When thinking about the world’s heaviest organism, many of us might picture the blue whale or perhaps a large elephant. However, interestingly enough, the heaviest organism is a single aspen called Pando. Situated in the high-altitude area of Utah’s Fishlake National Forest, Pando–a colony of quaking aspen trees–is known as one of the oldest and largest organisms to ever exist on Earth. Although there are 47000 individual Pando tree trunks in Utah, these trees are actually one large colony connected by an extensive underground root system. In summary, Pando, also known as the Trembling Giant, takes the metaphor, “the forest is a single organism,” and makes it literal.
With Pando being just one organism, every tree is genetically identical–reproduction occurs asexually through a process called “suckering.” This process occurs when one trunk (which is really just a stem) grows lateral roots that emerge out of the ground to become new “trunks.” Researchers like to describe this process as cloning. Another interesting attribute of this organism is its ability to “quake.” Similar to quaking aspens, Pando’s flat leaves tremble in the wind, creating the soothing sound of rustling leaves.
What is happening to Pando?
Research suggests that Pando is one of the oldest organisms on Earth. Its survival can be attributed to Utah’s past environmental conditions. In the last 80,000 years or so, Utah experienced frequent low intensity burns and climate shifts, prohibiting the successful growth of rival aspen trees to compete with Pando. Nonetheless, recent changes in ecosystems around Utah’s National Forests suggest that Pando’s growth is declining due to organisms that graze on premature trunks. Some of these organisms include deer, elk, sheep, and cattle. The deer, one of the most concerning Pando-eaters, used to have several predators in the Utah area. However, hunting activities have disrupted the balance of predators and prey, which ultimately led to a significantly greater number of deers in the Fishlake Forest.
Not only are animals such as sheep, deer, and elk restricting the growth of a new generation of Pando trunks, but the mature trunks have also been dying at higher rates. As observed by researchers at Utah State University, Pando’s size has been decreasing for decades, suggesting that the organism may be at risk of extinction. However, hope is not lost for these trees as scientists have been working to build fences around them to prevent other animals from eating premature trunks.
