects.

Urban green space and mental health

The large scale study featured 46,786 residents of three Australian urban regions. These subjects were interviewed between 2006 and 2008, with follow-up reports in between 2012 and 2015.

Participants were asked to rate their overall health and inform the researchers on whether or not they'd been diagnosed with anxiety or depression. They were also given questionnaires to determine their levels of psychological distress.

Researchers took this information and compared it with the natural features of where they lived within their mesh block — a small geographic unit that contains 30 to 60 residences. With the aid of satellite imagery, the team calculated the total amount of green space surrounding them, making sure to divide it into "separate green space types, including tree canopy, grass, or other low-lying vegetation."

Taking into account variables such as age, gender, household income, and education, the researchers confidently agreed that green space is associated with "lower odds of incident psychological distress."

Interestingly enough, they also found that exposure to low-lying greenery was not always associated with more positive health outcomes. Surprisingly grasslands were found to give greater odds of psychological distress:

"Plain, flat grassy areas may not be particularly attractive for walking, which is an important form of social and physical recreation for older adults."

All evidence points to trees being the prime reason for increased mental wellbeing. Tree-lined streets give a number of unintended benefits and must be protected. The researchers write,

"Street trees in prime building locations are at a particular risk of being cut down. Shorn of tree canopy, sidewalk temperatures can be higher, sidewalks can seem noisier, and walkers along them are exposed to more air pollution. Street trees provide a valuable aesthetic use, such as providing pleasant views from the side of an adjacent street."

Growing more trees

Living in areas where 30 percent or more of the space had tree canopy, researchers found that there were 31 percent lower odds of psychological distress compared to those living under no tree coverage — and to those living beneath 10 percent of it.

The greening of cities is gaining momentum. Paris has unveiled a massive plan, on top of their already successful reforestation initiative, they're also planning to cover half of the city's acreage with trees.

Green space amplifies mental health benefits by bringing back a natural biodiverse ecosystem that disrupts the stress-laden hustle of urban living.

Sitting under the cool shade of a tree might be all that you need to relieve your stress.

A new study says it's okay to eat red meat. An immediate uproar follows.

Even before publication, health agencies were asking the journal not to publish the research.

Photo by Isa Terli/Anadolu Agency/Getty Images

Surprising Science
  • A new study in the Annals of Internal Medicine found little correlation between red meat consumption and health problems.
  • A number of organizations immediately contested the evidence, claiming it to be based on an irrelevant system of analysis.
  • Beef and dairy production is one of the leading drivers of climate change, forcing humans to weigh personal health against the environment.
Keep reading Show less

CRISPR therapy cures first genetic disorder inside the body

It marks a breakthrough in using gene editing to treat diseases.

Credit: National Cancer Institute via Unsplash
Technology & Innovation

This article was originally published by our sister site, Freethink.

For the first time, researchers appear to have effectively treated a genetic disorder by directly injecting a CRISPR therapy into patients' bloodstreams — overcoming one of the biggest hurdles to curing diseases with the gene editing technology.

The therapy appears to be astonishingly effective, editing nearly every cell in the liver to stop a disease-causing mutation.

The challenge: CRISPR gives us the ability to correct genetic mutations, and given that such mutations are responsible for more than 6,000 human diseases, the tech has the potential to dramatically improve human health.

One way to use CRISPR to treat diseases is to remove affected cells from a patient, edit out the mutation in the lab, and place the cells back in the body to replicate — that's how one team functionally cured people with the blood disorder sickle cell anemia, editing and then infusing bone marrow cells.

Bone marrow is a special case, though, and many mutations cause disease in organs that are harder to fix.

Another option is to insert the CRISPR system itself into the body so that it can make edits directly in the affected organs (that's only been attempted once, in an ongoing study in which people had a CRISPR therapy injected into their eyes to treat a rare vision disorder).

Injecting a CRISPR therapy right into the bloodstream has been a problem, though, because the therapy has to find the right cells to edit. An inherited mutation will be in the DNA of every cell of your body, but if it only causes disease in the liver, you don't want your therapy being used up in the pancreas or kidneys.

A new CRISPR therapy: Now, researchers from Intellia Therapeutics and Regeneron Pharmaceuticals have demonstrated for the first time that a CRISPR therapy delivered into the bloodstream can travel to desired tissues to make edits.

We can overcome one of the biggest challenges with applying CRISPR clinically.


"This is a major milestone for patients," Jennifer Doudna, co-developer of CRISPR, who wasn't involved in the trial, told NPR.

"While these are early data, they show us that we can overcome one of the biggest challenges with applying CRISPR clinically so far, which is being able to deliver it systemically and get it to the right place," she continued.

What they did: During a phase 1 clinical trial, Intellia researchers injected a CRISPR therapy dubbed NTLA-2001 into the bloodstreams of six people with a rare, potentially fatal genetic disorder called transthyretin amyloidosis.

The livers of people with transthyretin amyloidosis produce a destructive protein, and the CRISPR therapy was designed to target the gene that makes the protein and halt its production. After just one injection of NTLA-2001, the three patients given a higher dose saw their levels of the protein drop by 80% to 96%.

A better option: The CRISPR therapy produced only mild adverse effects and did lower the protein levels, but we don't know yet if the effect will be permanent. It'll also be a few months before we know if the therapy can alleviate the symptoms of transthyretin amyloidosis.

This is a wonderful day for the future of gene-editing as a medicine.


If everything goes as hoped, though, NTLA-2001 could one day offer a better treatment option for transthyretin amyloidosis than a currently approved medication, patisiran, which only reduces toxic protein levels by 81% and must be injected regularly.

Looking ahead: Even more exciting than NTLA-2001's potential impact on transthyretin amyloidosis, though, is the knowledge that we may be able to use CRISPR injections to treat other genetic disorders that are difficult to target directly, such as heart or brain diseases.

"This is a wonderful day for the future of gene-editing as a medicine," Fyodor Urnov, a UC Berkeley professor of genetics, who wasn't involved in the trial, told NPR. "We as a species are watching this remarkable new show called: our gene-edited future."

UFOs: US intelligence report finds no aliens but plenty of unidentified flying objects

A new government report describes 144 sightings of unidentified aerial phenomena.

Photo by Albert Antony on Unsplash
Surprising Science

On June 25, 2021, the Office of the Director of National Intelligence released a much-anticipated report on UFOs to Congress.

Keep reading Show less