Quaking Aspen (Populus tremuloides) are white-barked, deciduous trees of the mountains with broad, trembling leaves. The leaf petiole (leaf stem) is laterally flattened (shaped like a knife blade) rather than round. The flattened petiole causes the leaf to wobble back and forth (tremble) under the gentlest of breezes.

Quaking Aspen are usually found in areas subject to avalanches where conifer trees can’t grow in the Transition (Yellow Pine Forest), Canadian (Pine-Fir Forest), and Hudsonian (Bristlecone Forest) life zones. During avalanches, Quaking Aspen bend under the weight of the snow, while conifers tend to break off.

Family: Willow (Salicaceae).

Other Names:

Plant Form: Shrub to tree.

Height: To about 40-ft.

Trunk: Bark white with horizontal ridges.

Leaves: Oval with a broad base and a bit of a tip, about 1-2 inches across and long; edges serrate. Petiole (leaf stem) flattened, causing the leaves to constantly flutter (quake), even in the lightest breeze.

Flowers: Catkins with cottony tips.

Seeds: Small, attached to white cottony hairs.

Distribution: Most of North America and Mexico.

Elevation: Mountainous areas (6,000 to 11,500 ft), mostly around meadows and where avalanche prevents conifers from growing.

Comments: In the old days, people carved names and images in the bark. It was fine back then, but carving damages the tree, and if we all do it now, we'll kill the trees we love so much.