Setting the Scene
Across Australia, Phytophthora dieback is quietly devastating native ecosystems, killing thousands of plant species, weakening forests, and putting entire landscapes at risk. Despite decades of awareness campaigns, the tools to stop its spread have remained limited. Every year, tonnes of construction materials are sourced from healthy forest just to avoid contamination, a costly, unsustainable approach that protects one ecosystem while damaging another.
That’s why the Dieback Working Group (DWG) set out to do something different: to prove that dieback-affected materials could be safely treated, tested, and reused, breaking the cycle of environmental loss.
The Turning Point: A Costly Containment Problem
For more than 50 years, Western Australia has been at the frontline of dieback management. The pathogen Phytophthora cinnamomi can survive in soil and gravel, meaning every load used in construction or roadwork has the potential to spread infection further.
Traditional management meant one thing: source new gravel from disease-free areas and avoid contamination at all costs. But this approach was unsustainable, clearing healthy jarrah forest to protect infested areas made little ecological or ethical sense.
To truly stop the spread, DWG needed to find a safe, scientifically proven way to neutralise the pathogen at its source.
The Response: A Collaboration Built on Science and Shared Responsibility
Under the Federal Government’s Saving Native Species Programme (Game Changer Grant), the Dieback Working Group assembled a powerhouse collaboration across science, industry, and government.
- DWG coordinated funding, logistics, and stakeholder engagement.
- ArborCarbon led experimental design and field implementation, developing and monitoring the trials on the ground.
- Murdoch University’s Harry Butler Institute conducted laboratory testing and environmental monitoring to validate outcomes.
- DBCA’s Vegetation Health Service provided technical support, inoculum preparation, and diagnostics.
- Culford Agri Industry managed the gravel processing, fumigation, and site safety systems.
- Main Roads WA and civil contractors supported testing and application pathways for industry use.
- First Nations partners extended training and relevance through the DWG Green Card Programme.
Together, the team trialled a new treatment process using metham sodium, a soil fumigant that converts into MITC gas, capable of killing the dieback pathogen within stockpiled gravel. The experiment tested variables like depth, temperature, and exposure time to identify the most effective treatment.
ArborCarbon’s scientists designed the on-ground trials, embedding inoculated samples into gravel piles at controlled depths. After 28 days, samples were retrieved and analysed both in the field and under laboratory conditions to confirm whether the pathogen had survived.
The Payoff: Turning Risk into Opportunity
The results were groundbreaking. The trials demonstrated that gravel previously considered “infected” could be successfully treated to eliminate the Phytophthora pathogen, offering a safe, scalable alternative to sourcing from pristine forest.
This finding has national implications. For the first time, industry, government, and land managers have a scientifically validated method for neutralising dieback risk in construction materials, a shift from avoidance to eradication.
Key outcomes:
- Verified fumigation method proven effective under WA field conditions.
- Compliance framework now in development for use in roadworks and rehabilitation.
- Reduced need to source raw material from uninfected forest areas.
- Expanded Green Card training to include biosecurity treatment and monitoring.
- Strengthened First Nations engagement in environmental biosecurity management.
As our Director, Giles Hardy summarised:
“This project is about turning decades of research into action. For the first time, we’re proving that dieback risk can be eliminated at its source, not just avoided. It’s a major step forward for national biosecurity and for every organisation managing land at risk.”
What It Means for Australia
This project represents a fundamental shift in how Australia approaches dieback management: from containment to control, and from individual responsibility to shared national action.
It demonstrates the power of collaboration with science, industry, and community working together to create practical solutions that protect both biodiversity and industry operations.
For ArborCarbon, it’s another example of how rigorous science, field expertise, and partnership can move the country closer to a future where environmental protection and productivity go hand in hand.
Project Partners and Sponsors
- Dieback Working Group (DWG) – Project Lead
- ArborCarbon – Scientific Design, Field Implementation, Analysis
- Harry Butler Institute, Murdoch University – Research and Validation
- Department of Biodiversity, Conservation and Attractions (DBCA) – Technical and Diagnostic Support
- Culford Agri Industry – Gravel Processing and Fumigation
- Main Roads WA & Civil Construction Partners – Industry Application Pathways
- First Nations Collaborators – Training and Cultural Integration
- Australian Government – Saving Native Species Programme (Game Changer Grant)
