It also has the lowest tree canopy in the Perth and Peel region with the newer coastal suburbs of Alkimos, Eglinton and Butler taking the title of the lowest tree canopy and vegetation cover in the city.
A City of Wanneroo spokeswoman said native vegetation planted in recently developed subdivisions would take time to mature, and low-lying coastal heath provided little canopy cover.
Like many councils it had developed an urban forest strategy to boost its canopy and protect existing trees.
“The strategy will measure the extent of the City’s urban canopy and vegetation cover and identify areas with higher temperatures (heat islands) with the aim of protecting and increasing tree and vegetation cover across the City through a range of initiatives,” the spokeswoman said.
At just 10 per cent tree canopy cover, the cities of Belmont and Canning are next on the list.
City of Canning mayor Patrick Hall said the council’s urban forest strategy aimed to more than double tree canopy cover in public open space to 40 per cent over the next 20 years by planting 110 hectares of trees.
Parkwood, Cannington, Bentley and St James have below-average canopy cover, ranging between 7 and 7.5 per cent, while parts of Leeming have just 5 per cent canopy cover.
Perth’s searing summer
On the last day of summer Bureau of Meteorology figures showed Perth’s average maximum temperature was 33.2 degrees — well above the previous record of 32.3 set in 2012/13.
Perth sweated through a record of 13 days above 40 degrees, six of which were consecutive.
Swanbourne recorded 43.7 degrees on Boxing Day last year, the highest December temperature ever recorded for the coastal suburb.
Record temperatures were recorded in Dwellingup, Bunbury, Busselton and Mandurah.
Many sites including Perth Airport, Pearce RAAF, Jandakot and Bickley had their highest mean maximum temperatures for January since 2010.
The industrial suburbs of Canning Vale and Welshpool have 4.7 per cent and 3.6 per cent canopy cover.
“The City is prioritising tree planting in suburbs which have been identified through thermal image mapping as having low tree canopy cover and high land surface temperatures,” Mr Hall said.
In the City of Belmont, boosting tree canopy is difficult, with Perth Airport taking up one-third of its land.
From quarter-acre blocks to 200 square metres: urban infill in Perth
The state government’s 2018 Perth and Peel @ 3.5 million framework set a 47 per cent urban infill and 53 per cent new housing target by 2050.
Even councils largely devoid of trees aren’t excluded from meeting the targets. Canning’s urban infill target is 11,440 additional dwellings by 2031 and the City of Belmont is 26,860.
Wanneroo has been set a target of 27,920 dwellings and 106,900 residents by 2050. There is concern that the push to create new lots within established residential areas is fuelling a reduction in plot sizes that leaves little space for a tree.
A state government spokesman said various departments had invested significantly in initiatives to support suburban greening measures to reduce the urban heat island effect and address the impacts of climate change.
He said recent updates to the residential design codes now required trees to be planted for all new developments, including apartments, and there are incentives for apartments to retain significant existing trees and provide adequate deep soil areas to ensure viable growth of new trees.
Just a decade ago residential infill development was about 32 per cent; in 2020 it was 44 per cent.
Where Perth is turning from grey to green
Professor Newman said urban infill didn’t have to mean concrete jungles and the answer to offsetting rising heat in the suburbs was simple – green our suburbs and weatherproof our homes.
But it needed a more coordinated approach on a local, state and national level that was relevant for lower socio-economic suburbs who are at greater risk of becoming heat islands.
Professor Newman warned some outer suburbs of Perth would be difficult to sell in coming decades because of their location, design and lack of tree canopy that meant they needed more energy to run.
“If you travel to the end of freeway north and south you will find suburbs being rolled out with big houses, big air-conditioners and I think they are not even appropriate for now let alone in 20 years time,” he said.
Professor Newman said the current review of the National Construction Code for the first time in 13 hadn’t gone far enough.
It made no reference to following Sydney’s footsteps and banning the construction of homes with dark-coloured roofs, or other measures such as painting roads white to lower ambient temperatures in the suburbs.
“You simply need to specify ‘net-zero homes’,” he said.
“We’ve had no leadership in this area from government for far too long.
“There’s a belief that the problem in Perth is that we are building too densely and chopping down too many trees.
“It is true, but that is mostly happening in middle suburbs like Innaloo, or Carlisle.
“But there’s still plenty of room to plant trees. Singapore does it by draping it over the buildings and in streets in the tiniest amount of soil.”
Professor Newman pointed to the East Village development in Fremantle as an example of energy-efficient residential infill development.
“This Development WA project requires each of the tiny blocks for sale (200 square metres for each of 36 townhouses and two apartment blocks with 100 units) to have a little area which has deep soil in it and that is for a tree,” he said.
“And it’s a requirement for every block.”
Effects on human health
Extreme heatwaves in Australia have caused more deaths than any other natural disaster in the past 200 years, according to the Bureau of Meteorology.
Royal Australian College of GPs president Karen Price said rising temperatures due to climate change was a key public health issue.
“An analysis of Australian coronial records relating to heatwave deaths between 2000 and 2018 found there were 473 deaths reported that were explicitly heat-related, of which 354 occurred during heatwave conditions,” Dr Price said.
“More vulnerable people, such as older people, people with disabilities, and those with pre-existing cardiovascular and respiratory diseases, are particularly at risk.
“The trouble is people may not be aware of the risk, and don’t prepare for hot days.”
As Perth councils struggle to plant trees, Professor Newman urged them to think big.
“Perth should not be visible from the sky because we have a complete canopy of trees,” he said.
“The hardest part is taking it seriously but we must. We’ve just had our hottest summer.”