How Pando Works
Pando is one tree that looks like a forest. Learn about how a single organism grows tens of thousands of trunks, keeps them connected underground, and has renewed itself for thousands of years — from the people who work to protect, monitor and care for Pando
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Friends of Pando FAQ's
Table of Contents
What is Pando?
Pando is the world’s largest tree by weight, land mass, and species — a single quaking aspen (Populus tremuloides) clone that has grown into a 106-acre forest of an estimated 47,000 genetically identical stems, all connected below ground by one shared root system. It isn’t a forest of separate trees; it’s one living organism that has been spreading across its Fishlake National Forest homeland for thousands of years.
Sources: Kemperman & Barnes 1976, Canadian Journal of Botany 54(22) | DeWoody et al. 2008, Western North American Naturalist 68(4)
What species of tree is Pando?
Pando is a Populus tremuloides Michx., and are commonly called Quaking Aspen or Trembling Aspen. Utahns also have another name for aspen; “quakies“.
The common name for aspen comes from the way the trees bend and the leaves shimmer or tremble in the wind.
Sources: USDA Forest Service — Fishlake National Forest, Pando
How does Pando reproduce?
Pando self-propagates through a process called suckering, driven by the hormone cytokinin. When cytokinin builds up along the edge of a root, it triggers a new stem called a “sucker” to emerge; given time, that sucker matures and sends out its own roots, starting the process again.
Sources: Schier, G.A. (1973), Canadian Journal of Forest Research 3(1)
Is there a limit to how long Pando can reproduce by suckering?
None known today — each new stem can send out roots that repeat the process indefinitely, as long as the tree stays healthy.
Suckering is separate from the tree’s ability to sexually reproduce through pollen. Pando’s pollen fertility is governed by its ploidy and genetics. Some researchers have speculated that clonal aspen may defy typical aging or senescence altogether, though this remains an unsettled question — as the main evidence (Ally, Ritland & Otto 2010) comes from a single study and hasn’t been broadly confirmed.
Sources: Blonder 2024, American Journal of Botany 111: e16325 | Ally, Ritland & Otto 2010, PLoS Biology 8(8) | Commentary: “We All Gotta Go Sometime,” PLoS Biology 2010
Is everything growing inside Pando part of Pando?
Generally, yes. When researchers worked to verify Pando in 2008, they also sampled the surrounding area and found 40 other distinct aspen clones nearby, some large enough to be mistaken for part of Pando itself. Spruce, juniper, and other non-Pando aspen occasionally take root within Pando’s boundary too. But Pando dominates its landmass so thoroughly — commanding the water, nutrients, and sunlight of the area — that almost nothing else gets the chance to establish and thrive there.
Sources: DeWoody et al. 2008, Western North American Naturalist 68(4)
Does Pando have one trunk, like a tree in my yard?
No — Pando has an estimated 47,000 stems, which look like individual tree trunks but are actually parts of a single tree connected by one massive root system.
Sources: Kemperman & Barnes 1976, Canadian Journal of Botany 54(22) | DeWoody et al. 2008, Western North American Naturalist 68(4)
If it's all one tree, why does it look like separate trees to me?
Each stem you see is a fully-formed part of Pando, with its own bark, branches, and leaves — which is why it’s natural to read it as a separate tree. Every stem is also connected below ground to the same root system, making it part of something much bigger than itself. What looks like a stand of individual aspens is really one organism showing you thousands of its above-ground parts at once.
Sources: Kemperman & Barnes 1976, Canadian Journal of Botany 54(22) | DeWoody et al. 2008, Western North American Naturalist 68(4)
I've heard Pando is an "aspen clone". What does that mean?
“Clone” (technically, a “genet”) means Pando reproduces itself through vegetative reproduction rather than seeds, with each new stem genetically identical to the last. This self-replicating growth is how Pando spread from a single seed into 47,000 connected stems.
Sources: Kemperman & Barnes 1976, Canadian Journal of Botany 54(22) | DeWoody et al. 2008, Western North American Naturalist 68(4)
Because Pando is a clone, does that mean it is not a single tree?
No — Pando behaves like a single tree, coordinating energy production, defense, and regeneration as one organism. Being a clone describes how it reproduces, not whether it functions as one connected being.
