22 February 2021.

New research using the 45 and Up Study has found that increasing urban tree canopy may help improve our physical health, restore mental health, and could even reduce the risk of dementia. These findings are now helping to improve city design.

headshot of Thomas Astell-Burt
Professor Thomas Astell-Burt

Professor Thomas Astell-Burt wants to see universal access to safe, inclusive, accessible and high quality green spaces in Australian cities. As Professor Astell-Burt points out: “Not all green spaces are the same. Some types of green space may be more effective for restoring and enabling better health than others. We wanted to generate new knowledge to maximise population health benefits of urban greening strategies.”

An NHMRC Leadership Fellow based in the University of Wollongong’s School of Health and Society, Professor Astell-Burt leads his lab of postdoctoral researchers and PhD students conducting environmental epidemiological studies of green space type and various health outcomes in the 45 and Up Study.

Among the many results he has published so far, Professor Astell-Burt found a 16% lower risk of developing dementia over 11 years, and 22%, 17%, and 31% lower odds of developing heart disease, hypertension, and diabetes, respectively, over six years. These results were from adults living in the cities of Sydney, Wollongong and Newcastle who had more than 30% tree canopy within a 1.6km walk, compared to those with less than 10% tree canopy.

He also found many of the same individuals with more than 30% tree canopy nearby had 33% lower odds of developing poor health in general, 31% lower odds of developing psychological distress, and 13% lower odds of having insufficient sleep over six years.

Exactly why trees are so good for our minds and bodies could be due to many reasons. Big trees with ample crowns offer shade from the sun. They are a natural distraction from stressful thoughts and bring us closer to other resident wildlife. They can also provide inspiring and attractive spaces for social and physical recreation.

Critically, the research offers new insights for urban planners and landscape architects – providing new, local evidence on just how valuable trees are, why we should protect them, and why we should plant more. “These results suggest, ideally, that everyone would have easy access to parks with lots of trees,” says Professor Astell-Burt. “The walk from home to parks, shops, bus stops, schools and workplaces would also, ideally, have plenty of tree canopy overhead to provide natural shade and keep us connected to nature.”

What this means for green space design

While the findings are intriguing, Professor Astell-Burt and his team at the University of Wollongong haven’t stopped there. They’ve been actively using the evidence to support the call to make urban neighbourhoods more liveable through urban greening, from giving a ‘Big Ideas’ talk, to reaching out to NSW Department of Planning, Industry and Environment, the Heart Foundation, Parks and Leisure Australia, Western Sydney Diabetes and various councils and local health districts to connect and share findings. Professor Astell-Burt and his team have also organised conferences and run monthly ‘PowerTalks’ and workshops that brought together scientists with councils, retirement communities, hospitals and NGOs to build capacities and drive local change – with evidence cited in the Wollongong City Council’s Urban Greening Strategy 2017-2037.

All of this translation work has contributed to a larger nation-wide discussion about the importance of protecting and restoring green space in our cities. In early 2019, the shift in interest in green spaces moved forward significantly when two new priorities were added to the NSW Premier’s Priorities. The first being to increase the proportion of homes in urban areas within 10 minutes’ walk of quality green, open and public space by 10% by 2023. And the second to increase the tree canopy and green cover across Greater Sydney by planting one million trees by 2022.

Professor Astell-Burt’s findings also support similarly ambitious canopy restoration programs being taken on by cities outside NSW, with 30% tree canopy targets set for the cities of Canberra, Seattle, Barcelona, and Vancouver.

How to create impact

Translating evidence into the real world can be a long road, but Professor Astell-Burt says that passion and perseverance are key. Here are his tips for creating impact:

  • Focus on research that you are interested in and could enrich the lives of others
  • Engage communities early on and listen to their feedback – incorporate what they value and why
  • Share your findings widely, beyond academic settings – back yourself and take the first step!

Meet other researchers who are using the 45 and Up Study for high-impact work.

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