Discovering the Wollemi Pine in 1994 was like finding a family of dinosaurs alive and well. Growing only in a deep sandstone gorge of the Blue Mountains, the Wollemi Pine has intrigued and frustrated scientists. The genetic diversity of the ancient pines is exceptionally low, perhaps the lowest for any plant in the world. Nearly all of the 80 trees are clones - they have identical genetic code. How has it managed to survive through 200 million years of shifting continents and changing climates? And what does it need to keep surviving in a human world? Catalyst joins a select team of specialists as they return to the Wollemi Grove and delve inside its hidden world - the trees and their cells, to find some answers. Blind-folded to protect the exact location, it's only the second time ever that a television crew have been permitted to see the last wild stand of trees.

Narration: We're travelling to a secret gorge where few have gone before. I'm hitching a ride to a real-life Jurassic Park...the last stand of one of the world's rarest and strangest trees... the Wollemi Pine.

I want to find out if we can help the endangered trees fight back, or if they're slipping into extinction.

My guide is National Parks manager Dave Crust. He's like the bouncer for the Wollemi Pines.

Mark Horstman, reporter: What if the Premier or the Prime Minister or the Queen wanted to see a Wollemi Pine in the wild?

Dave Crust: Well unless they're doing a PhD doctorate in research that'd have some potential impact on preserving the species I'm afraid the answer's going to be no.

Narration: As a security measure, I'm blindfolded to make sure the secret location remains just that...

Dave Crust: It's hood time.

Mark Horstman, reporter: Oh thanks Dave.

Dave Crust: Ok you're comfortable?

Mark Horstman, reporter: Yeah that's fine. Lucky I've got a window seat. Cheers.

Narration: But even if I could figure out where we are, I'd want to keep the secret anyway. The Wollemi Pine once shared the world with dinosaurs, but I doubt it could survive being trampled by herds of tourists.

Dave Crust: The site is legally closed to public access The plant's so rare and so vulnerable just clinging on. So we've really got to take quite a precautionary approach to make sure it's preserved.

Narration: It's a new genus called Wollemia, somewhere between a kauri pine and a hoop pine, but its closest relatives are fossils.

1994 ABC news reader: It's been missing, presumed dead, for 65 million years.

Narration: Until one day eleven years ago, a National Parks officer named David Noble abseiled into an unknown gorge... and found himself standing in a strange forest.

There was a time when conifers like the Wollemi Pine ruled the world...it's 200 million years ago, the Jurassic age. Australia is part of the super-continent Gondwana. The whole world is warm and wet, covered in lush rainforests. As the continents break up and Australia moves north, it gets drier and hotter, the conifer forests give way to flowering trees and grasses...

But a remnant of that old Gondwana rainforest still survives here...hidden away in the vast and rugged Wollemi National Park north-west of Sydney...a tiny pocket covering less than one hectare of one gorge among hundreds...

Dave Crust: OK you can take the blindfold off now.

Mark Horstman, reporter: Wow, fantastic.

Narration: I don't have a clue where we are...but there's the Wollemi Pines. Takes my breath away. It's hard to believe that trees so large and so different could stay hidden so close to our biggest city.

Because it's not easy to get to - you either stumble into it, or jump out of a chopper.

At the top of the gorge, I meet up with the team of scientists who visit twice a year to study these unique trees and check on their health.

Mark Horstman, reporter: Abseiling!

It's only about 50 metres from here to the bottom of the gorge, but I feel like I'm going back in time, hundreds of millions of years. Pretty good spot for my first abseil, I reckon.

Dr John Benson: I've been here, I don't know, about 15 times or so. And I come back into this, canyon and I think, "Well, this is like a lot of other canyons." And then I see the Wollemi Pine and I think, "No, this is like going back into, Gondwana Jurassic times." It's utterly ridiculous, because the pine looks totally out of place.

Narration: No-one can say for sure why they only grow here, and nowhere else. There's less than 100 pines in only 4 spots...so few that Dave Crust is reluctant to say exactly how many.

Dave Crust: Since the original discovery there has been discoveries of some additional smaller groves within the area. We've done a really extensive survey of basically the whole park and all the similar habitats in the park and we think we've got them all.

Narration: Nearly all the trees have more than one trunk, a clever strategy to stay ahead of their competitors, and survive fire and droughts. It's called coppicing, where they continually grow new trunks out of their roots.

Mark Horstman, reporter: This is King Billy?

Patricia Meagher: It is. It is.

Mark Horstman, reporter: It's the biggest Wollemi Pine on the planet.

Patricia Meagher: In fact it's got a number of trunks, as you can see, so it in fact has grown upwards a lot more than 38 meters. That gives them potential to survive as an individual for centuries, in fact millions of years really if you think about it. It's just crazy.

Narration: So to find out how many there are, you just count them, right? Well, it's not that simple. To answer that riddle, geneticist Rod Peakall analysed their DNA. And he couldn't believe what he found. All the plants have the same genes, as if they've been cloned in a lab.

Dr Rod Peakall: This is really and truly an exceptional case. The only plant in the world that we've studied, anyone's studied, where we've found no genetic diversity.

Narration: Thousands of years of inbreeding have smoothed out the differences in their DNA...and then there's that radically different way they grow.

