Aspen Leaf Sticker

Quaking Aspen (Populus tremuloides)

Aspen is a medium-sized deciduous tree, commonly 20 to 80 feet tall and 3 to 18 inches in diameter. Trees over 80 feet tall and larger than 24 inches in diameter are occasionally found. Their bark is smooth, greenish-white, yellowish-white, yellowish-gray, or gray to almost white in color. The green color is from chlorophyll in the bark. Their bark may become rough and fissured with age.

Aspen leaves are thin, firm, and nearly round, 1 1/2 to 3 inches in diameter. They are pointed at the apex and rounded at the base, with many small rounded to sharply pointed teeth along their margins. Aspen leaves are smooth, bright green to yellowish-green, and dull underneath until they turn brilliant yellow, gold, orange, or slightly red in the fall. The leaf's small stem (petiole) is flattened along its entire length, perpendicular to the leaf blade. The flattened stem allows the leaves to quake or tremble in the slightest breeze; hence, their name. The leaves of young sucker aspens may be much larger, sometimes 7 to 8 inches long.

Aspen trees usually do not live more than 150 years, though they may persist for more than 200 years. It grows on many soil types, especially sandy and gravelly slopes, and is quick to pioneer disturbed sites where there is bare soil. It grows best where soils are moist and sunshine is plentiful. Aspen is intolerant of shade and does not compete well with more shade-tolerant conifer species.

Quaking aspen is an aggressive pioneer species. It readily colonizes burned areas and can persist even when subjected to frequent fires. In the Central Rocky Mountains, the extensive stands of aspen are usually attributed to repeated wildfires. It may dominate a site until replaced by less fire-enduring but more shade-tolerant conifers.

Quaking aspen is the most widely distributed native North American tree species, growing in greatly diverse regions, environments, and communities. It occurs across Canada, through the United States, to Mexico, in a variety of habitats. In the western United States, aspen is generally found at 5,000 to 12,000 feet elevation. Aspen occurs in extensive pure stands in some areas, while in others, it is a minor component of the forest landscape. Most of the aspen forests in the United States are found in Utah and Colorado, though they are also scattered throughout all of the western states.

Aspen provides habitat for a wide variety of wildlife, including hare, moose, black bear, elk, deer, ruffed grouse, migratory birds, and a variety of smaller animals. Aspen stands produce livestock forage, and biomass, and are a source for a variety of wood products. Aspens are visually appealing, as they provide contrast to the dark conifers during all seasons; and in the autumn, tourists come to the West to see the brilliant fall colors of the aspen groves.

Take some time this year, during the spring, summer, or fall, and visit an aspen stand on one of our western national forests. Find a sunny spot, lay or sit down on the ground, and listen to the trees whisper to one another as they make their quaking sound. The soft whispering rustle of a quaking aspen is unlike the sound of any other tree in the forest.

Quaking aspen is America's liveliest tree. With just the slightest breeze, its round leaves tremble almost incessantly, like thousands of fluttering butterfly wings.

U.S. Forest Service, How Aspens Grow, October 2nd 2024, (https://www.fs.usda.gov/wildflowers/beauty/aspen/grow.shtml)