Since Pando is a clone, does that mean it is not the "World's Largest Tree"?
No — many trees reproduce by cloning, including Beech, Apple, Coastal Redwood, Locusts, Alder, and Oak, and Pando is still the largest tree by multiple measures. Some raise the point that clones (genets) behave differently from single-seed trees in important ways, but that doesn’t disqualify Pando from the title.
Source: Clones are a relatively common occurrence in the plant world (2015), Michael Schira
Is it better to think about Pando as a single Tree or, as a Clone?
Both framings matter, depending on the purpose. Day-to-day care for Pando happens stem-by-stem — checking individual growth, health, and threats — but understanding those stems as part of one connected whole is what makes that care effective, and it’s what opens up research questions that couldn’t be studied any other way.
Sources: Kemperman & Barnes 1976, Canadian Journal of Botany 54(22) | DeWoody et al. 2008, Western North American Naturalist 68(4)
Is there a "middle" of Pando, where I can touch the main trunk?
No. There’s no central trunk. Every trunk (aka: “ramet”, “stem”) is an equal part of Pando. Each trunk is connected to the same root system and shares in work to manage the tree’s energy production, defense, and regeneration.
Sources: Kemperman & Barnes 1976, Canadian Journal of Botany 54(22) | DeWoody et al. 2008, Western North American Naturalist 68(4)
Is every trunk connected to every other trunk?
Generally speaking – yes. Each of Pando’s trunks is connected to the others through a shared root system.
If a section becomes physically separated from the rest — for example, by a landslide or root damage — those trunks still operate and behave as part of Pando, even in isolation.
Can one part of the tree get disconnected from the larger tree?
Yes — as Pando’s roots build up and fan out over time, an outlying section can sometimes become isolated from the rest. Even so, that section keeps behaving like the larger tree, year to year. If every other part of Pando were lost except that one isolated section, it would carry on as the “new” Pando.
If one section of trunks went away, would that be the same as Pando dying?
No. If one section of Pando had no trees or roots, the rest of the tree would carry on. No single part of Pando holds up the whole.
How long can one trunk of live?
Around Pando, between 130 and a 150 years. Some may last longer, but this is more rare
Source: How Aspens Grow, US Forest Service
Has the shape of Pando remained the same all its life?
No — Pando shifts its shape and size over long periods of time based on water, sun, and soil conditions, and if ground disturbances like landslides, allow it to rapidly overtake new ground since it grows so fast.
Aspen can grown up to 3 ft a year. By our conservative estimates, this means during peak growing season (June to Sepetember), Pando can “spread” either upward (taller), outward (wider) or, across (over ground) by an estimated 4/10th of an inch (1cm) a day.
In terms of its shape, interestingly, today, there are 5 maps used to describe Pando’s shape. While the maps mostly agree -some only describe what is above ground, some by genetic sites, some by land management strategy. Friends of Pando catalogues these maps and monitors how Pando changes over time. You can see these maps via our Pando Living Map Project page.
Sources: Pando Living Map Project
If I hug one trunk, am I hugging the whole tree?
Technically, yes — hugging one trunk means hugging all of Pando. Each trunk is connected underground to the same root system as its neighbors. It’s one part of a larger living thing that covers 106 acres.
What does a typical trunk of Pando look like?
Pando’s stems look different depending on where they are in their growth and range from straw like baby stems, to mature trunks that can reach to 80 feet tall.
What kind of soil does Pando like?
Pando’s homeland sits on a complicated volcanic landscape that happens to suit aspen well — Trembling Aspen prefers acidic to neutral soils that are loamy and well-drained.
Most of Utah’s lowlands run highly alkaline (typically pH 7.5–8.5) due to the state’s arid climate, but Fish Lake Basin’s high elevation — around 8,900 feet — creates a cooler, wetter alpine environment where heavy conifer and aspen leaf litter builds up. That creates localized pockets of soil far more acidic than the state average, around pH 5.2–6.6.
Pando’s situation on a steep east-facing slope that drains down water and mineral-rich volcanic parent material, means Pando’s homeland is as close to an ideal landscape for a sub-alpine aspen as you can expect.
Sources: A Geologic History of Fishlake, Pando’s Home | USDA NRCS Soil Survey
What kinds of diseases would I have to treat if I had to take care of Pando?
