One of the world's oldest and most rare tree species — the Wollemi pine — is flourishing in Canberra at the National Arboretum.
To celebrate Canberra Tree Week, forestry enthusiasts gathered at the Arboretum to mark 21 years since the Wollemi pine discovery.
The species was believed to be extinct, but in 1994 New South Wales Parks and Wildlife ranger David Noble made a discovery while abseiling in Wollemi National Park.
Since the discovery, the challenge for tree specialists has been to learn how best to propagate the species.
Forestry specialist Dr Cris Brack, from the ANU Fenner School of Environment and Society, said it was vital large numbers of the species could be reproduced in other places outside Wollemi National Park.
"Even though we knew where they were, one simple accident like a disease or fire could wipe out the entire population," he said.
"Some conservationists were particularly worried that there would be a very small amount of genetic diversity, and the first seeds had very low success rates."
Dr Brack said the National Arboretum had played a key role in the conservation of the species.
"At the Arboretum, the established Wollemi pine is producing viable seeds, which is allowing the Arboretum to raise trees from seed crop," he said.
There are already over 80 Wollemi pine trees growing well at the arboretum, ranging in height from over two metres to less than a metre.
"The species once grew across the whole Australian continent and we have fossil records from about 121 million years ago," Dr Brack said.
"The whole planet was different that long ago and even the eucalypts and the acacias, which we now think of the Australia fauna, hadn't even evolved then — they're youngsters from about 66 million years ago.
"Of course Australia wasn't where it currently is that long ago; it's moved around itself but the Wollemi, or something very similar to it, was over the entire continent."
Dr Brack said while each of the trees differed visually, their genetic codes were identical.
"They all look rather different; some have female cones on them and some have male cones, some have neither and some have both," he said.
By cloning the tree species, specialists have been able to reproduce large numbers of them in a range of different environments.
As part of Canberra Tree Week celebrations, a new plaque was unveiled at the Arboretum beside a thriving Wollemi pine to mark 21 years since Mr Noble's discovery.