The ground squelches underfoot, the forest a mass of branches criss-crossing between the slender trunks of mountain swamp gum and the ferny undergrowth. This is Leadbeater's possum country. And one of the tiny critters is about to get a rude awakening.
It's late in the afternoon, but for the endangered nocturnal possum it's the middle of the night. Its round black eyes are fully alert by the time it has been scooped from its timber nest box high in a mountain swamp gum and popped into a brown cotton bag.
Still radiating the body heat it has generated and shared with its nest buddies, the young male is weighed and measured at ground level before being returned to his treetop home.
The annual weigh-in, which also gathers genetic data, is a vital opportunity for biologists to check the health of Victoria's faunal emblem and one of the rarest mammals in the country.
But what the surveying scientists are increasingly finding is a species under stress. Fire has destroyed much of its habitat, and conservationists say logging is putting pressure on the rest.
Now there are serious suggestions Victoria is watching its animal emblem head towards extinction. And there are calls for intervention.
After studying the marsupial for more than three decades, ecologist David Lindenmayer gives the possum's survival in the wild just 20 years. ''If we don't seriously look at conserving these intact areas of forest, then that's all we've got,'' he says. ''This is the time to make sensible decisions and go for it.''
At the Yellingbo Nature Conservation Reserve, a small patch of swampy forest is home to the last remaining lowland population. As its habitat shrinks, the past eight years has seen a 40 per cent decline in Leadbeater's possum there. Numbering no more than 60, they are now concentrated in an area measuring just four kilometres by 120 metres.
The situation is not much better for the other, larger, population of Leadbeater's in the tall, cool, mountain ash forests of Victoria's central highlands. Exact highlands numbers are unknown, but are likely to be somewhere under 2000.
On Black Saturday, more than one-third of public land within the Leadbeater's highland habitat range was burnt. Studies by researchers at the Australian National University and the Arthur Rylah Institute for Environmental Research have found that Leadbeater's have not returned. Highland possums like to live deep in hollows of old trees, so young trees tend not to be suitable. Victoria's central highlands are dominated by young forest – 99 per cent of the trees are from 1939 or later – and just 1 per cent of the mountain ash forest is old growth.
Lindenmayer says the front line of the fight to save the endangered species is the mountain forest, and that if the young forest isn't allowed to age, the possum will vanish.
Here lies the problem. As fire and felling shrinks forests, competition for the remaining resources between loggers and conservationists has intensified to such an extent that the petite possum, which weighs no more than an apple, is now a hefty political problem.
''Leadbeater's possum is an iconic species, somewhat like Victoria's tiger or panda,'' says Dan Harley, Healesville Sanctuary's threatened species biologist.
The dilemma facing the state government is that it wants to provide the timber industry with resource security to meet its contracts. That means nominating areas for the protection of Leadbeater's and other threatened species, and allowing logging elsewhere.