|Betula pendula (Silver birch)|
|Genus:|| Betula |
|Range of Betula|
A birch is a thin-leaved deciduous hardwood tree of the genus Betula ( // ), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae. The genus Betula contains 30 to 60 known taxa of which 11 are on the IUCN 2011 Red List of Threatened Species. They are a typically rather short-lived pioneer species widespread in the Northern Hemisphere, particularly in northern areas of temperate climates and in boreal climates.
Birch species are generally small to medium-sized trees or shrubs, mostly of northern temperate and boreal climates.The simple leaves are alternate, singly or doubly serrate, feather-veined, petiolate and stipulate. They often appear in pairs, but these pairs are really borne on spur-like, two-leaved, lateral branchlets. The fruit is a small samara, although the wings may be obscure in some species. They differ from the alders (Alnus, another genus in the family) in that the female catkins are not woody and disintegrate at maturity, falling apart to release the seeds, unlike the woody, cone-like female alder catkins.
The bark of all birches is characteristically marked with long, horizontal lenticels, and often separates into thin, papery plates, especially upon the paper birch.Distinctive colors give the common names gray, white, black, silver and yellow birch to different species.
The buds, forming early and full-grown by midsummer, are all lateral, without a terminal bud forming; the branch is prolonged by the upper lateral bud. The wood of all the species is close-grained with a satiny texture and capable of taking a fine polish; its fuel value is fair.
The flowers are monoecious, opening with or before the leaves. Once fully grown, these leaves are usually 3–6 millimetres (1⁄8–1⁄4 in) long on three-flowered clusters in the axils of the scales of drooping or erect catkins or aments. Staminate catkins are pendulous, clustered, or solitary in the axils of the last leaves of the branch of the year or near the ends of the short lateral branchlets of the year. They form in early autumn and remain rigid during the winter. The scales of the mature staminate catkins are broadly ovate, rounded, yellow or orange colour below the middle and dark chestnut brown at apex. Each scale bears two bractlets and three sterile flowers, each flower consisting of a sessile, membranous, usually two-lobed, calyx. Each calyx bears four short filaments with one-celled anthers or strictly, two filaments divided into two branches, each bearing a half-anther. Anther cells open longitudinally. The pistillate segments are erect or pendulous, and solitary, terminal on the two-leaved lateral spur-like branchlets of the year. The pistillate scales are oblong-ovate, three-lobed, pale yellow-green often tinged with red, becoming brown at maturity. These scales bear two or three fertile flowers, each flower consisting of a naked ovary. The ovary is compressed, two-celled, and crowned with two slender styles; the ovule is solitary. Each scale bears a single small, winged nut that is oval, with two persistent stigmas at the apex.
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Betula species are organised into five subgenera.
Note: many American texts have B. pendula and B. pubescens confused, though they are distinct species with different chromosome numbers.
The common name birch comes from Old English birce, bierce, from Proto-Germanic *berk-jōn (cf. German Birke, West Frisian bjirk), an adjectival formation from *berkōn (cf. Dutch berk, Low German Bark, Danish birk, Norwegian bjørk), itself from the Proto-Indo-European root *bʰerHǵ- ~ bʰrHǵ-, which also gave Lithuanian béržas, Latvian Bērzs, Russian berëza, Ukrainian beréza, Albanian bredh 'fir', Ossetian bærz(æ), Sanskrit bhurja, Polish brzoza, Latin fraxinus 'ash (tree)'. This root is presumably derived from *bʰreh₁ǵ- 'to shine, whiten', in reference to the birch's white bark. The Proto-Germanic rune berkanan is named after the birch.
The generic name Betula is from Latin, which is a diminutive borrowed from Gaulish betua (cf. Old Irish bethe, Welsh bedw).
Within Betulaceae, birches are most closely related to alder. The oldest known birch fossils are those of Betula leopoldae from the Klondike Mountain Formation in Washington State, USA, which date to the early Eocene (Ypresian) around 49 million years ago.
