Aceraceae -- Maple family
Russell S. Walters and Harry W. Yawney
Red maple (Acer rubrum) is also known as scarlet maple, swamp maple, soft maple, Carolina red maple, Drummond red maple, and water maple (33). Many foresters consider the tree inferior and undesirable because it is often poorly formed and defective, especially on poor sites. On good sites, however, it may grow fast with good form and quality for saw logs. Red maple is a subclimax species that can occupy overstory space but is usually replaced by other species. It is classed as shade tolerant and as a prolific sprouter. It has great ecological amplitude from sea level to about 900 m (3,000 ft) and grows over a wide range of microhabitat sites. It ranks high as a shade tree for landscapes.
Red maple grows up to 20 m tall, usually with a narrow compact crown, and may occur singly or in a clump of stems that resprouted from a single stump after cutting or fire. Young bark is smooth, thin, and gray; older trees develop furrowed bark with scaly or even shaggy ridges. Leaves are deciduous, opposite, with blades 6-10 cm long and usually about as wide, with 3 to 5 shallow short-pointed and serrate or toothed lobes. Flowers are pink to red, in fascicles (clusters) or drooping racemes. Individual trees are monoecious (male and female flowers on separated trees) or bisexual (male and female flowers on the same tree, or segregated by branches within the tree—technically polygamo-dioecious). Fruits are paired samaras (winged nutlets) 2-2.5 cm long, clustered on long stalks (Wikipedia 2011).
Red maple is one of the most widely distributed trees in eastern North America (see distribution map). It tolerates a wide variety of soil types and site conditions, ranging from swamps and poorly drained soils to drier uplands, savannas, sandy dunes, and barrens (Barnes and Wagner 2004, Burns and Honkala 1990, Michigan Flora Online 2011). It is widely planted as a shade tree and in parks, with more than 50 cultivars that vary in leaf shape, fall color, and tree form (Van Geldrin et al. 2010). It has various timber uses, can yield maple syrup (but less than sugar maple), and was used by Native Americans and pioneers for medicinal and other purposes (see uses).
Red maple has increased dramatically in abundance and distribution since the early 1800s, when early settlement records suggest that it was restricted to swampy sites. Fire suppression has allowed it to gain a competitive advantage and replace oaks in drier upland forests (Abrams 1998). It is a “supergeneralist” that can act as a pioneer species, quickly colonizing disturbed and cut-over sites, but capable of dominating later in succession (Abrams 1998). It is browsed less by deer and defoliated less by gypsy moths than oak species; the differential damage may indirectly benefit the red maple (Abrams 1998, Jedlicka et al. 2004). Its increased abundance may also be linked to the decline of Ulmus americana (American elm) from Dutch elm disease, and of Castanea dentata (American chestnut) from blight. By 2002, red maple was one of the 10 most abundant tree species in U.S. forests (FIA 2011). Its distribution has been further increased due to frequent naturalization from horticultural plantings.
Red maple leaves, twig, bark, and/or fruits are a food source for numerous mammals, birds, and insects. However, red maple leaves are extremely toxic to horses (Wikipedia 2011).
Acer rubrum L.
Mesic pine savannas (MPS-CP), wet pine flatwoods (WPF-T), wet pine savannas (SPS-T, SPS-RF, WLPS, VWLPS), roadsides.
Abundant. Jan–Mar ; Apr–Jul . If one chooses to recognize varieties within Acer rubrum , the specimens collected by the senior author are referable to var. Acer rubrum trilobum Torr. & A. Gray ex K. Koch. Thornhill 80, 265, 281 (NCSC). Specimens seen in the vicinity: Sandy Run [Hancock]: Taggart SARU 8 (WNC!; as Acer rubrum var. trilobum ); Sandy Run [Neck]: Wilbur 67089 (DUKE!). [= RAB;> Acer rubrum L. various varieties sensu Weakley]
General: Maple Family (Aceraceae). A native tree growing to 20 m tall, usually with a narrow compact crown, single-boled, or often in clumps of stems from one stump due to prolific sprouting; bark gray and thin, becoming furrowed into long narrow scaly ridges on older trunks and branches. The leaves are deciduous, opposite, long-petioled, blades 6-10 cm long and usually about as wide, with 3 shallow short-pointed lobes, sometimes with two smaller lobes near the base, dull green and smooth above, lighter green or silvery beneath and more or less hairy. The flowers are pink to dark red, about 3 mm long, the male (staminate) flowers fascicled and the female (pistillate) flowers in drooping racemes. The flowers appear to be bisexual but they are functionally male or female, and individual trees may be all male or all female or some trees may have both types, each type on a separate branch (the species technically polygamo-dioecious), or the flowers may be functionally bisexual. Fruits: winged nutlets (samaras) in a pair, 2-2.5 cm long, clustered on long stalks, red to red-brown. The common name is in reference to the red twigs, buds, flowers, and fall leaves.
Variation within the species: Red maple is highly variable and many varieties and forms have been identified. The following varieties are commonly recognized:
Var. drummondii (Hook. & Arn. ex Nutt.) Sarg.
Var. trilobum Torr. & Gray ex K. Koch
Red maple forms natural hybrids with silver maple (A. saccharinum): Acer X freemanii E. Murray.
Distribution: Red maple is one of the most widely distributed trees in eastern North America, extending from Newfoundland and Nova Scotia west to southern Ontario, Minnesota, Wisconsin, and Illinois, then south through Missouri, eastern Oklahoma, and southern Texas, and east to southern Florida. Its distribution has been increased past its native range through broad cultivation and naturalization of the cultivated forms.
Range and Habitat in Illinois
Regularity: Regularly occurring
Regularity: Regularly occurring
Global Range: Common tree species in eastern N. America; Nfld., Quebec, Ont., and Minn., south to Fla., and west to eastern Tex.
Occurrence in North America
LA ME MA MD MI MN MS MO NH NJ
NY NC OH OK PA RI SC TN TX VT
VA WV WI MB NB NF NS ON PQ
America . Its range extends from Newfoundland and Nova Scotia west
to southern Ontario, Minnesota, Wisconsin, and Illinois; south through
Missouri, eastern Oklahoma, and southern Texas; and east to southern
Florida . It is conspicuously absent from the bottomland forests of
the Corn Belt in the Prairie Peninsula of the Midwest, the coastal
prairies of southern Louisiana and southeastern Texas, and the swamp
prairie of the Florida everglades . It is cultivated in Hawaii .
Red maple is also one of the most successful and abundant species in the Eastern Deciduous Forest, arguably the most abundant, reproducing aggressively by seeds and sprouts after fire, logging, and abandonment of farmland. It is most abundant on bottomlands and is tolerant of waterlogged soils and flooding, but it is a “supergeneralist,” growing on the widest variety of sites and in the greatest range of conditions (sunny or shady, high or low nutrients, dry or moist) of any North American species, from 0-900 meters. Because red maple grows well in shade, is a key late-successional species, but it also is a successful early successional invader of disturbed sites. “It will probably continue to increase in dominance in the overstory during the next century, causing widespread replacement of the historically dominant trees of the forests of the eastern United States” (Abrams 1998, p. 355). Fire suppression has contributed greatly to the spread of red maple (the thin bark makes it highly susceptible to fire damage) but no single trait is responsible for its success.
Flowering: (February-)March-April, before the vegetative buds, one of the first trees to flower in the spring; fruiting: April-June, before leaf development is complete.
Red maple is a deciduous tree that grows 30 to 90 feet (9-28 m) tall and
up to 4 feet (1.6 m) in diameter [16,25]. The bark is smooth and gray
but darkens and becomes furrowed in narrow ridges with age [16,38].
Twigs are stout and shiny red to grayish brown .
The small, fragrant flowers are borne in slender-stalked, drooping,
axillary clusters [8,16,24,49]. The fruit is a paired, winged samara,
approximately 0.75 inch (1.9 cm) long . Samaras are red, pink, or
Range and Habitat in Illinois
Comments: Moist, deep, rich soils of ravines and coves; variety of soil and forest types; swamps; dry uplands; sea level-1400m.
