Our family has lived in Perth for over forty years. We love it. We love having access to some of the world’s most beautiful beaches. We love the pockets of bushland and parks that showcase our natural fauna and flora, and we love our trees. Tall towering eucalypts, magnificent paperbarks, banksia, to name just a few.
Tree canopy is not just aesthetically pleasing to look at, it’s vital to our health and wellbeing and that of the planet. Trees are natural air filters, actively removing toxins, absorbing and storing CO2 and pumping out life-giving oxygen. They provide shelter from the elements, the heat and the rain, and preserve our biodiversity.
Yet Perth has the lowest tree canopy of any Australian capital city and remains in decline. It’s currently at 16% in the Perth metropolitan area while new subdivisions earmarked for new housing developments are the worst, clear felled of any skerrick of vegetation.
This is not only nuts, at a time of climate change, it makes no sense not to be taking active steps to restore and improve our tree canopy and keep Perth inhabitable.
Reducing the urban heat island effect
Stepping out of an air-conditioned office block into St George’s Terrace in high summer is like stepping into an open-air oven. The heat almost knocks you over and your lungs struggle to inhale the hot air.
According to the World Economic Forum, cities are warming faster than rural areas. This is because all that concrete, pavement and bituminised roads absorb and retrain heat from the day keeping built-up areas hotter at night. Many more of us now live in cities. We are an urbanised species with over 55% of the global population living in cities expected to rise to 68% by 2050.
A new study published in The Lancet found that 1 in three deaths attributable to the heat island effect during summer could be avoided if tree canopy covers 30% of urban space. IF we can achieve 30% tree cover by 2040, scientists predict we’ll be able to lower city temperatures by up to 10 degrees centigrade.
Friends of the Earth UK found the cooling effect of trees and green spaces in cities also lowers nighttime temperatures by up to 5 degrees centigrade.
Here trees help by their process of evapotranspiration, absorbing water through their roots and releasing it as water vapour from their leaves.
So, theoretically, trees help to keep our city cooler, except the effect is diminished in extreme heatwaves because trees stop circulating their sap.
The need for more urban guerrilla gardeners
I’ve been reading Nikki Gemmell’s articles in the Weekend Australian for years. I enjoy her quirky and insightful musings. Her latest, which incorporated a confession on her part, floored me.
It turns out that Nikki has been an active operative for Guerilla Gardeners for a while. She’s part of a group of committed citizens who plant trees in order to “Sow beauty and wonder, and much-needed shade; to reap birdsong and joy.”
She continues, “Trees are the silent sentinels that live among us, that give so much. They lift us mentally with their beauty and collective smell, especially after rain. They cultivate happiness, draw people to them, shelter us and gift us an umbrella of coolness.”
She calls it a secret community fightback which I applaud, and have determined, that I too can play a part, as can we all.
It’s about recognising the value trees provide and choosing to replant appropriate native species in areas where tree cover has been denuded through development or neglect.
Remember tree cover is defined as vegetation of 5 metres or more in height.
Making our urban neighbourhoods greener and connecting more people to nature is a win-win. It doesn’t have to mean planting trees illegally either. Many councils are happy for their residents to have trees on verges. Just check with your local council to find out if they have any particular preference of species.
If your workplace lacks surrounding greenery, what would be possible to plant to help soften the monotony of too much grey concrete?
If you have space in your backyard, why not plant a tree? Though it’s important here not to plant something that will grow into a monster disturbing fences or walls. Many moons ago I planted a $2.50 cotton palm in our front garden never imagining it would morph into a 10-metre triffid, that also provided free housing for several colonies of rats. It’s gone now and fortunately, so have our murine friends.
There is something deeply satisfying in seeing a small sapling grow into something as tall and precious and long-lived as a beautiful tree.
Where will you plant a tree for your future and that of your kids?
