Populus tremuloides

Populus tremuloides Michx

by Terra Crampton, Native Plants Class 2003
Common names: aspen, quaking aspen, trembling aspen, mountain aspen, trembling poplar, white poplar, popple
Family: Salicaceae
Synonymy: Populus tremuloides var. aurea, Populus tremuloides var. magnifica, Populus tremuloides var. pendula, Populus tremuloides var. reniformis (1).
Etymology: Referring to the poplar shape (popul) and the trembling or shaking of the leaves (tremul) (2,3).

Identification
Growth form: The quaking aspen is a native deciduous tree 5-30 m high, usually less than 15 m, with spreading branches and a rounded crown and bark that is typically smooth, greenish-white to gray-white, often thin and peeling becoming thicker and furrowed with age, especially toward the base (4, 6). It has a rapid growth rate but a short life span (5).
Roots: The quaking aspen's roots are lateral and extend over 30 meters with vertical sinker roots extending downward for over 3 meters (4). Root sprouting is the most common means of regeneration with root suckers originating from meristems in the root's cambium during secondary growth (6).
Stems:
Leaves: Leaves are simple, orb- to ovately-shaped, 4-6 cm long, with small, rounded marginal teeth on a slender, flattened petiole, dark green and shiny above and pale green below turning bright yellow, yellow-orange, gold or reddish after the first frost (4,6). Leaves of seedlings are nearly lanceolate and during the first growing season vertical flattening of the petiole is not apparent and there is no lateral branching (6).
Inflorescences/flowers: Flowers are inconspicuous and blue. Quaking aspen catkins elongate before the leaves expand and it appears sustained air temperatures in excess of 12 degrees C for ~ 6 days trigger flowering. Female trees flower and leaf out before male trees (4, 6).
Fruit: The fruit of the quaking aspen isa tufted capsule bearing 6 to 8 seeds with a single female catkin bearing 70 to 100 capsules (6). The bloom period for P. tremuloides is mid springwith a high abundance of fruit /seed (5).
Similar species: Considerable genetic and morphological variation exists over the range of quaking aspen. A number of species and varieties have been described but presently none are recognized. P. tremuloides hybridizes naturally with P. grandidentata, P. angustifolia, P. blasamifera, and P. deltoids (4). Quaking aspen seedlings can be easily misidentified as cottonwood (Populus spp.) or willow (Salix spp.)as seedling leaves bear only the slightest of resemblance to the adult form (6).

Ecology
Life history: Perennial
Native/introduced: Quaking aspen is native to North America and is listed as a dominant species in over 100 habitat, plant community and vegetation typings (7). It is associated with Symphoricarpos oreophilus, Berberis repens, Rosa woodsii, Pachistima myrsinites and a number of Ribes species in the Rocky Mountains and is associated with so many forbs in the west the number is too diverse to list (7).
Photosynthetic pathway: C3
Phenology: Quaking aspen form clones connected by a common parent root system. It is typically dieocious, with a given clone being either male or female. However, some clones produce both stamens and pistils. Aspen stands may consist of a single clone or an aggregate of clones.
Distribution: The native quaking aspen is the most widely distributed tree in North America occurring from Newfoundland west to Alaska and south to Virginia, Missouri, Nebraska and northern Mexico. Density is greatest in Minnesota, Wisconsin, Michigan, Colorado and Alaska. It is also common in mixed conifer forests of Arizona, New Mexico and California (7). Quaking aspen grow on a wide variety of sites including moist upland woods, dry mountainsides, high plateaus, mesas, avalanche chutes, talus, parklands, alluvial terraces and along watercourses (6).

Uses
P. tremuloides is one of most important timber trees in the East and Great Lakes region where it is used for making paper, strandboard, particleboard, boxes, crates, pallets, furniture, waferboard, pulp, excelsior, matchsticks, and tongue depressors among many other uses. The wood is light and soft with little shrinkage (4). It is important forage for mule and white-tailed deer, moose, elk, rabbits, squirrels, pocket gophers, porcupines, beaver, ruffed grouse and many other birds. It is basically palatable to all wildlife and livestock and provides habitat for many species of animals as well (8). First Peoples used the Populus bark (including the quaking asoen) as a food source; they cut the inner bark into strips and ground it into a meal to be mixed with other starches for bread or mush. Catkins were eaten raw and the cambium was eaten raw or in a soup (4).

