By David Allen
Governments need to spend “hundreds of millions” expanding Melbourne’s tree canopy if the city’s west is to avoid the worst impacts of climate change, planning experts say.
Minister for the Environment Steve Dimopoulos and Minister for Planning Sonya Kilkenny on Sunday announced $9.5 million will be invested into the More Trees in Melbourne program, which will see 500,000 new trees planted in low coverage areas.
New regulations were also unveiled to limit the removal of mature trees, along with funding for a new digital canopy mapping tool for the city.
RMIT Centre for Urban Planning research fellow Dr Thami Croeser says Melbourne’s west still faces “a long road ahead” to achieve the tree coverage needed to cool its suburbs.
“We’re still at five to ten per cent canopy in many western suburbs and we really want to be at 30 to 40 per cent to avoid the scary heat impacts that were highlighted in the National Climate Risk Assessment,” he says.
“We need millions of new trees, and they need to be big, healthy trees planted close to homes and workplaces, and we’ve known this for a long time.”
The state government announced a target of 30 per cent tree canopy coverage for Melbourne as part of its 30-year plan to address climate change.
The National Climate Risk Assessment, released in September, found Melbourne will experience a 50 per cent increase in heat-related deaths due to the 1.5°C rise in global temperatures already recorded.
The report found that a 3°C rise in temperature will see Melbourne’s heat-related mortality rates climb over by 250 per cent.
Dr Croeser says the government is making positive strides by following on from the successful More Trees for a Cooler Greener West program, and the Greening the West model, which collectively planted 1.5 million new trees.
He also warns the new program’s funding only ran to about 19 dollars per tree and didn’t address the cost of planting and caring for the trees’ first year of life.
Dr Croeser says “hundreds of millions” will need to be spent to improve Melbourne’s canopy.
“Having around 30 to 40 per cent canopy within about 60 metres of homes is when we see significant cooling,” he says.
“There’s enough shade, and enough water being sucked up and blown out of the leaves [and] we avoid ‘heat island’ effects associated with lots of unshaded concrete and tarmac.”
Dr Croeser says protections making it harder to cut down existing trees are the real cause for celebration, calling them “a crucial piece of the puzzle”.
“We won’t make much progress with the canopy if we’re losing mature trees as fast as we plant saplings,” he says.
The protections require new permit approval for the removal of trees on residential lots within six metres of the front boundary and 4.5 metres from the rear boundary.
David Allen is a recent graduate from RMIT’s School of Journalism
