Trees of the Adirondacks:
Sugar Maple (Acer saccharum Marshall)

Trees of the Adirondack Park: Sugar Maple leaf on the Barnum Brook Trail (28 July 2012)
Trees of the Adirondacks: Sugar Maple leaves have five lobes. They lack the double-toothed edges of the Red Maple Leaf. The notches between the lobes of the Sugar Maple Leaf are u-shaped, in contrast to the v-shaped lobes on the Red Maple leaf. Sugar Maple leaf on the Barnum Brook Trail (28 July 2012)

The Sugar Maple (Acer saccharum) is a large, slow-growing, deciduous tree which flourishes in well-drained soil in the Adirondack Mountains. It is a member of the Soapberry Family. The Sugar Maple is one of about twenty species in the genius Acer which occur in North America. This species has a life span of 200-300 years, with some specimens in old-growth stands persisting to nearly 400 years.

The Sugar Maple is one of the most important trees in the eastern United States and Canada, both economically and ecologically. It is the dominant tree in the northern hardwood forest, along with American Beech.

Sugar Maples are also known as Hard Maple, Rock Maple, Head Maple, Sugartree, and Bird's-eye Maple. The Sugar Maple is the state tree of New York. It is also the national tree of Canada, as represented by the maple leaf on its flag.


Identification of the Sugar Maple

Trees of the Adirondacks: Sugar Maple at the Paul Smiths VIC (19 September 2012)
Trees of the Adirondacks: Sugar Maple leaves turn red, yellow, or orange in the fall. Sugar Maple at the Paul Smiths VIC (19 September 2012)

The mature Sugar Maple is a large tree, growing 50-70 feet tall, with a straight, single trunk. The branches are opposite, meaning that they emerge in pairs, opposite one another. Forest-grown Sugar Maples are generally free from branches on the lower third to two-thirds of the tree, with a narrow, rounded crown. Sugar Maple that grow in the open are oval in shape, with upswept lower branches and straight upper branches.

Like other maples, Sugar Maples have opposite, lobed leaves. The leaves of the Sugar Maple usually have five squarish, shallow lobes. Each of the largest three lobes has one to several sharp-pointed tips. There is a moderately deep U-shaped notch between the lobes. The upper surface of a Sugar Maple leaf is green in the summer; the lower surface is pale green to whitish. Sugar Maple leaves turn red, yellow, or orange in autumn, contributing to the brilliant palette of colors seen in September and early October in the Adirondacks.

Trees of the Adirondacks: Sugar Maple on the Barnum Brook Trail at the Paul Smiths VIC (28 July 2012).
Trees of the Adirondacks: Sugar Maple bark is gray, smooth when the tree is young and scaly when the tree gets older. Sugar Maple on the Barnum Brook Trail at the Paul Smiths VIC (28 July 2012).

The Sugar Maple flowers in mid- to late-spring, producing tiny greenish yellow flowers with five sepals. In the Adirondack Mountains, this tree usually flowers in mid-May with leaf expansion.

The seeds of Sugar Maple are the familiar “helicopters.” The seeds are green, turning reddish tan. The seeds drop in late summer.

The twigs of the Sugar Maple are glossy and reddish brown. The buds are brown and sharp; the buds are slender and pointed down. The bark of the Sugar Maple is smooth and gray when the tree is young, becoming irregularly furrowed, scaly, and dark gray on older trees.

Keys to differentiating the Sugar Maple from other maples include its leaves, bark, growth habit, and habitat.

  • The leaves of the Sugar Maple lack the irregularly and usually double-toothed margins of the Red Maple. The dips between the lobes of the Sugar Maple are u-shaped, while the indentations between the lobes of the Red Maple are pointy, forming a sharp "v." In addition, Red Maple trees are more tolerant of wet soil. A large, single-trunked maple tree growing near a marsh or other wetland is more likely to be a Red Maple.
  • The Striped Maple is a small understory tree, often divided into several branches from near the base. Its bark has distinctive narrow, white vertical stripes. In addition, its leaves are uniformly and finely double-toothed.
  • The Mountain Maple is another small understory tree. Its leaves are coarsely toothed.

