By Adam Carey
Developers are being pushed to leave space and soil for trees in private yards as councils complain that state policies to encourage greater housing density in outer Melbourne are creating heat islands that do not accommodate pedestrians.
The Victorian Planning Authority has proposed changing the state’s housing code for new suburban estates to encourage developers to include a “deep soil zone” of at least 2.5 square metres for a canopy tree on new properties of less than 300 square metres.
Vinu Shankar Ganesun in the middle of his Wyndham Vale street.Credit: Jacob Pattison
Councils have welcomed the proposal but called on the authority to go further and require developers to plant canopy trees on each property.
An update to the small-lot housing code would also restrict dark roofs on new homes, in another change aimed at curbing excessive heat retention in new suburban estates.
Council umbrella group the Municipal Association of Victoria said in its submission on the proposed update to the housing code: “We see these as significant opportunities to reduce heat absorption in dwellings and to cool and green growth-area neighbourhoods, which are some of the hottest parts of the urban landscape.
“A step further in the code to require planting of canopy trees would ensure cooler dwellings and neighbourhoods.”
Vinu Shankar Ganesun, with son Anirudh, would like developers to be forced to plant trees on new properties.Credit: Jacob Pattison
The number of homes built on smaller lots in new estates is exploding: the proportion grew from 5.8 per cent in 2011 to 34.7 per cent in 2021.
Vinu Shankar Ganesun lives on a smaller lot in Savana, one of Melbourne’s newest housing estates, in Wyndham Vale on Melbourne’s south-western fringe. Many of the houses in his neighbourhood have been built to comply with the small-lot housing code.
The estate is almost entirely devoid of shade-giving trees, either in yards, many of which are covered in synthetic lawn, or on nature strips that have fragile saplings that too often die, Ganesun said. When he walks around the area, there is almost no respite from the sun.
“It is just so hot during summer, I am literally looking for people who have tall fences, which give you that tiny bit of shade,” he said. “Depending on which direction the sun is, I try to walk on that side of the street. That’s my only hope of being in the shade.”
Ganesun would like to see growth-corridor developers do better than comply with the bare-minimum requirements of a code and for them to be pushed to create the kind of generously shaded streetscapes residents of Melbourne’s leafy east enjoy.
The small-lot housing code has been in place since 2011 and is aimed at speeding up housing construction in the state’s fastest growing and most affordable communities. Homes that comply with the code do not require a council planning permit.
But councils have told the Victorian Planning Authority that the code is backfiring, ushering in a slew of homes that create ugly and unsafe streetscapes that are too hot in summer and more likely to experience flash flooding during heavy storms.
The Allan government is considering the proposed updates to the housing code, including the requirements for deep soil zones and lighter roofs.
Thousands of homes are built to the code each year, and 22,000 undeveloped lots on Melbourne’s outskirts have been designated under the code, the planning authority says.
The City of Hume said the code is producing homes that detract from the public realm, such as this row of townhouses in Craigieburn with no place for trees. Credit: Luis Enrique Ascui
But councils have given the authority scathing feedback about its impact, with one urging a comprehensive review of the code rather than an update.
The City of Hume, in Melbourne’s outer north, said in a 2022 submission during consultation on the latest update to the housing code that homes built to the code “detract from the public realm”, with little to no tree plantings, streetscapes dominated by garage doors, compromised safety for pedestrians and excessive urban heat and stormwater run-off due to the high amount of space claimed by driveways.
It provided multiple examples of rows of homes in new parts of Craigieburn it said left no capacity for street tree planting.
The City of Melton said the code “has resulted in some poor design outcomes including garage-dominated streetscapes, an absence of street trees and poor passive surveillance outcomes”.
The reduced opportunity to plant trees in the streets was contributing to a “more pronounced heat island effect”, the council said in its submission.
Professor Joe Hurley, of RMIT’s Centre for Urban Research, has studied tree loss in suburban Melbourne.
Hurley said a deep soil zone for tree planting was a good inclusion in the code, even if it would not guarantee that a canopy tree was planted in those spaces.
“Deep soil zones are a way to create neighbourhoods that support trees on private land,” Hurley said.
A row of townhouses in Craigieburn that were built to comply with the small-lot housing code and have no space for substantial trees.Credit: Luis Enrique Ascui
“When you look at the leafy neighbourhoods of Melbourne, typically half of those trees are on private land, and if we’re not creating new suburbs that allow that to evolve, then we lose from the outset.”
Hurley said Melbourne could not rely solely on public space to provide green canopy and the kind of liveable and healthy environments that people value.
But the Housing Industry Association has opposed the inclusion of a deep soil zone, warning that placing trees so close to homes could cause structural problems such as “slab heave”, when moisture absorption cracks houses.
“Tree planting and associated irrigation requirements should not deliver outcomes that compromise the structural integrity of a new building or essential services infrastructure,” the association said.