Sir David Attenborough and Dr Jane Goodall have made an unusual intervention into Australian state politics by calling for a new national park to be created in Victoria to save the endangered Leadbeater’s possum.

Attenborough, who is visiting Australia, has thrown his support behind the establishment of the Great Forest national park, which would encompass much of the central highlands area of Victoria.

“The maintenance of an intact ecological system is the only way to ensure the continued existence of biodiversity, safeguard water supplies and provide spiritual nourishment for ourselves and future generations,” the naturalist and wildlife documentary maker said.

“It is for these reasons, and for the survival of the critically endangered Leadbeater’s possum, that I support the creation of the Great Forest national park for Victoria.”

Goodall, famous for her work with primates, said the national park would help secure the future of a threatened ecosystem.

“If we act now, we will be ensuring the forest can continue to provide services that support us - clean water, fresh air and storage of carbon,” she said. “If we fail now, what future will we have chosen for our grandchildren and their grandchildren?”

The new park would add 355,000 hectares of consolidated protected land to a patchwork of safeguarded forests north east of Melbourne.

An alliance of environmental groups, whose polling shows that nearly nine in 10 Victorians support the new park, say it would save the Leadbeater’s possum, Victoria’s faunal emblem, from extinction. They say it would also help secure Melbourne’s drinking water – 98% of which is regulated by the natural processes of the central highlands’ towering trees and other vegetation.

But the fight for the national park is as much about economic modernisation and reviving struggling rural towns as about saving small marsupials.

The beauty of the central highlands is offset by a soundtrack of logging trucks rumbling down its winding roads.

A logging truck sign seen at Cathedral range state park. Photograph: Paul Jeffers for the Guardian

The region’s majestic mountain ash trees are the tallest flowering plants in the world, occasionally topping 100m, but a heavily subsidised logging industry, along with bushfires such as the devastating Black Saturday fires of 2009, have reduced the ecologically vital old growth trees to just 1% of the forest area.

While the region has giant trees, rolling valleys, vineyards and impressive local produce, it has struggled to compete with other regions for tourists. The Great Forest national park would be a vital draw card, its supporters say.

The proposed park has become emblematic of the problems faced by many small Victorian towns which, despite sitting amid abundant natural beauty, suffer from high unemployment and substandard public services.

With the state election looming on 29 November, the seat of Eildon, which would include most of the park within its boundaries, is grappling with many of these problems.

The governing Coalition has ruled out any new national parks should it retain office, while the Greens support the new listing. Labor, which is being heavily lobbied by environment groups, is thought to be in favour despite union concerns, although its official position has yet to be revealed.

“There’s no question this area needs a massive injection of resources around tourism development,” says Sally Brennan, Labor’s candidate for Eildon. “I hear people say, ‘why can’t this town be an attraction like others in Victoria?’ Maybe the answer is some investment in marketing, but certainly tourism is key to economic recovery here.”

Logging has cut vast swathes through the forest, with some ridges suffering noticeable bald spots where the sought-after tall, straight trees have been clear-felled. Local people have noticed the knock-on effects.

“The forest appears to be drying out, it doesn’t seem as lush any more,” says Deanne Eccles, who has run a guesthouse near Toolangi for seven years. “Also, around January and February time people become frightened because of the Black Saturday fires and don’t come up here as much.”

For Eccles, the Great Forest national park would belatedly put the area on the map. She is excited by plans to put bike trails, wildlife walking tours, treetop walks and zip lines into the forest.

“It will bring Toolangi to life, which would be great,” she says. “It’s one of the most beautiful townships in Victoria but it’s dying. People are really struggling here.”

The Leadbeater’s possum is Victoria’s faunal emblem. Photograph: Healesville Sanctuary/AAP

Farmer Ken Deacon spent the Black Saturday fires fighting to save his family’s idyllic homestead. Treasured possessions were placed under blankets next to the dam as Deacon doused the house in water, watching nervously as the fire edged closer, only to be halted at the neighbouring field.

Deacon said the volume of water in the river that flows next to his cattle farm has fallen dramatically over the past 30 years due to the razing of trees. Saplings that take the place of felled trees are thirstier than older trees and suck up more water destined for the river.

“We were desperate during the Black Saturday fires, but I’d say we are just as desperate now,” he says. “Our water is on a downward slide and while I used to get a lot of solace from being up in the forest, I get quite dejected if I go there now. I’ve seen so much damage caused by logging I really think there should be a moratorium on it.”

Deacon’s family has run horse riding tours in the area for nearly 50 years but business has dropped by as much as 50% due to the shrinking forest.

“We have people coming up from Melbourne who enjoy riding in the forest but they become upset when they come across completely devastated areas,” he said. “We’ve been pushed out further and further from the forest.”

Despite being just an hour from Melbourne, the crown jewels of the central highlands lie hidden in plain sight. Cathedral Range state park, for instance, contains remnants of an ancient volcano that imploded about 375m years ago, leaving a 27km crater and changing the world’s climate thanks to the ash it spewed into the atmosphere. It is rarely on tourists’ radar.

We scrambled to the top of the jagged crater’s rim to survey the area with Dr Chris Taylor, a research fellow at the University of Melbourne, who has helped outline what the new national park would look like.

“There are so many sleepy town around here, so many spectacular sites that are under utilised,” Taylor says. “We’ve got the entire global population of Leadbeater’s possum here and the entire global population of the Mount Baw-Baw frog here. It’s appalling we don’t have a proper reserve system for them.

“The main threat to the forests is logging, because it prevents burned habitat from being replaced. We are logging the refuges of wildlife and removing biological legacies that take centuries to build up.”

Support for the new park is not universal. Those who value certain recreational pursuits, as well as those connected to the logging industry, fear ae future where they are locked out of the forest. Expletives have been traded at heated public meetings in Healesville.

But the campaign for the park is gaining traction and, crucially, funding. An online crowd funding push is just shy of its $60,000 target, and activists feel victory could soon be in their grasp.

Environmental activist Sarah Rees has lead the campaign the proposed Great Forest national park. Photograph: Paul Jeffers for the Guardian

“No one will be left out because this forest belongs to all of us, not the commercial interest of one entity,” says campaigner Sarah Rees, who has spearheaded the case for the new park. “The Great Forest national park is an idea whose time has come.”