Dr Carol Booth warns Invasive Species could risk half of Sydney's trees
New research from the Invasive Species Council says an invasive species could put almost half of Sydney’s urban trees at risk if the polyphagous shot-hole borer spreads east from Western Australia. Dr Carol Booth, the council’s policy director, said the beetle could arrive “tomorrow, next year or in five years’ time.”
Its spread would matter because the pest has already been blamed for wiping out thousands of trees in Perth, where a major quarantine is in place across the city. The council says figs, banksias, paperbarks and eucalypts could be vulnerable if the beetle reaches Sydney.
Dr Carol Booth on detection
Booth said early detection would shape the outcome. “Ideally, it would be detected within weeks to months after arrival,” she said, adding that “if detected early enough, there is potential to eliminate it in managed environments such as cities and horticultural crops. But it becomes much less feasible if it moves into native forests.”
She also said the beetle has spread to four new continents over the past quarter century and travels with people inside wood. Its spread, she said, depends on compliance with biosecurity rules about not moving wood. That leaves councils with a practical choice now: reassess planting species known to be host trees before the pest reaches the east coast.
Sydney tree species at risk
Booth said losing large stretches of tree canopy would make suburbs hotter, reduce wildlife habitat and strip streets of shade. She also said more species will be susceptible in eastern Australia, but “we won’t know which ones they are until the beetle invades.”
For Sydney, the immediate risk is not a hypothetical species list. It is the scale of exposure already identified in the council’s research: almost half of the city’s urban trees may be vulnerable if the beetle crosses state borders. Perth’s quarantine shows the pest is already forcing a city-wide response, while Sydney’s councils are being urged to avoid adding host trees to the problem before the insect arrives.
Western Australia quarantine
The shot-hole borer remains confined to Western Australia, but the council’s warning points to the next decision point for cities on the east coast. If the beetle arrives, Booth said the best chance of eliminating it lies in managed environments such as cities and horticultural crops, not in native forests.
That makes the current window the one that matters most for Sydney: planting choices, wood movement rules and early reporting will shape whether the pest becomes a short-term biosecurity response or a longer-term tree loss problem.