Red maple grows throughout throughout much of the deciduous forest of
eastern North America and into the fringes of the boreal forest .
It occurs on a variety of wet to dry sites in dense woods and in
openings . Red maple grows in low, rich woods, along the margins of
lakes, marshes, and swamps, in hammocks, wet thickets, and on
floodplains and stream terraces [13,17,24,79,82]. Red maple also occurs
in drier upland woodlands, low-elevation cove forests, dry sandy plains,
and on stable dunes [24,38,96]. Red maple is a common dominant in many
forest types and is considered a major species or associate in more that
56 cover types . In much of the Northeast it grows as an overstory
dominant only in swamps and other wet sites . Red maple grows in
association with more than 70 important tree species.
Soils: Red maple does well on a wider range of soil types, textures,
moisture regimes, and pH than does any other forest species in North
America . It develops best on moist, fertile, loamy soils  but
also grows on a variety of dry, rocky, upland soils . Red maple
grows on soils derived from a variety of parent materials, including
granite, shales, slates, gneisses, schists, sandstone, limestone,
conlgomerates, and quartzites . It also occurs on a variety of
lacustrine sediments, glacial till, and glacial outwash .
Elevation: Red maple grows from sea level to 3,000 feet (0-900 m) in
elevation . Elevational ranges by geographic location are as
Location Elevation Authority
s Appalachians up to 5,904 feet (1,800 m) Duncan & Duncan 1988
White Mountains, NH 1,968 to 2,778 feet (600-850 m) Leak & Graber 1974
Key Plant Community Associations
Red maple occurs as a dominant or codominant in several eastern
deciduous forests and deciduous swamp communities with black ash
(Fraxinus nigra), yellow birch (Betula alleghaniensis), northern red oak
(Quercus rubra), black oak ( Q. velutinus), aspen (Populus tremuloides),
and elm (Ulmus spp.). In mesic upland communities of the Southeast, it
grows as an overstory dominant with sweetgum (Liquidambar styraciflua)
and water oak (Quercus palustris). Red maple has been included as an
indicator or dominant in the following community type (cts) and plant
association (pas) classifications:
Location Classification Authority
AL forest cts Golden 1979
MA forest pas Spurr 1956
se MI deciduous swamp cts Barnes 1976
s MI forest cts Hammitt & Barnes 1989
NY forest cts Glitzenstein & others 1990
s ON general veg. cts Smith & others 1975
Habitat: Cover Types
This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
More info for the term: swamp
5 Balsam fir
12 Black spruce
14 Northern pin oak
17 Pin cherry
18 Paper birch
19 Gray birch - red maple
20 White pine - northern red oak - red maple
21 Eastern white pine
22 White pine - hemlock
23 Eastern hemlock
24 Hemlock - yellow birch
25 Sugar maple - beech - yellow birch
26 Sugar maple - basswood
27 Sugar maple
28 Black cherry - maple
30 Red spruce - yellow birch
31 Red spruce - sugar maple - beech
32 Red spruce
33 Red spruce - balsam fir
37 Northern white-cedar
39 Black ash - American elm - red maple
43 Bear oak
44 Chestnut oak
45 Pitch pine
46 Eastern redcedar
52 White oak - black oak - northern red oak
53 White oak
55 Northern red oak
59 Yellow-poplar - white oak - northern red oak
61 River birch - sycamore
62 Silver maple - American elm
65 Pin oak - sweetgum
73 Southern redcedar
74 Cabbage palmetto
75 Shortleaf pine
76 Shortleaf pine - oak
78 Virginia pine - oak
79 Virginia pine
81 Loblolly pine
82 Loblolly pine - hardwood
85 Slash pine - hardwood
87 Sweetgum - yellow-poplar
88 Willow oak - water oak - diamondleaf (laurel) oak
92 Sweetgum - willow oak
93 Sugarberry - American elm - green ash
95 Black willow
96 Overcup oak - water hickory
97 Atlantic white-cedar
98 Pond pine
103 Water tupelo - swamp tupelo
104 Sweetbay - swamp tupelo - redbay
108 Red maple
110 Black oak
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
K081 Oak savanna
K093 Great Lakes spruce - fir forest
K095 Great Lakes pine forest
K096 Northeastern spruce - fir forest
K097 Southeastern spruce - fir forest
K098 Northern floodplain forest
K099 Maple - basswood forest
K100 Oak - hickory forest
K101 Elm - ash forest
K102 Beech - maple forest
K103 Mixed mesophytic forest
K104 Appalachian oak forest
K106 Northern hardwoods (seral stages)
K107 Northern hardwoods - fir forest (seral stages)
K108 Northern hardwoods - spruce forest (seral stages)
K110 Northeastern oak - pine forest
K111 Oak - hickory - pine forest
K112 Southern mixed forest
K113 Southern floodplain forest
This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):
FRES10 White - red - jack pine
FRES11 Spruce - fir
FRES13 Loblolly - shortleaf pine
FRES14 Oak - pine
FRES15 Oak - hickory
FRES16 Oak - gum - cypress
FRES17 Elm - ash - cottonwood
FRES18 Maple - beech - birch
FRES19 Aspen - birch
Soils and Topography
Red maple grows on diverse sites, from dry ridges and southwest slopes to peat bogs and swamps. It commonly grows under the more extreme soil-moisture conditions either very wet or quite dry. The species does not show a strong affinity for either a north or a south aspect (48). Although it develops best on moderately well-drained, moist sites at low to intermediate elevations, it is common in mountainous country on the drier ridges and on south and west exposures of upper slopes. It is also common, however, in swampy areas, on slow-draining flats and depressions, and along small sluggish streams (26). In upper Michigan and New England, red maple grows on ridge tops and dry sandy or rocky upland soils and in almost pure stands on moist soils and swamp borders (13,40). In the extreme south, red maple is almost exclusively a swamp species.
Red maple is a prolific seed producer and trees as young as four years may begin to bear seeds. Good seed crops are usually produced in alternate years. Seedbed requirements are minimal and up to 95% of viable seeds germinate in the first 10 days; some survive in the duff and germinate the following year. Because the mature seeds are dispersed in spring and can germinate immediately, seedlings can become established with a 3-4 month advantage over most associated woody species. A bank of persistent seedlings often accumulates beneath a forest canopy.
Seedlings can survive 3-5 years of moderate shade, but establishment and early growth are best after disturbance. Male (staminate) trees may grow faster than female ones. Average longevity for red maple is about 80-100 years, but trees are known to reach 200 years of age.
Vegetative reproduction under natural conditions is common from sprouts from the stump or root crown or root suckers after fire or mechanical damage. Buds located at the base of stems commonly sprout 2-6 weeks after the stem is cut.
fruitbody of Pholiota aurivella is saprobic on dead, fallen, decayed trunk (large) of Acer rubrum
Associated Forest Cover
The red maple is most common in New England, Middle Atlantic States, upper Michigan, and northeast Wisconsin. It is rare farther west and south. Recognition of red maple as a separate cover type generally is attributed to disturbances that allowed red maple residuals to respond rapidly. The elimination of elm (Ulmus americana and U. thomasii) by Dutch elm disease and of the American chestnut (Castanea dentata) by the blight, and selective removal of yellow birch (Betula alleghaniensis) and sugar maple (Acer saccharum) have contributed to increasing the proportion of red maple stocking in many stands (13,40,48).
Throughout its range, red maple is associated with more than 70 different commercial tree species (26). Its more common associates from the north to the south include red spruce (Picea rubens), balsam fir (Abies balsamea), white pine (Pinus strobus), sugar maple, beech (Fagus grandifolia), yellow birch, paper birch (Betula papyrifera), gray birch (B. populifolia), sweet birch (B. lenta), eastern hemlock (Tsuga canadensis), eastern hophornbeam (Ostrya virginiana), striped maple (Acer pensylvanicum), northern white-cedar (Thuja occidentalis), aspen (Populus grandidentata and P. tremuloides), black ash (Fraxinus nigra), pin cherry (Prunus pensylvanica), black cherry (P serotina), northern red oak (Quercus rubra), American elm, chestnut oak (Q. prinus), Virginia pine (Pinus virginiana), yellow-poplar (Liriodendron tulipifera), silver maple (Acer saccharinum), black gum (Nyssa sylvatica), swamp white oak (Quercus bicolor), and loblolly pine (Pinus taeda) (13).
