Red Maple (
Acer rubrum)
DBH: 5.37 (cm) Measured on January 14, 2022
From Wikipedia, the free encyclopedia
Acer rubrum, thered maple, also known asswamp,waterorsoft maple, is one of the most common and widespread deciduoustreesof eastern and centralNorth America. The U.S. Forest service recognizes it as the most abundant native tree in eastern North America.[3]The red maple ranges from southeasternManitobaaround theLake of the Woodson the border withOntarioandMinnesota, east toNewfoundland, south toFlorida, and southwest to easternTexas. Many of its features, especially its leaves, are quite variable in form. At maturity, it often attains a height of around 30m (100ft). 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 inswamps, on poor drysoils, and almost anywhere in between. It grows well fromsea levelto about 900m (3,000ft). 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 formaple syrupproduction as well as for its medium to high quality lumber. It is also thestate treeof Rhode Island. The red maple can be considered weedy or even invasive in young, highly disturbed forests, especially frequently logged forests. Red maple is considered by many a pest, and many believe that it is taking over forests and displacing other native trees, such as sugar maple, this is only true in young forests where human disturbance is common. In a mature or old growth northern hardwood forest, red maple only has a sparse presence, while shade tolerant trees such as sugar maples, beeches, and hemlocks thrive. By removing red maple from a young forest recovering from disturbance, the natural cycle of forest regeneration is altered, changing the diversity of the forest for centuries to come.[4][not in citation given][5]
ThoughA. rubrumis usually easy to identify, it is highly changeable in morphological characteristics. It is a medium to large sized tree, reaching heights of 27 to 38 metres (90 to 120ft) and exceptionally over 41 metres (135 feet) in the southern Appalachians where conditions favor its growth.[4]The leaves are usually 9 to 11 centimetres (31⁄2to41⁄4in) long on a full-grown tree. The trunk diameter often ranges from 46 to 88cm (18 to 35in); depending on the growing conditions, however, open grown trees can attain diameters of up to 153 centimetres (60in). The trunk will remain free of branches until some distance up the tree on forest grown trees, while individuals grown in the open are shorter and thicker with a more rounded crown. Trees on poorer sites often become malformed and scraggly.[6]Generally the crown is irregularly ovoid with ascending whip-like curved shoots. Thebarkis 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.[7]The largest known living red maple is located nearArmada, Michigan, at a height of 38.1m (125ft) and a bole circumference, at breast height, of 4.95m (16ft 3in).[8]
Red Maple leaf from specimen in northern Florida
Theleavesof the red maple offer the easiest way to distinguish it from its relatives. As with all North American maple trees, they aredeciduousand arranged oppositely on the twig. They are typically 5–10cm (2–4in) long and wide with 3-5palmate lobeswith a serrated margin. Thesinusesare typically narrow, but the leaves can exhibit considerable variation.[6]When five lobes are present, the three at the terminal end are larger than the other two near the base. In contrast, the leaves of the relatedsilver maple,A. saccharinum, are much more deeply lobed, more sharply toothed and characteristically have 5 lobes. The upper side ofA. rubrum's leaf is light green and the underside is whitish and can be eitherglaucousor hairy. The leaf stalks are usually red and are up to 10cm (4in) long. The leaves can turn a characteristic brilliant red in autumn, but can also become yellow or orange on some individuals. Soil acidity can influence the color of the foliage and trees with female flowers are more likely to produce orange coloration while male trees produce red. The fall colors of red maple are most spectacular in the northern part of its range where climates are cooler.
Immature foliage of Acer rubrum (Red Maple)
Thetwigsof the red maple are reddish in color and somewhat shiny with smalllenticels. Dwarf shoots are present on many branches. Thebudsare 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 large size and reddish tint. The leaf scars on the twig are V-shaped and contain 3 bundle scars.[6]
Drawing showing male and female flower, leaf and samara
Theflowersare generally unisexual, with male and female flowers appearing in separatesessileclusters, 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 somemonoecious.[8]Under the proper conditions, the tree can sometimes switch from male to female, male to hermaphroditic, and hermaphroditic to female.[9]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-lobedcalyxborne in hanging clusters, usually at the twig tips. They are lineal to oblong in shape and are pubescent. The pistillate flowers have onepistilformed from two fused carpels with a glabrous superior ovary and two longstylesthat protrude beyond theperianth. The staminate flowers contain between 4 and 12stamens, often with 8.[10]
Thefruitis asamara15 to 25 millimeters (5⁄8to 1in) long that grows in pairs 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.[6]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.[8]
A. rubrumis one of the most abundant and widespread trees in easternNorth America. It can be found from the south ofNewfoundland,Nova Scotiaand southernQuebecto the south west of Ontario, extreme southeasternManitobaand northernMinnesota; south toWisconsin,Illinois,Missouri, easternOklahoma, and easternTexasin its western range; and east toFlorida. It has the largest continuous range along the North AmericanAtlantic Coastof any tree that occurs in Florida. In total it ranges 2,600km (1,600mi) from north to south.[8]The species is native to all regions of the United States east of the95th meridian. The tree's range ends where the −40°C (−40°F) mean minimumisothermbegins, namely in southeasternCanada.A. rubrumis not present in the Prairie Peninsula of the northernMidwest, thecoastal prairiein southernLouisianaand southeastern Texas and the swamp prairie of theFlorida Everglades.[8]Red maple's western range stops with the Great Plains where conditions become too dry for it. The absence of red maple from the Prairie Peninsula is most likely due to the tree's poor tolerance of wildfires. Red maple is most abundant in the Northeastern US, the Upper Peninsula of Michigan, and northeastern Wisconsin and is rare in the extreme west of its range and in the Southeastern US.[8]
