Populus tremuloides is a deciduous tree native to cooler areas of North America, one of several species referred to by the common name aspen. It is commonly called quaking aspen, trembling aspen, American aspen, mountain or golden aspen, trembling poplar, white poplar, and popple, as well as others. The trees have tall trunks, up to 25 metres tall, with smooth pale bark, scarred with black. The glossy green leaves, dull beneath, become golden to yellow, rarely red, in autumn. The species often propagates through its roots to form large clonal groves originating from a shared root system. These roots are not rhizomes, as new growth develops from adventitious buds on the parent root system.

Populus section Populus, of the Populus (poplar) genus, includes the aspen trees and the white poplar Populus alba. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere, extending south at high altitudes in the mountains. The White Poplar, by contrast, is native to warmer regions, with hot, dry summers. These trees are all medium-sized deciduous trees ranging 15–30 metres (49–98 ft) tall.