A secret operation by specialist firefighters has saved the world’s last stand of Wollemi pines, a prehistoric species known as “dinosaur trees,” from Australia’s unprecedented bush fires, officials said.

Fewer than 200 of the trees exist in the wild, hidden in a gorge in the World Heritage Blue Mountains northwest of Sydney, which have been hit by one of the biggest of the bush fires that have been ravaging much of Australia for months.

With flames approaching the area late last year, firefighters deployed air tankers to drop fire retardant in a protective ring around the trees and specialist firefighters were winched down into the gorge to set up an irrigation system to provide moisture for the grove, officials said.

Matt Kean, environment minister for New South Wales, the state that encompasses the Blue Mountains, described the operation as “an unprecedented environmental protection mission.”

While some of the trees were charred by the flames, the grove was saved from the fires, he said in a statement late Wednesday.

The pines, which fossil records indicate are more than 200 million years old — predating many dinosaurs — were believed to be extinct until the Wollemi grove was discovered in 1994.

Its location has remained a closely guarded secret to protect the trees from contamination by visitors.

“Illegal visitation remains a significant threat to the Wollemi pines’ survival in the wild due to the risk of trampling regenerating plants and introducing diseases which could devastate the remaining populations and their recovery,” Kean said.

The trees have been propagated and distributed to botanical gardens around the world to preserve the species, but the gorge holds the only wild stand.

Australia’s wildfires have since October claimed 28 lives, destroyed more than 2,000 homes and burned 10 million hectares (25 million acres) of land — an area larger than South Korea or Portugal.

About 1 billion animals may have died in the fires, which have driven many species closer to extinction, according to environmental groups.

The country was enjoying a long-awaited respite on Thursday as rainstorms blanketed much of Australia’s east, though a return to warm and dry weather was forecast for later in the summer.

In New South Wales, there were “good falls” on some blazes early Thursday, the local meteorology bureau reported.

In Melbourne, thunderstorms late on Wednesday helped to clear bush-fire smoke that had choked the city since the start of the week and disrupted the build-up to next week’s Australian Open tennis tournament.

More rain was forecast until the weekend, which would be the most sustained period of wet weather since the crisis began in September.

In New South Wales alone, 30 blazes were still burning out of control on Thursday, according to the state’s rural fire service.

Australia experienced its driest and hottest year on record in 2019, with its highest average maximum temperature of 41.9 degrees Celsius (107.4 Fahrenheit) recorded in mid-December.

Scientists say the bush fires are the type of extreme disasters the world can expect more of as global warming intensifies.

The past decade was the hottest on record globally, the United Nations said on Wednesday.

“What’s happening is persistent, not a fluke due to some weather phenomenon,” said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, which provided one of the data sets for the U.N. report. “We know that the long-term trends are being driven by the increasing levels of greenhouse gases in the atmosphere.”