populus tremuloides

File:2015-03-16 12 22 15 Aspen catkins on Idaho Street (Interstate 80 Business) in Elko, Nevada.JPGs in spring]]

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The quaking aspen is a tall, fast-growing tree, usually {{convert|15-18|m|5=ft|round=5|sp=us}} at maturity, with a trunk {{convert|25|cm|sp=us|frac=2}} in diameter;{{Cite book |last1=Arno |first1=Stephen F. |url=https://books.google.com/books?id=qDD4DwAAQBAJ |title=Northwest Trees: Identifying & Understanding the Region's Native Trees |last2=Hammerly |first2=Ramona P. |publisher=Mountaineers Books |year=2020 |isbn=978-1-68051-329-5 |edition=field guide |location=Seattle |pages=203–208 |language=en |oclc=1141235469 |orig-date=1977}} records are {{convert|36.5|m|ftin|abbr=on}} in height and {{convert|1.37|m|ftin|abbr=on}} in diameter. The bark is relatively smooth, whitish (light green when young), and is marked by thick black horizontal scars and prominent black knots. Parallel vertical scars are tell-tale signs of elk, which strip off aspen bark with their front teeth.

The leaves on mature trees are nearly round, {{convert|4|–|6|cm|frac=4|abbr=on}} in diameter with small rounded teeth, and a {{convert|3|–|7|cm|frac=4|adj=on|abbr=on}} long flattened petiole. The leaves are green above and gray below. Young trees and root sprouts have much larger ({{convert|10|–|20|cm|in|0|disp=comma|abbr=on}} long), nearly triangular leaves. (Some species of Populus have petioles flattened partially along their length, while the aspens and some other poplars have them flattened from side to side along the entire length of the petiole.)

Aspens are dioecious, with separate male and female clones. The flowers are catkins {{convert|4|–|6|cm|frac=4|abbr=on}} long, produced in early spring before the leaves. The fruit is a {{convert|10|cm|in|0|adj=mid|-long|abbr=on}} pendulous string of {{convert|6|mm|in|frac=16|adj=on|sp=us}} capsules, each capsule containing about ten minute seeds embedded in cottony fluff, which aids wind dispersal of the seeds when they are mature in early summer. Trees as young as 2–3 years old may begin seed production, but significant output starts at 10 years of age. Best seed production is obtained between the ages of 50 and 70 years.

Quaking aspen grows more slowly in the dry conditions of western North America than it does in the more humid east and also lives longer—ages of 80–100 years are typical, with some individuals living 200 years; the root system can live much longer. In the east, stands decay faster, sometimes in 60 years or less depending on the region.

The quaking or trembling of the leaves that is referred to in the common names is due to the flexible flattened petioles.{{Cite web |title=Populus tremuloides – Purdue Arboretum Explorer |url=https://www.arboretum.purdue.edu/explorer/plants/21350/ |access-date=2023-11-16 |language=en-US}} The specific epithet, tremuloides, evokes this trembling behavior and can be literally translated as "like (Populus) tremula", the European trembling aspen.

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Quaking aspen occurs across Canada in all provinces and territories, with the possible exception of regions of Nunavut north of the James Bay islands. In the United States, it can be found as far north as the northern foothills of the Brooks Range in Alaska, where road margins and gravel pads provide islands of well-drained habitat in a region where soils are often waterlogged due to underlying permafrost.{{Cite journal|last1=Ackerman|first1=Daniel|last2=Breen|first2=Amy|date=2016-06-06|title=Infrastructure Development Accelerates Range Expansion of Trembling Aspen ( Populus tremuloides, Salicaceae) into the Arctic|journal=Arctic|language=en|volume=69|issue=2|pages=130–136|doi=10.14430/arctic4560|issn=1923-1245|doi-access=free}} It occurs at low elevations as far south as northern Nebraska and central Indiana. In the Western United States, this tree rarely survives at elevations lower than {{convert|1500|ft|m}} due to hot summers experienced below that elevation, and is generally found at {{convert|5000|-|12000|ft|m}}.

