Pando (tree)

Pando
Image of the approximate land mass of Pando shaded green
Map
Location in Utah Show map of Utah Location in the United States Show map of the United States
Geography
Location	Sevier County, Utah, United States
Coordinates	38°31′30″N 111°45′00″W / 38.52500°N 111.75000°W / 38.52500; -111.75000
Elevation	2,700 m (8,900 ft)
Area	43.6 ha (108 acres)
Administration
Established	+14000; 11976 years' time (14000) BP
Ecology
Dominant tree species	Populus tremuloides

Pando (from Latin pando 'I spread'),^[1] is the world's largest tree, a quaking aspen (Populus tremuloides) located in Sevier County, Utah, United States, in the Fishlake National Forest. A male clonal organism, Pando has an estimated 47,000 stems (ramets) that appear to be individual trees, but are connected by a root system that spans 42.8 ha (106 acres). Pando is the largest tree by weight and landmass and the largest known aspen clone. Pando was identified as a single living organism because each of its stems possesses identical genetic markers.^[2] The massive interconnected root system coordinates energy production, defense and regeneration across the tree's landmass.^[3] Pando spans 1.08 km × 0.72 km (0.67 mi × 0.45 mi) at its widest expanse along of the southwestern edge of the Fishlake Basin and lies 0.69 km (0.43 mi) to the west of Fish Lake, the largest natural mountain freshwater lake in Utah.^[4] Pando's landmass spreads from 2,700 m (8,900 ft) above sea level to approximately 2,773 m (9,098 ft) above sea level along the western side of a steep basin wall.^[5] Pando is estimated to weigh collectively 6,000 tonnes (6,000,000 kg),^[6] or 13.2 million pounds, making it the heaviest known organism.^[7][8] The Pando Tree's 43-hectare (106-acre) expanse also makes Pando the largest tree by landmass.

Systems of classification used to define large trees vary considerably, leading to some confusion about Pando's status. Within the United States, the Official Register of Champion Trees defines the largest trees in a species specific way, in this case, Pando is the largest aspen tree (Populus tremuloides). In forestry, the largest trees are measured by the greatest volume of a single stem, regardless of species, in that case, the General Sherman Tree, is the largest unitary (single stem) tree. While many emphasize that Pando is the largest clonal organism, other large trees, including Redwoods can also reproduce via cloning. Pando being the heaviest tree and the largest tree by landmass, while also being the largest aspen clone leaves the Pando Tree in a class of its own.

Since the early 2000s, little information has been adequately corroborated about Pando's origins and how its genetic integrity has been sustained over a long period of time (between 9,000 and 14,000 years - 18,000 years by the latest (2024) estimate.^[9]). Researchers have argued that Pando’s future is uncertain due to a combination of factors including drought, cattle grazing, and fire suppression.^[10][11] In terms of drought, Pando's long lived nature suggests it has survived droughts that have driven out humans for centuries. In terms of grazing, a majority of Pando's land mass is fenced for permanent protection and management as a unique tree. In terms of cattle grazing, Cattle grazing is only permitted on a volume basis for 10 days a year in October, weather permitting in a small edge of Pando's expanse. In 2023, local grazers group 7 Mile Grazers signed off on a plan that would bring remaining portions of Pando into protective care under the "Pando Protection Plan", which would bring nearly 34 hectares (84 acres) of the tree into protective care. In terms of fire suppression, research indicates^[12] Pando has survived fires that would have likely leveled the tree many times, after which Pando regenerated itself from the root system. The same research also indicates large-scale fire events are infrequent, which may be owed to the fact that aspen are water heavy and naturally fire resistant, earning them the name "asbestos forest" by Canadian Forest Ecologist Lori Daniels.^[13] There is broad consensus that wildlife controls and protection from deer and elk who feed on the new growth faster than it can reach maturity is critical. Such protection systems are only meaningful if they are coupled with ongoing monitoring and restoration efforts, which are under way.^[14]

Friends of Pando^[15] and the United States Forest Service are official partners working to study and protect Pando and work alongside Utah Division of Wildlife Resources to care for and protect the Pando Tree.^[16] Notable organizations that also study and advocate to protect Pando's care include Western Aspen Alliance^[17] and Grand Canyon Trust.^[18]