As fires swept up the slopes of Mount Kilimanjaro, Africa’s tallest mountain, for the fifth day on Thursday, hundreds of volunteers from local villages joined firefighters racing to stop a blaze threatening to ravage one of the world’s richest and most diverse ecosystems.

The fires, which first started to burn at a rest stop for climbers, have been raging for five days with dry grass and strong winds hampering efforts to bring the flames under control.

“This devastating fire is cutting through the most prestigious natural space in the whole of Tanzania,” Padili Mikomangwa, an environmentalist based in the port city of Dar es Salaam, said in a telephone interview. “The nation at large is following this seriously and shocked.”

Already, vast areas of forest and low shrubs have been reduced to embers. Videos and images from the scene showed volunteers struggling to put out the fires as thick white smoke hung heavy in the sky behind them.

Helicopters were set to be deployed on Thursday for the first time to help stop the fires.

With a summit of 5,895 meters, or 19,341 feet, Mount Kilimanjaro is the highest point in Africa and is considered the highest free-standing volcanic mass in the world. The mountain’s snow-capped peaks and the surrounding national park were declared a UNESCO World Heritage Site in 1987, with endemic plants and dozens of animal species, including endangered ones, calling it home.

In recent years, the mountain and the surrounding ecosystem have faced challenges including water and air pollution, intrusion on the park’s perimeters, illegal logging, and poaching. Climate change has also pushed the mountain’s glaciers and icecaps to thaw.

With thousands of climbers arriving each year, concern has grown in recent years that overtourism threatens the natural splendor of Kilimanjaro.

“The extent of the fire which we see today is at a new level,” Marcell Peters, a senior lecturer at the University of Würzburg in Germany who has studied the ecosystems of Kilimanjaro since 2010, said in an email.

He said that the loss of plant life — particularly Erica and Podocarpus trees — could leave the area more vulnerable to fire in the coming years.

Tanzanian parks officials said the fires began on Sunday at the Whona rest area, which is popular with mountaineers using the Mandara and Horombo routes to scale the mountain.

The authorities said an investigation into the origin of the blaze was underway, but preliminary evidence suggested that it was sparked accidentally by porters warming food for visitors.

“It was all bad luck,” Pascal Shelutete, an official with Tanzania National Parks, told journalists this week. “But we will continue to follow the issue in depth.”

In addition to the plants and forests that have been destroyed, the fires have also razed facilities used by tourists at the Horombo Center.

No deaths or injuries have been reported.

Officials estimate that the fire has so far destroyed an alpine area stretching over roughly two miles.

“We are still in the midst of putting out the fire,” Hamisi Kigwangalla, Tanzania’s minister of natural resources and tourism, said on Twitter on Thursday, a day after visiting the site of the fire. “The task is harder and bigger than it is thought to be.”

The mountain has long held a special place in the imagination of the world, written about extensively by visitors awed by its majesty.

For those who live in its shadow, it has been both a source of income and pride. When Tanzania gained its independence in December 1961, the new leader, Julius K. Nyerere, dispatched a team of climbers to ascend the continent’s highest peak.

They planted a torch, meant to serve as a metaphor for the aspirations of a nation.

However, with presidential elections set for Oct. 28, there is concern that the nation is sliding into autocratic rule.

Since President John Magufuli was elected in 2015, the government has cracked down on the media and civil society, passing laws targeted at silencing critical voices.

“It’s no coincidence that the Tanzanian government has increased its repression of the opposition, activists groups, and the media so close to the elections,” Oryem Nyeko, Africa researcher at Human Rights Watch, said in a statement. “Instead of upholding the right to free expression at this critical time, authorities have instead adopted measures that raise concerns about the elections being free and fair.”

He is facing off a slew of candidates, including Tundu Lissu, an opposition figure who survived an assassination attempt three years ago and is now back in the country. No one has ever been arrested in the case.

The nation of roughly 58 million people depends heavily on tourism, and Mr. Magufuli has been eager to draw people back to the country after the coronavirus pandemic ground everything to a halt around the world.

Five months ago, he declared the nation coronavirus-free, an announcement that public health officials and neighboring nations alike greeted with skepticism. Mr. Magufuli’s government has restricted reporting about the virus in Tanzania, according to Human Rights Watch.

Tourism has been allowed to resume, including at Mount Kilimanjaro.

Mr. Mikomangwa said that the authorities could learn from the disaster by better equipping parks and firefighters to respond to fires. “They are now scrambling for a few helicopters,” he said. “But this episode shows that we need to take robust measures to better care for our resources and ensure we end this fire once and for all.”