Diseases and Parasites
Sprout clumps present some serious problems. More defects originate from branch stubs on the sprout stems than from the parent stump (43). Inonotus glomeratus can infect branch stubs and wounds above the butt in red maple. Nevertheless, a red maple sprout with only a slightly defective base and small and well-healed branch stubs has a potential for high future value. Criteria for selecting red maple sprouts for thinning are (1) select only stems with small, well-healed branch stubs, (2) reject sprout clumps with defective bases, and (3) cut all but one or two of the best dominant stem sprouts (50).
Many trunk rot fungi and stem diseases attack red maple. Inonotus glomeratus infects branch stubs and wounds on the stem and is most important. Second in importance is Oxyporus populinus, which forms a small, white fruit body that often has moss growing on top. Phellinus igniarius is another leading heart rot of red maple. Red maple may also be cankered by species of Nectria, Eutypella, Hypoxylon, Schizoxylon, Strumella, and others (48).
Red maple is susceptible to many leaf diseases, generally of minor importance. It is seldom or seriously damaged by root diseases, although Armillana mellea can enter through root or butt wounds. However, A. mellea kills only trees already weakened from other causes (18).
Mechanical injury is a common source of defect in hardwoods, and red maple is especially sensitive to wounding. Often, large areas of cambium surrounding the wound will die back. In shade tree maintenance, wound dressings have not proven effective in stimulating wound closure or internal compartmentalization of the damaged area (44). Increment boring causes discoloration and may lead to decay in red maple. Callus growth, when established, is reasonably rapid, but an extra year or two often is needed if cambial dieback has been extensive around the wound (26). Red maple was rated intermediate with respect to amount of damage after a severe glaze storm in Pennsylvania. In one study, major damage was sustained by 41 percent of the black cherry, 16 percent of the red maple, and 5 percent of the hemlock (18).
Many different insects feed on red maple, but probably none of them kill healthy trees. They do reduce vigor and growth leaving the tree more susceptible to attack from fungi. Insect feeding also may hasten the death of weakened trees. Susceptibility to insect attack is illustrated by a study in the Piedmont. Of 40 species investigated, red maple had the highest percentage (79 percent) of insect attacks. Among the more important borers attacking red maple were the gallmaking maple borer (Xylotreehus aceris), the maple callus borer (Synanthedon acerni), and the Columbian timber beetle (Corthylus columbianus). The common scale insects included the cottony maple scale (Pulvinaria vitis), the maple leaf scale (P acericola), and the oystershell scale (Lepidosaphes ulmi). The common leaf feeding moths were the gypsy moth (Lymantria dispar), the linden looper (Erannis tiliaria), the elm spanworm (Ennomos subsignaria), and the red maple spanworm (Itame pustularia). The forest tent caterpillar (Malacosoma disstria) avoids red maple, however (26).
Red maple is very sensitive to fire injury, and even large trees can be killed by a fire of moderate intensity. The fire-killed trees sprout vigorously, however, and red maple may become a more important stand component after a fire than before one (26).
Red maple is a desirable deer food and reproduction may be almost completely suppressed in areas of excessive deer populations. Snowshoe hares may also reduce the amount of red maple reproduction (26).
If sapsuckers attack red maple, ringshake may develop (42). Sapsucker damage may also result in mortality Healthy as well as unhealthy trees are attacked and nearly 40 percent of the trees attacked may be killed (41).
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 81 to >300
Comments: Numerous EOs throughout its range.
Broad-scale Impacts of Plant Response to Fire
Red maple is reportedly common on burned lands in the Maritime Provinces
, boreal forests on northern Minnesota [12,51,96], and hardwood
forests of the Allegheny Mountains . However, it is rarely observed
on burned sites in Rhode Island  and was reported to be greatly
reduced by prescribed fire in northern Indiana woodlands .
On the George Washington National Forest, West Virginia, a spring prescribed
fire increased red maple density in a mixed-hardwood forest. Average red maple
seedling densities before fire and in postfire year 5 were 132 and 368
seedlings/acre, respectively; red maple sprout densities were 1,368
sprouts/acre before and 1,395 sprouts/acre 5 years after the fire. See the
Research Paper of Wendel and Smith's  study for details on the fire
prescription and fire effects on red maple and 6 other tree species.
The following Research Project Summaries
provide further information on prescribed
fire use and postfire response of plant
community species, including red
maple, that was not available when this
species review was originally
- Early postfire effects of a prescribed fire in the southern Appalachians
of North Carolina
- Early postfire response of southern Appalachian Table Mountain-pitch
pine stands to prescribed fires in North Carolina and Virginia
- Effects of experimental burning on understory plants in a temperate
deciduous forest in Ohio
- Effects of surface fires in a mixed red and eastern white pine stand
Plant Response to Fire
Fire can stimulate sprouting of dormant red maple buds located on the
root crown . Trees top-killed by fire often sprout vigorously and
assume increased prominence in postfire stands . Seedlings also
sprout and may produce dense sprout clumps following fire .
Regrowth following fire is often rapid. Regrowth begins during the
first month following summer and fall burns, and significant increases
in stem density occur by the third and fourth postfire months. Martin
 observed red maple sprouts 2 weeks after a July fire in Nova
Scotia. Red maple establishes through seed from June through August
. Postfire increases in stem density commonly promotes red maple's
dominance within a stand .
Broad-scale Impacts of Fire
Season of burn: Late spring or early summer burns are most damaging to
understory hardwoods such as red maple . A series of consecutive
annual late spring and early summer burns killed the rootstocks of
progressively more individuals; however, as many as five consecutive
annual winter burns had no effect on sprouting ability of top-killed
Bark: Bark of red maple is intermediate in resistance to fire .
Mean number of seconds required for the cambium to reach 140 degrees (60
deg C) (often considered a lethal temperature) are as follows :
Bark thickness Seconds
0.20 inch 20.0
0.30 inch 56.8
0.40 inch 117.6
Immediate Effect of Fire
Red maple is intolerant of fire; even large individuals can be killed by
moderate fires . Postfire mortality is relatively high for
saplings, but because bark becomes thicker and more fire-resistant with
age, mortality is much lower for sawtimber . The effects of fire
also vary with fire severity, season of burn, and various site factors.
survivor species; on-site surviving root crown or caudex
off-site colonizer; seed carried by wind; postfire yrs 1 and 2
Red maple is a common fire type in the Acadian Forest of New Brunswick,
where mean fire intervals have been estimated at 370 years . In the
New Jersey Pine Barrens, mean fire intervals averaged 20 years in the
early 1900's, but due to a variety of factors including fire suppression
and increased prescribed burning, now average 65 years . Red maple
regeneration in the Pine Barrens is favored in the absence of fire .
In upland oak forests of central Pennsylvania fire suppression has led
to the replacement of oaks by red maple, beech, black cherry, and sugar
Red maple has also increased in the absence of fire throughout much of
the Southeast . In parts of the Appalachians, fire suppression has
allowed maple stems to grow large enough and develop bark thick enough
to enable them to survive fires . As a result, restoration to
presettlement conditions would be "a very long-term process" .
Red maple sprouts vigorously from the root crown after aboveground
vegetation is killed by fire . Seedling establishment may also
More info for the terms: climax, tree
Red maple is characterized by a wide ecological amplitude and occupies a
wide range of successional stages [54,83]. It is moderately tolerant of
shade in the North but intolerant of shade in the Piedmont . Red
maple commonly grows as a subclimax or mid-seral species [20,97], but
characteristics such as vigorous sprouting, prolific seeding, and
ability to compete enable it to pioneer on a variety of disturbed sites
[54,97]. This tree lives longer than most seral species  but
generally does not persist in late successional stages . In
even-aged stands which develop after clearcutting, red maple is commonly
overtopped by faster growing species such as northern red oak . In
a few locations in the Southeast, it grows as a climax dominant in
wet-site communities .