Historical Uses of the Sugar Maple

The Sugar Maple was the premier source of sweetener, along with honey, for both Native Americans and early European settlers. Native American tribes – including the Algonquin, Cherokee, Dakota, and Iroquois – used maple sap to make syrup and sugar. The Micmac also used the bark to make a beverage. The Ojibwa allowed the sap to sour to make vinegar, which was mixed with maple sugar to cook sweet and sour meat. The Potawatomi used maple sugar instead of salt to season all cooking. Cherokee used the wood for lumber and to make furniture. The Malecite used the wood to make paddles, torch handles, and oars. The Ojibwa used the wood to make bowls and other cooking tools.

Native American tribes also used the Sugar Maple for medicinal purposes. For example, the Iroquois used maple sap for sore eyes and a compound infusion of the bark as drops for blindness. It was also used as a blood purifier and dermatological aid. The Mohegans used the inner bark as a cough remedy.

Current Uses of the Sugar Maple

The Sugar Maple is currently one of the most valuable hardwood trees in the Northeast. Its wood has a wide variety of uses, including furniture, paneling, flooring, interior trim and veneer. Sugar Maple wood is also used for gun stocks, tool handles, plywood dies, cutting blocks, wooden ware, novelty products, sporting goods, bowling pins, and musical instruments. The wood is especially suited for bowling alleys. 

Some trees develop special grain patterns, including birdseye maple (with dots suggesting the eyes of birds) and curly and fiddleback maple (with wavy annual rings). Such variations in grain are highly prized in cabinet making.  Wood from the Sugar Maple is also a very good fuel, giving off a lot of heat and forming very hot embers. The ashes of the wood are rich in alkali and yield large quantities of potash.

Trees of the Adirondacks: Sugar Maple at the Paul Smiths VIC.
Trees of the Adirondacks: Production of maple syrup, maple sugar, and other maple products is a major use for Sugar Maples. Sugar Maple at the Paul Smiths VIC.

In addition, the Sugar Maple – with sap which has twice the sugar content of other maple species – is the mainstay of commercial syrup production. Production of maple syrup is a multi-million-dollar industry in the U.S. and Canada. Canada, primarily Quebec, produces over 70% of the world's maple syrup. The remainder is produced in the US, where maple syrup production in 2016 totaled 4.2 million gallons. The US value of production in 2015 was $126 million. Vermont is the largest US maple producer, producing 47% of US maple syrup in 2016. New York State is the second largest producer, with 17%.

Sugaring season begins in early spring, starting in February or early March in downstate regions. Nights below freezing and days at higher than 5°C are needed to ensure good sap flow. Each tree yields between 5 and 60 gallons of sap, depending on the health of the tree and the weather.

  • Early in the spring, when the maple trees are still dormant, temperatures rise above freezing during the day. As a result, positive pressure develops in the tree, causing the sap to flow out of the tree through a half-inch wide tap hole which has been drilled about 4.5 feet above the ground.
  • When the temperature drops back below freezing at night, suction develops, drawing water into the tree through the roots and replenishing the sap in the tree. This allows the sap to flow again during the next warm period.
  • This cycle of warm and cool periods is essential for sap flow.

The maple sap is then boiled to produce maple syrup. Fresh sap flowing out of the maple tree usually contains around 2% sugar. Finished maple syrup is 66-67% sugar. To create maple syrup from maple sap, it is necessary to increase the sugar concentration of sap. Many gallons of water need to be removed. Usually, about 40 gallons of sap are required to produce one gallon of finished syrup, depending on the sugar content of the sap, which in turn depends on the health and age of the tree and the time of the season.

Wildlife Value of the Sugar Maple

Birds of the Adirondacks: Black-throated Blue Warbler near Craig Wood Golf Course, Lake Placid (25 June 2016).
Trees of the Adirondacks: The Black-throated Blue Warbler is one of a number of bird species which breed in the habitats associated with Sugar Maples. Black-throated Blue Warbler near Craig Wood Golf Course, Lake Placid (25 June 2016).

Sugar Maple is a food source for several wildlife species. White-tailed Deermoose, and Snowshoe Hares commonly browse on Sugar Maple trees. Red Squirrels feed on its seeds, buds, twigs, and leaves. Porcupines eat the bark and can girdle the upper stem. The flowers appear to be wind-pollinated, but the early-produced pollen is important for Apis mellifera (honeybees) and other insects. In addition, the Sugar Maple is a caterpillar host for the Cecropia Silkmoth and the Rosy Maple Moth.

