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  • Writer's pictureBatrisyia Zumli

The Trembling Giant: Pando

Edited by Sky ye.

Pop quiz!

How many trees do you think are in the picture above?

Did you guess 100? 1000? Maybe even more than that?

Would you be shocked if I told you that any answer besides 1 would be incorrect?

Yes, what you’re looking at is the heaviest single organism on our planet, located in the Fremont River Ranger District in the USA.

A single clonal colony (basically, a bunch of clones in the same place) of an individual male quaking aspen, this behemoth of an organism clocks in at 6 million kilograms. Affectionately known as The Trembling Giant, Pando,¹ its existence was first discovered in 1976 by Jerry Keperman and Burton Barnes². However, it was researchers: Micheal Grant, Jeffrey Milton and Yan Linhart from the University of Colorado who baptized it as Pando, claiming Pando to be the heaviest single organism on earth.¹

Pando reproduces asexually through vegetative reproduction.⁴ This type of reproduction is quite common in plants. You’ve probably heard that strawberries and ginger reproduce by forming runners: horizontal stems that take root and propagate more of their species! Pando basically undergoes the same process, but on an incredibly large scale. Sending out underground roots horizontally, shoots known as ramets grow upwards from these roots, ultimately, forming what looks like multiple separate trees aboveground.⁴ In reality, they are all a singular tree connected by a singular root system.

Here’s where its name, Pando, latin for ‘I spread’, starts to make sense. Through this vast underground root system, Pando now occupies about 437 060 m² of land¹ with over 40 000 trunks that are replaced individually every time they die, a natural process that occurs every 100-130 years. These trunks were actually pivotal in determining the nature of Pando as a singular organism, through the identification of identical genetic markers³.

Pando also happens to be an ancient being, known as one of the oldest organisms still kicking it.⁵ It’s quite difficult to accurately pinpoint its age because we can’t use the tree ring numbering method since Pando’s ‘trees’ are replaced progressively every century or so. A lot of sources have more than a few discrepancies, with estimates ranging from 10 000 to 1 million years old. Thus, Pando’s true age can only be determined by the age of its extensive root system. Rough estimates had it at about 80 000 years old, but recent discoveries of an ice sheet covering Utah about 20 000 years ago makes this guess rocky since even the most resilient tree would have trouble surviving that. Thus, estimates now range between 10 000-16 000 years old.⁶

So basically, we’re dealing with an ancient singular organism, masquerading as thousands of organisms, that is also spreading extensively underground on a scale we can barely comprehend. Sounds like an old god to me!

I’m joking, of course, but therein lies the fascination behind Pando. Modern humans often think of organisms in a very individualistic sense; if a tree looks separate from every other tree, and it’s operating like a single one would, then it must be one tree. However, biology doesn’t work within the limits of our tiny mind. Even multicellular single organisms, like, you know, HUMANS, actually evolved from a bunch of cells just deciding to cooperate with each other over the course of millions of years. The hundreds of years it took for us to even acknowledge Pando, much less its status as a single organism isn’t any more than a mere blink of an eye to Pando itself.

However, Pando also serves as a bleak reminder to the destructive nature of modern humanity. Recent studies and field findings have discovered that the number of young Pando saplings is decreasing. Ecologist Paul Rogers of Utah State University has stated that Pando is now mostly made up of “very elderly citizens.”⁷

On the surface, the cause of this decline may seem like it has nothing to do with humans. Researchers have pinpointed mule deer and cattle helping themselves to the delicious young saplings as the primary cause behind Pando’s struggle to regenerate. Although the animals seem to be the perpetrators, we humans are actually still the root of this issue. Ranchers are allowed to let their cattle have a little snacking session for about two fun weeks a year under the U.S Forest Service grazing allotment. There’s also a lack of apex predators to naturally control the herbivore population because of local hunters who kill wolves, mountain lions and grizzly bears for kicks. There’s a fence around Pando, but it doesn’t really work when the mule deers can hop right over to get to their meal of delectable baby Pando saplings.⁷

In the end, it all seems to circle back to us. Pando’s discovery and downfall takes its roots in human curiosity and consumption, two unnervingly conjoined aspects of humanity.

Graham MacAree, an Editor-in-chief of Secret Base, quotes on this behavior;⁶

“We live in the first age that is able to grope its way back towards the true mysteries of biology. We also live in an age that seems preternaturally gifted at disrupting that biology, and in a civilization that only barely cares about the consequences.”

As bleak as this sounds, all is not lost. Some cool folks over at the Western Aspen Alliance, an organization working to nurture healthy aspen ecosystems, are figuring out how they can save our trembling giant. As the fencing solution was bypassed by the mule’s incredible determination to get to their snacks, the Western Aspen Alliance has turned to a more aggressive method of population control. Trained professionals are hired to shoot these troublesome mules (in a controlled manner that doesn’t cause environmental disturbance). Although this doesn’t sound ideal, there isn’t much we can do to repopulate predators fast enough before Pando dies out. Paul Roger tells Live Science, “It's really actually not a big number that are chronically feeding on that area”, which means beridding these overeaters won’t exactly cause endangerment towards the species.⁸

Of course, more sustainable efforts must be maintained for Pando’s survival. However, these efforts involve the tackling of climate change and irreversible damage to the environment, which can only be accomplished through large-scale, systematic, government funded change. It’s not like it’s impossible; the reparation of our deteriorated ozone layer can largely be credited to systematic, federal action. So, keep fighting for a better future. Protest and vote and stay educated on environmental issues. The survival of an ancient god depends on it.



  1. Grant, Michael C. “The Trembling Giant.” Discover Magazine, Discover Magazine, Oct. 1993, Accessed 3 July 2022.

  2. Kemperman, Jerry A., and Burton V. Barnes. “Clone Size in American Aspens.” Canadian Journal of Botany, vol. 54, no. 22, 15 Nov. 1976, pp. 2603–2607,, 10.1139/b76-280. Accessed 3 July 2022.

  3. DeWoody, Jennifer, et al. ““Pando” Lives: Molecular Genetic Evidence of a Giant Aspen Clone in Central Utah.” BYU ScholarsArchive, 2016, Accessed 3 July 2022.

  4. Mitton, Jeffry B., and Michael C. Grant. “Genetic Variation and the Natural History of Quaking Aspen.” BioScience, vol. 46, no. 1, Jan. 1996, pp. 25–31,, 10.2307/1312652. Accessed 3 July 2022.

  5. MOCK, K. E., et al. “Clonal Dynamics in Western North American Aspen (Populus Tremuloides).” Molecular Ecology, vol. 17, no. 22, Nov. 2008, pp. 4827–4844,, 10.1111/j.1365-294x.2008.03963.x. Accessed 8 Aug. 2022.

  6. MacAree, Graham. “Pando: The Aspen Colony That Might Be the Oldest Known Living Organism.”,, 22 Dec. 2020, Accessed 8 Aug. 2022.

  7. Katz, Brigit. “Pando, One of the World’s Largest Organisms, Is Dying.” Smithsonian Magazine, Smithsonian Magazine, 18 Oct. 2018, Accessed 8 Aug. 2022.

  8. Ghose, Tia. “The World’s Largest Organism Is Dying.”, Live Science, 6 Dec. 2017, Accessed 8 Aug. 2022.

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