Fewer than 200 of the trees exist in the wild, hidden in a gorge in the World Heritage Blue Mountains, northwest of Sydney, an area hit by one of the biggest bushfires that have ravaged much of Australia for months.

With flames approaching the area late last year, air tankers dropped fire retardant in a protective ring around the trees while specialist firefighters were winched 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 state where the Blue Mountains lie, described the operation as “an unprecedented environmental protection mission”.