It’s National Tree Day on Sunday, 28 July. This will probably cause some people a degree of annoyance because, despite the proven benefits of trees for cooling shade, biodiversity, amenity and human wellbeing, many Australians simply don’t like them.
Ignorance is one reason.
According to Dr Greg Moore, chair of TREENET [Tree and Roadway Experimental and Educational Network], many people don’t understand their value.
They may be afraid trees will fall on them. But while deaths from falling trees or branches might make national news headlines, the reality is people are more likely to die from a lightning strike, falling out of bed or choking on food.
“The odds of being killed by a tree are not greater than one in five million,” Moore says.
But extremely rare deaths from falling trees have sometimes resulted in thousands of trees being pre-emptively cleared from places like school playgrounds.
Some dislike the way trees shed barks, leaves, blossoms or fruits. Some have issues with tree roots potentially interfering with subsurface water pipes, buckling footpaths or impacting roads.
Moore who is also chair of the National Trust of Victoria’s Register of Significant Trees Committee and senior research associate at the University of Melbourne Burnley told The Fifth Estate says we can change all that.
For instance, we can build footpaths from flexible materials instead of impervious and rigid concrete. That way, tree roots would not be such a concern.
With roads, the type of construction and subsurface conditions can be the issue. Buckling or cracking might be blamed on nearby trees but can sometimes be caused by reactive clays below.
Tree roots in pipes might be because the pipe material, such as clay, is vulnerable, or poorly installed, so gaps or cracking might occur.
Instead of seeing dropped leaves, bark and other organic material as a problem Moore says you could also see them as mulch just begging to be used in gardens to reduce the need for watering, add carbon to the soil and reduce weed growth.
Trees can also reduce the impacts of high rainfall events because they can absorb up to 40 per cent of rainfall, reducing flows into stormwater systems and the degree of local flooding. They also reduce soil erosion and therefore sediments entering water systems.
Blame the planning laws
Planning laws have also played a part in disappearing trees, Moore notes, as front and back yards have become smaller and denuded of canopy.
Moore says state governments have historically considered urban trees a local government matter – however, now that health costs are kicking in, states recognise they have a vested interest.
In Victoria, it’s estimated that between one or two per cent of people walked or cycled, the health system could save $274 million a year.
At the federal level, the cost of cardio-vascular disease and type 2 diabetes is around $5 billion a year – so if green space encourages even a small percentage of people to get out and get active, millions of dollars could be saved.
We need to get past objections to trees, because in our ever-hotter cities, people can and do die from heat, Moore says.
There is growing evidence that trees reduce blood pressure and the impacts of type 2 diabetes.
Some of the effects are simple, such as providing shade and making parks attractive, so people are more likely to walk or ride a bike.
Moore says we need more trees in our cities if we want them to be liveable and enable residents to have healthy, long lives.
Anecdotally, many people have known this for a long time. The elderly person with the glorious garden full of trees is healthy partly because they are outside, amongst the trees, gardening regularly, he says.
Research is finally catching up to gardeners
Research and urban planning are catching up to what gardeners have known for decades. Trees contribute to physical, emotional and psychological health of humans, and to overall environmental health
Studies have shown that for every dollar spent on urban trees, there is a return of at least six dollars per dollar, and in some places as high as $12 per dollar.
“We can plant trees and get all these free benefits.”
Why trees are disappearing
Moore says trees are still disappearing from our streets and open space “at an alarming rate” because of widespread ignorance about their benefits.
In some cases, it is because individual selfishness outweighs community benefit. The tree removed from a yard because of leaf shedding has a collective cost.
It can also have an immediate impact on the neighbours’ power bill because they need to use more airconditioning.
In the bigger picture, providing a shaded and green environment that includes trees in our towns and cities is one of the only direct things most of us can do about climate change mitigation and adaptation, Moore says.
The four to five degrees of cooling it provides can literally be a lifesaver for vulnerable people.
The ideal canopy cover is 30 per cent in our cities, he says. And there are many local governments with sound targets and urban forest policies in Victoria, New South Wales and South Australia.
Five ways you can mark National Tree Day
- Grow your love for our tall and leafy citizens! Maybe watch the Judi Dench documentary, My Passion for Trees. Dench says her life is currently “now just trees…. Trees and …um… champagne.”
- Find a National Tree Day event near you and call a spade a weapon to fight climate change with.
- Read Planet Ark’s new research report – Living Cities: Trees in the Urban Environment.
- Look at the big picture – recent research has shown Australia is one of six countries that have 50 per cent of the world’s replanting opportunities – and that taking up that challenge could buy all of humanity a 20-year slowdown in the carbon emissions currently escalating the climate emergency. The World Resources Institute has also created an interactive online Atlas that identifies forest cover past and present, and the potential for future revegetation. Who knew Australia once looked so green, and could do so once more?
- Spend some time with the trees in your community, it will benefit your overall health and wellbeing. You could also tweet, Facebook or insta your outdoor moment and show decision-makers why people value urban forests! #NationalTreeDay #treehugsaregreathugs #treesbeatclimatechange #picnicwiththecarbonstorage #beatingurbanheat