Birches often form even-aged stands on light, well-drained, particularly acidic soils. They are regarded as pioneer species, rapidly colonizing open ground especially in secondary successional sequences following a disturbance or fire. Birches are early tree species to become established in primary successions, and can become a threat to heathland if the seedlings and saplings are not suppressed by grazing or periodic burning. Birches are generally lowland species, but some species, such as Betula nana , have a montane distribution. In the British Isles, there is some difference between the environments of Betula pendula and Betula pubescens, and some hybridization, though both are "opportunists in steady-state woodland systems". Mycorrhizal fungi, including sheathing (ecto)mycorrhizas, are found in some cases to be beneficial to tree growth.
A large number of lepidopteran insects feed on birch foliage.
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Because of the hardness of birch, it is easier to shape it with power tools; it is quite difficult to work it with hand tools.
The inner bark is considered edible as an emergency food, even when raw.It can be dried and ground into flour, as was done by Native Americans and early settlers. It can also be cut into strips and cooked like noodles.
The sap can be drunk or used to make syrup.Tea can be made from the red inner bark of black birches.
White-barked birches in particular are cultivated as ornamental trees, largely for their appearance in winter. The Himalayan birch, Betula utilis , especially the variety or subspecies jacquemontii, is among the most widely planted for this purpose. It has been cultivated since the 1870s, and many cultivars are available, including 'Doorenbos', 'Grayswood Ghost' and 'Silver Shadow'; 'Knightshayes' has a slightly weeping habit. Other species with ornamental white bark include Betula ermanii , Betula papyrifera , Betula pendula and Betula raddeana .
In the European Union, a prescription gel containing birch bark extract (commercial name Episalvan, betulae cortex dry extract (5-10 : 1); extraction solvent: n-heptane 95% (w/w)) was approved in 2016 for the topical treatment of minor skin wounds in adults. Although its mechanism of action in helping to heal injured skin is not fully understood, birch bark extract appears to stimulate the growth of keratinocytes which then fill the wound.
Preliminary research indicates that the phytochemicals, betulin and possibly other triterpenes, are active in Episalvan gel and wound healing properties of birch bark.
Over centuries, birch bark was used in traditional medicine practices by North American indigenous people for treating superficial wounds by applying bark directly to the skin.Splints made with birch bark were used as casts for broken limbs in the 16th century.
Wood pulp made from birch gives relatively long and slender fibres for a hardwood. The thin walls cause the fibre to collapse upon drying, giving a paper with low bulk and low opacity. The birch fibres are, however, easily fibrillated and give about 75% of the tensile strength of softwood.[ clarification needed ] The low opacity makes it suitable for making glassine.
In India, the birch (Sanskrit: भुर्ज, bhurja) holds great historical significance in the culture of North India, where the thin bark coming off in winter was extensively used as writing paper. Birch paper (Sanskrit: भुर्ज पत्र, bhurja patra) is exceptionally durable and was the material used for many ancient Indian texts. [ citation needed ]The Roman period Vindolanda tablets also use birch as a material on which to write and birch bark was used widely in ancient Russia as notepaper (beresta) and for decorative purposes and even making footwear (lapti) and baskets.
