Sizing Up Pando

Pando Vitals:

  • Name: “Pando” means “I spread” in Latin1
  • Size: 106 acres/43 ha
  • Weight: estimated 13 million lbs/5.8 million kg
  • Stems: estimated 47,000 (prior to recent mortality)
  • Age, Clone: Estimates have been made at between 100s-1000s of years. No good method currently exists to place an accurate age on the life span of Pando.
  • Age, Live Stems (ramets): Determined by tree coring, older living trees in the clone are currently between 120-150 years.

Chronology Since Pando Discovery:

  • 1970s - Large clone near Fish Lake, Utah, was estimated to be approximately 106 acres (43 ha) in size based on differentiating physical characteristics from adjacent aspen clones2.
  • 1987-88 – First logging experiments completed; approximately 4 acres/1.6 ha. No regrowth has taken place on these initial sites to the present.
  • 1992 – Land managers realized previous logging was not successfully regenerating. A larger (15 acre/6.1 ha) clearfell-coppice harvest took place, but was followed by perimeter fencing. A dense stand of aspen, approximately 20-25 ft. (6-7.6 m) in height, is visible today. This same year the clone was nominated as the largest living organism on earth.3
  • ~2005-present – Unfenced portions of Pando begin what appears to be a rapid die-off of the largest, mature, trees. Still, regrowth from root suckers is nearly non-existent; likely due to local browsers (deer, elk, or cattle). In most instances, an aspen clone will sprout via a chemical process resulting from matures tree dying (either en masse, small groups, or singly) which sends a “signal” to the root system to increase growth. It is not for lack of trying that Pando is not successfully regenerating. Small suckers can be found, and are clearly evident in enclosures, but they are consumed by browsers soon after they rise from the ground.
  • Present - Management actions are underway to protect aspen and stimulate suckering (see What Can Be Done).

1Mitton, J. B. and M. C. Grant. 1996. Genetic variation and the natural history of quaking aspen. Bioscience 46:25-31.

2Kemperman, J. A. and B. V. Barnes. 1976. Clone size in American aspens. Canadian Journal of Botany 54:2603-2607.

3Grant, M., J.B. Mitton, and Y.B. Linhart. 1992. Even larger organisms. Nature 360:216.