Acer saccharum, sugar maple, is a large tree native to North America; it is the official State Tree of New York, Vermont, West Virginia, and Wisconsin (USNA 2011). It has a dense, spreading crown, 25-40 m tall. The leaves are deciduous, opposite, 5-11 cm long and wide, with 5 shallow, blunt or short-pointed lobes, edges coarsely toothed, dark green in summer, turning intensely red, orange, or yellow in fall. Most trees are dioecious (either male or female) but some individuals are monoecious, bearing both male and female flowers. The fruits are samaras (winged nutlets) that occur in pairs.
Maples are classified in their own family, Aceraceae, or in the larger group, Sapindaceae. See
Systematics and
Taxonomy.
Maples were an important sweetener and source of winter nutrition for North American natives and early European settlers (see Uses in full entry). Production of maple syrup is a multimillion dollar industry in the U.S. and Canada (NASS 2011).
Sugar maple is widely planted as an ornamental or shade tree. Many cultivars have been developed, with variations in crown shape, height, fall color, leaf shape, and temperature tolerance. It does not tolerate street salt or soil compaction in urban plantings, so is no longer commonly planted as a street tree. Sugar maple is an important timber tree (see
Uses).
Sugar maple in North America is sometimes confused with Norway maple (
Acer platanoides), an introduced European species that looks similar, but is more resistant to pollution and has fewer insect pests. Norway maple has broader leaves with drooping lobes, and sap from a broken petiole is milky. Norway maple is considered invasive in 20 Northeastern U.S. states (USFS 2011), and in eastern Canada.
Sugar maple is widespread and dominant or codominant in many northern hardwood and mixed mesophytic forests of the eastern United States. It occurs in rich, mesic (moist) woods but also grows in drier upland woods. In 2002, it was one of the 10 most abundant tree species in the U.S. (FIA 2011). Sugar maple is declining in some northeastern forests (such as the Alleghenies), due to its sensitivity to acid rain and other pollution; it may be replaced by opportunistic species in frequently cut or highly disturbed forests (Wikipedia, 2011). In other regions, sugar maple has increased, possibly due to fire suppression (Potter-Witter and Lacksen 1993; MapleInfo.org 2011).
Animals that feed on sugar maple seeds, buds, twigs, and leaves include white-tailed deer, moose, snowshoe hare, red, gray, and flying squirrels, and numerous lepidopteran larvae and aphids. Porcupines consume the bark and can girdle the upper stem. Songbirds and woodpeckers, and cavity nesters nest in sugar maple. The flowers appear to be wind-pollinated, but the early-produced pollen is important for
Apis mellifera (honeybees) and other insects.
