Sugar maple (Acer saccharum)

Description

Acer saccharum, the sugar maple or rock maple, is a species of maple native to the hardwood forests of eastern Canada, from Nova Scotia west through Quebec and southern Ontario to southeastern Manitoba around Lake of the Woods, and the northern parts of the Central and Eastern United States, from Minnesota eastward to the highlands of the eastern states. Sugar maple is best known for its bright fall foliage and for being the primary source of maple syrup. Acer saccharum is a deciduous tree normally reaching heights of 25–35 m (80–115 ft), and exceptionally up to 45 m (148 ft). A 10-year-old tree is typically about 5 m (16 ft) tall. When healthy, the sugar maple can live for over 400 years. The flowers are in panicles of five to 10 together, yellow-green and without petals; flowering occurs in early spring after 30–55 growing degree days. The sugar maple will generally begin flowering when it is between 10 and 15 years old. The fruit is a pair of samaras (winged seeds). The seeds are globose, 7–10 mm (9⁄32–13⁄32 in) in diameter, the wing 2–3 cm (3⁄4–1 1⁄4 in) long. The seeds fall from the tree in autumn, where they must be exposed to 90 days of temperatures below −18 °C (0 °F) to break their coating down. Germination of A. saccharum is slow, not taking place until the following spring when the soil has warmed and all frost danger is past. It is closely related to the black maple, which is sometimes included in this species, but sometimes separated as Acer nigrum. The western American bigtooth maple (Acer grandidentatum) is also treated as a variety or subspecies of sugar maple by some botanists. The sugar maple can be confused with the Norway maple, which is not native to America but is commonly planted in cities and suburbs, and they are not closely related within the genus. The sugar maple is most easily identified by clear sap in the leaf petiole (the Norway maple has white sap), brown, sharp-tipped buds (the Norway maple has blunt, green or reddish-purple buds), and shaggy bark on older trees (the Norway maple bark has small grooves). Also, the leaf lobes of the sugar maple have a more triangular shape, in contrast to the squarish lobes of the Norway maple. The bark of the two trees is not similar at all. Although many people think a red sugar maple leaf is featured on the flag of Canada, the official maple leaf does not belong to any particular maple species; although it perhaps most closely resembles a sugar maple leaf of all the maple species in Canada, the leaf on the flag was specially designed to be as identifiable as possible on a flag waving in the wind without regard to whether it resembled a particular species' foliage.