Red maple commonly increases after disturbances such as windthrow,
clearcutting, or fire . In many locations, red maple has increased
in importance since presettlement times. Dutch elm disease and chestnut
blight have led to increases in the number of red maple stems in many
stands . In many parts of the East, red maple has increased in gaps
resulting from oak decline and gypsy moth infestations [43,65].
Seed: Red maple can bear seed as early as 4 years of age  and
produces good or better seed crops over most of its range in 1 out of 2
years . Bumper seed crops do occur. Trees are extremely prolific;
individual trees 2 to 8 inches (5-20 cm) in diameter commonly produce
12,000 to 91,000 seeds annually, and trees 12 inches (30 cm) in diameter
can produce nearly 1,000,000 seeds . Seed is wind dispersed .
Seed banking: In parts of Nova Scotia and Minnesota, red maple seed has
been found buried at depths of 0 to 6 inches (0-16 cm) [2,61,81], but
these seeds are usually not viable [2,61]. Up to 95 percent of viable
seed germinates with the first 10 days ; some seed survives within
the duff and germinates the following year [30,61].
Seedling establishment: Seedbed requirements for red maple are minimal
, and a bank of persistent seedlings often accumulates beneath a
forest canopy . Seedlings may number more than 11,000 per acre
(44,534/ha)  and can survive for 3 to 5 years under moderate shade
Vegetative regeneration: Red maple sprouts vigorously from the stump,
root crown, or "root suckers" after fire or mechanical damage
[32,96,97]. Lees  observed that at least three generations of stump
sprouts can "thrive on the same regenerating root system." Buds located
at the base of stems commonly sprout 2 to 6 weeks after the stem is cut
. Mroz and others  reported that sprouting is generally
confined to the root collar.
Growth Form (according to Raunkiær Life-form classification)
More info for the terms: chamaephyte, hemicryptophyte, phanerophyte
Undisturbed State: Phanerophyte (mesophanerophyte)
Burned or Clipped State: Chamaephyte
Burned or Clipped State: Hemicryptophyte
Fire Management Considerations
Low-intensity fires produced increases in protein levels during the
first postfire season, but no increases were noted the following season.
High-intensity fires produced significant increases in protein levels
during both the first and second seasons . Dills  reported,
however, that burning had no effect on the nutritive content of red
Reaction to Competition
Following a hurricane in central New England, the site was soon dominated by pin cherry, with red maple, northern red oak, paper birch, and a few eastern white pine. After 10 years, the pin cherry was giving way to dominance by red maple. After 40 years, however, northern red oak and paper birch had assumed dominance over the now codominant red maple (19). In northern hardwood types, red maple begins to give way to sugar maple and more tolerant hardwoods after about 80 years (26), but on certain wet sites, red maple can probably maintain itself indefinitely as an edaphic climax (13).
Red maple is generally very resistant to herbicides (28). Also, diffuse porous species such as red maple are difficult to kill by girdling. For example, 3 years after treatment, 70 percent of the girdled trees had live crowns (63). Stem injection, using cacodylic acid(12) and picloram (61), did successfully control red maple as did glyphosate applied by hydraulic sprayer; but not when applied by a mist blower (16). Generally, if treatment of red maple is planned, it is wise to consult current labels or experts in the field of chemical control to determine the latest allowable chemicals and the best methods of application.
Red maple roots are primarily horizontal and form in the upper 25 cm (10 in) of soil. After germination, a taproot develops until it is about 2 to 5 cm (1 to 2 in) long, then it turns and grows horizontally. As the woody roots extend sideways, nonwoody fans of feeder roots extend upward, mostly within the upper 8 cm (3 in) of mineral soil. The woody roots may be 25 m (80 ft) long (34). Although red maple trees and seedlings tolerate flooding, they can be damaged if silt and sand layers 7.6 cm (3 in) or more are deposited over their roots (6).
Life History and Behavior
Red maple is one of the first trees to flower in early spring .
Specific flowering dates are largely dependent on weather conditions,
and latitude and elevation [8,97]. Flowers generally appear several
weeks before vegetative buds. Bud break may be affected by soil
factors, and is typically delayed for 7 to 10 days on copper-, lead-,
and zinc-mineralized sites . Fruit matures in spring before leaf
development is complete [39,97].
Generalized fruiting and flowering dates by geographic location are as
Location Flowering Fruiting Authority
Adirondack Mtns. Apr June Chapman &
Blue Ridge Mtns. Feb-Mar ---- Wofford 1989
FL Panhandle Jan-Apr ---- Clewell 1985
Gulf & Atlantic
Coasts Jan-May ---- Duncan & Duncan
MD Mar-Apr ---- Batra 1985
MA ---- mid May-early June Abbott 1974
MI late Apr-early May ---- Sakai 1990
NC, SC Jan-Mar Apr-July Radford & others 1968
e TN ---- mid-May-early Apr Farmer &
TX Feb ---- Simpson 1988
Nova Scotia late Apr-early May ---- Roland & Smith 1969
Red maple is difficult to propagate from cuttings and success varies considerably. Some rooting has been obtained by treating cuttings with a concentration of 200 mg per liter (200 p/m) of indolebutyric acid for 3 hours. Cuttings collected in June seem to root better than those taken later in the growing season. Cuttings from the lower part of the crown root better than those from the upper part, and cuttings from male clones or female clones, which fruit sparingly, root better. Successful bud grafting on an experimental basis has been reported with red maple and with sugar maple on red maple stocks, and layering has been observed in central Pennsylvania. For the most part, however, the species is difficult to propagate vegetatively, except by means of stump sprouts (26).
Moist mineral soil seems the best seedbed for red maple, and a thin layer of hardwood leaf litter does not hinder germination and early survival. Many red maple seeds germinate each year in abandoned old fields, in cutover areas and burns, and in the forest. Reproduction has also been observed on strip-mine Spoil banks in Pennsylvania, West Virginia, and Ohio (26). Not many new seedlings can survive under a closed forest canopy, but enough do survive to perpetuate the species in abundance.
Presently, red maple is important in many stands where it was formerly a limited associate; it is enabled to increase by disturbances such as disease, windthrow, fire, and harvesting (5,15,19,3740). In southeastern Ohio, 6 years after clearcutting a 3.4 ha (8.5 acre) mature oak-hickory stand, the new stand contained more than 2,200 red maple seedlings per hectare (900/acre) taller than 1.4 m (4.5 ft), together with many yellow-poplar and oak seedlings (Unpub. data, Vinton Furnace Experimental Forest, McArthur, OH). The original stand on the plot contained no red maple. There were occasional red maples in nearby stands. Red maple does not show a strong affinity for either northern or southern exposures (48), but its best growth form is often found on northeast slopes (40). The young seedlings are shade tolerant, and abundant 1- to 4-year-old seedlings are often found under the canopy of older stands. Many of these seedlings die each year if they are not released by opening of the main crown canopy, but new ones replace them. Thus, a reservoir of seedlings and ungerminated seed is available to respond to increased sunlight resulting from disturbance. Pre-existing red maples in a cut stand add greatly to the new stand stocking through stump sprouts (21). In some species, disturbances of small areas often restrict development of new age classes because the canopy over small areas closes in from the side too quickly. Red maple, however, is sufficiently shade tolerant to respond and may increase in prominence after small disturbances (20,37).
Red maple shows an early tendency to develop root system characteristics according to soil conditions, enabling it to grow on greatly different sites ranging from swamp to dry upland (62). On wet sites, red maple seedlings produce short taproots with long, well-developed laterals. On dry sites, they develop long taproots with much shorter laterals (26). Red maple seedlings are classified as moderately tolerant of soil saturation. In one study, their growth was only slightly retarded after 60 days in saturated soils (24). Red maple seedlings were very tolerant of flooding, showing no sign of stem or leaf damage after 60 days of flooding (7). This capacity to withstand conditions of wetness or dryness enables survival and growth on a wide variety of site conditions where red maple grows naturally.
