Making urban environments just 10 per cent greener by planting more trees could prevent thousands of premature deaths every year, study shows
- Researchers used multiple studies to calculate the impact of trees on health
- They focused on the impact trees would have on the US city of Philadelphia
- The authors say their universal findings apply to any city around the world
Planting trees and making urban environments greener – especially in poorer neighbourhoods – can prevent thousands of deaths per year, researchers claim.
Scientists at the Barcelona Institute for Global Health projected the impact of increasing tree cover in the city of Philadelphia on public health.
By increasing the number of trees in an urban environment by just 10 per cent, researchers say millions of premature deaths could be prevented in the city.
They say that having greener cities may also reduce the impact of climate change, support biodiversity and boost the economy by millions of pounds annually.
Scientists at the Barcelona Institute for Global Health projected the impact of increasing tree cover in the city of Philadelphia on public health but did so in a way that the findings could be applied to any city in the world
The findings, published in The Lancet Planetary Health, follow recent analysis by the WHO which studied more than eight million people globally and found green spaces around homes could protect against early death by any cause.
For the first time researchers analysed the impact of increasing green spaces in an entire city by using nine different longitudinal reports and say the findings can apply to any city – not just Philadelphia.
Scientists studied three possible scenarios for the American city of Philadelphia in the year 2025 – with results replicable for other cities around the world.
The most ambitious was based on the city’s current goal of increasing tree coverage by 10 per cent in each of the city’s neighbourhoods – which would take the canopy from 20 to 30 per cent for the city as a whole.
The other two scenarios of five and 10 per cent were less ambitious.
Analysis showed 403 premature adult deaths could be prevented if Philadelphia achieves its goal of increasing tree coverage to 30 per cent of the city by 2025.
That figure represents three per cent of the city’s annual deaths but even the more moderate scenarios were associated with significant reductions in annual mortality.
A 10 per cent increase in tree canopy could see 376 fewer deaths each year, and a five per cent increase could see deaths fall by 271.
The study showed poorer neighbourhoods would benefit most from any increase in green spaces and increasing the tree canopy to 30 per cent of land area in the city could yield an estimated annual economic benefit of almost four billion dollars.
Study coordinator Dr Mark Nieuwenhuijsen from the Barcelona Institute for Global Health said every city has its own characteristics but this study works globally.
‘Many lives can be saved by increasing trees and greening urban environments, even at modest levels,’ he said.
Massive development of new multi-story apartment buildings in Sydney including tree cover. By increasing the number of trees in an urban environment by just 10 per cent, researchers say millions of premature deaths could be prevented in the city
‘What’s more, green spaces increase biodiversity and reduce the impact of climate change, making our cities more sustainable and more liveable.’
Study first author Dr Michelle Kondo from the United States Forest Service said many of the prevented deaths would be in the poorest parts of the city.
She said a notable reduction in deaths in poorer areas could be achieved with a small increase in tree coverage.
‘Urban reforestation programmes are not only essential for improving public health, they are also a way to reduce health inequities and promote environmental justice.’
She added: ‘Achieving this goal does not come without challenges.
‘Large tree planting initiatives are faced with many problems, including losses from climate change, tree pests and invasive species, and urban development.’
They also found that you can get a similar health benefit from simply making areas greener – not just from trees.
The research has been published in the journal The Lancet Planetary Health.