silver maple (Acer saccharinum)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

COMMON NAMES:
silver maple
soft maple

 

SCIENTIFIC SYNONYMS:
Acer sacchatum Mill.
Acer dasycarpum Ehrh.
Acer saccharinum var. laciniatum Pax
Acer saccharinum var. wieri Rehd.
Argentacer saccharinum (L.) Small

 

CONFIRMATION STATUS: Confirmed.

 

TAXONOMY: The currently accepted scientific name for silver maple
is Acer saccharinum L. There are no currently accepted infrataxa. Hybrids
(Acer X fremanii Murr.) with red maple (Acer rubrum) have been reported.

 

NATIVE STATUS: Native, United States and Canada.

 

GENERAL BOTANICAL CHARACTERISTICS: Silver maple is a
native, deciduous, medium-sized tree.  Mature height ranges from 90 to
120 feet (27-36 m). Silver maple is characterized as a fast growing species.
The trunk is often separated into several upright branches near the ground.
The crown is usually open and rounded. The bark of young stems is smooth;
it becomes darker and furrowed to flaky on older stems. The root system is
shallow and fibrous.  The deepest roots of 35-year-old silver maples planted
on clay soil in North Dakota were 55 inches (139.7 cm).  The longest roots
extended horizontally 49 feet (14.9 m).  The fruit is a winged samara, 1.4 to
1.9 inch (3.5-5 cm) long and up to 0.48 inch (12 mm) wide.

 

Silver maples can live to 130 years or longer. The national champion silver
maple (1972) was found in Michigan.  It was 125 feet (38.1 m) tall, 22.58
feet (82.6 m) in circumference, and had a crown spread of 111 feet (33.8 m).

 

REGENERATION PROCESS: The minimum seed bearing age for sil-
ver maple is 11 years.  Large seed crops are produced annually. The fruits
are primarily wind dispersed, with a minor amount of water dispersal. Re-
lease of fruits is dependent on relatively high wind speeds, ensuring long
distance dispersal. The seeds germinate immediately upon dispersal.

Natural regeneration is most successful on moist mineral soil with consid-
erable organic matter.  Silver maple seed also germinates well on moist
litter.  Seedling establishment requires full sun, but subsequent growth is
best with partial shade.  Seedlings are often stunted in saturated soils, but
can recover when soil moisture drops.  In Wisconsin, silver maple seedlings
were found with higher frequency in the spring than in the fall.

 

Silver maple can be propagated from cuttings and bud grafts, and by layer-
ing.  It sprouts prolifically from the stump or root crown.  The best sprout-
ing occurs from stumps less than 12 inches (30 cm) in diameter.  Larger
trees tend to lose the ability to sprout.

 

SITE CHARACTERISTICS: Silver maple is typical of wet bottomlands,
riverbanks, and lake edges. It is less common on upland sites. In Illinois,

silver maple was reported only from bottonland wet-mesic sites; it did not
occur on drier sites of even slightly higher elevation. In New York, silver
maple occurs on limestone, outwash, and alluvial soils. Best growth is on
moist, well-drained, fine-textured alluvial soil. Silver maple is found from
100 feet (30.5 m) to 1,600 feet (488 m) elevation in the Adirondacks, and
is uncommon above 1,980 feet (600 m) elevation in the Appalachians. In
drier areas silver maple is only found along streams.

 

Silver maple is usually found on soils with pH above 4.0, but has been
reported from muck and shallow peat soils with a pH from 2.0 to 3.3.

Silver maple is intermediate in tolerance to water-saturated soils, but can
tolerate prolonged periods of inundation.  It is a member of some greentree
reservoir systems that are flooded during the dormant season to provide
waterfowl habitat and drained before the onset of the growing season.
These sites usually have saturated soils most of the growing season.
Silver maple seedlings survived 60 days of continuously saturated soils,
but seedlings of low vigor died after only 2 days of complete inundation.

 

The shade tolerance of silver maple is not well defined. It ranges from
moderately tolerant to very intolerant of shade, depending on site quality
and location.  Silver maple tends to be more shade tolerant on good sites
and less tolerant on poor sites.

