Wollongong City Council has finally admitted what many residents have known for quite some time: the gum trees planted in Crown Street Mall have been a failure.
On Monday, releasing the results of a lengthy review into why the trees kept blowing down in strong wind, the council owned up to a long list of reasons.
For instance, the “strong summer reflective heat” of the mall saw them grow at 2.5 times the rate they would in their normal habitat, and the watering system installed during the mall construction “meant the roots didn’t need to spread out to reach a water supply”.
Also, the tree grates on the ground restricted air flow to the soil and roots and the soil used to plant them was not dense enough to provide a solid foundation for the roots.
“We are the first to acknowledge that this has been a challenging process and that people want to know what we are going to do about the trees in the mall and to solve the issue of the spotted gums,’’ Lord Mayor Gordon Bradbery said.
“The mall is a unique urban environment and we needed to understand why the trees didn’t work, so we could look to a long term solution.”
That solution, the council announced, will be to replace the gums with deciduous Japanese elms and native Weeping Lilli Pilli trees.
Four Lilli Pillis and 12 elms will be planted between Keira and Church Streets during March and April.
Cr Bradbery said these species were chosen because they complimented each other in the urban environment.
The mix of evergreen – Lilli Pilli and the existing Illawarra Flame – and deciduous trees will offer shade in summer and opening the mall up to winter sunlight while retaining some green foliage.
“By using the elms in the western end of the mall, we’re able to minimise the risk they will be damaged by the strong winds we regularly get in August,’’ Cr Bradbery said.
“They’ll have lost their leaves and this means, unlike the spotted gums, the wind should be able to pass through them with less resistance.’’
The council has emphasised that the elms and gums drop a roughly the same number of leaves within a year.
Before the trees are planted, there will be a new irrigation system installed into each of the tree pits. The system will be able to phase watering close the root ball and then further away as the tree grows.
In addition, the tree grates will be removed and replaced once the trees are established, and a new tree anchor system will be used to hold the root ball firmly in the ground.
The tree guards will remain.
A brief history of Crown Street Mall's gum woes
OCTOBER 28, 2013
Workers plant spotted gum trees and complete other works before the barrier fences come down in the refurbished mall.
OCTOBER 29, 2013
The gum trees spark heated online debate, with the danger posed by falling branches the main cause for concern. Council defends choice, saying they are not a limb-dropping species.
DECEMBER 16, 2013
First temporary, then permanent, steel cages are erected to protect the trees after vandals rip off branches. The council puts the damage bill at nearly $50,000.
MARCH 12, 2014
A group of spotted gum saplings are treated for an infestation of bugs that have turned their leaves a mottled white, as if flaked in sea salt.
JUNE 7, 2016
At least a dozen trees are lopped in half after being decimated by strong winds.
AUGUST 25. 2017
Another 24 gums are chopped down after wild weather, with Wollongong City Council appearing to realise the wrong species may have been chosen for the location. It goes back to “review” which trees are best to plant in their place.