More than half of the timber harvested through WA's ecological thinning program is chipped and burned, with a small portion exported overseas.
The revelation has prompted criticism from environmentalists, who claim the program is being driven by commercial rather than environmental imperatives.
The WA government is set to review the trial over the next two years.
More than half of the trees harvested through Western Australia's ecological thinning trial are being chipped or burned, according to new information tabled in state parliament.
Native logging was officially banned in WA in 2024, resulting in mill closures and job losses in timber communities.
Soon after that the Department of Biodiversity, Conservation and Attractions (DBCA) began the ecological thinning trial, which involves the strategic removal of trees to alleviate water stress and ecological imbalance in regrowing forests.
The practice has been criticised by an independent scientist and environmentalists, who argue the approach is driven by profit rather than environmental benefit.
The state-owned Forest Products Commission (FPC) did not answer repeated questions about the commercial buyers of timber harvested from the program.
The uses of ecologically thinned wood were revealed in WA's Legislative Council last week, in response to questions from Greens MLC Jess Beckerling.
Since the beginning of the program in 2024, 58.6 per cent of thinned wood is being chipped or burned.
Some 93,510 tonnes have gone to the Japanese-owned company Simcoa, which relies on the wood to manufacture silicon at the Kemerton industrial estate.
Perth-based laminated lumber manufacturer Wesbeam is the next-highest buyer, purchasing 41,670 tonnes.
Japanese-owned company WA Plantation Resources (WAPRES), previously known as WA Chip and Pulp, has purchased 22,688 tonnes.
The company exports 1 million tonnes of woodchips a year to Japan and China.
WAPRES chief executive Ian Telfer said no ecologically thinned wood had been chipped and exported overseas.
"It is a viable market, but certainly at the moment, despite any other hysteria there is, we're not receiving or exporting any fibre," he said.
Mr Telfer said a 28-tonne consignment of raw jarrah logs was exported to China as part of a trial this year.
Forestry Minister Jackie Jarvis said that trial was a "one-off".
"[This was] to inform the development of alternative local wood-processing opportunities that maximise the value of jarrah log typically too small for milling," she said.
Ms Jarvis said the government was working to ensure the wood harvested in ecological thinning was being put to "productive use".
Ms Beckerling said the public was being deceived about the program.
"It absolutely should not be going overseas in whole log form and it should absolutely not be going to woodchip or charcoal unless that is genuinely the only possible use," she said.
West Australian Forest Alliance convenor Jason Fowler said the end uses of the wood were contributing to carbon emissions, negating any net environmental benefits of the trial.
"It is quite alarming because we can see that at least half of it or more is being burnt straight away," he said.
"That means that the carbon is released and it contributes to climate change, which speeds up the stress and pressure on those forests."
The ecological thinning trial increased its output by more than 70 per cent in the past year.
In 2024/25 73,307 tonnes of ecologically thinned wood was harvested.
In 2025/2026 the amount increased to 124,922.
But Mr Telfer, who is also president of the Forest Industries Federation of WA, rejected suggestions from activists that the trial was being driven by an industry keen to replace native logging.
"It's a coordinated operation but it's not driven by industry, it's not driven by commercial utilisation," he said.
"It's driven by the forest management and healthy forest objectives of the state government."
The ecological thinning trial is set to be reviewed over the next two years.