Aspen trees are all native to cold regions with cool summers, in the north of the
northern hemisphere, extending south at high-altitude areas such as mountains or high plains. They are all medium-sized
deciduous trees reaching 15–30 m (50–100 ft) tall. In North America, the aspen is referred to as quaking aspen or trembling aspen because the leaves "quake" or tremble in the wind. This is due to their flattened
petioles which reduce
aerodynamic drag on the trunk and branches.