A number of birds build nests in Sugar Maples, including American RedstartsEvening GrosbeaksBaltimore Orioles, and Northern Cardinals. Twigs from Sugar Maple trees are sometimes used by Chimney Swifts as nest-building material. For several species – including the Cerulean WarblerScarlet TanagerHairy Woodpecker, and Summer Tanager – the Sugar Maple is one of the preferred trees for foraging for insects.

Bird species which breed in the northern hardwood forest and mixed woods forests associated with Sugar Maples include:

Distribution of the Sugar Maple

Sugar Maples are restricted to regions with cool, moist climates. This species is widespread and abundant in the eastern and mid-western United States, into southern Canada. Sugar Maple are found throughout New England and the mid-Atlantic states. This species grows from Nova Scotia and New Brunswick westward to Ontario and Manitoba, North Dakota and South Dakota, southward into eastern Kansas into Oklahoma, and southward in the east through New England to Georgia.

Sugar Maple is present in all New York State counties. It can be found in all counties that fall within the Blue Line.

Habitat of the Sugar Maple

Trees of the Adirondacks: Squirrel Corn near Craig Wood Golf Course, Lake Placid (19 May 2011). 
Trees of the Adirondacks: Squirrel Corn, a spring ephemeral which emerges and blooms before the canopy trees leaf out, is usually found under Sugar Maples, which make a rich humus allowing this species to exist. Squirrel Corn near Craig Wood Golf Course, Lake Placid (19 May 2011). 

The Sugar Maple is one of the most shade-tolerant species in the Adirondacks. Its seedlings will survive on the forest floor for years, growing very slowly until the death of a large tree or some other disturbance opens up the canopy. The seedlings will then begin growing rapidly, eventually reaching crown level. This species is generally regarded as a climax species in eastern hardwood forests.

Sugar Maple grows in a wide variety of soils, but does best on deep, fertile, well-drained soils. It is rarely found in swamps. This species does not grow well on soil that is too poorly drained or too shallow. On these marginal sites, it will probably be out-competed by other species such as Red Maple or Yellow Birch.

The Sugar Maple – growing in abundance with Yellow BirchEastern HemlockAmerican Beech, and Eastern White Pine – is an indicator species for the northern hardwood forest. This species is also common in mixed forests. The under-story in this habitat is often dominated by Striped Maple and Hobblebush. Herbaceous species which thrive here include Painted Trillium, GoldthreadCommon Wood SorrelCarolina Spring Beauty, Pink Lady's Slipper, and Wild Sarsaparilla. Ecological communities in the Adirondack Park where Sugar Maples are found include beach-maple mesic forests, hemlock-hardwood forests, and spruce-northern hardwood forests.

Outlook for Adirondack Sugar Maples

The future of Sugar Maples in the Adirondack Park is uncertain. In the 1980s, Sugar Maples appeared to be in a serious state of decline over a wide variety of locations in both Canada and the northeast US. Characteristics of the decline include branch die back, reduced growth, and, in some cases, unusually high levels of mortality. Growing concern over the Sugar Maple's future led to the creation of the North American Maple Project (NAMP) in the late eighties, with the goal of evaluating and monitoring the health of Sugar Maples, based on assessments of crown conditions. The results, while not definitive, suggested that temporary and reversible stressors, such as insect damage, were the main factors and that air pollution was not causing region-wide maple decline.

More recent research is less reassuring. Sugar Maple declines are continuing in our area. For instance a 2015 analysis of growth rings from hundreds of trees across the Adirondack Mountains revealed a decline in the growth rate for a majority of sugar maple trees after 1970. The causes of this decline are unclear. Some researchers have linked the changes to acid rain, noting that Sugar Maples appear to be highly vulnerable to the loss of calcium in the soil caused by the nitric and sulphuric acid in acid rain. Others point to the warmer temperatures associated with climate change. Most specialists concur that Sugar Maple decline is the result of a combination of factors, each of which plays a part in weakening the tree. 

Adirondack Tree List


References

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Trees of the Adirondack Mountains

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