Sugar Maple is a native deciduous tree is large, growing to 100 feet but usually under 60 feet, with a rounded dense crown.
Bark is variable, brownish on younger trees and light gray to dark gray on old trunks becoming rough and deeply furrowed into narrow scaly ridges that have flat irregular surfaces.
Twigs are slender, shiny, brown to reddish-brown, with lighter lenticels while new. Spring growth is smooth and green. The terminal buds are slender with sharp points and tightly wrapped scales.
Leaves are opposite, about as long as wide - 3-1/2 to 5 inches - on long stalks that are usually smooth. They are palmate, usually with 5 deep, long-pointed lobes, but the sinus between the lobe points is nicely rounded and smooth. The sides of the terminal lobe are almost parallel. Leaf bases are truncated or a little heart-shaped. The upper surface is dull green and the lower surface paler in color. Fall color is yellow, orange to red and will vary from year to year.
Flowers: The tree can be monoecious, that is with separate male and female flowers or can be dioecious, with the flowers on different trees. Male flowers (staminate) are in drooping umbels (tassel-like clusters) up to 3 to 4 inches long, on hairy stalks. Each cluster will have 8 to 14 and each individual flower is only about 1/8 inch long with a 5-toothed yellow-green calyx and around 6 to 8 stamens, no petals. The female flowers (pistillate)are also in drooping clusters, but shorter, 1 to 2 inches long. They are the same size and color as the male flowers but with the ovary and a divided style. Both flowers appear with the leaves and can be together in the same cluster when the tree is monoecious. Flowers are wind pollinated.
Seed: Female flowers mature to a one-seeded samara, about 1 inch long, with a broad wing that is paired with another seed forming an angle of 60 to 90 degrees, green initially and turning light brown. These mature in late summer, drop from the tree and are wind dispersed. It usually takes 30 to 40 years for a tree to produce a quantity of seed.
Habitat: Sugar Maple grows best in rich woods and uplands with moist to mesic soil and full sun but can also grow in drier upland woods. It can be a dominant canopy tree. It grows from a branched root system some of which are deep but like most maples has a number of relatively shallow components. Stem cuttings can be rooted and spring planting of the seed gives the best results. It generally re-sprouts from a stump. It can tolerate shade for many years in the understory but will be an odd shape and not produce much. Sap is quite clear in consistency. The largest threat to the tree seems to be a condition called "maple decline" which causes die-off.
Names: The genus, Acer, is the Latin word for 'maple'. The species name, saccharum, means sweet, referring to the sap. The author name for the plant classification - ‘Marshall’ is for Humphry Marshall (1722-1801), American Botanist, who published in 1785 - Arboreteum Americanum: The American Grove, an Alphabetical Catalogue of Forest Trees and Shrubs, Natives of the American United States. Botanists have recently move the maples into the Sapindaceae family from the older Aceraceae family.
Comparisons: The closest maple that is confusing with Sugar Maple is the Black Maple, Acer nigrum where the sap is also used for syrup. The leaves of Black Maple have more droopy edges and the sinuses of the lower lobes are less open; samaras have a bit more divergence. The leaves are similar to Norway Maple, A. platanoides, but it has milky sap and the samaras have a much greater angle where they are paired.
Above: Sugar Maple can become a large tree with a dense rounded crown. The fall color can range from yellow to red (see below - the leaves are from the same tree, different years.)
Below: Leaves usually have 5 deep, long-pointed lobes, but the sinus between the lobe points is nicely rounded and smooth. The sides of the terminal lobe are almost parallel. 2nd photo - Fall color can sometimes be very reddish.
Below: 2nd photo - Bark is light gray to dark gray on old trunks becoming rough and deeply furrowed into narrow scaly ridges that have flat irregular surfaces. 3rd photo - Twigs are slender, shiny, brown to reddish-brown, with lighter lenticels. The terminal buds are slender with sharp points and tightly wrapped scales.
Below: Flower and seed development. 1st photo - Drooping cluster of male flowers on hairy stalks. 2nd photo - Stamens of the male flowers. 3rd photo - A cluster of female flowers on their hairy stalks. Note divided style.
Below: Three stages of development of the paired samaras. The pairing angle is 60 to 90º
Below: A leaf comparison of the common maples. Images not to scale.
Notes: Sugar Maple is not indigenous to the Garden area. Eloise Butler introduced the plant in May 1909 with plants obtained from the Park Board Nursery. She added another in Oct. 1917, same source. Garden Curator Susan Wilkins added additional plants in 2008. The tree is found in North America from the central plains eastward in the U.S., although more concentrated in the northern tier of States, particularly New England, and in Ontario, Quebec and P E Island in Canada. Within Minnesota it is native to most of the wooded parts of the state, which excludes the SW old prairie areas and the far NW lowlands.
Eight species of Maple are found in the wild in Minnesota: A. negundo, Box Elder; A. nigrum, Black Maple; A rubrum, Red Maple; A. saccharinum, Silver Maple; A. saccharum, Sugar Maple; A. spicatum, Mountain Maple; A. ginnala, Amur Maple and A. platanoides, Norway Maple. The latter two are not native but introductions that have naturalized.
Uses: Sugar Maple is a tough, hard, heavy and strong wood, used for furniture, flooring, panels, veneer, tool handles and other wooden ware requiring a hard wood. Some trees produce a variation in the grain pattern resulting in the specialty woods known as 'birds-eye' and 'curly' maple. Of course, the best known product of this tree is the clear sap used in the production of Maple Syrup. Large trees can yield up to 60 gallons of sap and it takes 32 gallons to make one gallon of maple syrup. Densmore reports (Ref. #5) that the Minnesota Chippewa made paddles for stirring maple syrup from the wood.
In regards the curly and bird's-eye effect, Botanist Francois Michaux (son of Andre) wrote in his North American Sylva (Ref. #26d): "This wood exhibits two accidental forms in the arrangement of the fibre, of which cabinet-makers take advantage for obtaining beautiful articles of furniture. The first consists in undulations like those of the Curled Maple [Red Maple], the second, which takes place in old trees which are still sound, and which appears to arise from an inflexion of the fibre from the circumference towards the centre, produces spots of half a line in diameter, sometimes contiguous, and sometimes several lines apart. The more numerous the spots, the more beautiful and the more esteemed is the wood: This variety is called Bird's-eye Maple. Like the Curled Maple, it is used for inlaying Mahogany. Bedsteads are made of it, and portable writing desks, which are elegant and highly prized. To obtain the finest effect, the log should be sawn in a direction as nearly as possible parallel to the concentric circles."
Eloise Butler wrote in 1911: "The hard or Sugar Maple becomes conspicuous by reason of its drooping sprays of cream colored flowers, swaying on threadlike stems. The hard maple is certainly our finest deciduous tree. When grown in the open it forms a compact dome-like head, which affords refreshing shade from summer’s heat. The leaves usually turn a bright yellow in the autumn. This tree will prove an ornament of stately beauty for the street or lawn, and a beneficent testimonial to the wisdom of the planter, calling forth the gratitude of countless passersby, long after he is dust." From her May 14, 1911 Newspaper Article.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"