Most massive plant

Most massive plant
Who
Quaking aspen, Populus tremuloides, Pando
What
6000 tonne(s)/metric ton(s)
Where
United States (Wasatch Mountains)
When
December 1992

Several scientists have speculated that Pando, a network of quaking aspen (Populus tremuloides) growing in the Wasatch Mountains of Utah, USA, is the world's most massive plant, as well as the heaviest organism. The clonal forest, comprised of around 47,000 individual stems, was confirmed in December 1992 to be a single root system, covering 43 ha (106 acres) and weighing an estimated 6,000 tonnes (6,614 US tons). The clonal system is genetically uniform and acts as a single organism, with all the component trees (part of the willow family) changing colour or shedding leaves in unison.

Quaking aspen wood is used for boxes and crates, pallets, core stock in plywood panels, laundry appliances, poultry supplies, clothespins, rough construction, and veneer for containers. The logs are used for cabin construction and, when kept away from the ground, produce satisfactory service.

It's been speculated that Pando might also be the oldest living organism, with some estimates ageing the clonal tree system at 14,000 years or more, though this is hotly debated among dendrologists.

Aspens are not the only clones that can be extremely old. The creosote bush (Larrea tridentata) is a plant of the American Southwest that can live to great age. King Clone, in the Mojave Desert of California, is estimated to be 11,700 years old. Frank Vasek, a professor at the University of California, Riverside studied the plant, and radiocarbon dated wood fragments to estimate the rate of clone expansion. Then, by measuring the diameter of the expanding ring (averaged 14 m/46 ft diameter), came up with an estimate of total age of the clone. The Mojave Desert climate, however, has changed frequently and dramatically since the last ice age, so the expansion rate of the clone could have potentially varied during that time.

Another ancient clone involves a conifer in Tasmania, Australia. The Huon pine (Lagarostrobos franklinii) is one of the oldest recorded species of Podocarps in the world. Crossdated specimens >1,000 years old are known, and ring-counted increment cores with 2,500 rings have been sampled at Mount Read near Rosebury. What makes this story particularly interesting is that the population at Mount Read consists 100% of genetically identical male plants, so cloning is their only option. The nearest female plant of Lagarostrobus is more than 20 km (12.5 mi) away. Further, Lagarostrobus pollen was collected in nearby Lake Johnston that was dated at 10,500 years, indicating this clone may be at least that old.

Tasmania, Australia, has perhaps an even older clone: King’s lomatia (Lomatia tasmanica) is an exceedingly rare shrub that has no capability of sexual reproduction. In fact, only one single colony is known in the wild, which consists of about 600 genetically identical stems. Nearby, subfossil remains were found in 43,600-year-old beds, indicating this clonal species may be that old.