It grows at high elevations as far south as Guanajuato, Mexico. It grows in isolated areas in northeastern Mexico as well as Baja California, Jalisco, the State of Mexico, Michoacán, Sinaloa, Sonora, and Veracruz.{{cite web |last1=Hassler |first1=Michael |title=World Plants |url=https://www.worldplants.de/world-plants-complete-list/complete-plant-list#plantUid-150785 |website=Synonymic Checklist and Distribution of the World Flora. Version 18.3 |access-date=10 January 2024 |date=3 January 2024}}

Quaking aspen grows in a wide variety of climatic conditions. January and July average temperatures range from {{convert|-30|C|F}} and {{convert|16|C|F}} in the Alaska Interior to {{convert|-3|C|F}} and {{convert|23|C|F}} in Fort Wayne, Indiana. Average annual precipitation ranges from {{convert|1020|mm|in|abbr=in}} in Gander, Newfoundland and Labrador to as little as {{convert|180|mm|in|abbr=in|frac=4}} in the Alaska Interior. The southern limit of the species' range roughly follows the {{convert|24|C|F}} mean July isotherm.

In the sagebrush steppe, aspens occur with chokecherry, serviceberry, and hawthorn, forming a habitable haven for animal life.{{Cite book|last=Taylor|first=Ronald J.|url=https://www.worldcat.org/oclc/25708726|title=Sagebrush Country: A Wildflower Sanctuary|publisher=Mountain Press Pub. Co|year=1994|isbn=0-87842-280-3|edition=rev.|location=Missoula, MT|pages=174|language=en|oclc=25708726|orig-year=1992}} Shrub-like dwarf clones exist in marginal environments too cold and dry to be hospitable to full-size trees, for example at the species' upper elevation limits in the White Mountains.{{Cite book |url=https://publishing.cdlib.org/ucpressebooks/view?docId=ft3t1nb2pn;brand=ucpress |title=Natural history of the White-Inyo Range, eastern California |date=1991 |publisher=University of California Press |isbn=0-520-06895-5 |editor-last=Hall |editor-first=Clarence A. |location=Berkeley |pages=91 |oclc=23653610}}

File:Quakingfallcolors.JPG in Alaska]]

Quaking aspen propagates itself primarily through root sprouts, and extensive clonal colonies are common. Each colony is its own clone, and all trees in the clone have identical characteristics and share a single root structure. A clone may turn color earlier or later in the fall than its neighboring aspen clones. Fall colors are usually bright tones of yellow; in some areas, red blushes may be occasionally seen. As all trees in a given clonal colony are considered part of the same organism, one clonal colony, named Pando, is considered the heaviest{{Cite journal |last1=Mitton |first1=Jeffry B. |last2=Grant |first2=Michael C. |date=1996–2001 |title=Genetic Variation and the Natural History of Quaking Aspen |url=http://dx.doi.org/10.2307/1312652 |journal=BioScience |volume=46 |issue=1 |pages=25–31 |doi=10.2307/1312652 |jstor=1312652 |s2cid=87362686 |issn=0006-3568|url-access=subscription }} and oldest{{Cite journal |last=Jenkins |first=Michael |date=1993-01-01 |title=Fire History Determination in the Mixed Conifer/Aspen Community of Bryce Canyon National Park |journal=UW National Park Service Research Station Annual Reports |volume=17 |pages=31–35 |doi=10.13001/uwnpsrc.1993.3135 |issn=2693-2407|doi-access=free }} living organism on the planet. Pando spans across 43 hectares and weighs six million kilograms. Most scientists agree that the Pando seed set down sometime between 8,000 and 12,000 years ago when climate currents in the region shifted at the end of the last ice age.{{Cite web |title=Pando: Documenting a Tree That Redefines What a Tree Can Be |url=https://www.nationalforests.org/blog/pando-documenting-a-tree-that-redefines-what-trees-can-be |access-date=2024-10-24 |website=National Forest Foundation |language=en}} Aspens do produce seeds, but seldom grow from them. Pollination is inhibited by the fact that aspens are either male or female, and large stands are usually all clones of the same sex. Even if pollinated, the small seeds (three million per pound) are only viable a short time as they lack a stored food source or a protective coating.Ewing, Susan. The Great Alaska Nature Factbook. Portland: Alaska Northwest Books, 1996.

