Their mission was secret, and its location even more so.

As wildfires scorched Australia, helicopters dove inside a gorge in the sandstone plateau. Deeper below, hundreds of feet past the looming cliffs, specialists jumped out of the choppers to a site known only to a handful of people. Their objective: Save the trees.

In what Australian officials called “an unprecedented environmental protection mission,” firefighters were deployed in recent weeks into a remote sliver of rainforest, about 125 miles northwest of Sydney, to preserve wild Wollemi pines — a prehistoric species that was once believed to be extinct and is now considered one of Earth’s few living connections to the times of dinosaurs.

“With less than 200 left, we knew we needed to do everything we could to save them,” said Matt Kean, environment minister for the province of New South Wales.

The scene of the government operation — which remained a secret until this week — was like a military operation. Water-bomber planes and air tankers encircled the area inside Wollemi National Park, spreading flame retardant. On the ground, firefighters tapped a river to moisten the soil and slow the approach of a potential fire.

Getting into the gorge, a mere crack between two cliffs, was a challenge, said Cris Brack, a professor at Australian National University.

The operation posed danger, too. As they have raged across eucalyptus forest, wildfires have picked off bark and lit it aflame, meaning that in the worst of cases, fire could have fallen on the firefighters.

The risk was worth it, Kean said, to save a cluster of the pines: alternately described as “dinosaur trees,” time-traveling clones, and the Sydney Opera House of the natural world.

“We have this amazing plant that has effectively traveled through time and survived millions of years,” Matthew Brookhouse, a senior lecturer at ANU, said. “That would not just be a loss for Australia. That’s a loss for the entire world.”

The Wollemi pine is not really a pine; it’s a type of conifer. Most plant species have genes that vary from one plant to another, but the Wollemi pine is each identical genetically to all the others, including those that stood during the time of dinosaurs.