Australia Weather News

City Services' employee Kevin Warhurst marks one of Canberra's many dying trees. - ABC

If you park your car on the nature strip, beware — you're killing Canberra's street trees and the ACT Government will track you down.

Thousands of the bush capital's trees are suffering from a combination of extreme heat and very little rain — and ACT City Services Minister Chris Steel believes motorists are compounding the damage.

"It is illegal to park under street trees on public land, on verges," Mr Steel said.

"[It] damages tree roots by compacting the soil, stops nutrients from getting to the tree and puts them at risk of dying.

"So we will be stepping up education and compliance in relation to illegal parking under trees."

Canberra's "urban forest" recently had about 750,000 trees, but many thousands have succumbed to the capital's record-breaking summer of extreme heat and dryness.

"This is the worst summer I can remember," horticulturalist Scott Burns said.

"[A] combination of the wind, the heat, absolutely no rain — and it just parched everything ridiculously quickly."

Mr Burns said even the most established trees had been affected.

"Just look around town at a lot of the European trees that were planted way back in [Charles] Weston's time … Half of them are dead, or looking really, really, really poor," he said.

"Fully mature, 50-plus-year-old trees that are more dead than alive from lack of water and … the really stressful environment."

One in four tree species in Canberra 'unsuitable' for changing climate

Mr Steel announced yesterday a "rescue package" for the city's urban trees, which included increasing the number that were hand-watered.

He said the Government had been watering about 22,000 young trees that were less than five years old, but 6,000 mature trees would now be added to its list.

Mr Steel said the focus would be on Canberra's heritage areas, such as City Hill, Ainslie and Limestone avenues, and Telopea Park.

Contractors would also be brought on to spread tonnes of extra mulch to lock the moisture in.

But Mr Burns said the Government also needed to rethink which tree species it planted.

"I think that's a really wise move — to use and plant trees that are more suitable to a more arid climate," he said.

"Your exotic species, which are more deciduous than evergreen, will have a relationship with the soil profile and everything they're growing with. So they can cool the ambient air temperature by 5 degrees [Celcius].

"And the grass underneath them, being in a bit of shade, will also stay green even if the soil's quite dry, so it'll cool everything down."

Mr Steel said recent Australian National University research indicated many of Canberra's existing tree species would not flourish as the climate became hotter and drier.

"Twenty-eight per cent of our current tree species are unsuitable for the conditions that we will be experiencing over the next few decades," he said.

ABC