On a hot day in Whitehorse, the concrete and metal skylines of Box Hill lock in heat while the mature trees lining Blackburn’s suburban streets create a shade from the harsh conditions.
The council is planting more than 3,000 trees a year, but local advocates and experts say the loss of mature trees on both public and private land means the council is fighting an uphill battle.
What’s happening? Whitehorse councillors endorsed a new Tree Management Policy on September 14, including guidelines for tree plantings and a goal to achieve canopy cover of 30 percent by 2050.
The policy includes guidelines such as requiring every house to have at least one tree planted within its nature strip and two new trees to be planted by council for every tree it removes.
A long wait: RMIT’s Dr Thami Croeser said removing large mature trees and replacing them with saplings has already led to a “generational loss of cooling, amenity and habitat”, as saplings took 10 to 15 years to provide sufficient canopy coverage.
🗣️ “It’s a massive downgrade, just like if you swapped a Lamborghini for a rusty ‘91 Honda Civic or knocked down a hospital and replaced it with a first aid shed,” he told the Eastern Melburnian.
Shade shifts: According to a study of the changes in Melbourne’s tree canopy between 2014 and 2018, canopy coverage decreased in the eastern region by about 2.3 percent over a four year period.
In Burwood East, only 18.2 percent of land was covered by tree canopy in 2023.
In Whitehorse, total coverage jumped from 21.6 percent to 25.8 percent from 2018-2023.
What’s needed? Croeser said if the retention of trees did not keep up with removal, the net loss in canopy would increase the heat island effect exposure for “at least a decade or two”, increasing local temperatures by five to 10 degrees.
🗣️ “A neighbourhood can lose about one percent of its mature trees annually, if it’s replacing them, without going backward on canopy overall,” Croeser said. “We really need to be planting the 200 small trees and protecting the 100 big ones.”
Noticeably hotter: Blackburn and District Tree Preservation Society president David Morrison said he can notice a change in temperature driving into the centre of Blackburn from the shady suburban street, with Whitehorse and other nearby councils fighting against “a rapidly increasing loss of trees on private land”.
Climate impacts: The Whitehorse area already experiences 11 days a year where temperatures exceed 35 degrees, with predictions estimating this would increase to 16 days per year, on average, by 2050.
The closest Bureau of Meteorology weather recording station in Viewbank found 2025 had 23 days above 35 degrees, the highest since records began in 1999.
Lopping proposal: On the corner of Jeffrey Street and Lake Road in Blackburn, there stands a single gum tree at about 18 metres tall.
However, Jeffrey Street Association secretary Simone Taylor said United Energy is arguing the tree is too close to unbundled power lines and needs to be removed.
🗣️ “If that tree is removed, it would mean that the whole northern corner of Jeffrey Street would then be without its significant trees.”
Thumbnail Image Credit: Pema Gyamtsho