Acer is agenus oftrees andshrubs commonly known asmaples. Thegenus is placed in the soapberry familySapindaceae.[1][2] There are approximately 132species, most of which are native toAsia,[3] with a number also appearing inEurope, northernAfrica, andNorth America. Only one species,Acer laurinum, extends to theSouthern Hemisphere.[4] Thetype species of the genus is the sycamore mapleAcer pseudoplatanus, one of the most common maple species in Europe.[5] Most maples usually have easily identifiablepalmate leaves (with a few exceptions, such asAcer carpinifolium,Acer laurinum, andAcer negundo) and all share distinctivewinged fruits. The closest relative of the maples is the small east Asian genusDipteronia, followed by the more widespread genusAesculus (buckeyes and horse-chestnuts).[1]Maple syrup is made from the sap of some maple species. It is one of the most common genera of trees in Asia. Many maple species are grown in gardens where they are valued for their autumn colour and often decorative foliage, some also for their attractive flowers, fruit, or bark.[6]
The closest relative ofAcer isDipteronia, which only has two living species in China, but has a fossil record extending back to the middlePaleocene in North America. The oldest known fossils ofAcer are from the late Paleocene ofNortheast Asia and northern North America, around 60 million years old. The oldest fossils ofAcer in Europe are fromSvalbard, dating to the lateEocene (Priabonian ~38–34 million years ago).[7]
Most maples or acers are trees growing to a height of 10–45 m (33–148 ft). Others are shrubs less than 10 meters tall with a number of smalltrunks originating at about ground level. Most species aredeciduous, and many are renowned for theirautumn leaf colours, but a few in southern Asia and theMediterranean region are mostlyevergreen. Most areshade-tolerant when young and are often riparian, understory, or pioneer species rather than climax overstory trees. There are a few exceptions such assugar maple.[clarification needed] Many of theroot systems are typically dense and fibrous, inhibiting the growth of other vegetation underneath them. A few species, notablyAcer cappadocicum, frequently produceroot sprouts, which can develop intoclonal colonies.[5]
Acer circinatum (vine maple) leaves showing the palmate veining typical of most species
Maples are distinguished by oppositeleaf arrangement. The leaves in most species arepalmate veined and lobed, with 3 to 9 (rarely to 13) veins each leading to a lobe, one of which is central or apical. A small number of species differ in having palmate compound,pinnate compound, pinnate veined or unlobed leaves. Several species, includingAcer griseum (paperbark maple),Acer mandshuricum (Manchurian maple),Acer maximowiczianum (Nikko maple) andAcer triflorum (three-flowered maple), have trifoliate leaves. One species,Acer negundo (box-elder or Manitoba maple), has pinnately compound leaves that may be simply trifoliate or may have five, seven, or rarely nine leaflets. A few, such asAcer laevigatum (Nepal maple) andAcer carpinifolium (hornbeam maple), have pinnately veined simple leaves.
Maple species, such asAcer rubrum, may bemonoecious,dioecious orpolygamodioecious. Theflowers are regular,pentamerous, and borne inracemes,corymbs, orumbels. They have four or fivesepals, four or fivepetals about 1–6 mm long (absent in some species), four to tenstamens about 6–10 mm long, and twopistils or a pistil with two styles. Theovary is superior and has twocarpels, whose wings elongate the flowers, making it easy to tell which flowers are female. Maples flower in latewinter or earlyspring, in most species with or just after the appearance of the leaves, but in some before the trees leaf out.[8]
Maple flowers are green, yellow, orange or red. Though individually small, the effect of an entire tree in flower can be striking in several species. Some maples are an early spring source ofpollen andnectar forbees.
