Pando (tree)
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2008-06-20T17:13:36Z
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'''Pando''' (or '''The Trembling Giant''')<ref name="discovery">{{cite web |url=http://discovermagazine.com/1993/oct/thetremblinggian285 |title=The Trembling Giant |accessdate=2008-05-08 |publisher=Discover Magazine |date=1993-10-01 |author=Grant, Michael C. }}</ref> is a [[clonal colony]] of a single male [[Populus tremuloides|Quaking Aspen]] (''Populus tremuloides'') tree located in the [[United States|U.S. state]] of [[Utah]], all determined to be part of a single living organism by identical genetic markers<ref> [http://www.fs.fed.us/newcentury/organism.htm Pando] by the [[National Park Service]]</ref> and one massive underground [[root|root system]]. The plant is estimated to weigh collectively 6,000 [[tonne]]s (6,615 [[ton]]s),<ref name="oecd">{{cite paper
| author = OECD Environment Directorate
| title = Consensus Document on the Biology of ''Populus'' L. (Poplars)
| publisher = [[OECD]]
| year = 2000
| url = http://www.olis.oecd.org/olis/2000doc.nsf/4f7adc214b91a685c12569fa005d0ee7/c125692700623b74c1256a0600551816/$FILE/JT00103743.DOC
| format = [[Microsoft Word]] document
| accessdate = 2006-10-08 }}</ref> making it the [[Largest organisms|heaviest known organism]].<ref name="multiple1">Genetic Variation and the Natural History of Quaking Aspen, Jeffry B. Mitton; Michael C. Grant, ''BioScience'', Vol. 46, No. 1. (Jan., 1996), pp. 25-31.</ref> The root system of Pando is claimed by some to be among the [[list of long-living organisms|oldest known living organisms]] in existence at 80,000 years of age,<ref>[http://www.nps.gov/brca/naturescience/quakingaspen.htm Quaking Aspen] by the [[Bryce Canyon]] [[National Park Service]]</ref> though the method used to produce this estimate (an estimate on when climatic conditions were last suitable for seedling germination) is not supported by current evidence of germination.<ref name=feis>U.S. Forest Service Fire Effects Information System: [http://www.fs.fed.us/database/feis/plants/tree/poptre/all.html#BOTANICAL%20AND%20ECOLOGICAL%20CHARACTERISTICS ''Populus tremuloides'' botanical and ecological characteristics]</ref>
==Name==
The name "Pando" was chosen because it is [[Latin]] for "I spread",<ref name="discovery" /><ref>{{cite journal
| author = Research and Development Information Outreach, USDA Forest Service
| date =
| year = 1999
| month = Fall
| title = Quaking in Their Roots: The Decline of Quaking Aspen
| journal = Natural Inquirer
| volume = 2
| issue = 1
| pages = 7–11
| doi =
| id =
| url = http://www.naturalinquirer.usda.gov/NIKids.cfm?act=viewarticle&issue=4&article=25
| accessdate = 2006-10-08
| publisher = US Department of Agriculture
}}</ref> while the nickname "The Trembling Giant" can be attributed to the common name of ''Populus tremuloides'', the trembling aspen, whose leaves frequently rattle.
==History==
[[Image:AspenOverview0172.JPG|thumb|An aspen grove at [[Fishlake National Forest]]]]
Pando is thought to have grown for much of its lifetime under ideal circumstances: frequent fires have prevented its main competitor, [[Pinophyta|conifers]], from colonizing the area, and climate change, transitioning from a wet and humid weather pattern to semi-arid, has obstructed widespread seedling establishment and the accompanying rivalry from younger aspens.
During intense fires, the organism survived by its root system, sending up new stems in the aftermath of each wildfire. If its postulated age is correct, the climate into which Pando was born is markedly different from that of today, and it may be as many as ten millennia since Pando's last successful flowering, according to an [[OECD]] report:
{{Quote|Clonal groups of ''P. tremuloides'' in eastern [[North America]] are very common, but generally less than 0.1 ha in size, while in areas of Utah, groups as large as 80 ha have been observed (Kemperman and Barnes 1976). In the [[semi-arid]] [[western United States]], some argue that widespread seedling establishment has not occurred since the last glaciation, some 10,000 years ago (Einspahr and Winton 1976, McDonough 1985). Indeed, some biologists feel that western clones could be as old as 1 million years (Barnes 1966, 1975). It has been claimed that a single clone, nicknamed "Pando" (Latin for ''I spread''), covers 43 hectares, contains more than 47,000 stems and weighs in excess of 6 million kg, making it the largest known organism (Grant et al. 1992, Mitton and Grant 1996)|[[OECD]]|''Consensus Document on the Biology of ''Populus'' L. (Poplars)''<ref name="oecd" />}} However, others have observed that both flowering, and successful large-scale seedling establishment, occur frequently, even during dry years, in the modern period,<ref name=feis/> invalidating the dating method.
Pando was discovered by Burton V. Barnes of the University of Michigan in the 1970s. Barnes was widely considered an expert on North American aspen at the time, having been one of the first to describe the clonal growth of aspen from an extensive root system as part of his dissertation at Michigan in the late 1950s. Barnes had described Pando as a single organism based on its morphological characteristics. Michael Grant of the [[University of Colorado at Boulder]] re-examined Pando and claimed it to be the world's most massive organism in 1992.
