bigtooth aspen

not listed

N5? - Secure

SNR - Unranked

not listed

FACU - Facultative upland

FACU - Facultative upland

FACU - Facultative upland

Bigtooth aspen is a fast growing, short lived, deciduous, hardwood tree. It rises on a single stem from a shallow, wide-spreading root system. Reproduction is usually from root suckers, and seedlings are rare. It is usually found as a stand of 12 to 24 clones. Mature trees in the state are usually 40′ to 60′ tall and 10″ to 12″ in diameter at breast height. On poor sites stands begin to deteriorate in 40 to 45 years. On favorable sites stands will begin to deteriorate after 50 to 70 years. Large individuals can reach 90′ in height and 24″ in diameter and last more than 100 years.

The trunk is straight, slender, and free of branches on the lower part. The branches are short, stout, and ascending. The crown is short, open, and rounded.

The bark on young trees is smooth and olive green or grayish-green, sometimes with an orangish cast. It is darker than the bark of quaking aspen and does not peel like paper birch. As it ages it becomes olive-green near the top of the tree and thick and dark gray with deep furrows and flat ridges near the base of the tree.

The current-season twigs are stout, dull, grayish- or reddish-brown with orange dots (lenticels). They are downy when the leaves are unfolding, becoming hairless by the end of the first year. They are round in cross section and have white, star-shaped pith. They turn gray and rough in the second year.

Terminal buds are reddish-brown to gray, about ¼″ long, egg-shaped, and blunt pointed. They are covered with fine, whitish hairs giving them a dusty appearance. They are not aromatic. Lateral buds are similar but slender, point away from the twig, and have 3 or visible scales. The leaf scars are raised and triangular with 3 bundle scars.

The leaves are deciduous, alternate, and not lobed or divided (simple). They are attached to the twig on 1½″ to 3″ long leaf stalks. The leaf stalk is shorter than the leaf blade and is flattened, at least near the base. The leaf blade is firm, broadly egg-shaped to almost round, 2″ to 4″ long, and 1¾″ to 3½″ wide. They are 1.0 to 1.3 times as long as wide. They are rounded or somewhat squared off at the base and taper to a short point at the tip. They unfold 7 to 10 days later than leaves of quaking aspen. When unfolding the leaves are densely covered with white, wooly hairs. When they mature the upper surface is dark green, waxy, and hairless. The lower surface is paler green and remains hairy somewhat longer. The margins have 6 to 15 large, sharp or blunt teeth per side. In autumn the leaves turn yellow and orange.

Male and female flowers are borne on separate trees. They appear before the leaves in early late mid-April to mid-May. Both male and female flowers are borne in crowded, pendulous, stalkless catkins on 2^nd year branchlets. Male catkins are 1″ to 3½″ long, female catkins are 1¼″ to 3⅛″ long. Female catkins elongate when fruiting, becoming 3½″ to 5⅞″ long.

The fruit is an egg-shaped, ⅛″ to 3 ⁄16″ long, 2-valved capsule. Each capsule contains numerous seeds. The seeds are released late May to mid-June. They have cottony hairs attached and are dispersed by wind.

40′ to 90′

The champion bigtooth aspen in Minnesota is on private property near Sandstone, in Kanabec County. In 2018 it was measured at 111′ tall and 116″ in circumference (37″ in diameter), with a crown spread of 54′.

Bigtooth aspen is also a champion tree in the National Champion Tree Register.

Reddish or greenish-yellow

White poplar (Populus alba) leaves are palmately lobed and remain densely white-hairy on the underside at maturity.

All other Populus species in Minnesota have hairless buds and smaller teeth on the leaf margins.

Moist. Uplands. Full sun.

Late mid-April to mid-May

Sources

2, 3, 4, 5, 7, 8, 24, 28, 29, 30.

Native

Common

Bigtooth Aspen leaf, Freeborn County, Minnesota, October 2017

Big-tooth aspen branching

Big-tooth aspen bark

Tree

Sapling

Leaves

Young Leaves

Bud

Young Bark

Location: Freeborn County, Minnesota

Bigtooth Aspen leaf

Location: Freeborn Co.

Big-tooth aspen branching