References
1. http://www.fs.fed.us/database/feis/plants/tree/poptre/introductory.html

2. http://ancienthistory.about.com/gi/dynamic/offsite

3. http://www.winternet.com/~chuckg/dictionary.html

4. National Resouces Conservation Services, USDA Plants website, http://plants.usda.gov/populus tremuloides

5. http://plants.usda.gov/cgi_bin/plant_attribute.cgi?symbol+POTR5

6. http://www.fs.fed.us/database/feis/plants/tree/poptre/botanical_and_ecological_characteristics

7. http://www.fs.fed.us/database/feis/plants/tree/poptre/distribution_and_occurrence.html

8. http://www.fs.fed.us/database/feis/plants/tree/poptre/management_considerations.html

Populus tremuloides Michx by Terra Crampton, Native Plants Class 2003 Common names: aspen, quaking aspen, trembling aspen, mountain aspen, trembling poplar, white poplar, popple Family: Salicaceae Synonymy: Populus tremuloides var. aurea, Populus tremuloides var. magnifica, Populus tremuloides var. pendula, Populus tremuloides var. reniformis (1). Etymology: Referring to the poplar shape (popul) and the trembling or shaking of the leaves (tremul) (2,3). Identification Growth form: The quaking aspen is a native deciduous tree 5-30 m high, usually less than 15 m, with spreading branches and a rounded crown and bark that is typically smooth, greenish-white to gray-white, often thin and peeling becoming thicker and furrowed with age, especially toward the base (4, 6). It has a rapid growth rate but a short life span (5). Roots: The quaking aspen's roots are lateral and extend over 30 meters with vertical sinker roots extending downward for over 3 meters (4). Root sprouting is the most common means of regeneration with root suckers originating from meristems in the root's cambium during secondary growth (6). Stems: Leaves: Leaves are simple, orb- to ovately-shaped, 4-6 cm long, with small, rounded marginal teeth on a slender, flattened petiole, dark green and shiny above and pale green below turning bright yellow, yellow-orange, gold or reddish after the first frost (4,6). Leaves of seedlings are nearly lanceolate and during the first growing season vertical flattening of the petiole is not apparent and there is no lateral branching (6). Inflorescences/flowers: Flowers are inconspicuous and blue. Quaking aspen catkins elongate before the leaves expand and it appears sustained air temperatures in excess of 12 degrees C for ~ 6 days trigger flowering. Female trees flower and leaf out before male trees (4, 6). Fruit: The fruit of the quaking aspen isa tufted capsule bearing 6 to 8 seeds with a single female catkin bearing 70 to 100 capsules (6). The bloom period for P. tremuloides is mid springwith a high abundance of fruit /seed (5). Similar species: Considerable genetic and morphological variation exists over the range of quaking aspen. A number of species and varieties have been described but presently none are recognized. P. tremuloides hybridizes naturally with P. grandidentata, P. angustifolia, P. blasamifera, and P. deltoids (4). Quaking aspen seedlings can be easily misidentified as cottonwood (Populus spp.) or willow (Salix spp.)as seedling leaves bear only the slightest of resemblance to the adult form (6). Ecology Life history: Perennial Native/introduced: Quaking aspen is native to North America and is listed as a dominant species in over 100 habitat, plant community and vegetation typings (7). It is associated with Symphoricarpos oreophilus, Berberis repens, Rosa woodsii, Pachistima myrsinites and a number of Ribes species in the Rocky Mountains and is associated with so many forbs in the west the number is too diverse to list (7). Photosynthetic pathway: C3 Phenology: Quaking aspen form clones connected by a common parent root system. It is typically dieocious, with a given clone being either male or female. However, some clones produce both stamens and pistils. Aspen stands may consist of a single clone or an aggregate of clones. Distribution: The native quaking aspen is the most widely distributed tree in North America occurring from Newfoundland west to Alaska and south to Virginia, Missouri, Nebraska and northern Mexico. Density is greatest in Minnesota, Wisconsin, Michigan, Colorado and Alaska. It is also common in mixed conifer forests of Arizona, New Mexico and California (7). Quaking aspen grow on a wide variety of sites including moist upland woods, dry mountainsides, high plateaus, mesas, avalanche chutes, talus, parklands, alluvial terraces and along watercourses (6). Uses P. tremuloides is one of most important timber trees in the East and Great Lakes region where it is used for making paper, strandboard, particleboard, boxes, crates, pallets, furniture, waferboard, pulp, excelsior, matchsticks, and tongue depressors among many other uses. The wood is light and soft with little shrinkage (4). It is important forage for mule and white-tailed deer, moose, elk, rabbits, squirrels, pocket gophers, porcupines, beaver, ruffed grouse and many other birds. It is basically palatable to all wildlife and livestock and provides habitat for many species of animals as well (8). First Peoples used the Populus bark (including the quaking asoen) as a food source; they cut the inner bark into strips and ground it into a meal to be mixed with other starches for bread or mush. Catkins were eaten raw and the cambium was eaten raw or in a soup (4). References 1. http://www.fs.fed.us/database/feis/plants/tree/poptre/introductory.html 2. http://ancienthistory.about.com/gi/dynamic/offsite 3. http://www.winternet.com/~chuckg/dictionary.html 4. National Resouces Conservation Services, USDA Plants website, http://plants.usda.gov/populus tremuloides 5. http://plants.usda.gov/cgi_bin/plant_attribute.cgi?symbol+POTR5 6. http://www.fs.fed.us/database/feis/plants/tree/poptre/botanical_and_ecological_characteristics 7. http://www.fs.fed.us/database/feis/plants/tree/poptre/distribution_and_occurrence.html 8. http://www.fs.fed.us/database/feis/plants/tree/poptre/management_considerations.html