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Earth’s most massive living thing is struggling to survive

What looks like 47,000 separate trees spread out over 106 acres in Utah are actually all offshoots from a single, massive Aspen tree root. It’s known as Pando and it is believed to be the largest living organism on Earth. But scientists say that overgrazing by deer and elk is now threatening Pando's survival. NewsHour Weekend's Christopher Booker reports.

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  • Megan Thompson:

    As far as science knows, the largest animal that has ever lived is the blue whale. But if you think that means it's the largest living thing in the world, well, think again. There's something a lot bigger … but its life is in danger. NewsHour Weekend's Chris Booker reports from Utah.

  • Christopher Booker:

    Whether you're sitting under its canopy, or looking at it from above, its difficult to comprehend that all of these leaves, the branches and the trunks that support them, are one single organism. What looks like a forest is actually one single tree. Located in Utah's Fishlake National Forest- the tree spans 106 acres- the equivalent of 80 football fields. But what's up top, covers what's happening below: an intricate root system that supports the most massive living thing known to exist on earth. It's called Pando.

    The nickname is Latin for "I spread" but the tree is what's known as a Quaking Aspen clone. That means each leaf, branch and trunk are genetically identical. Some leaves may be larger, some trunks taller, but if you look at the DNA, there is no difference. Aspen clones of various sizes can be found all over the Northern Hemisphere.

    There is debate about just how old this tree is – some scientists estimate that it has existed for thousands of years, but its' remarkable longevity is at risk. Pando is starting to die. Professor Paul Rogers is the director of Utah State University's Western Aspen Alliance. He compares Pando to a human community.

  • Paul Rogers:

    Imagine a town. In this case the Pando clone of 47000 people but they're all kind of the same age. They're all 90, 100, 115 years of age and that's no way to sustain a community be it an ecological one or a human one.

  • Christopher Booker:

    For the past 10 years, he and his colleagues have been working to raise the alarm about Pando's impending demise.

  • Paul Rogers:

    We have no babies, we have no teenagers, we have no young adults we have only senior citizens and those are starting to die very rapidly at this time.

  • Christopher Booker:

    In October, Rogers and co-author Darren McAvoy published a study documenting Pando's dramatic change. Using over 70 years of aerial photographs as a guide, Rogers' and his team sampled and studied 3 different plots within Pando to try to understand what may be happening. They found that Pando is suffering a complex ecological breakdown- a disruption that is hindering the way the giant Aspen clone replaces the dying portions of itself.

    A Quaking Aspen clone like Pando grows not from a seed, but from small saplings that sprout from the expanding root structure. The saplings growing into the white trunks that can stand for well over 100 years. And as older ones die, they are replaced by new green saplings.

    But there's a problem. The saplings have long served as snacks for the wide array of herbivores, animals that scientists call browsers, that regularly pass through aspen forests of the Northern Hemisphere.

    For the majority of Pando's existence, these browsers- everything from rabbit, to deer, to elk- were not able to linger very long. Predators kept them spending too much time inside the giant aspen clone.

  • Christopher Booker:

    So historically if you were an elk or a deer or one of the browser's, the threat would be you are sitting here grazing on a sapling and you could be eaten by a wolf or a mountain lion or a bear?

  • Paul Rogers:

    Yeah, and that would keep things more or less in balance.

  • Christopher Booker:

    But the number of predators has been reduced dramatically by human related activities – everything from hunting to development. With nothing to threaten them, the browsers moved in… and Pando wasn't ready.

  • Paul Rogers:

    It's really good, when it is damaged or moved around, its reaction is to sprout. And it has gotten along very well for a very long period, with that mechanism. However, when we took away those carnivores and we threw that system off so now there's too many browsers- now we have a system spinning out of whack.

  • Christopher Booker:

    Because the forest is now a popular recreation destination, hunting is restricted. Also, during the summer months, cattle from nearby ranches are allowed to graze in the area. Some parts of Pando have been fenced off and saplings have started to return in those areas. But Rogers argues fences only address part of the problem and ignore the broader ecological breakdown that Pando's struggle represents.

  • Paul Rogers:

    Now we've we've introduced some experiments and we've had at least one good response and one not so good response in these different fenced areas.. However if you multiply the situation across the whole West and Pando is a microcosm or a laboratory really for the West we cannot fence all the West. It's difficult and expensive even to fence that 106 acres that is the Pando Aspen clone.

  • Christopher Booker:

    Because that's the current temporary solution if you will is to get a large enough fence that would surround this 106 acres.

  • Paul Rogers:

    Exactly so I call this aspen triage. We have a real emergency here. We can throw up fences. I consider fences dumb. It's a simple solution because the more difficult solution involves in people with different interests. We've got to get people to come to the table and try to compromise. Well, we have people are interested in hunting and healthy deer populations. We have people who are recreationists. We have people that run cattle in that area. So how do we get all these people to compromise? And are we going to be able to convince them that this giant aspen clone thought to be the largest living thing on earth at this time is important?

  • Christopher Booker:

    What happens if we lose Pando?

  • Paul Rogers:

    I think it's a reflection of us. Is this going to come apart during our time and it's clearly our problem the fingers pointed directly back at us. And this is a bellwether or a harbinger of perhaps a lot of other environmental or ecological issues.

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