While the bushfires that ravaged Tasmania over the summer are no longer threatening communities, photos show the charred remnants of the state's wild south-west.

Key points: Thousands of hectares of UNESCO World Heritage wilderness has been burned this bushfire season

Thousands of hectares of UNESCO World Heritage wilderness has been burned this bushfire season The blazes have threatened fire-sensitive vegetation

The blazes have threatened fire-sensitive vegetation Aerial photos show the full extent of the damage

Parts of the Tasmanian Wilderness World Heritage Area (TWWHA) have been in the path of the fires for weeks, and experts hold grave concerns for the future of the UNESCO site, as dry lightning strikes increase and rainfall declines into summer.

The photos show the scorched earth left behind after the Gell River fire, which began just after Christmas.

Flames tore through the foothills of Mount Eliza and Mount Anne in the Southwest National Park, blackening the once-pristine landscape, and shrouding ancient old-growth forests in smoke and ash.

Lake Rhona was particularly affected by weeks of bushfires. ( Supplied: Luke Tscharke )

Photographer Luke Tscharke said he felt compelled to show the damage to the rest of the world.

"I believed it was important to get out there and document it, the best way to do that was to get out and photograph it," he said.

"You see the scale of what can disappear overnight."

Lake Rhona, which includes a popular hiking track, looked particularly bad, he said.

"There's a very stark line between where it was burnt up to the edge of the lake," Tscharke said.

"I was actually planning to do a hike into Lake Rhona this year, so to see it how it was, was quite upsetting."

The fire damage around the Mount Anne track has alarmed many bushwalkers. ( Supplied: Dylan Toh )

Ancient vegetation under threat

Lynda Prior, a fire ecology and forest growth researcher at the University of Tasmania, said the photos showed patches of plants that were sensitive to fire, and other patches that weren't.

"It's classic south-western Tasmania, with lots of different types of vegetation, all intermixed with each other, and some are fire sensitive and some are quite fire tolerant," she said.

"You can see in the photos the fire has eaten around the edges of the vegetation in many cases.

"Because the trees aren't so flammable, and they're often in the damper parts of the landscape, the fire can't penetrate the area quite as easily."

Some burnt-out areas contained vegetation that was fire-sensitive and vegetation that was not. ( Supplied: Luke Tscharke )

Dr Prior said in certain areas in the TWWHA, the fire had burnt close to precious vegetation like Nothofagus, Huon pine and other low-altitude conifers like the King Billy pine.

She said if those species are burned, they may never grow back.

"They are very slow to recover. In some cases, they might take centuries," she said.

'Primed to ignite'

Dr Prior said the fires were the "biggest series the state has seen in terms of area covered".

The TFS is using eight or nine helicopters and fixed-winged planes to fight the Gell River fire. ( Supplied: NSW Rural Fire Service )

Climate change is broadly considered to be a contributing factor, and she said successive fires would gradually make the whole landscape more flammable, putting the fire-sensitive vegetation at increased risk.

"Given the fires in recent years, and the increase in dry lightning fires since the year 2000, it's not looking good," she said.

"The reason that these fires are happening more now is because it's getting hotter and drier.

"The whole summer we've had these strange weather patterns with westerly systems moving through, but they haven't brought any rain, so everything's dried out and primed to ignite when we get lightning."