There are fears Perth’s coastline could look dramatically different in the coming years because of a disease that is killing the decades-old Norfolk Island pine trees which line the city’s beachside suburbs.
- Experts say the pines are being affected at an “alarming rate”
- Eight are being chopped down this week, but many more are at risk
- There are calls for a science roundtable to try to save the trees
Eight trees in the Town of Cambridge, including some along the West Coast Highway, are being chopped down this week after being affected by the fungal disease Neofusicoccum parvum, colloquially known as the “top-down” disease because it kills the branches at the top of the tree first.
The Town of Cottesloe removed two of its Norfolk Island pine trees in May, but experts are fearful popular beachside areas could lose many more.
“I really fear for the health of many of our Norfolk Island pine trees in Perth,” horticulturalist Sabrina Hahn said.
“I’m pretty pessimistic about it … I think we’re going to lose many, many trees.”
Ms Hahn said the disease had wreaked havoc in coastal New South Wales areas including Manly Beach and Byron Bay where the disease was not diagnosed until it was too late.
She was fearful the same might happen in Perth.
“It’s a great reminder to all of us to try and preserve all of our old trees and to have a maintenance plan for old trees, not to wait until something like this disease comes through,” she said.
Alarming rate of decline
Ms Hahn said the fungal disease was not the only factor contributing to the death of the pine trees, but drier weather conditions and warmer winters were also putting the trees under stress.
Botanist Kingsley Dixon has been monitoring the trees from his City Beach home and said in the last two years the health of many of the trees had quickly deteriorated.
“These trees have stood the test of time. They’ve been through cyclones, heat spells but now they’re really toppling at an astonishing and really alarming rate,” Professor Dixon said.
“Whether the disease has been resident for a few years and has waited for a warmer winter or a hotter summer to express itself that’s not clear at all, but it’s certainly moving at a pace which is breathtaking,”
Professor Dixon said the airborne disease produced small spores, and while there was no definitive answer to how the disease spread, some scientists believed white cockatoos might be responsible.
‘This is a tree pandemic’
The Town of Cambridge is monitoring and treating 52 of its pine trees, while the Town of Cottesloe said it was also treating and assessing a number of its pines, which it expected to receive results on later this month.
But Professor Dixon said more needed to be done.
“This is a tree pandemic,” he said.
“I think there would be a great role for the State Government in drawing together the local governments that have them for a science roundtable.”
He said if the approach from authorities was ad hoc, the trees might not be saved.
New trees being planted
The Town of Cambridge said it had planted nearly 30 new Norfolk Island pine trees this year in response to the removal of the eight trees and planned to plant more next year.
Ms Hahn said the towns of Cambridge and Cottesloe had both looked at various ways they could save the trees to avoid having to remove them, but ultimately they had no choice.
“They’ve drenched the soil, they’ve sprayed the trees, but unfortunately none of that has worked,” she said.