==Size and age==
[[Image:QuakiesSEP2005.JPG|thumb|The trunk or stem of a Quaking Aspen]]
The clonal colony encompasses 43 hectares (107 acres) and has around 47,000 stems, which continually die and are renewed by its roots. Many of the stems are connected by its root system. The average age of Pando's trunks (or technically, stems) is 130 years, as deciphered by tree rings. [[Michael Grant]] in ''[[BioScience]]'' said:
{{Quote|...quaking aspen regularly reproduces via a process called suckering. An individual stem can send out lateral roots that, under the right conditions, send up other erect stems; from all above-ground appearances the new stems look just like individual trees. The process is repeated until a whole stand, of what appear to be individual trees, forms. This collection of multiple stems, called ramets, all form one, single, genetic individual, usually termed a clone.}}
==Debate==
[[Image:October 12 2005 Alpine Loop Utah United States.JPG|thumb|Quaking Aspen in Utah]]
Some experts speculate that Pando's reign since 1992 as the heaviest-known organism may be short lived. Less well-studied Quaking Aspens in Utah may be 80 hectares in extent and one million years old. Other large colonies could exist elsewhere. A clonal colony of at least seven [[Sequoia|Coastal Redwood]]s could weigh more,<ref>[http://www.nativetreesociety.org/measure/world_largest.htm Bob van Pelt]</ref> although no such stand is known to exist. Other scientists think that portions of Pando's root system may be dead and might have led the plant to split into separate groups and therefore would not be one organism, though the collective groups would remain the same singular, genetic individual.
Tree experts also note that the organism's age cannot be determined with the level of precision found in [[tree ring|tree rings]]; some claim Pando's age is closer to 1 million years.<ref name="multiple1"/> Its current 80,000 year designation is based on a complex set of factors including the history of its local environment such as: The evidence indicating that there are few if any naturally occurring new aspens in most of the [[western United States]] since a climate shift took place 10,000 years ago and eliminated favorable soil conditions for seedlings; the rate of growth (including the differences of rates in distinct [[climate|climates]] when accounting for its local-climate history, that males grow slower than females, and that aspens grow slower at higher elevations – Pando is at 2697 m, or 8,848 ft, above sea level); its size; and its [[gene|genetic code]] in comparison to the [[Genetic mutation|mutations]] found among aspens born in the modern era. Michael Grant summed it thus:
{{Quote|Despite enormous crops of viable seeds, successful seedling establishment appears to be a rare event in the semiarid West, but the establishment of new trees from seeds appears to be common in the moist, humid forests of [[New England]]... aspen establishment from seeds probably has not occurred in the western United States since the last glaciation, some 10,000 years ago... Part of the rationale behind current age estimates for aspen clones is that sexual reproduction is effectively frustrated by the rarity of a favorable suite of conditions in semiarid environments... High levels of genetic variation and excesses of heterozygotes are found in [the aspen of] semiarid environments... Clonal reproduction is more common in arid environments... Heterozygotes often exhibit superior longevity in forest trees [across many species]... growth rate of aspen decline with elevation, steepness of slope, age of the ramet, and exposure to wind... growth rate decreased dramatically with elevation... The researchers reported that the area of the female clones was 41% greater than males, the number of female ramets 52% greater, and the basal area of females 56% greater [when compared at the same age and environment]...}}
This is however not supported by other observations in the region, which show that seedling establishment of new clones is regular, and often abundant on sites exposed by [[wildfire]].<ref>Kay, Charles E. (1993). Aspen seedlings in recently burned areas of Grand Teton and Yellowstone National Parks. ''Northwest Science''. 67(2): 94-104.</ref> J. L. Howard (U.S. Forest Service ''Fire Effects Information System'') states:<ref name=feis/>
{{Quote|Kay documented postfire quaking aspen seedling establishment following 1986 and 1988 fires in [[Grand Teton National Park|Grand Teton]] and [[Yellowstone National Park|Yellowstone]] National Parks, respectively. He found seedlings were concentrated in kettles and other topographic depressions, seeps, springs, lake margins, and burnt-out riparian zones. A few seedlings were widely scattered throughout the burns. In Grand Teton National Park, establishment was greatest (950-2,700 seedlings/[[hectare|ha]]) in 1989, a wet year, but hundreds to thousands of seedlings established each year despite [[drought]] conditions in 1986-1988 and 1990-1991. Seedlings surviving past one season occurred almost exclusively on severely burned surfaces.}}
Other candidates for oldest living organism include possibly older [[Fungus|fungal mats]] in [[Oregon]], older [[Creosote bush|Creosote Bushes]], and strands of the marine plant ''[[Posidonia oceanica]]'' in the [[Mediterranean Sea]].
==Location==
Pando lives near [[Fish Lake, Utah|Fish Lake]] on the Fish Lake Plateau located at the western edge of the [[Colorado Plateau]] in South-central Utah.
==Trivia==
{{trivia|date=May 2007}}
[[Image:LgstPlant39_sgl_BGv2.jpg|thumb|US Postal Stamp depicting Pando]]
*The [[United States Postal Service]] has made a stamp in commemoration of the aspen, calling it one of the forty "Wonders of America."<ref>[http://www.usps.com/communications/news/stamps/2006/wash06downloads.htm Wonders of America: Land of Superlatives] at ''[[usps.com]]''</ref>
*In 2005 [[Lewis Libby]] wrote a letter to [[Judith Miller]] of the New York Times, who was jailed for refusing to reveal her sources in the White House, which used the Pando an allegory for teamwork.<blockquote> Out West, where you vacation, the aspens will already be turning. They turn in clusters, because their roots connect them.</blockquote>
==See also==
*[[Largest organism]]
*[[List of long-living organisms]]
*[[Vegetative reproduction]]
*[[Genet (biology)|Genet/Ramet]]
*[[Rhizome]]
*[[Basal shoot]]
==References==
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<references />
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[[Category:Individual trees]]
[[Category:Salicaceae]]
[[Category:Flora of Utah]]
[[es:Pando (árbol)]]
[[fr:Pando (arbre)]]