The distinctivefruits are calledsamaras, "maple keys", "helicopters", "whirlybirds" or "polynoses". Theseseeds occur in distinctive pairs each containing one seed enclosed in a "nutlet" attached to a flattened wing of fibrous, papery tissue. They are shaped to spin as they fall and to carry the seeds a considerable distance on the wind. People often call them "helicopters" due to the way that they spin as they fall. During World War II, the US Army developed a special airdrop supply carrier that could carry up to 65 pounds (29 kg) of supplies and was based on the maple seed.[9] Seed maturation is usually in a few weeks to six months after flowering, withseed dispersal shortly after maturity. However, one tree can release hundreds of thousands of seeds at a time. Depending on the species, the seeds can be small and green to orange and big with thicker seed pods. The green seeds are released in pairs, sometimes with the stems still connected. The yellow seeds are released individually and almost always without the stems. Most species requirestratification in order togerminate, and some seeds can remain dormant in the soil for several years before germinating.[5]
The genusAcer, together with genusDipteronia, were formerly often classified in afamily of their own, theAceraceae, but recent botanical consensus, including theAngiosperm Phylogeny Group system, includes them in the familySapindaceae; their exclusion from Sapindaceae would leave that familyparaphyletic. Within Sapindaceae,Acer is placed in thesubfamilyHippocastanoideae.[1] The genus is subdivided by its morphology into a multitude of sections and subsections.[10][11] Molecular studies incorporating DNA sequence data from both chloroplast and nuclear genomes, aiming to resolve the internal relationships and reconstruct the evolutionairy history of the group, suggest a Late Paleocene origin for the group, appearing first in the northeastern Palearctic. Rapid lineage divergence was followed by several independent dispersals to the Nearctic and Western Palearctic regions.[12][13] Fifty-four species of maples meet theInternational Union for Conservation of Nature criteria for being under threat of extinction in their native habitat.[4]
The leaves are used as a food plant for thelarvae of a number of the orderLepidoptera (see List of Lepidoptera that feed on maples). In high concentrations, caterpillars, like the greenstriped mapleworm (Dryocampa rubicunda), can feed on the leaves so much that they cause temporary defoliation of host maple trees.[14]Aphids are also very common sap-feeders on maples. In horticultural applications adimethoate spray will solve this.
Infestations of theAsian long-horned beetle (Anoplophora glabripennis) have resulted in the destruction of thousands of maples and other tree species in Illinois, Massachusetts, New Jersey, New York, and Ohio in the United States and Ontario, Canada.[15][16]
Maples are affected by a number offungal diseases. Several are susceptible to Verticillium wilt caused byVerticillium species, which can cause significant local mortality.Sooty bark disease, caused byCryptostroma species, can kill trees that are under stress due todrought. Death of maples can rarely be caused byPhytophthoraroot rot andGanoderma root decay. Maple leaves in late summer and autumn are commonly disfigured by "tar spot" caused byRhytisma species andmildew caused byUncinula species, though these diseases do not usually have an adverse effect on the trees' long-term health.[17]
The Canadian flag incorporates a stylized maple leafThe maple leaf and samaras in the coat of arms ofSammatti
Amaple leaf appears on thecoat of arms of Canada, and is on theCanadian flag. The maple is a common symbol of strength and endurance and has been chosen as the national tree of Canada. Maple leaves are traditionally an important part ofCanadian Forces military regalia, for example, the military rank insignia for generals use maple leaf symbols. There are 10 species naturally growing in the country, with at least one in each province. Although the idea of the tree as a national symbol originally hailed from the province ofQuebec[18] where thesugar maple is significant, today's arboreal emblem of Canada rather refers to a generic maple.[19] The design on theflag is an eleven-point stylization modeled after a sugar maple leaf (which normally bears 23 points).[20]
It is also in the name of the Canadian ice hockey team, theToronto Maple Leafs.
The first attested use of the word was in 1260 as "mapole", and it also appears a century later inGeoffrey Chaucer'sCanterbury Tales, spelled as "mapul".[21] The maple is also a symbol ofHiroshima, ubiquitous in the localmeibutsu.
A maple leaf, along with samaras, appears in the coat of arms ofSammatti, a former municipality ofUusimaa,Finland.[22][23]
A red maple tree highlighted betweenspruce treesAcer palmatum (Japanese maple) has over 1,000cultivars. This cultivar isA. palmatum 'Sango kaku', sometimes called "coralbark maple"
Some species of maple are extensively planted asornamental trees by homeowners, businesses, and municipalities due to their fall colour, relatively fast growth, ease of transplanting, and lack of hard seeds that would pose a problem for mowing lawns. Particularly popular areNorway maple (although it is considered invasive in North America),silver maple,Japanese maple, andred maple. Thevine maple is also occasionally used as an ornamental tree. Other maples, especially smaller or more unusual species, are popular as specimen trees.[5]
Numerous maplecultivars that have been selected for particular characteristics can bepropagated only byasexual reproduction such as cuttings,tissue culture, budding orgrafting.Acer palmatum (Japanese maple) alone has over 1,000 cultivars, most selected in Japan, and many of them no longer propagated or not in cultivation in theWestern world. Some delicate cultivars are usually grown in pots and rarely reach heights of more than 50–100 cm.
Acer palmatum var. 'Kiyohime' asbonsai during fallabscission. This dwarf hybrid cultivar is prized for its small leaves and bright red fall colors.
