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Not just a part of the landscape, the trembling aspen thrives in the wake of disturbance and feeds a plethora of forest wildlife.
It only takes a slight breeze to cause the trembling aspen—one of Canada’s most widely distributed trees—to shimmy and shake. The tree’s leaves, with their long, flat stems, move more easily in the wind compared to the leaves of other trees. But stellar dance moves aren’t this tree’s only claim to fame. Here are five more facts about Populus tremuloides.
Popping Up All Over
Trembling aspen (also called quaking aspen) is considered a “weed tree” because it can spring up promptly after forest fires, clear-cutting, or other disturbances. Canada’s other native aspen, largetooth aspen, is similar. You’ll sometimes find both species growing in the same area, but telling them apart is easy enough: largetooth aspen leaves, at 5 to 10 cm, are almost twice as long as trembling aspen leaves.
Skin in the Game
Aspens are among the tree species that have bark that can photosynthesize; because it contains chlorophyll, the bark can, just like leaves, convert sunlight and carbon dioxide into energy to run the tree. A trembling aspen’s pale bark — it looks a little like a white birch’s, but it’s less papery or prone to peeling — can photosynthesize in early spring temperatures as low as -3℃. Even in the summer, when an aspen’s leaves have sprouted, its bark performs up to 15% of photosynthesis.
But Wait, There’s More
A trembling aspen’s bark helps fuel the tree, but it’s also a key food source for porcupines, hares, mice, and beavers, among other mammals. In spring, bears feast on trembling aspen leaves, and moose and deer eat its twigs and catkins — woolly tassels of tiny flowers. Meanwhile, trees sick with heart rot eventually become housing for mammals and birds that make their homes in tree cavities: bats, saw-whet owls, and flying squirrels, to name a few.
Send in the Clones
Some trembling aspens are male, and release pollen; others are female, and drop small seeds produced by their catkins. But most new aspens are actually clones that grow from the roots of “parent” trees. This means that one large underground root system can connect a huge stand of genetically identical trees. The most well-known example is Pando, in Utah, a huge colony of more than 40,000 trembling aspen. Scientists estimate Pando is more than 80,000 years old, weighs 13 million pounds, and may be the largest organism ever found on Earth.
They Like To Move It
Research shows that trembling aspen are “migrating” northward as climate change impacts their ideal growing conditions. According to predictions from Natural Resources Canada, by 2071, the tree’s core range will shift from the prairie provinces and central/southern Ontario and Quebec up into areas such as the Northwest Territories and the Yukon. The trembling aspen isn’t the only tree or plant expected to experience this. According to the latest update to Canada’s Plant Hardiness Zone map — released in the summer of 2025 — the northernmost regions of Canada are becoming hospitable to vegetation that previously couldn’t survive there, while the southern parts of Canada could eventually become too hot.
Want more wild facts? Read about the great horned owl and the Canada lynx.
