Australian National University ecology professor, David Lindenmayer, said he "can't believe" that areas across central Victoria with significant numbers of the threatened possum were being targeted for logging.

He backed Yarra Ranges Council's opposition to VicForests' plans to log 20coupes near conservation reserves that protected threatened species.

The plan outlines 144 logging coupes including Toolangi, Powelltown, Noojee and Marysville in the east of Yarra Ranges Shire.

"Surprisingly there is some small patches of old forest important to the animal being targeted by VicForests for harvesting - a couple of areas have significant numbers of Leadbeater's possum," Professor Lindenmayer said.

He is part of an ANU team monitoring the possums in the region. He estimates about 1000 Leadbeater's possums remain in Victoria - the possum's only known address in the world.

Small numbers lived in Toolangi, despite the area being "belted" by bushfires and logging in the past 100 years, he said.

The species faced a high probability of extinction within 30-50 years unless logging stopped in its ever-shrinking habitat.

The council last week also voted to sign The Wilderness Society's ethical paper pledge not to use native-forest sourced paper.

The society's ethical paper campaign allows groups to pledge not to support Australian Paper and its Reflex product until the company stops using native-forest timber pulp.

Cr Samantha Dunn, who moved the motion, said the pledge wouldn't cost the council, which already uses paper from recycled and plantation timber sources.

VicForests spokesman David Walsh said about a third of timber from Victoria's forests was sold for furniture and flooring, because not all parts of a tree could be used for high-value products.

"Much of the wood that does not meet the high standards required for sawlog is utilised to produce quality writing and office paper."