Written By
Molly McShane
College
College of Science and Engineering
Publish Date
2 February 2023
Related Study Areas
Converting flooded cane into carbon compounds
Carbon is the unseen powerhouse in many elements of life on Earth. Carbon compounds regulate temperature, provide humans with energy through the air we breathe and make up the food that sustains us. Beyond that, carbon is key to climate change mitigation.
Harbouring this powerhouse is the melaleuca. The common melaleuca ‘paper-bark’ tree could potentially not only store carbon but filter farm nutrient runoff. Farmers and scientists are teaming up to understand how big of an impact these native trees have.
In one of the most sugarcane-dominated catchments in Queensland, JCU’s Dr Adam Canning is working with Ingham farmer John Cardillo and Greening Australia in leading a project that has the potential to be scaled up across the Great Barrier Reef catchment.
Together, they have converted 15 acres of flood-prone cane paddocks into melaleuca plantations. These paddocks back on to Palm Creek, which is fed by the Herbert River and flows down into the Great Barrier Reef.
“The paddocks would have once been a wetland made up almost entirely of paper-bark trees,” Canning says. “Water frequently inundates this land, and melaleucas — being water tolerant trees — would have grown naturally here.”
Canning is investigating the amount of carbon stored by these plantations compared to non-restored areas, and their role in capturing nutrients from farm run-off mobilised during high rainfall to reduce nutrient pollution to the Reef.
Dual benefits for the environment and farmers
Canning notes that this project goes beyond simple restoration. He is also investigating how restoring wetlands can fit in with the agricultural landscape, where there are benefits for both farmers and the environment.
“Planting melaleuca plantations on flood-prone farms has dual benefits,” he says. “They are powerful carbon sinks and can help improve water quality. But if agricultural land is restored, it could be at a loss to farmers so, we need to think about how restoration can have co-benefits for farmers.”
The restoration project examines how farmers could generate income while offering farmland to be converted into wetlands, specifically when the paddocks back onto key waterways.
“It’s restoration that fits within the farming landscape, which can potentially add to profitability rather retract.”
Scientists working on the project use techniques to measure the carbon and nutrients in the soil, how they move, and the microbial powerhouses behind them, allowing them to fully understand how effectively melaleuca trees can store carbon. The aim is to use this data to inform potential income from carbon credit schemes and water quality improvement schemes.
Cane farmer John Cardillo, who has been involved in various revegetation projects, says the low-lying paddocks were wasted on sugar cane because they were flood prone.
“These paddocks never produced much sugar,” he says. “They are continually flooded, and a wasted paddock.”
Canning and Cardillo met at the restoration site in 2022, shortly after a rain event. Together, they walked the flooded paddocks, where water had inundated both the melaleuca plantation and the unrestored cane paddock, talking about the project.
“Revegetating these paddocks is a good way to use this land,” Cardillo says. “These paddocks are so close to the coast, the water runs straight into a main creek. The planted trees are great for holding back sediment and it helps with erosion during floods like this.
"It might seem like a drop in the ocean, but this all adds up."
Funding makes a better future possible
This pilot project is funded by Greening Australia, one of the country’s largest landscape restoration organisations in Australia.
Greening Australia’s Dr Lynise Wearne says, “Land which isn’t good for cane can be converted to carbon farming both from vegetation and blue carbon methods — bringing additional income to landholders.
“Greening Australia’s work with JCU to measure the water quality benefit of melaleuca wetlands means that farmers may also be able to receive a Reef Credit payment to increase the overall value of restoration.
“This project is finding the best way to use these flood-prone paddocks to support the long-term success of the agricultural economy by leveraging emerging ecosystem service markets."
Dr Lynise Wearne, Greening Australia
A carbon farming future
In the Great Barrier Reef catchment, there are hundreds of farms with low-performing paddocks just like Cardillo’s farm. It’s both Canning and Cardillo’s hope that this project will pave the way to incentivise other farmers to get involved in restoration projects.
“There are likely many flood-prone paddocks in Queensland that can be converted to melaleuca wetlands, and the results from this project could play a big role in future restoration initiatives in the agricultural landscape,” Canning says.
“We have been scoping the potential for planting over 120 other water-tolerant native tree species in locations across the Great Barrier Reef catchment to support carbon sequestration, nutrient runoff treatment and biodiversity.”
Canning is looking into other projects such as removing tidal barriers to bring back natural processes between saltwater and freshwater — another initiative to help improve Queensland’s coastline and thereby improve water quality, biodiversity and carbon storing opportunities.
“There are a lot of funding opportunities right now for blue carbon restoration projects,” he says. “But I think we really need to think about a more integrated approach to design restoration that will work for our future, for food security, and for the wellbeing of farmers.
“By capitalising on payment for ecosystem service schemes, like carbon and water quality, we can make ecosystem restoration profitable for landholders.”
Want to know more about the transformational work being done in wetlands restoration? Visit TropWATER to explore their projects and find out how you can get involved.