 

SUCCESSIONAL STATUS: Silver maple is a dominant species in elm-
ash-cottonwood forest types which are pioneer to intermediate in succes-
sion.  These forests cannot be maintained without management or natural
disturbance.  The silver maple-American elm type is usually a subclimax
type, following willows and eastern cottonwood.  The type is described as
climax for southern Ontario, where it regenerates in willow and red-osier
dogwood thickets.

 

Silver maple is one of a number of species that follow eastern cottonwood to
form a mixed hardwood bottomland community.  It is described as an early,
fast-growing species.  In a northern Missouri floodplain community, in plots
where silver maple was the most important overstory species, there were
many large silver maples in the understory.  Silver maple will probably re-
main the canopy dominant for some time since there are also large old east-
ern cottonwoods present, which, when they die, will create openings large
enough for silver maple seedling establishment.  Similarly, the presence of
American elms will allow new silver maple establishment if they succumb
to Dutch elm disease (as is likely).  Numerous silver maple seedlings and
saplings were present in a silver maple dominated forest on the Wabash
River in Illinois and Indiana, which should ensure the continued dominance
of silver maple on this site for so me time.

 

Silver maple is typically found in riparian forests which are more or less fre-
quently disturbed by floods.  It is also found both on sites that have been
disturbed by stream channelization projects. It forms stands at low eleva-
tions where new alluvium has been deposited and will colonize bottomland
clearings and adjacent slopes. Silver maple was present on 28-year-old and
40-year-old abandoned agricultural clearings in western Tennessee. It in-
vades sedge (Carex spp.)  meadows in northern Wisconsin and southern
Quebec. Silver maple invades cutover areas when seed sources are present.

Silver maple was a member of a plant community that established on a
small, frequently flooded island in Wisconsin. On this island, silver maple
was quite common and there was a relatively large number of silver maple
seedlings. Most of the large silver maple stems were of sprout origin, and
overall mortality rate for silver maple was lower than that for most other
species. Apparently, flood damage breaks off aboveground portions of sil-
ver maple. The remaining stems sprout vigorously and may therefore in-
crease in number after such damage. The largest stems of all species were
found on the downstream end of the island, where they experienced less
destructive disturbance.

 

SEASONAL DEVELOPMENT: Silver maple is one of the earliest
flowering species within its range; flowering occurs over a short period
from late February to April or May, depending on latitude. All flowers
on one individual are within a day or so of each other in development;
the period of pollen receptivity lasts from a few days to a week. The
flowers often fall before the leaves are fully grown. The seeds ripen and
are released over a very short period, usually less than 2 weeks from
April to June. Germination usually occurs shortly after dispersal.

 

GENERAL DISTRIBUTION: The range of silver maple extends from
New Brunswick to west to northern Michigan, northern Wisconsin and
northern Minnesota; south to southeastern South Dakota and eastern
Oklahoma; east to northern Georgia; and north through western South
Carolina and western North Carolina to Maine.  It is found in northwest-
ern Florida on the Apalachicola and Choctawhatchee rivers but is not
otherwise found on the Gulf or Atlantic Coastal Plain.

 

SKY MEADOWS DISTRIBUTION:

 

Tree specimens can be found on trails marked in red.

 

       Bleak House
       Appalachian Trail/Old Trail
       South Ridge/North Ridge
       Gap Run
       Snowden
       Woodpecker Lane

       Sherman's Mill
       Rolling Meadows/ Lost Mountain
       Fish Pond

 

HABITAT TYPES AND PLANT COMMUNITIES: Silver maple is a
dominant canopy species only in streamside communities and lake fringes,
and occasionally in swamps, gullies, and small depressions of slow drainage.
The elm-ash-cottonwood type is defined as bottomland forest in which elms
(Ulmus spp.), green ash (Fraxinus pennsylvanica), eastern cottonwood
(Populus deltoides), silver maple, or red maple comprise a plurality of the
stocking.

 

Silver maple and/or American elm (Ulmus americana) are usually the
dominant tree species in southern Wisconsin floodplain forests. In Illinois,
silver maple was the leading dominant on floodplain sites that were flooded
at least 25 percent of the time. With increased elevation other species
increased, although silver maple continued to be dominant on sites that
were flooded 3 to 5 percent of the time. Silver maple, sycamore (Platanus
occidentalis), and green ash communities occurred at the lowest elevations;
silver maple, sycamore, green ash, American elm, hackberry (Celtis occi-
dentalis), and other species were found at higher elevations. In central
New York, silver maple-green ash swamps are relatively low in species
diversity and density.  Silver maple dominance decreases with decreasing
latitude; it is relatively rare in many southern floodplain forests.

