Maple

from the Late Eocene in the Florissant Formation, Florissant, Colorado, United States The closest relative of Acer is Dipteronia, which only has two living species in China, but has a fossil record extending back to the middle Paleocene in North America. The oldest known fossils of Acer are from the late Paleocene of Northeast Asia and northern North America, around 60 million years old. The oldest fossils of Acer in Europe are from Svalbard, dating to the late Eocene (Priabonian ~38–34 million years ago). ==Morphology==

'' (sugar maple) Most maples or acers are trees growing to a height of . Others are shrubs less than 10 meters tall with a number of small trunks originating at about ground level. Most species are deciduous, and many are renowned for their autumn leaf colours, but a few in southern Asia and the Mediterranean region are mostly evergreen. Most are shade-tolerant when young and are often riparian, understory, or pioneer species rather than climax overstory trees. There are a few exceptions such as sugar maple, which may form monodominant forests. Many of the root systems are typically dense and fibrous, inhibiting the growth of other vegetation underneath them. A few species, notably Acer cappadocicum, frequently produce root sprouts, which can develop into clonal colonies. 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. of a μCT scan of a samara. Resolution is about 45 μm/voxel. The distinctive fruits are called samaras, "maple keys", "helicopters", "whirlybirds" or "polynoses". 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. 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 of supplies and was based on the maple seed. 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 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 require stratification in order to germinate, and some seeds can remain dormant in the soil for several years before germinating. Molecular studies incorporating DNA sequence data from both chloroplast and nuclear genomes, aiming to resolve the internal relationships and reconstruct the evolutionary 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. Fifty-four species of maples meet the International Union for Conservation of Nature criteria for being under threat of extinction in their native habitat. ==Pests and diseases==

fungus on Acer pseudoplatanus'' leaf The leaves are used as a food plant for the larvae of a number of the order Lepidoptera (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. Aphids are also very common sap-feeders on maples, they are a natural part of herbivorous insect communities on maples, though they may become pests when accumulated in large densities. In horticultural applications a dimethoate spray will solve this. Aphid abundance has been shown to depend on tree condition and host species. 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 that 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. ==Cultural significance==

A maple leaf appears on the coat of arms of Canada, and is on the Canadian 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 of Canadian 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 of Quebec where the sugar maple is significant, today's arboreal emblem of Canada rather refers to a generic maple. The design on the flag is an eleven-point stylization modeled after a sugar maple leaf (which normally bears 23 points). It is also in the name of the Canadian ice hockey team, the Toronto Maple Leafs. The first attested use of the word was in 1260 as "mapole", and it also appears a century later in Geoffrey Chaucer's Canterbury Tales, spelled as "mapul". The maple is also a symbol of Hiroshima, ubiquitous in the local meibutsu. A maple leaf, along with samaras, appears in the coat of arms of Sammatti, a former municipality of Uusimaa, Finland. ==Uses==

