Trembling Aspen (Populus tremuloides)

trembling aspen
General Appearance
  • Is a slender, deciduous tree with a long, cylindrical trunk.
  • Crown is short and rounded.
  • Bark is smooth, ranging in colour from grey-green to beige with black patches. As tree matures, bark becomes darker and increasingly rough.
  • A medium-sized tree; grows up to 30 metres (98.4 feet) in height.
  • Small fruiting bodies hang from branches, called catkins.
  • Pistillate (female) and staminate (male) flowers found on different trees.
  • A cylindrical capsule, green in colour and holding thousands of very small, hairy seeds.
details of trembling aspen leaves, catkins and bark
  • Alternate, simple and in slender stalks.
  • Oval shaped (nearly round) with a sharp point and finely rounded teeth along the margins.
  • Length ranges from 4 to 7.5 centimetres (1.57 to 2.95 inches).
  • Leaf-stems (petioles) are flattened, thus causing leaves to ?tremble' in the wind.
  • Colour is dark green above and light green below; leaf colour changes to yellow before being shed in autumn.
  • Is widespread throughout Alberta.
  • Considered the dominant species within the Boreal Mixedwood forest in the north-central part of the province. Has scattered distribution in the southeast.
Natural History

  • Is considered a pioneer species ? the first species to appear after a disturbance such as fire or logging ? and cannot tolerate shade. Is found on a wide range of soils in terms of texture and chemistry.
  • Considered a pioneer species as it is one of the first species to appear after a disturbance such as wildfire or harvesting.
  • Well-drained, moist, fertile and loamy soils provide the best conditions for growth.
  • Requires adequate moisture, nutrients and full sun for growth and does not tolerate fully shaded sites.
Reproduction and Growth
  • Primarily Dioecious ? male and female flowers occur on different trees.
  • Staminate (male) catkins emerge in early spring growing to a length of six centimetres (2.36 inches). Once fully mature, catkins release pollen to be carried by the wind to pistillate (female) catkins.
  • Once pollinated, pistillate (female) catkins mature and grow to a length of 10 centimetres (3.94 inches). Within these mature catkins, thousands of seeds will be produced with characteristic white ?fluff' to aid in seed dispersal.
  • Once flowering is complete, seed capsules on pistillate catkins will break open. Seed, along with white ?fluff' is released and dispersed upon the wind.
  • Most common mode of reproduction is asexual through root suckering, however, large quantities of short lived seed are also produced through sexual reproduction which can lead to significant seedling establishment on favourable sites.
  • Is a short lived tree but most trees (individual stems) are part of a collective clone with a common root system that can be very old.
Conservation and Management

Trembling aspen is classified as Secure in the General Status of Alberta Wild Species report. See: ?

For more information about the content of this document, contact
This information published to the web on March 30, 2016.
Last Reviewed/Revised on March 16, 2018.