Throughout the northern portion of its range, with respect to shade, red maple seedlings are rated moderately tolerant to tolerant and are often abundant in the understory advance reproduction. In the Piedmont, red maple seedlings were found to be shade intolerant however; and, in the lower Mississippi Basin, red maple seedlings grow well only in openings. The species was found to be more shade tolerant on good sites than on poor sites. Overall, it ranks more shade tolerant than yellow birch or white ash (Fraxinus americana) but less so than sugar maple, American beech, or eastern hophornbeam (26).
Sugar maple is one of the first species to start stem elongation in the spring, and red maple starts only a few days later. In one study, red maple stem elongation was one-half completed in 1 week. Growth then slowed and was 90 percent completed in 54 days (27). Under favorable light and moisture, red maple seedlings can grow 0.3 m (1 ft) the first year and as much as 0.6 m (2 ft) each year for the next few years. Some sprouts can grow 0.9 m (3 ft) or more the first year (26), but they soon slow to about the same rate as seedlings.
Although red maple naturally germinates and becomes established on many types of seedbeds, direct seeding in an old field failed. Survival was only 37 percent after the first year (2). Planting of seedlings has not succeeded on strip-mine spoil banks (26) or old fields (45). First year survival generally is low and survivors may show poor growth rate and form. Planted red maple infected with mycorrhizae may grow somewhat better, especially on strip-mine spoil banks (10). In the nursery, red maple seedling growth was increased when 4 hours of supplemental light and an aluminum foil soil mulch were provided, and when the soil was treated with the insecticide Disulfoton. In 1 year, these seedlings compared favorably with 2- to 3-year-old seedlings grown by conventional methods (8). If planting of red maple is desired, container-grown stock seems to offer some promise. Ninety-eight percent of the red maple tubelings planted in a New Hampshire forest clearcutting during August survived. The stock had been grown for 8 weeks in containers. Two container sizes-41 cm³ (2.5 in³) and 125 cm³ (7.6 in³) were compared, with no difference in results (17).
Red maple is a common associate in second-growth cherry-maple Allegheny hardwood stands. But after clearcutting, red maple seedlings often grow poorly, whereas the black cherry seedlings do well. A chemical from black cherry, perhaps benzoic acid, may interfere with red maple development (22). Black cherry leaves have been identified as a source of benzoic acid and as a potential allelopathic inhibitor of red maple (23).
Seed Production and Dissemination
The fruit, a double samara, ripens from April to June before leaf development is complete. After ripening, seeds are dispersed for a 1- to 2-week period during April through July. The seed does not require pregermination treatment and can germinate immediately after ripening. The fruits are among the lightest of the maple fruits, averaging about 51,000 cleaned seeds per kilogram (23,OOOflb). In general, fruits are heavier in northern latitudes. Red maple fruit from Canada, Wisconsin, and Michigan, where the normal growing season is 80 to 150 days, averaged 23 gr (1.5 g)/100 fruits. On the other hand, in Rhode Island, Kentucky, and South Carolina, with a frost-free period of 180 to 240 days, the weight averaged 17 gr (1.1 g)/100 fruits. Because the fruits are small and winged, they disperse efficiently in the wind. Germination may be 75 to 80 percent in 2 to 6 days. Total germination is often 85 to 91 percent (59,66).
Growth and Yield
Although red maple height growth starts relatively early in the spring, radial growth starts late in the season. Radial growth then proceeds rapidly, becoming half complete in 50 to 59 days and fully complete in 70 to 79 days. In a New York study, red maple total height growth was somewhat better than that of the other species studied (26).
Growth during early life is rapid but slows after trees pass the pole stage. Red maple responds well to thinning. In upper Michigan, thinning was more effective than fertilization for stimulating red maple growth (49). In the Canadian Maritimes, a 35-year-old coppice red maple stand was thinned by reducing each sprout clump to one of the better stems. The number of red maple stems was reduced from 2,610 to 560/ha (1,057 to 227/acre). Ten years later, these residual trees had more than doubled their volume to 63.8 m³/ha (911 ft³/acre). In another study, a partial cutting was made on a 40-year-old stand of Allegheny northern hardwoods. Of all the species, red maple grew best. In the 10-year period after cutting, dominant red maple trees grew an average of 5.7 cm (2.25 in) in diameter. In the north, the young red maple trees grow faster than sugar maple, beech, or yellow birch, but slower than aspen, paper birch, or white ash. In southern bottom lands, the growth rate of red maple compares favorably with that of other hardwood species. An average diameter growth of 7.5 to 9 cm (3.0 to 3.5 in) in 10 years is possible (26).
Early crop tree release of red maple seedlings and sprouts is feasible in young, even-aged stands. It should be done when the new stand has crown closure and crown dominance is being expressed. This occurred on 9- to 12-year-old trees in West Virginia (56,57). Only 10 percent of red maple sprout clumps did not have a sprout of potential crop tree quality (29). Released red maple trees have a low susceptibility to epicormic sprouting (46).
Molecular Biology and Genetics
Experimental crosses of red and silver maple have been made (26). Also, red maple is known to hybridize naturally with silver maple (33).
Barcode data: Acer rubrum
Statistics of barcoding coverage: Acer rubrum
Public Records: 15
Specimens with Barcodes: 24
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Reasons: Numerous individuals; wide range; ready colonizer; no major threats.
Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status, such as, state noxious status and wetland indicator values. This species has been introduced in many areas of the U.S., outside of its native range.
Toxicity: Red maple browse is toxic to cattle and horses, particularly
during the summer and late fall [5,15,58].
Insects/disease: Loopers, spanworms, the gallmaking maple borer, maple
callus borer, Columbian timber borer, and various scale insects are
common damaging agents [4,97]. Red maple has experienced periodic
declines in past decades. Although the precise pathogens have not been
identified, evidence suggests that insects can weaken the trees, making
them more vulnerable to decline .
Damage: Red maple is tolerant of water-logged soils and flooding [3,6]
and is intermediately tolerant of ice damage. Red maple is susceptible
to decay after mechanical damage. Butt rot, trunk rot fungi, heart rot,
and stem diseases are common in damaged trees; even increment boring can
cause result in serious decay.
Pollution: Red maple is relatively tolerant of landfill-contaminated
gases , but ambient air pollution can damage the foliage . Red
maple persists in industrially damaged woodlands near Sudbury, Ontario,
despite the accumulation of heavy metals in the soil .
Chemical control: Red maple is resistant to herbicides and girdling
[66,97]. Picloram or cacodylic acid injected directly into the stems
can control red maple.
Silviculture: Red maple is often poorly regarded as a timber species
due to its susceptibility to defects and disease, and poor form of
individuals of sprout-clump origin . Red maple usually grows
rapidly after heavy cutting or high-grading, and crop tree release may
be a low-cost management option . Mechanical thinning of clumps can
produce good-quality sawlogs on good sites .
Cultivars, improved and selected materials (and area of origin)
Many cultivars of red maple have been developed. Selections have been made for color tints and brightness, timing of onset of coloration, crown shape and branching pattern, cold hardiness, leaf size, only male flowers (no seeds or seedlings), and leafhopper resistance.
Red maple is easily transplanted and is one of the easiest trees to grow. It is abundantly available in commerce, in ball-and-burlap and in container, but where other fertile trees grow in the area, volunteers usually are common. Propagation of cultivars is by budding onto seedling understock or rooted stem cuttings – the species form (although rarely propagated) by rooted stem cuttings or by seeds. Softwood cuttings are propagated under mist, using 1000-3000 ppm IBA, in about four weeks.