The buds and bark supply food for snowshoe hares, moose, black bears, cottontail rabbits, porcupines, deer, grouse, and mountain beavers. The shoots are eaten by sheep, goats, and cattle. Sheep and goats also browse the foliage, as do game animals including elk.{{cite book |last=Whitney |first=Stephen |url=https://archive.org/details/westernforests00whit/page/390 |title=Western Forests (The Audubon Society Nature Guides) |date=1985 |publisher=Knopf |isbn=0-394-73127-1 |location=New York |page=[https://archive.org/details/westernforests00whit/page/390 390]}}{{cite book |last=Peattie |first=Donald Culross |author-link=Donald C. Peattie |title=A Natural History of Western Trees |year=1953 |publisher=Bonanza Books |location=New York |page=320}} Grouse and quail especially eat the buds in winter. Mammals such as beavers and rabbits eat the bark, foliage, and buds. Beavers also store aspen logs for winter food. Other animals nest in aspen groves. The leaves of the quaking aspen and other species in the genus Populus serve as food for caterpillars of various moths and butterflies.{{Cite journal |last1=Lindroth |first1=Richard L. |last2=St. Clair |first2=Samuel B. |date=2013-07-01 |title=Adaptations of quaking aspen (Populus tremuloides Michx.) for defense against herbivores |url=https://www.sciencedirect.com/science/article/pii/S0378112712006949 |journal=Forest Ecology and Management |series=Resilience in Quaking Aspen: restoring ecosystem processes through applied science |volume=299 |pages=14–21 |doi=10.1016/j.foreco.2012.11.018 |issn=0378-1127|url-access=subscription }} Quaking aspen trees also serve as hosts to certain damaging insects such as the large aspen tortrix.{{Cite book |last=Parry |first=Dylan |url=https://www.worldcat.org/oclc/36695777 |title=The relationship between trembling aspen phenology and larval development of the large aspen tortrix |date=1997 |publisher=Canadian Forest Service, Northern Forestry Centre |others=W. J. A. Volney, C. R. Currie, Northern Forestry Centre |isbn=0-662-25404-X |location=Edmonton |oclc=36695777}}

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File:2014-10-05 14 33 30 Aspens showing autumn foliage coloration in Lamoille Canyon, Nevada.JPG

Increased mortality in trembling aspen stands have been reported since the early 1990s across North America.{{Cite journal |last1=Hogg |first1=E H |last2=Brandt |first2=James P |last3=Kochtubajda |first3=B |date=2002-05-01 |title=Growth and dieback of aspen forests in northwestern Alberta, Canada, in relation to climate and insects |url=http://www.nrcresearchpress.com/doi/10.1139/x01-152 |journal=Canadian Journal of Forest Research |language=en |volume=32 |issue=5 |pages=823–832 |doi=10.1139/x01-152 |issn=0045-5067|url-access=subscription }} As this accelerated in 2004, a debate over causes began. This increased dieback has been linked to multiple stressors, such as defoliation by the forest tent caterpillar (Malacosoma disstria), wood-boring beetles such as the poplar borer (Saperda calcarata) and the bronze poplar borer (Agrilus liragus), and fungal disturbances such as those by the Cytospora canker (Valsa sordida).{{Cite journal |last1=Worrall |first1=James J. |last2=Egeland |first2=Leanne |last3=Eager |first3=Thomas |last4=Mask |first4=Roy A. |last5=Johnson |first5=Erik W. |last6=Kemp |first6=Philip A. |last7=Shepperd |first7=Wayne D. |date=2008-03-20 |title=Rapid mortality of Populus tremuloides in southwestern Colorado, USA |url=https://www.sciencedirect.com/science/article/pii/S0378112707007104 |journal=Forest Ecology and Management |volume=255 |issue=3 |pages=686–696 |doi=10.1016/j.foreco.2007.09.071 |issn=0378-1127|url-access=subscription }}

