Pando tree is the heaviest living organism

Pando Tree (Pando), also known as the trembling giant, is a clonal colony of a single tree of one of the poplar species — quaking aspen or trembling aspen (Populus tremuloides). Essentially, this poplar forest is a single living organism with identical DNA markers and a unique massive root system.

The Pando tree occupies an area of 43.6 hectares. It is believed that the weight of the entire plant is about 6,000 tons, making it the heaviest known organism.

Due to the gradual replacement of stems and roots, the overall age of the poplar clone cannot be determined by annual rings. It is generally believed that the age of Pando's root system is approximately 80,000 years, making this plant one of the oldest living organisms.

Pando has more than 40,000 stems (trunks), which die individually and are replaced by new stems growing from its roots. Individual trunks of this type of poplar usually do not live more than 100–130 years, and mature sections of trunks within Pando are approaching this limit.

This poplar colony grows in the USA in Utah, in the “Fishlake National Forest” reserve. It was discovered in 1968 by Burton Barnes, who noticed the identical behavior of the trees within it. Michael Grant, Jeffrey Mitton, and Ian Linhart from the University of Colorado in Boulder (Colorado, USA) re-examined the clone in 1992, naming it Pando and claiming it to be the largest organism in the world by weight.

Researchers Mitton and Grant describe the development of stems in Pando as follows:

“Quaking aspen regularly reproduces through a process called suckering. An individual stem can send out lateral roots, which under the right conditions send up other upright stems; from all above-ground appearances, new trunks look just like individual trees. The process repeats until a whole stand, consisting of separate trees, is formed. This collection of multiple stems, called ramets, forms a single genetic individual, commonly referred to as a clone.”

Since this species of poplar is dioecious (when male and female flowers are on separate individuals), and since the tree represents a single male specimen reproducing through root sprouts, measures are being taken to protect it from deer that eat the leaves and shoots.

It is believed that Pando is dying. Although the exact reasons are unknown, the most likely combination is drought, impact from hoofed animals, human activity, and fire prevention. Research conducted in October 2018 indicates that the tree has not been growing for the last 30–40 years.

Next, we will post several videos that we have selected for you, so you can get a better look at the Pando tree and learn more interesting facts about it.