 

In the Central Forest Region, understory associates of silver maple include
willows (Salix spp.), redberry elder (Sambucus pubens), red-osier dogwood
(Cornus sericea), and greenbriers (Smilax spp.).  In the Northern Forest
Region associates include swamp white oak (Quercus bicolor), sycamore,
pin oak (Quercus palustrus), black tupelo (Nyssa sylvatica), and eastern
cottonwood.  In New England and eastern Canada, associates include sweet
birch (Betula lenta), paper birch (Betula papyrifera), and gray birch
(Betula populifolia).  In New York, associates include white ash (Fraxinus
americana), slippery elm (Ulmus rubra), rock elm (Ulmus thomassii),
yellow birch (Betula allegheniensis), black tupelo, sycamore, eastern hem-
lock (Tsuga canadensis), bur oak (Quercus macrocarpa), and swamp
white oak. In the elm-ash-cottonwood type, other associates include black
willow (Salix niger), boxelder (Acer negundo), and sycamore.

 

IMPORTANCE AND USES: Silver maple produces abundant annual
seed crops; the seeds are eaten by many birds, including evening gros-
beaks, finches, wild turkeys and other game birds, and small mammals,
especially squirrels and chipmunks. Silver maple seeds were the most
important food in the diet of breeding wood ducks in southeastern Miss-
ouri. The early buds of silver maple are an important food for squirrels
when cached food is depleted. Silver maple bark ranks high as a food
source for beavers in southeastern Ohio. White-tailed deer and rabbits
browse the foliage.

 

In New Brunswick, wood ducks and goldeneyes frequently nest in silver
maples. The soft wood of silver maple has a tendency to develop cavities
which are used by cavity-nesting birds and mammals, and which otherwise
provide shelter for a number of species including raccoons, opossums,
squirrels, owls, and woodpeckers. Silver maple was one of a few species
of deciduous trees used as communal roosts by red-winged blackbirds,
common grackles, starlings, and brown-headed cowbirds in Ohio.

 

Silver maple groves and the riparian communities in which silver maple
occurs are excellent habitat for wildlife.  Silver maple is a dominant mem-
ber of riparian communities in Indiana that are important to the endan-
gered Indiana bat.  However, it was not listed as a species in which mater-
nity colonies were observed.  Silver maple is often a dominant member of
seasonally flooded flats, which are important to tree- and shrub-nesting
species, colony-nesting waterbirds, and passerines.  It also occurs in wood-
ed swamps and other riparian communities which are valuable breeding
habitat for wood ducks, black ducks, herons, egrets, warblers, flycatchers,
woodpeckers, thrushes, nuthatches, vireos, rose-breasted grosbeaks,
hawks, owls, grackles, and many passerines.

 

In the Appalachian Mountains, succession on strip-mined lands can include
silver maple if a seed source is present.  Silver maple was planted on sur-
face-mined lands in Indiana between 1928 and 1975, and was listed sixth
(in order of number planted) out of 26 hardwood species that were used
for surface mine afforestation.

 

Silver maple wood is moderately hard, brittle, and close-grained. It is not
as heavy or hard as that of sugar maple (Acer saccharum). Silver maple
wood is used for furniture, boxes, crates, food containers, paneling, and
core stock.  Silver maple is cut and sold with red maple as 'soft maple' lum-
ber.  It is a valued timber species in the Midwest, and may prove to be
equally valuable in the Northeast.

 

On good sites silver maple can be managed for timber. On poor sites, it
can be managed for cordwood.  It has potential for short-rotation inten-
sive cropping sytems for woody fuel biomass plantations.

 

Silver maple has been planted as an ornamental, but the limbs are easily
broken in ice and snow storms.  Its use as an ornamental has declined due
to frequent breakage, tendency to rot, and prolific sprouting.  The shallow
roots invade water systems, the seeds are a nuisance, and it sheds a lot of
twigs.

 

Silver maple sap can be used to make maple syrup.

 

 

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