Many areas of the Western US have experienced increased diebacks which are often attributed to ungulate grazing and wildfire suppression. At high elevations where grasses can be rare, ungulates can browse young aspen sprouts and prevent those young trees from reaching maturity. As a result, some aspen groves close to cattle or other grazing animals, such as deer or elk, have very few young trees and can be invaded by conifers, which are not typically browsed. Another possible deterrent to aspen regeneration is widespread wildfire suppression. Aspens are vigorous resprouters and even though the above-ground portion of the organism may die in a wild-fire, the roots, which are often protected from lethal temperatures during a fire, will sprout new trees soon after a fire. Disturbances such as fires seem to be a necessary ecological event in order for aspens to compete with conifers, which tend to replace aspens over long, disturbance-free intervals. The current dieback in the American West may have roots in the strict fire suppression policy in the United States.{{cite journal |last1=Haskins|display-authors=etal|title=Impact of fire suppression on aspen populations |journal=Forestry and Wildlife Management |date=2007 |volume=19 |issue=3 |pages=54–57}} On the other hand, the widespread decimation of conifer forests by the mountain pine beetle may provide increased opportunities for aspen groves to proliferate under the right conditions.{{cite journal |doi=10.1016/j.foreco.2013.01.008 |volume=299 |title=How will aspen respond to mountain pine beetle? A review of literature and discussion of knowledge gaps |journal=Forest Ecology and Management |pages=60–69|date=July 2013 |last1=Pelz |first1=Kristen A. |last2=Smith |first2=Frederick W. }}

Increased mortality has also been linked in turn to climate change. Thaw-freeze events and light snowfall in late winter as a result of increased temperatures has led to increased dieback in Southern and Western Canada. Furthermore, climate records show that historically, most periods of aspen decline have been paired with periods of severe drought, which has worsened in recent years due to a changing climate.{{Cite journal |last1=Worrall |first1=James J. |last2=Rehfeldt |first2=Gerald E. |last3=Hamann |first3=Andreas |last4=Hogg |first4=Edward H. |last5=Marchetti |first5=Suzanne B. |last6=Michaelian |first6=Michael |last7=Gray |first7=Laura K. |date=2013-07-01 |title=Recent declines of Populus tremuloides in North America linked to climate |url=https://www.sciencedirect.com/science/article/pii/S0378112712007645 |journal=Forest Ecology and Management |series=Resilience in Quaking Aspen: restoring ecosystem processes through applied science |volume=299 |pages=35–51 |doi=10.1016/j.foreco.2012.12.033 |issn=0378-1127|url-access=subscription }} Many stands of aspen that have been affected by climate change in recent years have poor regeneration potential, leading to concerns of widespread loss of aspen cover in the future.

Because of vegetative regeneration by aspen, where an entire group of trees are essentially clones, there is a concern that something that hits one will eventually kill all of the trees, presuming they share the same vulnerability. A conference was held in Utah in September 2006 to share notes and consider investigative methodology.{{cite news|url=https://www.nytimes.com/2006/09/26/science/earth/26aspen.html |work=The New York Times |first=Katie |last=Kelley |title=Emblem of the West Is Dying, and No One Can Figure Out Why |date=26 September 2006}}

Aspen bark contains a substance that was extracted by indigenous North Americans and European settlers of the western U.S. as a quinine substitute.