Despite its value and wide use (even to the point of over-planting in some areas), red maple has some drawbacks as a lawn and street tree. As a street tree, it often becomes too large, and it does not respond well to some urban stresses, particularly protracted drought because of the planting site or long spells of hot dry weather. One of the "soft maples," red maple branches are weak and somewhat brittle and are subject to storm damage. The bark is thin and easily damaged by mechanical impact (including lawn mowers, weed eaters, and even increment boring) as well as fire, allowing entry of various damaging fungi and insects – butt rot, trunk rot fungi, heart rot, and stem diseases are common in damaged trees, although pests and pathogens otherwise are relatively few. As in some other maples, feeder roots develop close to the surface and turf and other shallow-rooted plants must compete directly with the tree for water. Turf beneath the canopy often is stunted and mowing may be difficult because of the protruding roots.
Growth in alkaline soils may lead to leaf chlorosis and a weakly growing tree, especially among the cultivars. Fertilization in spring can help overcome this. Graft incompatibilities have appeared between some cultivars of red maple and their rootstock, the trees often breaking off at the union between scion and rootstock, but propagation by softwood cutting has circumvented this problem.
Relevance to Humans and Ecosystems
Maples provide cover for many species of wildlife . The screech
owl, pileated woodpecker, and common flicker nest in cavities in many
species of maple . Cavities in red maples in river floodplain
communities are often well suited for cavity nesters such as the wood
duck . Riparian red maple communities provide autumn roosts for
blackbirds in central Ohio .
of the individual plant, plant part, position in the crown, phenological
development, and geographic location [22,28]. Soil moisture, soil
nutrients, fire history, and climatic conditions also influence food
Other uses and values
foliage . Red maple was first cultivated in 1656 , and many
cultivars are available [23,63,84]. Red maple can be used to make maple
syrup, although sugar maple is much more commonly used [55,97.
Value for rehabilitation of disturbed sites
propagated by seed or by various vegetative techniques. Cleaned seed
averages approximately 23,000 per pound (51,100/kg). Red maple is
reported to be somewhat tolerant of municipal landfill leachates .
Seedlings have been observed colonizing strip mine spoils in parts of
Maryland, West Virginia, and Florida [45,72], but seedlings transplanted
onto strip-mine spoil banks often do poorly . Direct seeding in
old-field communities has not been successful .
Importance to Livestock and Wildlife
deer, moose, elk, and snowshoe hare . It is a particularly valuable
white-tailed deer browse during the late fall and winter, and is
considered an important deer food in New Brunswick, Nova Scotia, Maine,
and Minnesota [31,51,60,70,94]. Although red maple is browsed by moose,
it is often only lightly used . Irwin , however, reported that
red maple is an important fall and winter moose browse in parts of
Wood Products Value
often overlooked as a wood resource . The wood is used for
furniture, veneer, pallets, cabinetry, plywood, barrels, crates,
flooring, and railroad ties [25,49,62].
Minnesota ; stump sprouts are especially sought out by deer [74,92].
Brilliant fall coloring is one of the outstanding features of red maple. In the northern forest, its bright red foliage is a striking contrast against the dark green conifers and the white bark and yellow foliage of the paper birches. Red maple is widely used as a landscape tree.
Although the hard maples-sugar and black maple (Acer nigrum) are principally used for syrup production, red maple is also suitable. When sap and syrup from sugar maple were compared with those of red and silver maple, boxelder (A. negundo), and Norway maple (A. platanoides), they were found to be equal in sweetness, flavor, and quality (30). The buds of red and silver maple and boxelder break dormancy much earlier in the spring than sugar maple, however, and the chemical content of the sap changes, imparting an undesirable flavor to the syrup. Consequently, the tapping season for red and silver maple is shorter than that for sugar maple.
Red maple is a highly desirable wildlife browse food. Elk and white-tailed deer especially use the current season's growth of red maple and aspen as an important source of winter food (25). Timber harvesting slash can provide an important source of browse to help sustain the animals. Red maple, sugar maple, and paper birch trees cut any time after leaf fall provide browse as nutritious as, and more acceptable than, trees cut immediately before leaf fall (3).
Red maple can be used to produce maple syrup, but because the sap contains less sucrose than sugar maple, it is not used commercially. Native Americans used red maple bark as an analgesic, an eye wash, for treating coughs and diarrhea, and as a remedy for hives and muscular aches. Pioneers made dyes and ink from bark extracts, and used maple splints for basketry (PFAF 2011).
Red maple has long been valued as an ornamental tree (shade, specimen, autumn accent, or wet site) because of its ease of establishment, rapid growth, brightly colored flowers and fruit, and fall leaf colors (ranging from clear yellow to orange to vivid red) displaying coloring during different seasons of the year. This tree is preferred over silver maple or boxelder when a fast growing maple is needed. Red maple can be planted onto many types of disturbed sites in rehabilitation projects.
The white, fine-grained wood is used for furniture, flooring, cabinetry, paneling, veneer, musical instruments, tool handles, cutting boards, butcher blocks, wooden bowls, boxes and crates, and many other uses. Red maple is an excellent wood for fuel and is also used for saw timber and pulpwood. But because of susceptibility to defects and disease and poor form of individuals of sprout-clump origin, the timber is often low in quality.
The sap of red maple is sometimes used for producing maple syrup. Although its sap has only about half the sugar content as sugar maple (A. saccharum), the syrup tastes good. Saponins in
the sap may cause excessive frothing of the concentrate.
Native Americans used red maple bark as an analgesic, wash for inflamed eyes and cataracts, and as a remedy for hives and muscular aches. Tea brewed from the inner bark has been used for treating coughs and diarrhea. Pioneers made cinnamon-brown and black dyes from a bark extract. Iron sulphate was added to the tannin from red maple bark to make ink.
Because of the abundance and wide distribution red maple, its early-produced pollen may be important to the biology of bees and other pollen-dependent insects. Most references describe red maple as wind pollinated, but insect pollination may be important, as many insects, especially bees, visit the flowers. The seeds, buds and flowers are eaten by various wildlife species. Squirrels and chipmunks store the seeds. White-tailed deer, moose, elk browse red maple, and rabbits, which find the stump sprouts especially palatable, especially in fall and winter. Cavities in red maples in river floodplain communities are often well suited for cavity nesters such as the wood duck and others.
Acer rubrum (Red Maple, also known as Swamp, Water or Soft Maple), is one of the most common and widespread deciduous trees of eastern North America. The U.S. Forest service recognizes it as the most common variety of tree in America. The red maple ranges from southeastern Manitoba around the Lake of the Woods on the border with Ontario and Minnesota, east to Newfoundland, south to near Miami, Florida, and southwest to east Texas. Many of its features, especially its leaves, are quite variable in form. At maturity it often attains a height of around 15 m (49 ft). It is aptly named as its flowers, petioles, twigs and seeds are all red to varying degrees. Among these features, however, it is best known for its brilliant deep scarlet foliage in autumn.
Over most of its range, red maple is adaptable to a very wide range of site conditions, perhaps more so than any other tree in eastern North America. It can be found growing in swamps, on poor dry soils, and most anywhere in between. It grows well from sea level to about 900 m (3,000 ft). Due to its attractive fall foliage and pleasing form, it is often used as a shade tree for landscapes. It is used commercially on a small scale for maple syrup production as well as for its medium to high quality lumber. It is also the State Tree of Rhode Island. The red maple can be considered weedy or invasive. It is taking over forests in the eastern US, replacing traditional mainstays like oaks, as well as hickories and pines.
Though A. rubrum is usually easy to identify, it is highly changeable in morphological characteristics. It is a medium to large sized tree, reaching heights of 18 to 27 metres (59 to 89 ft) and exceptionally over 35 metres (115 feet). The leaves are usually 9 to 11 centimetres (3.5 to 4.3 in) long on a full grown tree. The trunk diameter can range from 46 to 76 cm (18 to 30 in), depending on the growing conditions. Its spread is about 12 m (39 ft). A 10-year-old sapling will stand about 6 m (20 ft) tall. In forests, the bark will remain free of branches until some distance up the tree. Individuals grown in the open are shorter and thicker with a more rounded crown. Generally speaking, however, the crown is irregularly ovoid with ascending whip-like curved shoots. The bark is a pale grey and smooth when the individual is young. As the tree grows the bark becomes darker and cracks into slightly raised long plates. The largest known living red maple is located near Armada, Michigan, at a height of 38.1 m (125 ft) and a bole circumference, at breast height, of 4.95 m (16.2 ft).