Baltic birch is among the most sought-after wood in the manufacture of speaker cabinets. Birch has a natural resonance that peaks in the high and low frequencies, which are also the hardest for speakers to reproduce.[ citation needed ] This resonance compensates for the roll-off of low and high frequencies in the speakers, and evens the tone. Birch is known for having "natural EQ".[ citation needed ]
Drums are often made from birch. Prior to the 1970s, it was one of the most popular drum woods. Because of the need for greater volume and midrange clarity, drums were made almost entirely from maple until recently,[ clarification needed ] when advances in live sound reinforcement and drum microphones have allowed the use of birch in high-volume situations. Birch drums have a natural boost in the high and low frequencies, which allows the drums to sound fuller.[ citation needed ]
Birch wood is sometimes used as a tonewood for semiacoustic and acoustic guitar bodies, and occasionally for solid-body guitar bodies. It is also a common material used in mallets for keyboard percussion.[ citation needed ]
Birches have spiritual importance in several religions, both modern and historical. In Celtic cultures, the birch symbolises growth, renewal, stability, initiation, and adaptability because it is highly adaptive and able to sustain harsh conditions with casual indifference. Proof of this adaptability is seen in its easy and eager ability to repopulate areas damaged by forest fires or clearings. Birches are also associated with Tír na nÓg , the land of the dead and the Sidhe , in Gaelic folklore, and as such frequently appear in Scottish, Irish, and English folksongs and ballads in association with death, or fairies, or returning from the grave. The leaves of the silver birch tree are used in the festival of St George, held in Novosej and other villages in Albania.
The birch is New Hampshire's state tree and the national tree of Finland and Russia. The yellow birch is the official tree of the province of Quebec (Canada). The birch is a very important element in Russian culture and represents the grace, strength, tenderness and natural beauty of Russian women as well as the closeness to nature of the Russians. [ citation needed ]It's associated with marriage and love. There are numerous folkloric Russian songs in which the birch tree occurs. The Ornäs birch is the national tree of Sweden. The Czech word for the month of March, Březen, is derived from the Czech word bříza meaning birch, as birch trees flower in March under local conditions. The silver birch tree is of special importance to the Swedish city of Umeå. In 1888, the Umeå city fire spread all over the city and nearly burnt it down to the ground, but some birches, supposedly, halted the spread of the fire. To protect the city against future fires, wide avenues were created, and these were lined with silver birch trees all over the city. Umeå later adopted the unofficial name of "City of the Birches (Björkarnas stad)". Also, the ice hockey team of Umeå is called Björklöven , translated to English "The Birch Leaves".
"Swinging" birch trees was a common game for American children in the nineteenth century. American poet Lucy Larcom's "Swinging on a Birch Tree" celebrates the game.The poem inspired Robert Frost, who pays homage to the act of climbing birch trees in his more famous poem, "Birches". Frost once told "it was almost sacrilegious climbing a birch tree till it bent, till it gave and swooped to the ground, but that's what boys did in those days".
Alders are trees comprising the genus Alnus in the birch family Betulaceae. The genus comprises about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few species extending into Central America, as well as the northern and southern Andes.
Betulaceae, the birch family, includes six genera of deciduous nut-bearing trees and shrubs, including the birches, alders, hazels, hornbeams, hazel-hornbeam, and hop-hornbeams numbering a total of 167 species. They are mostly natives of the temperate Northern Hemisphere, with a few species reaching the Southern Hemisphere in the Andes in South America. Their typical flowers are catkins and often appear before leaves.
Hornbeams are hardwood trees in the flowering plant genus Carpinus in the birch family Betulaceae. The 30–40 species occur across much of the temperate regions of the Northern Hemisphere.
Betula pendula, commonly known as silver birch, warty birch, European white birch, or East Asian white birch, is a species of tree in the family Betulaceae, native to Europe and parts of Asia, though in southern Europe, it is only found at higher altitudes. Its range extends into Siberia, China, and southwest Asia in the mountains of northern Turkey, the Caucasus, and northern Iran. It has been introduced into North America, where it is known as the European white birch or weeping birch and is considered invasive in some states in the United States and parts of Canada. The tree can also be found in more temperate regions of Australia.
Betula pubescens, commonly known as downy birch and also as moor birch, white birch, European white birch or hairy birch, is a species of deciduous tree, native and abundant throughout northern Europe and northern Asia, growing farther north than any other broadleaf tree. It is closely related to, and often confused with, the silver birch, but grows in wetter places with heavier soils and poorer drainage; smaller trees can also be confused with the dwarf birch.