Like other poplars, aspens make poor fuel wood, as they dry slowly, rot quickly, and do not give off much heat. Yet they are still widely used in campgrounds because they are cheap and plentiful and not widely used in building lumber. Pioneers in the North American west used them to create log cabins and dugouts, though they were not the preferred species.https://www.fs.usda.gov/nrs/pubs/LSFES_aspen_reports/1947_lakestates_aspen_15.pdf

Aspen wood is used for pulp products (its main application in Canada) such as books, newsprint, and fine printing paper. It is especially good for panel products such as oriented strand board and waferboard. It is light in weight and is used for furniture, boxes and crates, core stock in plywood, and wall panels.https://www.fpl.fs.usda.gov/documnts/usda/amwood/217aspen.pdf

The quaking aspen is the state tree of Utah.{{cite web |title=S.B. 41 State Tree Change |url=http://le.utah.gov/~2014/bills/static/SB0041.html |publisher=Utah State Legislature}}

The cultivar 'Prairie Gold' was introduced to the plant trade by the Nebraska Statewide Arboretum and a local nursery with a claim that it is better adapted the warmer conditions and lower humidity of lower elevations. It is rated as hardy only to USDA zone 4.{{cite web |title=Prairie Gold Aspen |url=https://jfschmidt.com/all-trees/introductions/prairie-gold-aspen/ |website=J. Frank Schmidt & Son Co. |access-date=22 April 2025 |date=n.d.}}

Typically, quaking aspens in cultivation are hardy in USDA zones 1 to 6. They require good drainage and moist or occasionally wet soils. With good drainage they adapt to clay, silt, sand, or shallowly rocky soil conditions.{{cite web |last1=NCE |title=Populus tremuloides (Quaking Aspen) |url=https://plants.ces.ncsu.edu/plants/populus-tremuloides/ |website=North Carolina Extension Gardener Plant Toolbox |publisher=North Carolina State University; North Carolina Agricultural and Technical State University |access-date=22 April 2025 |date=n.d.}}

{{Commons category}}

• Pando, an exceptionally large clonal colony of P. tremuloides determined to be a single male tree
• Largest organisms

{{Reflist}}

• [http://www.fs.fed.us/database/feis/plants/tree/poptre/all.html US Forest Service Fire Effects Information System: Populus tremuloides]
• [https://web.archive.org/web/20091126010525/http://www.abtreegene.com/trees.html Alberta Forest Genetic Resources Council: Populus tremuloides]
• [http://www.plantmaps.com/nrm/populus-tremuloides-quaking-aspen-native-range-map.php Interactive Distribution Map for Populus tremuloides] {{Webarchive|url=https://web.archive.org/web/20151113113120/http://www.plantmaps.com/nrm/populus-tremuloides-quaking-aspen-native-range-map.php |date=2015-11-13 }}
• Farrar, John Laird. Trees In Canada. Fitzhenry and Whiteside, 1995
• Hickman, James C., ed. [http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?7038,7039,7044 The Jepson Manual: Higher Plants of California], {{ISBN|0520082559}}. University of California Press, 1993.
• {{PFAF|Populus tremuloides}}

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tremuloides

Category:Trees of Northern America

Category:Taxa named by André Michaux

Category:Plants used in traditional Native American medicine

Category:Flora of Western Canada

Category:Flora of Eastern Canada

Category:Flora of the Northwestern United States

Category:Flora of the North-Central United States

Category:Flora of the Northeastern United States

Category:Flora of the Southwestern United States

Category:Flora of the South-Central United States

Category:Flora of Northeastern Mexico

Category:Flora of Baja California

Category:Flora of Delaware

Category:Flora of Jalisco

Category:Flora of Maryland

Category:Flora of the State of Mexico

Category:Flora of Michoacán

Category:Flora of North Carolina

Category:Flora of Sinaloa

Category:Flora of Sonora

Category:Flora of Veracruz

Category:Flora of Virginia

Category:Flora of Alaska

Category:Flora of the Northwest Territories

Category:Flora of Nunavut

Category:Flora of Yukon