In several other locations, the tree is absent from large areas but still present in a few specific habitats. An example is theBluegrass regionof Kentucky, where red maple is not found in the dominant open plains, but is present along streams.[11]Here the red maple is not present in the bottom land forests of theGrain Belt, despite the fact it is common in similar habitats and species associations both to the north and south of this area. In the Northeastern US, red maple can be a climax forest species in certain locations, but will eventually give way to sugar maple.[8]
A. rubrumdoes 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.A. rubrum's high pH tolerance means that it can grow in a variety of places, and it is widespread along the eastern United States.[12]It grows on glaciated as well as unglaciated soils derived from the following rocks:granite,gneiss,schist,sandstone,shale,slate,conglomerate,quartzite, andlimestone.Chlorosiscan occur on veryalkalinesoils, though otherwise its pH tolerance is quite high. Moist mineral soil is best for germination of seeds.[8]
Red maple can grow in a variety of moist and dry biomes, from dry ridges and sunny, southwest-facing slopes topeat bogsandswamps. While many types of tree prefer a south- or north-facing aspect, the red maple does not appear to have a preference.[8]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 northernMichiganandNew 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.[8]Additionally, red maple is one of the most drought-tolerant species of maple in the Carolinas.[13]
Red maple is far more abundant today than when Europeans first arrived in North America. It only contributed minimally to old growth upland forests, and would only form same-species stands inriparian zones.[8]The density of the tree in many of these areas has increased 6- to 7-fold, and this trend seems to be continuing, all of which is due to human factors, mainly continued heavy logging and a recent trend of young, shrubby forests recovering from past human disturbances. Also, the decline of American elm and American chestnut due to introduced diseases has contributed to its spread. Red maple dominates such sites, but largely disappears until it only has a sparse presence by the time a forest is mature. This species is in fact a vital part of forest regeneration in the same way thatpaper birchis.[4]
Because it can grow on a variety of substrates, has a high pH tolerance, and grows in both shade and sun,A. rubrumis a prolific seed producer and highly adaptable, often dominating disturbed sites. While many believe that it is replacing historically dominant tree species in the eastern United States such assugar maples,beeches,oaks,hemlocksandpines, red maple will only dominate young forests prone to natural or human disturbance. In areas disturbed by humans where the species thrives, it can reduce diversity, but in a mature forest it is not a dominant species; it only has a sparse presence and adds to the diversity and ecological structure of a forest.[4]Extensive use of red maple in landscaping has also contributed to the surge in the species' numbers as volunteer seedlings proliferate. Finally, disease epidemics have greatly reduced the population of elms and chestnuts in the forests of the US. While mainline forest trees continue to dominate mesic sites with rich soil, more marginal areas are increasingly being dominated by red maple.[14]
Red maple's maximum lifespan is 150 years, but most live less than 100 years. The tree's thin bark is easily damaged from ice and storms, animals, and when used in landscaping, being struck by flying debris from lawn mowers, allowing fungi to penetrate and cause heart rot.[8]Its ability to thrive in a large number of habitats is largely due to its ability to producerootsto suit its site from a young age. In wet locations, red maple seedlings produce shorttaprootswith long, well-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 25cm (9.8in) of the ground. Mature trees have woody roots up to 25m (82ft) 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.[8]
A. rubrumis 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 20cm (2.0 and 7.9in) in diameter can produce between 12,000 and 91,000 seeds in a season. A tree 30cm (0.98ft) in diameter was shown to produce nearly a million seeds.[8]Red maple produces one of the smallest seeds of any of the maples.[13]Fertilization has also been shown to significantly increase the seed yield for up to two years after application. The seeds areepigealand 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 closedforest canopysituations. However, one- to four-year-old seedlings are common under dense canopy. 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, for instance to 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 afterclearcuttinga 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 1.4m (4.6ft).[8]One of its associates, theblack cherry(Prunus serotina), contains benzoic acid, which has been shown to be a potentialallelopathicinhibitor 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 30cm (0.98ft) in their first year and up to 60cm (2.0ft) each year for the next few years, making it a fast grower.[8]
The red maple is used as a food source by several forms of wildlife.Elkandwhite-tailed deerin particular use the current season's growth of red maple as an important source of winter food. SeveralLepidoptera(butterflies and moths) utilize the leaves as food, including larvae of the rosy maple moth (Dryocampa rubicunda); seeList of Lepidoptera that feed on maples.
Due toA. 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. In Florida, at the extreme south of the red maple's range, it is limited exclusively to swamplands. 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 such variation, there is much genetic potential for breeding programs with a goal of producing red maples for cultivation. This is especially useful for making urbancultivarsthat require resistance fromverticillium wilt, air pollution, and drought.[8]
Red maple frequently hybridizes withSilver Maple; thehybrid, known as Freeman's MapleAcer x freemanii, is intermediate between the parents.