According to observations of naturalists and beekeepers.
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Quaking aspen is native to and the most widely distributed tree in North America. It occurs from Newfoundland west to Alaska and south to Virginia, Missouri, Nebraska, and northern Mexico. A few scattered populations occur farther south in Mexico to Guanajuato. Quaking aspen is distributed fairly continuously in the East. Distribution is patchy in the West, with trees confined to suitable sites. Density is greatest in Minnesota, Wisconsin, Michigan, Colorado, and Alaska; each of those states contains at least 2 million acres of commercial quaking aspen forest. Maine, Utah, and central Canada also have large acreages of quaking aspen.
Quaking aspen is a native deciduous tree. It is small- to medium-sized, typically less than 48 feet (15 m) in height and 16 inches (40 cm) dbh. It has spreading branches and a pyramidal or rounded crown. The bark is thin. Leaves are orb- to ovately shaped, with flattened petioles. The fruit is a tufted capsule bearing six to eight seeds. A single female catkin usually bears 70 to 100 capsules. The root system is relatively shallow, with wide-spreading lateral roots and vertical sinker roots descending from the laterals. Laterals may extend over 100 feet (30 m) into open areas.