As bushfires blackened forests last summer, one tree species was protected by a specialist team of firefighters: the Wollemi pine.
These trees have a deeply ancient lineage dating back to when dinosaurs walked Gondwana 100 million years ago. Back then, rainforests – including Wollemi pines (or their cousins) – covered what became Australia.
So when a handful of Wollemi pines were discovered alive in 1994 on the brink of extinction, it caused a frenzy of interest that has barely died down among plant enthusiasts.
Today, fewer than 100 mature pines are left in the wild. But their exact location is one of the best kept secrets in Australian plant conservation, to protect them from pathogens such as the root-rotting phytophthora that might hitch a ride on human visitors.
But while rare in nature, our ongoing research with citizen scientists is finding Wollemi pines grow in backyards all over the world, in a range of environments, and this information can inform how we can protect them in the wild.
The Wollemi pine is considered the iconic poster-child for plant conservation. It’s an unusual-looking plant – each wild tree has many trunks covered in bark resembling bubbling chocolate and branches of lime or grey-green fern-like leaves. And in the wild, they grow to more than 40 metres tall.
The species is a member of the southern conifer family Araucariaceae, and its cousins include the monkey puzzle tree and the Norfolk Island pine. While considered a rainforest tree, many remaining in the wild exist between rainforest and dry eucalypt woodland, on the ledges of a sandstone gorge.
Since the Wollemi pine was discovered 26 years ago, the protection effort has been intense, focusing on conservation in the wild.
One of the first strategies was cultivation. Horticultural scientists at the Australian Botanic Garden Mount Annan (Sydney) worked out how to propagate the species so it could be grown and enjoyed in gardens, reducing the risk of illegal visitation in the wild.
Wollemi pines are dinosaur trees
After the Australian Botanic Garden established a basic “insurance population” of plants propagated from the wild trees, some of the first cultivated Wollemi pines were distributed to botanic gardens in Australia and overseas, including in the UK’s Royal Botanic Gardens Kew.
In 2005, Wollemi pines were auctioned to the public at a Sothebys Auction. Since then, they’ve been exported to many nurseries around the world, and now grow in many public and private gardens.
When plants are very rare in the wild, or are very restricted in their distributions, conservation away from the site (ex situ) can play an important role in their survival.
Enter our I Spy A Wollemi Pine project. Fifteen years after the Wollemi pine became available for sale, our study asks people to report where Wollemi pines are growing in gardens across the world.
So far, results from the online survey have revealed the species grows across 27 different countries, from Australia to Russia, and the UK to Peru.
The tallest trees so far – stretching to 7 metres tall (though dwarfed by their wild counterparts) – have been reported from the UK. To date, 987 people have contributed data about Wollemi pines.
Reading comments from survey participants – from “Has survived minus 10 degrees” to “I just love it” – has been a source of interest and joy for us researchers.
When the survey is finished, we’ll analyse the responses to understand what influences the growth of this species, such as different climates and soils.
Knowing how Wollemi pines grow in other parts of the world will provide gardening tips for home growers, but more importantly it will inform future conservation efforts in the wild in the face of climate change.
For example, this research will provide information on what environments the Wollemi pine can tolerate. We’re discovering the hottest, coldest, wettest and driest places on earth this species can survive in.
This information can help us find places to establish new populations of Wollemi pines. It may also provide clues on the evolutionary history of this species and how it managed to survive multiple ice ages and other dramatic climate changes in deep history.
Conserving Wollemi pines in backyards is not quite the same as Wollemi pines in the wild – in the same way its important to have pandas in the wild, and not just in zoos. But using cultivation for conservation does mean these species have much greater distribution today than they have ever had in the past.
In fact, this isn’t the first time a rare tree has ended up in gardens. The dawn redwood, thought to be extinct in the wild, was rediscovered in China in the 1940s and can now be found in gardens across the world.
And the internet is a great place to foster conservation. In online forums, people share every stage of their Wollemi babies’ growth, from seed germination to pine cone production.
This love and connection to Wollemi pines might even help address “plant blindness”: the propensity for people to see, recognise and focus on animals rather than plants, despite plants being central to providing us with food, the air we breathe and our climate.
So, as more species are threatened with extinction every day, everyone’s actions – even in their own backyards or online – can make a difference.
If you have a Wollemi pine in your backyard, or know of a Wollemi pine in a park or garden, and would like to get involved in our citizen science survey, please click here.
