Acer (maple) is a genus of trees or shrubs. They are variously classified in a family of their own, the Aceraceae, or (together with the Hippocastanaceae) included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group classification, favour inclusion in Sapindaceae. There are approximately 125 species, most of which are native to Asia, but several species also occur in Europe, northern Africa, and North America.Maple trees roots go from about 5 meters to 30 meter.
The word Acer is derived from a Latin word meaning "sharp" (referring to the characteristic points on the leaves) and was first applied to the genus by the French botanist Joseph Pitton de Tournefort in 1700. The type species of the genus is Acer pseudoplatanus (Sycamore Maple).
Maples are mostly trees growing to 10-40 meters (30-130 ft) in height. Others are shrubs less than 10 metres tall with a number of small trunks originating at ground level. Most species are deciduous, but a few in southern Asia and the Mediterranean region are evergreen. Most are shade-tolerant when young, and are often late-successional in ecology; many of the root systems are typically dense and fibrous. A few species, notably Acer cappadocicum, frequently produce root sprouts, which can develop into clonal colonies.
Maples are distinguished by opposite leaf arrangement. The leaves in most species are palmate veined and lobed, with 3-9 (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, including Acer griseum (Paperbark Maple), Acer mandshuricum (Manchurian Maple), Acer maximowiczianum (Nikko Maple), and Acer triflorum (Three-flowered Maple), have trifoliate leaves. One species, Acer negundo (Box-elder), has pinnately compound leaves that may be simply trifoliate or may have five, seven, or rarely nine leaflets. A few, such as Acer laevigatum and Acer carpinifolium (Hornbeam Maple), have pinnately-veined simple leaves.
The flowers are regular, pentamerous, and borne in racemes, corymbs, or umbels. They have four or five sepals, four or five petals about 1–6 mm long (absent in some species), four to ten stamens about 6-10 mm long, and two pistils or a pistil with two styles. The ovary is superior and has two carpels, whose wings elongate the flowers, making it easy to tell which flowers are female. Maples flower in late winter or early spring, in most species with or just after the leaves appear, but in some before them.
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 of pollen and nectar for bees.
The distinctive fruit are called samaras or "maple keys". These seeds 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. Children often call them "helicopters" due to the way that they spin as they fall. Seed maturation is usually in a few weeks to six months after flowering, with seed dispersal shortly after maturity. However, one tree can release hundreds of the seeds at a time. Depending on the species, the seeds can be small and green to yellow 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 require stratification in order to germinate, and some seeds can remain dormant in the soil for several years before germinating.
The genus is subdivided by its morphology into a multitude of sections and subsections.
The leaves are used as a food plant for the larvae of a number of Lepidoptera species (see List of Lepidoptera that feed on maples). Aphids are also very common sap-feeders on maples. In horticultural applications a dimethoate spray will solve this.
Maples are affected by a number of fungal diseases. Several are susceptible to Verticillium wilt caused by Verticillium species, which can cause significant local mortality. Sooty bark disease, caused by Cryptostroma species, can kill trees which are under stress due to drought. Death of maples can rarely be caused by Phytophthora root rot and Ganoderma root decay. Maple leaves in late summer and autumn are commonly disfigured by "tar spot" caused by Rhytisma species and mildew caused by Uncinula species, though these diseases do not usually have an adverse effect on the trees' long-term health.
Maple collections, sometimes called aceretums, occupy space in many gardens and arboreta around the world including the "five great W's" in England: Wakehurst Place Garden, Westonbirt Arboretum, Windsor Great Park, Winkworth Arboretum and Wisley Garden. In the United States, the aceretum at the Harvard-owned Arnold Arboretum in Boston is especially notable. In the number of species and cultivars, the Esveld Aceretum in Boskoop, Netherlands is the largest in the world.
The particularly spectacular fall colours of the Acer rubrum (Red Maple) are a major contributor to the seasonal landscape in southeastern Canada and in New England. Fall tourism is a boon to the economy of this region, especially in Quebec, Vermont, New Hampshire and Western Massachusetts. In the American Pacific Northwest and British Columbia it is the spectacular fall colours of Acer circinatum (Vine Maple) that draw tourists and photographers.
Some of the larger maple species have valuable timber, particularly Sugar Maple in North America, and Sycamore Maple in Europe. Sugar Maple wood, often known as "hard maple", is the wood of choice for bowling pins, bowling alley lanes, pool cue shafts, and butcher's blocks. Maple wood is also used for the production of wooden baseball bats, though less often than ash or hickory due to the tendency of maple bats to shatter when broken.
Some maple wood has a highly decorative wood grain, known as flame maple and quilt maple. 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. Birdseye maple is another distinctive grain pattern.
Most drums are made from maple. From the 70s to the 90s, maple drum kits were a vast majority of all drum kits made. In recent years, Birch has become popular for drums once again. Electric guitar necks are commonly made from maple. The necks of the Fender Stratocaster and Telecaster were originally an entirely maple one piece neck, but later were also available with rosewood fingerboards. Maple fingerboards have a brighter sound than rosewood.
The tops of Gibson's Les Paul guitar are made from carved maple. Many Les Pauls have quilted or flamed maple tops, and these models are particularly prized by players and collectors. Very few solid body guitars are made entirely from maple, as it is considered too heavy. Many guitars do, however, have maple tops or veneers. Gibson uses laminated maple in the manufacture of many of its semi-hollowbody guitars.