The leaves of the red maple offer the easiest way to distinguish it from its relatives. As with nearly all maple trees, they are deciduous and arranged oppositely on the twig. They are typically 5–10 cm (2.0–3.9 in) long and wide with 3-5 palmate lobes with a serrated margin. The sinuses are typically narrow, but the leaves can exhibit considerable variation. When 5 lobes are present, the three at the terminal end are larger than the other two near the base. In contrast, the leaves of the related silver maple, A. saccharinum, are much more deeply lobed, more sharply toothed and characteristically have 5 lobes. The upper side of A. rubrum's leaf is light green and the underside is whitish and can be either glaucous or hairy. The leaf stalks are usually red and are up to 10 cm (3.9 in) long. Furthermore, the leaves can turn a brilliant red in autumn, but can also become yellow or orange on some individuals.
The twigs of the red maple are reddish in color and somewhat shiny with small lenticels. Dwarf shoots are present on many branches. The buds are usually blunt and greenish to reddish in color, generally with several loose scales. The lateral buds are slightly stalked, and in addition there may be collateral buds present as well. The buds form in fall and winter and are often visible from a distance due to their reddish tint. The leaf scars on the twig are V-shaped and contain 3 bundle scars.
The flowers are generally unisexual, with male and female flowers appearing in separate sessile clusters, though they are sometimes also bisexual. They appear in spring from April to May (though as early as late January in the southern part of its range), usually coming before the leaves. The tree itself is considered Polygamodioecious, meaning some individuals are male, some female, and some monoecious. The red maple will begin blooming when it is about 8 years old, but it significantly varies between tree to tree: some trees may begin flowering when they are 4 years old. The flowers are red with 5 small petals and a 5-lobed calyx borne in hanging clusters, usually at the twig tips. They are lineal to oblong in shape and are pubescent. The pistillate flowers have one pistil formed from two fused carpels with a glabrous superior ovary and two long styles that protrude beyond the perianth. The staminate flowers contain between 4 and 12 stamens, often with 8.
The fruit is a 15 to 25 millimeter (.5 to .75 inch) long double samara with somewhat divergent wings at an angle of 50 to 60 degrees. They are borne on long slender stems and are variable in color from light brown to reddish. They ripen from April through early June, before even the leaf development is altogether complete. After they reach maturity, the seeds are dispersed for a 1 to 2 week period from April through July.
Distribution and habitat
A. rubrum is one of the most abundant and widespread trees in eastern North America. It can be found from the south of Newfoundland, Nova Scotia and southern Quebec to the south west of Ontario, extreme southeastern Manitoba and northern Minnesota; south to Wisconsin, Illinois, Missouri, eastern Oklahoma, and eastern Texas in its western range; and east to Florida. It has the largest continuous range along the North American Atlantic Coast of any tree that occurs in Florida. In total it ranges 2,600 km (1,600 mi) from north to south. The species is native to all regions of the United States east of the 95th meridian west, with only three exceptions, namely the Prairie Peninsula of the Midwest, the coastal prairie in southern Louisiana and southeastern Texas and the swamp prairie of the Florida Everglades. In several other locations, the tree is absent from large areas but still present in a few specific habitats. An example is the Bluegrass region of Kentucky, where it is not found in the dominant open plains, but is present along streams. Here the red maple is not present in the bottom land forests of the Grain Belt, despite the fact it is common in similar habitats and species associations both to the north and south of this area.
The tree's range ends where the −40 °C (−40 °F) mean minimum isotherm begins, namely in southeastern Canada. On the other hand, the western range is limited by the much drier climate of the Great Plains. Nonetheless, it has the widest tolerance to climatic conditions of all the North American species of maple. The absence of red maple in the Prairie Peninsula is due to the species intolerance of fire.
A. rubrum does very well in a wide range of soil types, with varying textures, moisture, pH, and elevation, probably more so than any other forest tree in North America. It grows on glaciated as well as nonglaciated soils derived from the following rocks: granite, gneiss, schist, sandstone, shale, slate, conglomerate, quartzite, and limestone. Chlorosis can occur on very alkaline soils, though otherwise its pH tolerance is quite high. As concerns levels of moisture, the red maple grows everywhere from dry ridges and southwest facing slopes to peat bogs and swamps. It occurs commonly in rather extreme moisture conditions, both very wet and quite dry. While many types of tree prefer a south or north facing aspect, the red maple does not appear to have a preference. Its ideal conditions are in moderately well-drained, moist sites at low or intermediate elevations. However, it is nonetheless common in mountainous areas on relatively dry ridges, as well as on both the south and west sides of upper slopes. Furthermore, it is common in swampy areas, along the banks of slow moving streams, as well as on poorly drained flats and depressions. In northern Michigan and New England, the tree is found on the tops of ridges, sandy or rocky upland and otherwise dry soils, as well as in nearly pure stands on moist soils and the edges of swamps. In the far south of its range, it is almost exclusively associated with swamps.
Red Maple is far more abundant today than when Europeans first arrived in North America, where along with its cousin Silver Maple, it may have comprised a mere 5% of forest area and was confined mostly to riparian zones. The density of the tree in many of these areas has increased 6 to 7 fold and this trend seems to be continuing. A series of disturbances to the oak and pine forests since European arrival, such as the suppression of forest fires and global warming, are most likely responsible for this phenomenon. Concern has been expressed, as the ongoing spread of the red maple is changing the nature of eastern forests by reducing the number of oaks and pines that would otherwise dominate.
Red maple seldom lives longer than 150 years, making it short to medium lived. It reaches maturity in 70 to 80 years. Its ability to thrive in a large number of habitats is largely due to its ability to produce roots to suit its site from a young age. In wet locations, red maple seedlings produce short taproots with long and developed lateral roots, while on dry sites, they develop long taproots with significantly shorter laterals. The roots are primarily horizontal, however, forming in the upper 25 cm (9.8 in) of the ground. Mature trees have woody roots up to 25 m (82 ft) long. They are very tolerant of flooding, with one study showing that 60 days of flooding caused no leaf damage. At the same time, they are tolerant of drought due to their ability to stop growing under dry conditions by then producing a second growth flush when conditions later improve, even if growth has stopped for 2 weeks. Red maple is one of the most drought-tolerant species of maple in the Carolinas.
A. rubrum is one of the first plants to flower in spring. A crop of seeds is generally produced every year with a bumper crop often occurring every second year. A single tree between 5 and 20 cm (2.0 and 7.9 in) in diameter can produce between 12,000 and 91,000 seeds in a season. A tree 30 cm (0.98 ft) in diameter was shown to produce nearly a million seeds. Red maple produces one of the smallest seeds of any of the maples. Fertilization has also been shown to significantly increase the seed yield for up to two years after application. The seeds are epigeal and tend to germinate in early Summer soon after they are released, assuming a small amount of light, moisture, and sufficient temperatures are present. If the seeds are densely shaded, then germination commonly does not occur until the next Spring. Most seedlings do not survive in closed forest canopy situations. However, one- to four-year-old seedlings are common under dense canopy and though they eventually die if no light reaches them, they serve as a reservoir, waiting to fill any open area of the canopy above. Trees growing in a zone 9 or 10 area such as Florida will usually die from cold damage if transferred up north, Canada, Maine, Vermont, New Hampshire and New York, even if the southern trees were planted with northern red maples. Due to their wide range, genetically the trees have adapted to the climatic differences.
Red maple is able to increase its numbers significantly when associate trees are damaged by disease, cutting, or fire. One study found that 6 years after clearcutting a 3.4 hectares (8.4 acres) Oak-Hickory forest containing no red maples, the plot contained more than 2,200 red maple seedlings per hectare (900 per acre) taller than 1.4 m (4.6 ft). One of its associates, the black cherry (Prunus serotina), contains benzoic acid, which has been shown to be a potential allelopathic inhibitor of red maple growth. Red maple is one of the first species to start stem elongation. In one study, stem elongation was one-half completed in 1 week, after which growth slowed and was 90% completed within only 54 days. In good light and moisture conditions, the seedlings can grow 30 cm (0.98 ft) in their first year and up to 60 cm (2.0 ft) each year for the next few years making it a fast grower.
