Natural Resources Canada
www.nrcan-rncan.gc.ca
Common menu bar links
Acer saccharum Marsh. Sugar maple
Also known as: hard maple, rock maple.
Habitat
Sugar maple is typically found on hillsides and hilltop situations where soils are well drained and reasonably fertile. It often grows in mixture with beech and yellow birch. As it is very shade tolerant, it may be found in the understorey as well as the overstorey.
Form
Sugar maple can grow up to 27 m in height, with stem diameters up to 70 cm. The crowns of older trees are generally rounded in outline and occupy 30–40% of the tree height in a stand. In open situations, the broadly oval crowns may reach nearly to the ground.
Morphology
The leaves are deciduous, simple, and borne in pairs. Each is 10–25 cm long, with a petiole about as long as the palmately five-lobed lamina. The sinuses between the lobes are rounded and the lobe margins are smooth. The outer three lobes tend to be parallel sided below their two round-pointed side teeth from which the margins extend in a smooth concave manner to the longer, round-pointed lobe ending.
The shoots (twigs) are either fully preformed short shoots (usually with one or two pairs of leaves) or preformed (or partially preformed and partially neoformed) long shoots with more than two pairs of leaves. On the long shoots, the neoformed leaves near the shoots’ ends tend to have longer and narrower lobes than do the preformed leaves on short shoots or at the bases of long shoots.
Sharp-pointed buds with overlapping brown scales develop in each leaf axil, while a larger, sharp-pointed terminal bud forms at each shoot end. When the leaves fall, a V-shaped leaf scar is left below each lateral bud. Twig surfaces are smooth and brown and slightly mottled by small, pale brown lenticels.
The greenish-yellow flowers are each carried in hanging clusters on a long, limp stalk, emerging just before the leaves expand. Male and female flowers are separate in each cluster. The male flowers fall after shedding their pollen, while the female ones go on to form the fruits. Each fruit is a double samara—it has two almost round seed pockets, the coverings of which extend into flattened wings carried almost parallel to each other. Quite often, only one of the seed pockets carries a seed.
The bark is smooth and grey on young trees. Later, it becomes deeply furrowed with scaly brownish-grey ridges.
Notes
Sugar maple produces a heavy, hard, diffuse-porous wood, often called hard maple or rock maple, that is used in furniture, flooring, and specialty goods such as bowling pins and cutting boards. Sometimes flecks or flares occur in the wood, making it suitable for use in “bird’s-eye maple” or “fiddleback” products. Rising sap is often tapped in the spring and boiled down for maple syrup and other maple-sugar products.
The so-called “maple dieback” has affected trees since the 1980s. It is suspected that this has been brought on by environmental changes, such as the increasing incidence of acid deposition in precipitation.
Sugar maple produces vigorous stump sprouts from latent buds in the bark around a cut stump. There is evidence that many single-stemmed trees originated from a coalescence of several stump sprouts from earlier cutting operations.
Sugar maple can be confused with Norway maple (Acer platanoides L.) because their leaves are superficially similar. However, the leaves of Norway maple mostly have seven lobes, the lobe tips and other teeth are longer and more finely pointed than those of sugar maple, and the sap that emerges from the base of the petiole when a leaf is removed is milky, not clear. Also, the buds are plump and rounded, not pointed, the twigs are seldom brown, the flowers are borne in multibranched, outwardly growing, strong clusters, and the fruits are much larger, with wide wings carried almost at 180º to each other.