Pando (Latin for "I spread"), also known as the Trembling Giant, is a clonal colony of an individual male quaking aspen (Populus tremuloides) determined to be a single living organism by identical genetic markers and assumed to have one massive underground root system. The plant is located in the Fremont River Ranger District of the Fishlake National Forest, at the western edge of the Colorado Plateau in south-central Utah, United States: around 1 mile Southwest of Fish Lake. Pando occupies 108 acres and is estimated to weigh collectively 6,000 tonnes: making it the heaviest known organism. The root system of Pando is estimated to be several thousand years old, placing Pando among the oldest known living organisms.

      Due to the progressive replacement of stems and roots, the overall age of an aspen clone cannot be determined from tree rings. In Pando's case, ages up to 1 million years have therefore been suggested. An age of 80,000 years is often given for Pando, but this claim derives from a National Park Service web page that does not provide a source for its number and is inconsistent with the Forest Service's post ice-age estimate. Glaciers repeatedly formed on the Fish Lake Plateau over the past several hundred thousand years and the Fish Lake valley occupied by Pando was partially filled by ice as recently as the last glacial maximum. Ages greater than approximately 16,000 years therefore require Pando to have survived at least the Pinedale glaciation, something that appears unlikely under current genetic estimates of Pando's age and modeling of variation in Pando's local climate.

        (from Wikipedia)

       Despite the apparent debate as to the old god's age, Pando may very well exceed every expectation, as trees of all kinds are often underestimated. They worry that he is dying due to climate change and other factors, but with the longevity of the Giant - having seen ages come and go in the world - it will likely be several dozen of our lifetimes before this world loses him.