Pando lives with diseases common to aspen throughout the Intermountain West. Forest Service pathologists have documented sooty-bark canker, black canker and Cytospora canker — fungal infections that attack the the body or the bark — along with Ganoderma root disease, a fungus affecting the root collar which can kill new growth.
Insects can also impact Pando. Bark beetles, ants, caterpillars and aphids can also do damage to Pando on their own while their actvity can also open entry points for diseases to enter.
Unsubstantiated claims describe disease prevalence in Pando as covering 90% of the tree based on statistical models. Those claims and that % has never been independently replicated on the landmass scale. What’s more, disease doesn’t always indicate certain death. Just like we get colds and survive, Pando can deal with disease and not die.
Sources: Common Insects and Diseases of Aspen, Colorado State University (Retrieved 2026)
How drought tolerant is Pando?
Aspen are quite drought tolerant. Pando has almost certainly weathered severe, sustained droughts before, in fact, the current era has been described as a severe drought period.
The best-documented examples megadrought in the region is the “Great Drought” of 1276–1299 CE, identified through tree-ring studies in the Colorado Plateau — the broader region Pando’s homeland. The Great Drought lasted more than two decades and reshaped the region’s human history. Pando was already thousands of years old by that point and lived through it.
Pando’s homeland in a large watershed likely buffers it from extremes that would destroy other trees.
Sources: Stahle & Dean, “North American Tree Rings, Climatic Extremes, and Social Disasters”
Does Pando make seeds?
No — Pando is male, so it only produces pollen and can’t make seeds on its own. It can (and likely has) crossed with female aspen in its homeland meaning Pando could have sons and daughters spread throughout the Fish Lake Basin.
Researchers are still exploring whether Pando’s pollen fertility has changed with age; a 2010 study found pollen viability can decline gradually over thousands of years in other aspen clones.
Sources: Ally, Ritland & Otto 2010, PLoS Biology 8(8) | Blonder 2024, American Journal of Botany 111: e16325
What is "triploidy," and does it matter for Pando?
Triploidy means an organism carries three sets of chromosomes instead of the usual two, and it’s surprisingly common in western North American aspen — found in up to 69% of clones studied, especially in the drier, drought-prone regions where the largest clones tend to grow. Most evidence points to Pando itself being triploid, and ongoing research on Pando’s genome appears to support earlier findings from USU conservation geneticist Karen Mock, whose team found that triploid aspen stems grow faster than diploid ones — consistent with what we see in Pando, where individual stems can grow up to 3 feet a year.
Sources: Mock et al. 2012, “Widespread Triploidy in Western North American Aspen,” PLoS ONE 7(10): e48406 | DeRose, Mock & Long 2015, “Cytotype differences in radial increment…,” Canadian Journal of Forest Research 45:1–8
Can Pando survive a wildfire?
Yes — aspen, including Pando, tolerate low-to-medium intensity ground fires well, since their stems hold enormous amounts of water while their crowns reach high above the flames. Fire is even used in some cases to help stimulate regeneration, with research showing aspen suckering nearly doubles after fire, highest following high-severity burns.
Sources: Kitchen et al. 2019, RMRS-GTR-390, USDA Forest Service | Brewen et al. 2021, PLOS ONE
If a fire was hot enough to burn Pando down, would that be the end of Pando?
No — the growth hormones that spur regeneration are concentrated in Pando’s roots, distributed across the countless nodes of the root network. If a stem is burned, cut, or knocked over, the hormone balance in the roots shifts, starting the regeneration process over again. In fact, prescribed fire has been used to purposefully trigger regeneration in aspen, including Pando.
Sources: Kitchen et al. 2019, RMRS-GTR-390, USDA Forest Service | Brewen et al. 2021, PLOS ONE
Friends of Pando FAQ Collection
Answers from the people who work to care for Pando every day
Friends of Pando is dedicated and working to educate the public, support research and preservation efforts and inspire stewardship of Pando, the world’s largest tree.
Friends of Pando is a proud partner of Pando’s public land stewards, Fishlake National Forest of the U.S. Forest Service, Department of Agriculture. Learn more about our partnership.
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Friends of Pando
PO Box 12
Richfield, UT, 84701
Phone: 435-633-1893
IRS EIN: 87-3958681