Some of the larger maple species have valuabletimber, particularly Sugar maple in North America and Sycamore maple in Europe. Sugar maple wood—often known as "hard maple"—is the wood of choice forbowling pins, bowling alley lanes,pool andsnookercue shafts, andbutcher's blocks. Maple wood is also used for the manufacture of woodenbaseball bats, though less often thanash orhickory due to the tendency of maple bats to shatter if they do break. The maple bat was introduced toMajor League Baseball (MLB) in 1998 bySam Bat founder Sam Holman. Today it is the standard maple bat most in use by professional baseball.[26] Maple is also commonly used in archery as the core material in the limbs of arecurve bow due to its stiffness and strength.[citation needed]
Maple wood is often graded based on physical and aesthetic characteristics. The most common terminology includes the grading scale from common #2; which is unselected and often used for craft woods; common #1, used for commercial and residential buildings; clear; and select grade, which is sought for fine woodworking.[27]
Some maple wood has a highly decorativewood grain, variously known asflame maple,quilt maple,birdseye maple andburl wood. This condition occurs randomly in individual trees of several species and often cannot be detected until the wood has been sawn, though it is sometimes visible in the standing tree as a rippled pattern in the bark.[citation needed]
These select decorative wood pieces also have subcategories that further filter the aesthetic looks. Crotch wood, bees wing, cats paw, old growth and mottled are some terms used to describe the look of these decorative woods.[28]
Maples have a long history of use for furniture production in the United States.[29] TheCherokee people would produce a purple dye from maple bark, which they used to dye cloth.[30][31]
Maple is considered atonewood, or a wood that carries sound waves well, and is used in numerousmusical instruments. Maple is harder and has a brighter sound thanmahogany, which is another major tonewood used in instrument manufacturing.[32]
Electric guitar necks are commonly made from maple, having good dimensional stability. The necks of the FenderStratocaster andTelecaster were originally an entirely maple one piece neck, but later were also available withrosewood fingerboards.Les Paul desired an all maple guitar, but due to the weight of maple, only the tops ofGibson's Les Paul guitars are made from carved maple, often using quilted or flamed maple tops. Due to its weight, very fewsolid body guitars are made entirely from maple, but many guitars have maple necks, tops or veneers.[citation needed]
Manydrums are made from maple. From the 1970s to the 1990s, maple drum kits were a vast majority of all drum kits made, but in recent years,birch has become popular for drums once again. Some of the best drum-building companies use maple extensively throughout their mid-pro range.[5] Maple drums are favored for their bright resonant sound.[33] Certain types of drum sticks are also made from maple.[citation needed]
During late winter to early spring in northeasternNorth America, when the night-to-day temperatures change from freezing to thawing, maple trees may be tapped forsap to manufacturemaple syrup.[34] The sap is sent via tubing to asugar house where it is boiled to produce syrup or made intomaple sugar ormaple taffy. It takes about 40 litres (42 US qt) of sugar maple sap to make 1 litre (1.1 US qt) of syrup.[34] While anyAcer species may be tapped for syrup, many do not have sufficient quantities of sugar to be commercially useful, whereassugar maples (A. saccharum) are most commonly used to produce maple syrup.[34]Québec, Canada is a major producer of maple syrup, an industry worth about 500 millionCanadian dollars annually.[34][35]
Also, as these trees are a major source ofpollen in early spring before many other plants have flowered, maple flowers are a source of foraging forhoneybees that play a commercially important role in general agriculture and in natural habitats.[36]
Maple is used aspulpwood. The fibers have relatively thick walls that prevent collapsing upon drying. This gives good bulk and opacity inpaper. Maple also gives paper good printing properties.
Many maples have brightautumn foliage, and many countries have leaf-watching traditions. The sugar maple (Acer saccharum), whose leaves turn brilliant orange, is the primary contributor to fall "foliage season" in north-easternNorth America. InJapan, the custom of viewing the changing colour of maples in the autumn is calledmomijigari.Nikkō andKyoto are particularly favoured destinations for this activity. In Korea, the same viewing activity is calleddanpung-nori and theSeoraksan andNaejang-san mountains are among the best-known destinations.
^Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 [and more or less continuously updated since].http://www.mobot.org/MOBOT/research/APweb/.
^Xu, Tingzhi; Chen, Yousheng; de Jong, Piet C.; Oterdoom, Herman John; Chang, Chin-Sung."Acer".Flora of China. Vol. 11. Retrieved27 May 2012 – via eFloras.org,Missouri Botanical Garden, St. Louis, MO &Harvard University Herbaria, Cambridge, MA.
^Knight, Oliver (1956–57), "History of the Cherokees, 1830–1846",Chronicles of Oklahoma, Oklahoma City: Oklahoma Historical Society, p. 164,OCLC647927893
.jpg)