The red maple is a used as a food source by several forms of wildlife. Elk and white-tailed deer in particular use the current season's growth of red maple as an important source of winter food. Several Lepidoptera (butterflies and moths) utilize the leaves as food; see List of Lepidoptera that feed on maples.
Due to A. rubrum's very wide range, there is significant variation in hardiness, size, form, time of flushing, onset of dormancy, and other traits. Generally speaking, individuals from the north flush the earliest, have the most reddish Fall color, set their buds the earliest and take the least winter injury. Seedlings are tallest in the north-central and east-central part of the range. The fruits also vary geographically with northern individuals in areas with brief frost free periods producing fruits that are shorter and heavier than their southern counterparts. As a result of the variation there is much genetic potential for breeding programs with a goal of producing red maples for cultivation. This is especially useful for making urban cultivars that require resistance from verticillium wilt, air pollution, and drought.
The leaves of red maple, especially when dead or wilted, are extremely toxic to horses. The toxin is unknown, but believed to be an oxidant because it damages red blood cells, causing acute oxidative hemolysis that inhibits the transport of oxygen. This not only decreases oxygen delivery to all tissues, but also leads to the production of methemoglobin, which can further damage the kidneys. The ingestion of 700 grams (1.5 pounds) of leaves is considered toxic and 1.4 kilograms (3 pounds) is lethal. Symptoms occur within one or two days after ingestion and can include depression, lethargy, increased rate and depth of breathing, increased heart rate, jaundice, dark brown urine, colic, laminitis, coma, and death. Treatment is limited and can include the use of methylene blue or mineral oil and activated carbon in order to stop further absorption of the toxin into the stomach, as well as blood transfusions, fluid support, diuretics, and anti-oxidants such as Vitamin C. About 50% to 75% of affected horses die or are euthanized as a result.
Red maple is widely grown as an ornamental tree in parks and large gardens, except where soils are too alkaline or salty. In parts of the Pacific Northwest, it is one of the most common introduced trees. Its popularity in cultivation stems from its vigorous habit, its attractive and early red flowers, and most importantly, its flaming red fall foliage. The tree was introduced into the United Kingdom in 1656 and shortly thereafter entered cultivation. There it is frequently found in many parks and gardens, as well as occasionally in churchyards.
Red maple is a good choice of a tree for urban areas when there is ample room for its root system. It is more tolerant of pollution and road salt than Sugar Maples, although the tree's fall foliage is not as vibrant in this environment. Like several other maples, its low root system can be invasive and it makes a poor choice for plantings near paving. It attracts squirrels, who eat its buds in the early spring, although squirrels prefer the larger buds of the silver maple.
Numerous cultivars have been selected, often for intensity of fall color, with 'October Glory' and 'Red Sunset' among the most popular. Toward its southern limit, 'Fireburst', 'Florida Flame', and 'Gulf Ember' are preferred. Many cultivars of the Freeman maple are also grown widely. Below is a partial list of cultivars:
- 'Armstrong' - Columnar to fastigate in shape with silvery bark and modest orange to red fall foliage
- 'Autumn Blaze' - Rounded oval form with leaves that resemble the silver maple. The fall color is orange red and persists longer than usual
- 'Autumn Flame' - A fast grower with exceptional bright red fall color developing early. The leaves are also smaller than the species.
- 'Autumn Radiance' - Dense oval crown with an orange-red fall color
- 'Autumn Spire' - Broad columnar crown; red fall color; very hardy
- 'Bowhall' - Conical to upright in form with a yellow-red fall color
- 'Burgundy Bell' - Compact rounded uniform shape with long lasting, burgundy fall leaves
- 'Columnare' - An old cultivar growing to 20 metres (66 feet) with a narrow columnar to pyramidal form with dark green leaves turning orange and deep red in fall
- 'Gerling' - A compact, slow growing selection, this individual only reaches 10 metres (33 feet) and has orange-red fall foliage
- 'Northwood' - Branches are at a 45 degree angle to the trunk, forming a rounded oval crown. Though the foliage is deep green in summer, its orange-red fall color is not as impressive as other cultivars.
- 'October Brilliance' - This selection is slow to leaf in spring, but has a tight crown and deep red fall color
- 'October Glory' - Has a rounded oval crown with late developing intense red fall foliage. Along with 'Red Sunset', it is the most popular selection due to the dependable fall color and vigorous growth. This cultivar has gained the Royal Horticultural Society's Award of Garden Merit.
- 'Redpointe' - Superior in alkaline soil, strong central leader, red fall color
- 'Red Sunset' - The other very popular choice, this selection does well in heat due to its drought tolerance and has an upright habit. It has very attractive orange-red fall color and is also a rapid and vigorous grower.
- 'Scarlet Sentinel' - A columnar to oval selection with 5-lobed leaves resembling the silver maple. The fall color is yellow-orange to orange-red and the tree is a fast grower.
- 'Schlesingeri' - A tree with a broad crown and early, long lasting fall color that a deep red to reddish purple. Growth is also quite rapid.
- 'Shade King' - This fast growing cultivar has an upright-oval form with deep green summer leaves that turn red to orange in fall.
- 'V.J. Drake' - This selection is notable because the edges of the leaves first turn a deep red before the color progresses into the center.
In the lumber industry Acer rubrum is considered a soft maple. The wood is close grained and as such it is similar to that of A. saccharum, but its texture is softer, less dense, and has a poorer figure and machining qualities. High grades of wood from the red maple can nonetheless be substituted for hard maple, particularly when it comes to making furniture. As a soft maple, the wood tends to shrink more during the drying process than with the hard maples.
Red maple is also used for the production of maple syrup, though the hard maples Acer saccharum (sugar maple) and Acer nigrum (black maple) are more commonly utilized. One study compared the sap and syrup from the sugar maple with those of the red maple, as well as those of the Acer saccharinum (silver maple), Acer negundo (boxelder), and Acer platanoides (Norway maple), and all were found to be equal in sweetness, flavor, and quality. However, the buds of red maple and other soft maples emerge much earlier in the spring than the sugar maple, and after sprouting chemical makeup of the sap changes, imparting an undesirable flavor to the syrup. This being the case, red maple can only be tapped for syrup before the buds emerge, making the season very short.
Red maple is a medium quality firewood, possessing high heat energy, nominally 5.4 MJ/m³ (18.7 million BTU (mbtu) per cord), than other hardwoods such as Ash: 7 MJ/m³ (24 mbtu/cord), Oak: 7 MJ/m³ (24 mbtu/cord), or Birch: 5.8 MJ/m³ (20 mbtu/cord).
Red Maple make vibrant and colorful Bonsai, and have year around attractive features for display.
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- D'Cruz, Mark. "Acer Rubrum Bonsai Care Guide". Ma-Ke Bonsai. Retrieved 2010-10-20.
Names and Taxonomy
Comments: Distinct species, 3 varieties (drummondii, rubrum, trilobum), each widespread; var. tomentosum (sometimes recognized) included in var. rubrum by Kartesz (1999). Occasionally hybridizes A. saccharinum.
great morphological variation and has been included in a highly variable
complex of related taxa [79,97]. The currently accepted scientific name
of red maple is Acer rubrum L. . Many varieties and forms have been
identified, but most are no longer recognized. The following varieties
are commonly recognized:
Acer rubrum var. drummondii (Hook. & Arn. ex Nutt.) Sarg.
Acer rubrum var. trilobum Torr. & Gray ex K. Koch
Several forms, differentiated on the basis of various morphological
characteristics, are commonly delineated [38,86]:
Acer rubrum f. tomentosum (Tausch) Siebert & Voss
Acer rubrum f. rubrum
Acer rubrum f. pallidum
Red maple hybridizes with silver maple (A. saccharinum) under natural
conditions . A hybrid product of this cross has been identified:
Acer X freemanii E. Murray .
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