Maples Of North America
About twelve tree-sized species of maples grow naturally in North America, along with other shrub-sized species. Other, non-native species of maples have been widely introduced to North America as attractive, ornamental plants.
The most widespread native species is sugar or rock maple (Acer saccharum), a prominent tree in temperate forests of eastern Canada and the northeastern United States. Sugar maple is extremely tolerant of shade and is a major component of mature and older-growth angiosperm forests on rich, well-drained sites within its range. Sugar maple grows as tall as 115 ft (35 m), can achieve a diameter of more than 3 ft (1 m), and can live to be older than four centuries. The roughly five-lobed leaves of sugar maple turn a beautiful, orange-yellow color in the autumn, when the green color of chlorophyll fades, exposing the yellow and orange pigments in the leaves. Sugar maple is the national tree of Canada, and a stylized leaf of this species is featured prominently on the Canadian flag. This species was subjected to a widespread decline and die-back over parts of its range during the 1980s, but has since apparently recovered.
Black maple (A. nigrum) is rather similar in appearance to sugar maple, but its leaves have a more three-lobed appearance. Florida maple (A. barbatum) replaces the sugar maple in southeastern North America.
Red maple (A. rubrum) is another widely distributed species, occurring over much of eastern North America, from northern Ontario to southern Florida. The habitat of red maple is highly varied, ranging from flooded swamps to dry hills and rocky slopes. The foliage of this species turns a brilliant scarlet in the autumn. The natural distribution of the silver maple ( A. saccharinum) is largely restricted to swamps and floodplains.
There are fewer species of maples in western North America. The bigleaf maple (A. macrophyllum) has leaves that can be 12 in (30 cm) in diameter, turning a yellow-brown in the autumn. Vine maple (A. circinatum) has scarlet leaves in the fall.
The box-elder or Manitoba maple (A. negundo) is the only species of maple that has a compound leaf, consisting of three to seven leaflets. This fast-growing species is common in moist sites near water, and is an urban weed in many areas.