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We all like to spend time in green space and in our local parks and gardens, but are these just a perk that boost property values?
Or are trees and parks essential infrastructure, like roads, rail and high-speed internet? It’s a question for us to ponder as the ACT Government launches a public inquiry into the “value of the natural environment to an urbanising Canberra”.
In cities the world over, population growth is putting pressure on parkland, while private outdoor space shrinks. Many people are losing access to green space – something that has implications for the environment and the long-term health and wellbeing of people.
The World Health Organization has summarised the physical and mental health benefits of green space, and the findings make for compelling reading. Living close to urban green spaces can increase our levels of physical activity, enhance respiratory health, boost immune systems and reduce rates of obesity. Astoundingly, proximity to parks has also been found to lower the incidence of domestic violence, stress and depression and may even mitigate attention deficit disorder in children.
A recent report published by engineering firm AECOM has also found that money really does grow on trees. AECOM examined three Sydney suburbs, identifying a positive trend between street trees and land value. Where there was a 10 percent difference in net leaf canopy coverage, property prices were on average $50,000 higher.
In fact, a study from the University of Wisconsin has found that green space is even more important than money. Researchers found a person on a very low income living near greenery was more likely to report a higher level of peace and happiness than a wealthier person living in an area with less greenery.
Green space also plays an important role in biodiversity, can lower pollution levels, improve water quality, reduce flooding and even dampen noise levels.
The Nature Conservancy, a global not-for-profit working to bring nature back to our cities, has studied the effects of trees on air quality in 245 of the world’s largest cities and has found that trees and vegetation can filter up to 30 percent of the fine particles that form air pollution.
Green space also combats the “urban heat island effect” which can see temperatures in cities soar. One study, for example, estimated that doubling the leaf canopy in Melbourne would cut heat-related deaths by around a quarter.
Kip Tanner, a Director with Canberra Town Planning, says no one wants to live in a city with no green space. “Green infrastructure is the lungs of the city,” he explains.
“If you pave a city with bitumen and concrete it is much hotter over the day and the heat sticks around at night. So, the impacts from heat waves are far worse. And then everyone inside buildings cranks up the air-conditioning, which then contributes to climate change. The best way to combat this is to have shade trees and irrigated spaces.”
CSIRO’s research backs up this view. A team of scientists recently mapped Canberra’s urban heat temperatures, finding the parts of our city with above-average surface temperatures were characterised by “large expanses of impervious surface cover such as rooftops and paving, and few trees, common in commercial and industrial areas, carparks and new housing developments”.
In contrast, the coolest areas in Canberra typically had “green irrigated vegetation, more tree cover, are near lake edges, or are shaded by buildings or topography”.
Despite all this evidence, it remains a tricky task to quantify the benefits of green infrastructure. Everyone wants it, but no one wants to pay for it.
“It’s difficult to build a business case,” Kip says.
“It’s the same problem we face with investment in sport, recreation facilities or active transport. We know that investing in these things builds healthier, more resilient communities and significantly reduces our long-term health costs. It’s preventative maintenance of the collective population – but it’s really hard to attribute a dollar saved to a dollar spent, and to close the economic loop”.
And so back to the ACT Government’s inquiry. We all value green space, but the question is crystal clear: are we willing to pay for it?
We need the ACT Government to take on the role of “custodian” of our green infrastructure. Currently, Transport Canberra and City Services do not have the funding to manage green infrastructure – only to ensure stormwater discharges properly, grass is slashed and roads repaired.
Other Australian cities are investing in large-scale initiatives that recognise the importance of green infrastructure. The City of Melbourne, for example, has mapped its 70,000 street trees to maintain its urban forest.
And the City of Sydney is increasing its canopy cover by planting thousands of trees, has upgraded 68 small parks over the last decade and installed 154 rain gardens. The council plans to plant 50,000 new trees and shrubs in city parks and street gardens each year until 2021.
Meanwhile, Canberra’s green infrastructure is seen as a liability with recurring maintenance costs, rather than an essential city asset. So, if green space is so important why aren’t we funding it properly?