Acer ( ) is a
genus
of
trees or
shrubs
commonly known as
Maple.
Maples 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 system, favour inclusion in Sapindaceae. The
type species of the genus is
Acer pseudoplatanus
(Sycamore Maple).
There are approximately 125
species, most of
which are native to
Asia, , with a number also
appearing in
Europe, northern
Africa, and
North
America.
The word
Acer is derived from a
Latin word meaning "sharp", referring to the
characteristic points on
maple leaves. It
was first applied to the genus by the
French botanist
Joseph Pitton de Tournefort in
1700.A red maple leaf is the prominent feature of the
flag of Canada.
Morphology
Maples are mostly
trees growing to 10-45 meters
(30-145 ft) in height. Others are
shrubs less
than 10 meters 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
(Nepal Maple) 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, or 'whirlybirds,' 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
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.
The genus is subdivided by its morphology into a multitude of
sections and subsections.
Pests and diseases
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.
Uses
Horticulture
Maples are planted as
ornamental
trees by homeowners, businesses and municipalities.
Acer platanoides (Norway
Maple) is especially popular as it is fast-growing and extremely
cold-resistant, though it is also an
invasive species in some regions. Other
maples, especially smaller or more unusual species, are popular as
specimen trees.
Cultivars
Numerous maple
cultivars which have been
selected for particular characteristics can be
propagated only by
asexual reproduction such as cuttings,
tissue culture, budding or
grafting.
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 the
western
world. Some delicate cultivars are usually grown in pots and
rarely reach heights of more than 50-100 cm. Maple is also a key
wood in the construction of
percussion instruments like
drum kits. Some of the best drum building companies
like DW (
Drum Workshop) use maple
extensively throughout their mid-pro range.
Bonsai
are a popular choice for the art of
bonsai.
Acer palmatum (Japanese
Maple),
Acer buergerianum
(Trident Maple),
Acer ginnala
(Amur Maple),
Acer campestre
(Field Maple) and
Montpellier
Maple (
A. monspessulanum) are popular choices and
respond well to techniques that encourage leaf reduction and
ramification, but most species
can be used.
Collections
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.
Tourism
Many maples have bright
autumn
foliage, and many countries have leaf-watching traditions.
In
Japan
, the custom of viewing the changing colour of
maples in the autumn is called "momijigari". Nikko and
Kyoto are
particularly favoured destinations for this activity.
In addition, in Korea,
the same viewing activity is called "Danpung-Nori" and Seoraksan
and Naejang-san
mountains are very famous places for
it.
The
particularly spectacular fall colours of the Acer saccharum (Sugar 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.
Commercial uses
Maples are important as source of syrup and
wood. Dried wood is often used for the
smoking of food. They are also cultivated
as
ornamental plants and have
benefits for
tourism and
agriculture.
Maple syrup
The
Sugar Maple (
Acer
saccharum) is tapped for
sap, which
is then boiled to produce
maple syrup or
made into
maple sugar or
maple taffy. It takes about 40 liters of Sugar
Maple sap to make a liter of syrup. Syrup can be made from
closely-related species as well, but their output is
inferior.
Food
The seeds are sometimes consumed after they are boiled in water to
remove bitter tasting compounds.
Timber

A bench made of highly-figured maple
wood
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
block. 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.
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 the other major tonewood used in instrument manufacture.
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 guitars 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. The back and sides of most violins are made from
maple.
Maple is also used to make
bassoons and
double basses.
Agriculture
As they are a major source of
pollen in early
spring before many other plants have flowered, maples are important
to the survival of
honeybees that play a
commercially-important role later in the spring and summer.
Gallery
Image:Acer cappadocicum spring.jpg|
Acer cappadocicum (Cappadocian
Maple)Image:Acer carpinifolium.jpg|
Acer carpinifolium
leavesImage:Paperbark Maple Acer griseum Leaves Closeup
2856px.jpg|
Acer griseum
compound (trifoliate) leafImage:BigleafMaple 0304.jpg|
Acer macrophyllum flowers and young
leavesImage:Acer laevigatum 3.jpg|
Acer laevigatum leaves and
fruitImage:Acer sempervirens leaves.jpg|
Acer sempervirens foliageImage:Acer
ginnala.jpg|
Acer ginnala
foliageImage:redmaple.jpg|
Acer
rubrum trees in
autumnImage:TenryujiMomiji.jpg|
Acer
palmatum trees and bamboo in JapanImage:Bi-colored Maple
Tree.jpg|
Acer
grandidentatum in autumn colourImage:Maple leaf
Fcb981.JPG|
Acer
platanoides leafImage:Red maple leaf.jpg|
Acer palmatum leaf in
autumn
References
- Sunset Western Garden Book, 1995:606–607
- van Gelderen, C. J. & van Gelderen, D. M. (1999).
Maples for Gardens: A Color Encyclopedia
- Huxley, A., ed. (1992). New RHS Dictionary of
Gardening. Macmillan ISBN 0-333-47494-5.
- Classification of maples
- Phillips, D. H. & Burdekin, D. A. (1992). Diseases of
Forest and Ornamental Trees. Macmillan. ISBN
0-333-49493-8.