sugar maple (Acer saccharum)
SCIENTIFIC SYNONYMS: There are no scientific synonyms for Acer
CONFIRMATION STATUS: Confirmed.
TAXONOMY: The currently accepted scientific name of sugar maple is
Acer saccharum Marsh. Sugar maple is highly variable genetically and
taxonomic controversy abounds. Some taxonomists recognize two to six
varieties, but others recognize these entities as forms or subspecies.
Florida maple (Acer barbatum), chalk maple (Acer leucoderme), and black
maple (Acer nigrum) hybridize and intergrade with sugar maple and are
often included in the sugar maple complex. Some authorities recognize these
taxa as subspecies of sugar maple, but most delineate them as discrete
species. Sugar maple hybridizes with red maple (Acer rubrum) in the field,
and with bigleaf maple (Acer macrophyllum) under laboratory conditions.
Acer x senecaense Slavin is a hybrid derived from an Acer leucoderme x
sugar maple cross. Acer skutchii is closely related to sugar maple and is
treated as a subspecies by some taxonomists.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS: Sugar maple is a
deciduous tree which reaches 90 to 120 feet (27-37 m) in height and 30
to 36 inches (76-91 cm) in d.b.h. Extremely large specimens have reached
more than 130 feet (40 m) in height and more than 5 feet (1.5 m) in d.b.h.
Sugar maple is long-lived and plants can survive for 300 to 400 years.
The bark is light gray to gray-brown and becomes deeply furrowed and
rough with age. Twigs are a shiny, reddish-brown. Sugar maple is relatively
deep-rooted, with many extensively-branched laterals. Sugar maple is
monoecious or dioecious. Small, greenish-yellow flowers are borne in
tassellike clusters or racemes. Each drooping cluster contains 8 to 14
flowers. Fruit is a paired, papery-winged samara which averages 1 inch
(2.5 cm) in length.
REGENERATION PROCESSES: Sugar maple reproduces through seed
and by vegetative means.
Sugar maple possesses extremely effective outbreeding mechanisms, and
flowers are readily wind pollinated. Minimum seed-bearing age is 30 to 40
years. Forty- to sixty-year-old trees with 8-inch (20 cm) d.b.h. produce
light crops, whereas 70- to 100-year-old trees with d.b.h. of 10 to 14 inches
(25-36 cm) produce moderate seed crops. Large fluctuations in annual seed
crops have been reported. Seed production is partly dependent on genetic
factors, and some trees produce an abundance of flowers nearly every year.
In north-central Wisconsin, good or better crops are produced at 1- to 4-
year intervals. Elsewhere in the United States, good crops occur at 2- to
5-year intervals, and in Canada, at 3- to 7-year intervals. In good crop
years, 264 seeds per meter square may be produced.
Seed is primarily dispersed by wind, which can carry the relatively large
seeds for up to 330 feet (100 m). However, most seeds do not travel more
than 49 feet (15 m) from the forest edge. Some sugar maple seed may also
be dispersed by water.
Seedling recruitment varies annually; periodic high seedling densities may
function as a predator avoidance mechanism. In favorable years seedling
recruitment may reach 18.7 seedlings per meter square, but in poor years
no seedling recruitment occurs. Seedlings can survive for long periods
when suppressed beneath a forest canopy and respond quickly to release.
Seedlings in very dense young stands may survive for only 5 years, but in
stands where trees average 10 inches (25 cm) or more in d.b.h., seedlings
commonly persist for many years. Initial seedling growth is slow, and
mortality is often high.
Sugar maple is a prolific sprouter in the northern part of its range, but at
the southern edge of its range, it sprouts less vigorously than associated
hardwoods. Stump-sprouting and root-sprouting are moderately common.
Layering occasionally occurs.
SITE CHARACTERISTICS: Sugar maple most commonly occurs in rich,
mesic woods but also grows in drier upland woods. It grows in level areas or
in coves and other sheltered locations on adjacent lower slopes. Sugar maple
is often associated with stream terraces, streambanks, valleys, canyons,
ravines, and wooded natural levees. It is occasionally found on dry rocky
hillsides. At the western edge of its range, sugar maple grows as scattered
canopy seed trees or as abundant seedlings in protected ravines and
relatively mesic north-facing slopes. It is a prominent component of mesic
hardwood forests, Great Lakes pine forests, spruce-fir forests, and northern
hardwood forests. Sugar maple forms pure stands but also grows mixed
with other hardwoods and scattered conifers.
Common associates include American basswood, yellow birch (Betula alleghaniensis), black cherry (Prunus serotina), red spruce (Picea rubens),
white spruce (Picea glauca), beech, eastern white pine (Pinus strobus),
eastern hemlock (Tsuga canadensis), northern red oak (Quercus rubra),
white oak (Quercus alba), and yellow-poplar (Liriodendron tulipifera).
Understory associates of sugar maple are both varied and numerous.