There’s a tree that once covered the whole of Australia, then dwindled to a dozen examples, and is now spread around the world. We call it the Wollemi pine (Wollemia nobilis), but you could call it the dinosaur tree.
Fossil evidence indicates that between 200 million and 100 million years ago, Wollemi pine was present across all of Australia. A dryer, more flammable continent is likely to have driven the tree to near extinction over the millennia, leaving just a very small remnant of the Wollemi in a secluded deep gully not far from Sydney.
And there these trees remained, hidden, until they were discovered by a canyoning National Park worker in 1994.
The reaction to the discovery of this tree, thought to have disappeared 100 million years ago and only known through its fossils, was spectacular. Great secrecy was maintained around the site of the find. Because there were so few, the individual trees in the gorge were given their own names to celebrate their importance and acknowledge the efforts of those trying to protect them.
Scientists, arborists and botanists swung into action to discover ways to propagate more trees and establish other colonies of the Wollemi as insurance against that single refuge being lost.
There was a great sigh of relief when it was discovered that trees could be successfully cloned, and new trees were potted up in the Sydney and Mount Annan Botanic Gardens. The interest in these original cloned offspring was so great that they were auctioned off by Sotheby’s, with the profits going back to support more research into this little-known living fossil.
Students and staff from my school at the Australian National University pooled together to bid for a clone of the Wollemi, christened the “John Banks” – named for our colleague Dr John C.G. Banks, who was one of the first researchers to describe the tree’s dendrology. We planted our tree in memory of John, with a cage around it because it was so rare and valuable.
In 2006, just over a decade after the original discovery, huge numbers of cloned Wollemi Pine seedlings were released from the official nursery in Queensland.
Every major nursery in Australia stocked potted Wollemi Pines for sale to a public who were keen to own a piece of ancient life and help ensure it didn’t go extinct. Enthusiasts around the world also bought their own dinosaur trees.
But it’s not just gardeners who have spread the Wollemi back to all corners of Australia and across the seas. Special Wollemi pines are also in the diplomatic service, having been presented by Australian prime ministers and foreign affairs ministers to various dignitaries.
Seedlings are an obvious choice to represent long-term friendship and trust, as the act of planting a tree is one of hope for the future and a common good. A seedling that can trace its history back more than 100 million years, and which represents the reversal of an extinction, is even better.
Wollemi were thought to be extinct long before humans arrived in Australia, so there is no opportunity for humans to have used it in any specific way. However, ancient species may have properties or traits that are no longer present in evolved plants and these may be useful. For example, extracts from Wollemi pine leaves have been found to be successful in inhibiting a pest that affects winter wheat production – which may help control an expensive problem without herbicides.
Scientists found that extracts from the leaves of the Wollemi contained chemicals that had never previously been described, and which suppressed annual ryegrass (Lolium rigidum). The ryegrass, like many modern weeds, has evolved in the absence of Wollemi and thus was unlikely to have developed resistance to its chemistry.
Little was known about Wollemi pines when the remnant was found. We knew the conditions of the gorge where they grew, but not whether these were optimal. Could the tree survive in hotter or cooler, drier or wetter, more clay or gravelly soils?
We now know from planting experience outside the National Park that Wollemi pines can grow on exposed rock slopes, surviving frost and temperatures lower than -5℃ with the help of a waxy coat it puts on top of its growing buds. They can also survive heat greater than 45℃ in full sun.
Some Wollemi pines have been known to happily sit in small pots on verandas or decks, growing to over 3 metres – only to die within weeks of being transplanted into carefully prepared holes. They can be slow-growing, but given good light and moisture they can grow more than 50cm per year. Horticulturalists and the Sydney Royal Botanic Gardens continue to work on finding the best ways of tending these pines.
Wollemi pines, unlike their nearest neighbours in the Araucariaceae, can also produce coppice or epicormic shoots in response to drought or fire. It is likely that this ability is responsible for the survival of the original remanants in the National Park, with new upper stems regenerating from below-ground stocks century after century.
A potential issue with clonal reproduction is the lack of genetic diversity, which could make the pines susceptible to further environmental changes or pests. However, many trees are maturing and producing viable seeds, and there is certainly diversity in the phenology with some Wollemi of the same age producing female cones, some male cones (and some both).
Despite the ability to survive cold and heat and even recover from damage using epicormics, Wollemi Pines may not make ideal street trees, as the branches on the trunk shed relatively quickly. Shedding leaves, bark or branches are regularly complained about by residents in cities. But in the right place in a backyard – with low frost intensity, warm summers and enough moisture – you can grow your very own dinosaur tree.