Betula nigra, the black birch, river birch or water birch, is a species of birch native to the Eastern United States from New Hampshire west to southern Minnesota, and south to northern Florida and west to Texas. It is one of the few heat-tolerant birches in a family of mostly cold-weather trees which do not thrive in USDA Zone 6 and up. B. nigra commonly occurs in floodplains and swamps.
Ostrya is a genus of eight to 10 small deciduous trees belonging to the birch family Betulaceae. Common names include hop-hornbeam and hophornbeam. It may also be called ironwood, a name shared with a number of other plants.
Betula papyrifera is a short-lived species of birch native to northern North America. Paper birch is named for the tree's thin white bark, which often peels in paper like layers from the trunk. Paper birch is often one of the first species to colonize a burned area within the northern latitudes, and is an important species for moose browsing. The wood is often used for pulpwood and firewood.
Betula alleghaniensis, the yellow birch, golden birch, or swamp birch, is a large tree and an important lumber species of birch native to northeastern North America. Its vernacular names refer to the golden color of the tree's bark. In the past the species name was Betula lutea.
Betula lenta is a species of birch native to eastern North America, from southern Maine west to southernmost Ontario, and south in the Appalachian Mountains to northern Georgia.
Birch bark or birchbark is the bark of several Eurasian and North American birch trees of the genus Betula.
Betula nana, the dwarf birch, is a species of birch in the family Betulaceae, found mainly in the tundra of the Arctic region.
Birch sap,birch water or birch juice is the sap directly tapped from birch trees, Betula pubescens, Betula pendula, Betula lenta, Betula papyrifera, and Betula fontinalis.
Betula neoalaskana or Alaska birch, also known as Alaska paper birch or resin birch, is a species of birch native to Alaska and northern Canada. Its range covers most of interior Alaska, and extends from the southern Brooks Range to the Chugach Range in Alaska, including the Turnagain Arm and northern half of the Kenai Peninsula, eastward from Norton Sound through the Yukon, Northwest Territories, British Columbia, Alberta, Saskatchewan, Manitoba, southern Nunavut, and into northwestern Ontario.
Betula platyphylla, the Asian white birch or Japanese white birch, is a tree species in the family Betulaceae. It can be found in subarctic and temperate Asia in Japan, China, Korea, Mongolia, and Russian Far East and Siberia. It can grow to be 30 m (98 ft) tall.
Betula occidentalis, the water birch or red birch, is a species of birch native to western North America, in Canada from Yukon east to Northwestern Ontario and southwards, and in the United States from eastern Washington east to western North Dakota, and south to eastern California, northern Arizona and northern New Mexico, and southwestern Alaska. It typically occurs along streams in mountainous regions, sometimes at elevations of 2,100 metres and in drier areas than paper birch.
Betula ermanii, or Erman's birch, is a species of birch tree belonging to the family Betulaceae. It is an extremely variable species and can be found in Northeast China, Korea, Japan, and Russian Far East. It can grow to 20 metres (66 ft) tall. It is noted for its peeling bark, which can sometimes be removed in sheets, but usually shreds and hangs from the trunk and under branches. Yellow-brown male catkins appear with the leaves in spring.
Betula cordifolia, the mountain paper birch is a birch species native to Eastern Canada and the Northeastern United States. Until recently it was considered a variety of Betula papyrifera, with which it shares many characteristics, and it was classified as B. papyrifera var. cordifolia (Regel) Fern.
Myzia oblongoguttata, commonly known as the striped ladybird, is a species of beetle in family Coccinellidae. It is found in the Palearctic.
Another method cited was that of splints made of birch bark soaked in water until quite soft. They were then carefully fitted to the limb and tied with bark thongs. On drying, they became stiff and firm. There is no record of the use of extension, but, nevertheless, very few crippled and deformed Indians were to be seen.