Street Trees must take Priority
Our street trees are a major part of cooling our cities and suburbs.
Urban heat kills more people than floods and fires, but is less obvious. With Australian suburbs becoming dangerously hot - especially for the old, young, already ill or on medication - it is a health and social equity as well as an environmental issue.
Our street trees are a major part of cooling our cities and suburbs. Councils and government organisations have the job of increasing tree canopy, but they must deal with residents refusing or killing new street trees, and reduced urban space available for planting. And the battle of the budget continues: do voters want money spent on street trees or roads?
As well as thinking about how we vote at election time, it is in our best interests to work together to line our streets with trees to cool our homes naturally and reduce the costs of cooling.
As part of addressing climate change, we need to reduce the dominance of cars and the associated roads and parking on our landscape. Cooler, tree-lined streets are a vital ingredient of making active transport - walking, cycling, and public transport - practical and attractive. The more trips that we can move from private cars to active transport, the less traffic congestion for those who genuinely need to drive.
We also need to care for the trees. Driving and parking on the ground surrounding the trees compacts the soil and damages the roots. Compacted soil can send the roots above the surface looking for oxygen, only to be scalped by mowers. Strimmers or whippersnappers damage the trunks. Herbicides and pesticides reduce soil health and biodiversity.
This tree on a grass verge struggles on despite regular attacks from mowing equipment.
Some disputes about verge gardens have been about well-meaning gardening activities that put the health of street trees at risk by smothering their roots, digging around their roots, or building up rich garden beds around their trunks.
Other actions kill the tree with kindness. Thick mulch may suppress weeds, but it also reduces the likelihood of your tree roots receiving oxygen and rainwater. Grass clippings piled around the trunk, dubbed volcano mulching because of the heat generated, kill trees.
Street trees are a long-term proposition. They are best managed by councils who have arborists and access to climate research. We need to trust those qualified within councils to decide which trees and where - not amateur gardeners and not politicians.
But we can’t just plant trees. We don’t have time to wait 10 or 20 years for saplings to grow into mature trees that cool our streets. This is where verge gardens help. Their cooling effects start this year and they provide a better environment for the young street trees to thrive.
This tree in the centre of a verge garden has an undamaged trunk and a healthy flare at the base. The tree is thriving compared to its sad neighbour above.
Gardens around the street trees also signal to drivers that this is not a parking space and reduce the temptation for vandals to shake an isolated young tree or snap its truck.
This free article is part of the Understanding the Space section: bite-sized introductions to gardening in these small but wonderfully complex spaces.