Common shrub associates include beaked hazel (Corylus cornuta), Atlantic
leatherwood (Dirca palustris), redberry elder (Sambucus pubens), alternate
-leaf dogwood (Cornus alternifolia), dwarf bush-honeysuckle (Diervilla
lonicera), Canada yew (Taxus canadensis), red raspberry (Rubus idaeus),
and blackberries (Rubus spp.). Springbeauty (Claytonia caroliniana),
large-flowered trillium (Trillium grandiflorum), anemone (Anemone spp.)
marsh blue violet (Viola cucullata), downy yellow violet (Viola pubescens),
Solomon's-seal (Polygonatum pubescens), false Solomon's-seal (Smilacina
stellata), sweet cicely (Osmorhiza spp.), adderstongue (Ophioglossom
vulgatum), jack-in-the-pulpit (Arisaema atrorubens), clubmosses
(Lycopodium spp.), and largeleaf aster (Aster macrophyllus).
Sugar maple can grow on a wide variety of soils, but typically grows best on
deep, moist, fertile, well-drained soils. It grows on sand, loamy sand, sandy
loam, silty loam, and loam. Sugar maple is commonly associated with alluvial
or calcareous soils but also grows on stabilized dunes. This tree is intolerant
of flooded soils and generally grows poorly on dry, shallow soils. In parts of
New England, sugar maple commonly grows on soils rich in organics. Sugar
maple occurs on strongly acidic (pH=3.7) to slightly alkaline (pH=7.3) soils
but grows best where soil pH ranges from 5.5 to 7.3. Soils are derived from
a variety of parent materials including shale, limestone, and sandstone.
In the southern and southwestern portions of its range, sugar maple
generally grows at intermediate elevations.
SUCCESSIONAL STATUS: Sugar maple is very tolerant of shade and
can persist for long periods beneath a dense forest canopy. It is noted for
its ability to quickly occupy gaps created in the forest canopy. A bank of
abundant seedlings remains suppressed until gaps are created by windfall
or other disturbances. Seedlings and saplings typically respond vigorously
and rapidly to release and can overtop competitors such as northern red
oak. Openings or gaps in the canopy allow more nutrients, light, and water
to become available. In many areas, sugar maple is a dominant species in
gaps created by dying American elms. Sugar maple is generally regarded as
a late seral or climax species in many eastern deciduous forests. In the
absence of disturbance, forests composed of jack pine, eastern white pine,
eastern hemlock, yellow birch, or red pine are replaced by sugar maple and
American basswood. However, it should be noted that disturbances, par-
ticularly fire, were common in eastern deciduous forests in presettlement
times. In some locations, succession to sugar maple-American basswood
stands may have taken as long as 650 years.
SEASONAL DEVELOPMENT: Growth initiation of sugar maple
varies geographically. Flower buds generally begin to swell prior to the
development of vegetative buds and generally emerge 1 to 2 weeks
before the leaves appear. Male and female flowers mature at slightly
different rates, which promotes cross-pollination. Fruit ripens
approximately 12 to 16 weeks after the flowers appear. Fruit begins to
fall approximately 2 weeks after ripening. Leaves turn yellow to orange
or deep red in the fall and generally drop just after seeds have fallen.
At the southern edge of the species' range, dead brown leaves tend to
remain on the trees through much of the winter. Trees from the northern
portion of the species' range become dormant earlier than do those from
GENERAL DISTRIBUTION: Sugar maple grows from Nova Scotia
and New Brunswick westward to Ontario and Manitoba, southward
through Minnesota, and eastern Kansas into northeastern Texas. It
extends eastward to Georgia and northward through the Appalachian
Mountains into New England. Local populations occur in northwestern
South Carolina, northern Georgia, and northeastern South Dakota.
Disjunct populations are known from the Wichita Mountains of
SKY MEADOWS DISTRIBUTION:
Tree specimens can be found on trails marked in red.
Appalachian Trail/Old Trail
South Ridge/North Ridge
Rolling Meadows/ Lost Mountain
HABITAT TYPES AND PLANT COMMUNITIES: Sugar maple
grows in a wide variety of plant communities throughout eastern North
America. It is a dominant or codominant in many northern hardwood and
mixed mesophytic communities. Common codominants include beech
(Fagus grandifolia), birch (Betula spp.), and American basswood (Tilia
IMPORTANCE AND USES: Sugar maple is commonly browsed by
white-tailed deer, moose, and snowshoe hare. In Nova Scotia and New
Brunswick, white-tailed deer and snowshoe hare use is heaviest during
the winter. The red squirrel, gray squirrel, and flying squirrels feed on
the seeds, buds, twigs, and leaves of sugar maple. The porcupine consumes
the bark and can, in some instances, girdle the upper stem. Sugar maple is
at least somewhat palatable to deer in most areas. Samaras are palatable
to squirrels and many other small mammals.
Numerous species of songbirds nest in sugar maple. Cavity nesters such
as the black-capped chickadee excavate nest cavities or utilize preexisting
cavities. The common flicker, pileated woodpecker, and screech owl also
nest in maples.
Sugar maple has potential value for rehabilitation of disturbed sites.
Sugar maple wood is tough, durable, hard, heavy, and strong. It is well
suited for many uses and is commonly used to make furniture, paneling,
flooring, and veneer. It is also used for gunstocks, tool handles, plywood
dies, cutting blocks, woodenware, novelty products, sporting goods, bowling
pins, and musical instruments.
Sugar maple is the primary source of maple sugar and syrup. The maple
syrup industry is important throughout much of eastern North America
and accounted for more than 100 million dollars in trade during 1989.
Maple sugar and syrup were used as trade items by many Native
Sugar maple is an attractive shade tree and is widely planted as an
ornamental. It is sometimes used in shelterbelt plantings.
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