Dr Rod Peakall: A bit like strawberries in your, in your backyard, the Wollemi Pine might be able to reproduce by ah, you know by producing a clump here and then running a root along here and then producing another clump here.

Narration: ...each time making a genetic copy of itself. In a way, the Wollemi forest is one big woody organism - and that could be a fatal flaw.

Dr Rod Peakall: Although there are a hundred different clumps of trees in the, in the gorge, in a genetic sense that's equivalent to maybe just one or two individuals, and if those individuals are genetically susceptible to pathogens then effectively the entire population is susceptible.

Narration: So far their isolation has been their greatest protection. Apart from a tray of disinfectant, the pines have no defence against Phytophthora, a microscopic fungus that infects tree roots with mobile spores.

Dave Crust: If someone introduces that to the site the impact's going to be catastrophic. It could potentially kill the whole population.

Narration: One for all, and all for one. The small family of clones crowd onto ledges along a few hundred metres of creek bank.

Imprisoned by their own biology and stranded by a shifting climate, we're seeing the endgame of a long evolutionary career. Could seedlings breathe new life into the grove?

Dr Tony Auld: We've got this big grove of trees and we're wondering whether they're just the living dead.

Mark Horstman, reporter: What are you finding?

Dr Tony Auld: Well, we're finding they are, they are producing seedlings, and that's positive. Every year they drop seeds, and a few come up and they seem to persist.

Mark Horstman, reporter: Especially in these light gaps here?

Dr Tony Auld: That's right...What we've found is that they grow about a centimetre a year, if that, and produce one small branch here. So that plant up the top you can see, that's probably about 50 years old... It's sitting, waiting for a gap for 50 years.

Mark Horstman, reporter: How many make it through?

Dr Tony Auld: We don't know. We've only seen one that has any evidence of making it through.

Narration:The several hundred seedlings in the gorge get their best chance when a tree falls over. John and Patricia discover the second tallest tree of 30 metres, no. 17A with 21 other trunks, has been toppled by a wind storm.

Dr John Benson: But the extraordinary thing is we've got these little shoots coming out of this stem, and this tree's actually completely snapped off, it's not joined to any root system, and yet the thing's still sprouting.

Patricia Meagher: They don't want to give up do they. You can see why they still survive and the dinosaurs haven't.

Dr John Benson: It's hard to kill.

Patricia Meagher: Yeah, definitely.

Mark Horstman, reporter: The Wollemi Pines have survived millions of years of global change, in fact everything that nature can throw at it. But for these last few trees to survive do they need a helping hand from us, or would it be better that we just left them completely alone?

Narration: Today there's many more alive than when they were first discovered. What most of us don't know is that thousands are held captive in a secret factory run by the Queensland Government...

This is the DPI Forestry nursery near Gympie ...surrounded by 8000 volts of electric fence, it looks more like a detention centre than a plant nursery.

Mal Baxter: A Well, it looks a bit like that, but there's less than a hundred trees in the wild and the rest of the trees are here, so it's very important that we look after our investment here...

Barb McGeoch: And also the site is a quarantine nursery site which means that all the entrances are covered by these foot baths and that stops any diseases from coming into the nursery.

Narration:This is the only Wollemi Pine factory in the world. Seven years ago, they started out with cuttings taken from the wild. But like other plantation trees, Mal Baxter says the future of mass production is in tissue culture.

Mal Baxter: Just in this greenhouse alone we have over fifty thousand.

Mark Horstman, reporter: And in the whole facility here, what's your estimation?

Mal Baxter: We hope by the time we got into full production, we will be in the vicinity of half a million plants a year.

Narration: With so many potted pines ready to be set free and sold to raise funds for their wild cousins, some suggest it's time to take direct action...and replant another gorge.

Dr Rod Peakall: Why can't we use that to advantage, use that resource to create another wild population, a reintroduced wild population, which people can go and visit and in sense the experience the awe of seeing this ancient tree growing in the wild.

Dr John Benson: I would not support restocking just at the moment. We, we, I think we should monitor the population here to see how it's going. It seems to be ticking over.

Narration: The current logic behind national park policy is that we should not play God, and only fix problems that humans have caused.

Dave Crust: This whole sort of question about, you know, gardening in national parks is, is a difficult it may well be an option in the future to, to maybe create some openings in the canopy to try and encourage some seedling growth.

Narration: Meanwhile we'll just have to settle for turning our gardens into national parks. Back at the nursery, Barbara McGeoch has just the thing.

Barb McGeoch: These are what we call our collectors' edition and what is unique about these is that they are the first plants grown on from the original cuttings from the wild population. And this wonderful plant here is the child of King Billy, the largest Wollemi Pine in the wild.

Narration: Ironically, if some day the Wollemi Pine dies out in the wild, it will live on as a garden ornament or an indoor plant. There's reason for hope though, that a dinosaur in the hand is worth two in the bush.

Patricia Meagher: We're looking at a plant that was supposedly extinct that has been on the earth over an enormous, physical change and is still here and every time we look at it, it shows us something different.

Mark Horstman, reporter: What's left to find out?

Dr John Benson: Well, we haven't found any dinosaurs yet. Still hoping for, you know, a little velociraptor to come out of the woodwork and surprise us!