Nestled in the Wasatch Mountains of western US, above a spring-fed lake, lies an extraordinary single organism that supports an entire ecosystem, upon which various plants and animals have depended for millennia.

Located in my home state of Utah, “Pando” spans an impressive 106 acres and comprises a vast stand of genetically identical quaking aspen clones.

While it may appear as a serene forest filled with individual trees, characterized by their striking white bark and delicate trembling leaves, Pando (which translates to “I spread” in Latin) actually consists of approximately 47,000 interconnected stems that spring from a unified root system.

Collectively, this single organism weighs around 6,000 metric tons, making it the heaviest known organism on the planet.

Aspen trees, known for forming clonal stands, abound in other regions; however, Pando’s remarkable size sets it apart. Many clonal aspen stands in North America measure only a fraction of Pando’s expanse, with western US examples averaging a mere 3 acres.

Pando’s existence may stretch back up to 14,000 years, although individual stems generally have a lifespan of about 130 years. This impressive longevity, combined with its isolated location, has fostered a diverse ecosystem comprising 68 plant species and numerous animal inhabitants thriving in its shade.

Yet, for this ecosystem to persist, the health of Pando is crucial. Despite being safeguarded by the US National Forest Service and not at risk of deforestation, it faces existential threats from various factors.

Vulnerability to Overgrazing

One significant concern is overgrazing by deer and elk. Historical predator populations, such as wolves and cougars, once kept these herbivore numbers in check; however, their decline has resulted in burgeoning deer and elk populations.

These animals are increasingly drawn to Pando, as its protective woodland provides them with respite from hunting pressure. As older trees perish, more sunlight penetrates the forest floor, prompting the growth of new clonal stems. Yet, when these growths are grazed down by deer and elk, little new growth sustains the ecosystem.

Impact of Diseases and Climate Change

Additionally, the older stems of Pando are succumbing to multiple diseases, including sooty bark canker and leaf spot. While aspen diseases have historically existed, the long-term implications for Pando’s ecosystem remain uncertain, given the lack of new growth and escalating threats.

Climate change poses the most pressing challenge, as Pando emerged after the last ice age and has thrived under relatively stable climatic conditions. Increasingly warm temperatures, prolonged droughts, and reduced water supplies threaten not only Pando’s magnitude but also the entire ecosystem it supports.

Despite these concerns, Pando has demonstrated resilience throughout its history, navigating rapid environmental changes since European settlement and facing disease and grazing pressures. Conservation efforts, including initiatives by the Friends of Pando, aim to preserve this remarkable organism and its ecosystem for future generations.