Two Aussie cities failing at 'incredible' planning tactic being embraced overseas
The ‘3-30-300' rule is revolutionising the liveability of cities in Europe and the United States, but few people know of it in Australia.
After mapping 2.5 million buildings across eight cities including Sydney and Melbourne, researchers have uncovered a worrying problem. The RMIT team was examining how a planning ideal that’s taken route internationally was being embraced in Australia.
The concept is called the ‘3-30-300' rule, and it’s seen as essential for human well-being. It states that every home, workplace and school should have the following:
A view of at least three trees
Be in a neighbourhood with at least 30 per cent tree canopy cover
Sit within 300 metres of a park
Lead researcher Dr Thami Croeser explained to Yahoo News how he became aware of the rule. “I was in a meeting in Spain and someone mentioned this incredible test, and I thought I don’t think anyone has tested it in Australia. I wonder if anyone knows about it?” he said.
Maps reveal where Aussie cities lack canopy
Choosing a city with access to a shady tree canopy and green open spaces is important for physical and mental health. People with a lack of access are known to suffer higher rates of depression, anxiety, obesity and heatstroke.
Maps created by RMIT and Dutch firm Cobra Groeninzicht clearly show massive differences between Sydney and Melbourne, with red highlighting very little shade and green indicating areas that are close to the 30 per cent benchmark.
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Melbourne which has reasonably affordable property prices and proudly boasts being one of the world’s most liveable cities, fared particularly poorly with only 3 per cent of its innermost suburbs having adequate canopy coverage. At 17 per cent Sydney was better, but it certainly didn’t pass muster.
There were two cities that Croeser examined that did have more than adequate canopy cover, the city-state of Singapore had 45 per cent, and US city of Seattle had an impressive 75 per cent.
The research was authored by Roshan Sharma, Wolfgang Weisser and Sarah Bekessy and published in the journal Nature Communications on Tuesday.
How can tree canopy planning be improved?
The ‘3-30-300' rule was devised in 2021 by Dutch urban forestry expert Professor Cecil Konijnendijk. It's gained momentum in Europe and the US, where six cities have implemented the measure into their planning strategies, but it’s been largely overlooked here.
Croeser analysed two local cities to see how they stacked up against the concept by using high-quality data provided by the City of Sydney and the City of Melbourne.
While his research focused on human health and wellbeing, he believes subsequent studies should focus on how diverse the canopy cover is, and whether it is useful habitat.
“You could have a line of trees down the street that are all London plane trees, and a little bit of understory that’s all agapanthus. But for native wildlife that’s useless,” Croeser said.
Croeser believes satellite mapping coupled with AI technology could soon help planners examine which areas are serving native animals and birds. This is something he is actively researching.
“Imagine you're a native bird. Just having the native species there is good, but have you got enough structure in your landscape? Are there enough bushes? Or if you are a bug, are there enough flowers?
“Is there enough water, and are the trees linked up enough so they can move between them?”
How do we make our cities more beautiful?
Most buildings examined by RMIT had views of at least three trees, but they lacked adequate canopy cover. This led the research team to conclude the problem could be that the trunks weren’t being allowed to grow tall enough.
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Croeser thinks the issue is that urban trees are heavily pruned. But they also don’t live long, and they grow slowly.
“The reason is that we plant them in holes in the concrete. If you looked under a modern footpath you’d find crushed rock under the pavers. We cut a hole, put a bit of soil in it and plant the tree,” he said.
“If you walk around, you’ll see lots of weird street trees. It would be the same if you fed me once a week — I’d be looking pretty sick — and I probably wouldn’t grow 6 feet tall.”
To fix the problem Croeser believes city planners need to rethink the standard which dedicates 80 per cent of street space to road and car spaces. But that doesn’t mean radically handing entire streets back to pedestrians.
“It could be as small a change as turning one in 10 parking spaces into a little island in which you have a tree that’s actually planted in a proper volume of soil,” he said.
“Some places have gone further, narrowed the street a bit and got nice big trees. Certainly in some European cities they’re getting a really stunning effect when they say we don’t need that much parking.”
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