Native forest logging is banned in WA, but trucks still drive on roads

By Neve Brissenden

ABC South West WA

Topic:Forestry, Logging and Timber Industry

In short:

The WA government is ecologically thinning native forests to address problems left behind after the banning of native logging.

A South West landowner says contractors are ripping up trees without thought, and an independent scientist argues there is no scientific basis for the practice.

What's next?

Almost 146,000 hectares of state forests and timber reserves have been earmarked as potentially suitable for ecological thinning.

Deep in Western Australia's South West, an ecological experiment is being carried out across swathes of state forests and timber reserves.

"Ecological thinning" involves removing smaller trees, with the goal of allowing those remaining to flourish.

The eventual goal is a return to the old-growth forests of the past.

But as logging trucks continue to stream up the region's highways, the practice is facing scrutiny from locals and independent scientists.

They are questioning whether eco-thinning is just native logging under another name.

DBCA scientists are monitoring an ongoing trial of ecological thinning across state forests. (ABC South West WA: Jon Daly)

Experiment in drying forests

The scientific rationale behind eco-thinning is that trees are increasingly competing for water in the South West region's drying climate, causing stress and, in some places, collapse of karri, jarrah, and marri regrowth forests.

These forests, globally recognised biodiversity hotspots, were clear-felled by loggers for almost 200 years, until native logging was banned entirely in 2024.

Unthinned (left) and thinned (right) sites near Manjimup in South West WA. (ABC South West WA: Jon Daly)

"We are slowly moving into this warmer drying period, which has put a lot of stress on the forest ecosystems," Department of Biodiversity, Conservation and Attractions (DBCA) scientist Katinka Ruthrof told the ABC during a visit to a thinned site.

Katinka Ruthrof from the Department of Biodiversity Conservation and Attraction. (ABC South West WA: Jon Daly)

Dr Ruthrof is walking among the sparse, retained trees, saved from the saw by white spray-paint markers.

The remaining stumps have been sprayed with glyphosate to prevent more regrowth.

A dense patch of untouched regrowth forest stands in stark contrast across the road.

"[We] can have a look at how stressed the [trees are], and we've compared that with the unthinned area, and the trees in the thinned area are less stressed," she said.

'Logging by another name'

Native logging was banned in Western Australia in 2021, and phased out entirely in 2024.

Since then, approximately 3,000 hectares of state forest have been ecologically thinned, representing 0.2 per cent of WA's forest and timber reserves.

But to local landowners, it does not seem like much has changed from the preceding years of native logging.

Retired teacher and volunteer firefighter Jeff Thornton has been watching the contractors thin forest around his block near Pemberton, 320 kilometres south of Perth, for the past 18 months.

Jeff Thornton lives near Pemberton and says ecological thinning is logging by another name. (ABC South West WA: Neve Brissenden)

"I say it's native logging by euphemism," he said.

Mr Thornton showed the ABC a recently thinned site near his property, where a number of larger stumps sat, while smaller trees seemed to have been left.

"There's no big trees," he said.

"Where are all the big trees?"

An ecologically thinned forest in South West WA. (ABC South West WA: Neve Brissenden)

But Mr Thornton was mostly worried about the wildlife.

"Every year since I've been here, I've had black cockatoos nesting on the property," he said.

"This year, the first time: nothing."

Jeff Thornton in a forest in South West WA. (ABC South West WA: Neve Brissenden)

The DBCA told the ABC it undertakes independent inspections and assessments of the sites, managed by WA's Forest Products Commission, which oversees plantation and native forestry across the state.

Planning for the future

With ecological thinning still a relatively new concept, scientists are relying on evidence from thinned sites during the native logging era to inform their practice.

"We use that historical data to have a look at how those catchments respond to drought and heatwaves in 2011 and 2024," Dr Ruthrof said.

DBCA is also doing the research as the thinning occurs, with early indications the thinned sites are experiencing less water stress.

"That information is coming in already, which suggests we're going in the right direction," Dr Ruthrof said.

DBCA scientists conducting thinning monitoring in South West WA. (ABC South West WA: Jon Daly)

Both the scientists and the department argue the thinning process differs from native logging, as only smaller trees are removed.

But there is no consistent maximum tree diameter across the program, with Forest Products Commission (FPC) supply contracts differing from site to site.

Contractors are instead trained by departmental silviculturists, experts in the growth and maintenance of forest landscapes, to identify which trees to thin.

Ecologically thinned logs on the side of the road near Manjimup. (Supplied: Jeff Thornton)

The contractors engaged by the FPC are former native logging companies.

'No scientific basis'

Australian National University professor David Lindenmayer has been doing extensive research on thinning practices internationally, including in Western Australia.

A globally acknowledged expert in conservation biology and landscape ecology, Professor Lindenmayer said there was limited scientific evidence to support ecological thinning.

"The reality is that forests have been in Australia for about 180 million years and that means that people haven't been messing with them for 179,930 years, and they've survived very well … without those kinds of interventions."

Professor Lindenmayer said forest thinning should only be done when invasive species were taking over.

David Lindenmayer is highly sceptical of the WA government's trial of ecological thinning. (Supplied: ANU)

"Certainly in the karri and jarrah forests in Western Australia, I would not be recommending those kinds of interventions," he said.

"Temperatures are increased on the forest floor, there's more logging slash or debris that's left on the ground, which acts as fuels and it's windier and drier.

"All the ingredients that you need to make fires worse are created when you thin a forest."

Professor Lindenmayer disputed the claims the practice could correct the history of logging and dense forest regrowth.

"Forests will naturally self-thin as they grow older — that is a dynamic that we see in every kind of forest all over the world."

Agriculture Minister Jackie Jarvis, who oversees the FPC as part of her portfolio responsibilities, declined the ABC's request for an interview.

In a statement to the ABC, Environment Minister Matthew Swinbourn said ecological thinning would help make the South West's forests more resilient.

“Research has shown that thinning forests can improve groundwater recharge and streamflow," Mr Swinbourn said.

"It can also reduce the vulnerability of forests to drought and heatwaves over the medium to long term."

He said the practice would be reviewed over the next two years to determine the program's effectiveness.

Header image: A recently thinned forest in South West WA. (ABC South West WA: Neve Brissenden)

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