Horticulture trees (Japanese maple) has over 1,000 cultivars. This cultivar is A. palmatum'' 'Sango kaku', sometimes called "coralbark maple" Some species of maple are extensively planted as ornamental 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 are Norway maple (although it is considered invasive in North America), silver maple, Japanese maple, and red maple. The vine maple is also occasionally used as an ornamental tree. Other maples, especially smaller or more unusual species, are popular as specimen trees. Collections '' is widely grown for its decorative bark 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. They are also cultivated as ornamental plants and have benefits for tourism and agriculture. Timber 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 and snooker cue shafts, and butcher's blocks. Maple wood is also used for the manufacture of wooden baseball bats, though less often than ash or hickory due to the tendency of maple bats to shatter if they do break. The maple bat was introduced to Major League Baseball (MLB) in 1998 by Sam Bat founder Sam Holman. Today it is the standard maple bat most in use by professional baseball. Maple is also commonly used in archery as the core material in the limbs of a recurve bow due to its stiffness and strength. 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. Some maple wood has a highly decorative wood grain, variously known as flame maple, quilt maple, birdseye maple and burl 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. 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. Maples have a long history of use for furniture production in the United States. The Cherokee people would produce a purple dye from maple bark, which they used to dye cloth. Tonewood Maple is considered a tonewood, or a wood that carries sound waves well, and is used in numerous musical instruments. Maple is harder and has a brighter sound than mahogany, which is another major tonewood used in instrument manufacturing. The back, sides, and neck of most violins, violas, cellos, and double basses are made from maple. Electric guitar necks are commonly made from maple, having good dimensional stability. The necks of the Fender Stratocaster and Telecaster were originally an entirely maple one piece neck, but later were also available with rosewood fingerboards. Les Paul desired an all maple guitar, but due to the weight of maple, only the tops of Gibson's Les Paul guitars are made from carved maple, often using quilted or flamed maple tops. Due to its weight, very few solid body guitars are made entirely from maple, but many guitars have maple necks, tops or veneers. Maple is also often used to make bassoons and sometimes other woodwind instruments such as recorders. Many drums 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. Certain drum sticks are also made from maple. Agriculture During late winter to early spring in northeastern North America, when the night-to-day temperatures change from freezing to thawing, maple trees may be tapped for sap to manufacture maple syrup. The sap is sent via tubing to a sugar house where it is boiled to produce syrup or made into maple sugar or maple taffy. It takes about of sugar maple sap to make of syrup. Also, as these trees are a major source of pollen in early spring before many other plants have flowered, maple flowers are a source of foraging for honeybees that play a commercially important role in general agriculture and in natural habitats. Pulpwood Maple is used as pulpwood. The fibers have relatively thick walls that prevent collapsing upon drying. This gives good bulk and opacity in paper. With a lignin content of approximately 21%, maple is often processed into high yield pulp to enhance printing properties. Tourism Many maples have bright autumn 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-eastern North America. In Japan, the custom of viewing the changing colour of maples in the autumn is called momijigari. Nikkō and Kyoto are particularly favoured destinations for this activity. In Korea, the same viewing activity is called danpung-nori and the Seoraksan and Naejang-san mountains are among the best-known destinations. These are examples of ecosystem services are examples of cultural ecosystem services that hold relational value. Gallery File:台灣三角楓 Acer buergerianum var. formosanum 20220411100147 08.jpg|Acer buergerianum var. formosanum leaves and fruit Image:Acer cappadocicum spring.jpg|Acer cappadocicum (Cappadocian maple) Image:Acer carpinifolium.jpg|Acer carpinifolium leaves Image:Acer ginnala.jpg|Acer ginnala foliage Image:Bi-colored Maple Tree.jpg|Acer grandidentatum (bigtooth maple) in autumn colour Image:Paperbark Maple Acer griseum Leaves Closeup 2856px.jpg|Acer griseum (paperbark maple) Image:Acer laevigatum 3.jpg|Acer laevigatum leaves and fruit Image:Acer macrophyllum 0304.jpg|Acer macrophyllum flowers and young leaves File:青楓 Acer serrulatum 20210419095802 02.jpg|Acer oliverianum trunk Image:TenryujiMomiji.jpg|Acer palmatum trees and bamboo in Japan Image:Red maple leaf.jpg|Acer palmatum leaf in autumn Image:Maple leaf Fcb981.JPG|Acer platanoides leaf Image:Helicopter leaves.jpg|Acer platanoides (Norway maple) samaras File:Acer rubrum 1-eheep (5097479399).jpg|Acer rubrum leaves File:Red maple.png|Acer rubrum tree in autumn Image:Acer sempervirens leaves.jpg|Acer sempervirens foliage Image:Autumn Blaze Maple Foliage.jpg|Acer × freemanii 'Autumn Blaze' (a cross between A. rubrum and A. saccharinum File:Maple acer stem 1 year 100x.jpg|Maple acer stem 1 year 100x actual diameter 2.0-2.2mm ==See also==