Scientists say Australia's endangered greater glider is at a heightened risk of extinction after logging rules were changed without their input.
The Environment Protection Authority has ditched a requirement for the Forestry Corporation to search for glider den trees before logging state forests.
Instead the corporation must increase the number of hollow-bearing, or potentially hollow-bearing, trees it retains per hectare.
Experts who study Australia's largest gliding marsupial are appalled and say the changes will fast-track the glider's extinction.
They have questioned why the EPA did not seek their advice.
Australian National University Professor David Lindenmayer is a leading forest ecologist who has studied greater gliders for more than 40 years, and has trained other scientists who do the same.
He says the decision to abandon den tree surveys is "crazy, ill informed and not based on evidence".
And he warns it won't result in viable habitat for heat-sensitive gliders, with each animal needing a network of den trees for shelter, and breeding.
He says food sources will also go, with loggers able to harvest right up to the base of retained trees.
"This is absolutely ridiculous. When you have an endangered species that has declined so dramatically, in such a short time, you don't do this."
Wilderness Australia glider ecologist Andrew Wong says EPA chief executive Tony Chappel reached out over the weekend, asking for the contact details of other experts on the species.
"I think they had a go, got it wrong, and now they've understood they've gotten it wrong, they are making attempts to talk to people," he told AAP.
"Their consultation efforts so far have been non existent. They are now reaching out and we are about to find out whether it will be genuine consultation or whether it is essentially a PR exercise."
The greater glider became an endangered species under federal and NSW laws in 2022, after the Black Summer bushfires wiped out over a third of its habitat.
Ecologist Dr Anne Kerle is a former chair of the NSW Threatened Species Scientific Committee and contributed to the work that led to the NSW listing.
Like Prof Lindenmayer, she's dismayed.
"The ability for that species to be able to survive into the long term, and not continue to diminish in numbers, is being eroded really badly by forestry activities," she told AAP.
"For a start they have no idea how many are there. They might say they have, but they don't."
Dr Kerle, who is now a director for Wilderness Australia, said it was critical to get "proper experts to assess what they are doing".
Dr Kita Ashman is a threatened species ecologist with WWF-Australia and has spent months corresponding with the EPA over Forestry Corporation's alleged failings to identify glider den trees in the Tallaganda State Forest.
The EPA imposed a series of stop work orders in that forest after a greater glider was found dead near harvesting operations last year. Forestry Corporation remains under investigation over its activities in Tallaganda.
Dr Ashman, who has published research on gliders, says some stakeholders were invited to a Friday briefing where the EPA said experts had been consulted.
But a later email referred to one unnamed expert.
The EPA did not answer AAP's questions about who it consulted but says it' is confident the additional hollow-tree protections play an important role in protecting habitat.
"We also acknowledge that additional scientists have raised concerns around the value of surveys and we will be working with them to ensure the value of what these surveys provided isn't lost, along with listening to any additional stakeholder concerns."
AAP has also sought comment from the Forestry Corporation.
