Betula pubescens

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Betula pubescens
Betula pubescens - Burgwald 002.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fagales
Family: Betulaceae
Genus: Betula
Subgenus: Betula subg. Betula
Species:
B. pubescens
Binomial name
Betula pubescens
Betula pubescens range.svg
Distribution map
Synonyms [2]
List
    • Betula acuminataKindb.
    • Betula albaL.
    • Betula alba var. glabrata(Wahlenb.) Muñoz Garm. & Pedrol
    • Betula alba subsp. glutinosa(Trautv. ex Regel) Holub
    • Betula ambiguaHampe ex Rchb.
    • Betula andrejiV.N.Vassil.
    • Betula asplenifoliaRegel
    • Betula × aurata var. rhombifolia(Tausch) Tzvelev
    • Betula aureaSteud.
    • Betula baicaliaV.N.Vassil.
    • Betula borealisSpach
    • Betula borysthenicaKlokov
    • Betula broccembergensisBechst.
    • Betula browiczianaGüner
    • Betula callosaNotø
    • Betula canadensisK.Koch
    • Betula carpaticaWaldst. & Kit. ex Willd.
    • Betula caucasicaLitv. ex Leskov
    • Betula concinnaGunnarsson
    • Betula coriifoliaTausch ex Regel
    • Betula czerepanoviiN.I.Orlova
    • Betula czerepanovii var. nasaroviiTzvelev
    • Betula dalecarlicaL.f.
    • Betula glabraDumort.
    • Betula glaucaWender.
    • Betula glutinosaWallr.
    • Betula golitsiniiV.N.Vassil.
    • Betula hackeliiOpiz ex Steud.
    • Betula jacuticaV.N.Vassil.
    • Betula kryloviiG.V.Krylov
    • Betula × kusmisscheffii(Regel) Sukaczev
    • Betula laciniataThunb.
    • Betula lentaDu Roi
    • Betula litwinowiiDoluch.
    • Betula macrostachyaSchrad. ex Regel
    • Betula majorGilib.
    • Betula megalopteraKindb.
    • Betula microdontiaKindb.
    • Betula murithiiGaudin ex Regel
    • Betula nigricansWender.
    • Betula odorataBechst.
    • Betula odorata var. tortuosa(Ledeb.) Rosenv.
    • Betula ovataK.Koch
    • Betula platyodontiaKindb.
    • Betula ponticaLoudon
    • Betula pubescens var. appressaKallio & Y.Mäkinen
    • Betula pubescens subsp. borealis(Spach) Á.Löve & D.Löve
    • Betula pubescens f. columnarisT.Ulvinen
    • Betula pubescens subsp. czerepanovii(N.I.Orlova) Hämet-Ahti
    • Betula pubescens f. hibernifoliaT.Ulvinen
    • Betula pubescens f. rubraT.Ulvinen
    • Betula recurvata(I.V.Vassil.) V.N.Vassil.
    • Betula rhombifoliaTausch
    • Betula rotundataBeck
    • Betula sajanensisV.N.Vassil.
    • Betula sokolowiiRegel
    • Betula stenocarpaKindb.
    • Betula subarcticaOrlova
    • Betula subarctica var. pojarkovaeTzvelev
    • Betula subodorataKindb.
    • Betula tomentosaReitter & Abeleven
    • Betula torfacea(Custor) Schleich.
    • Betula tortuosaLedeb.
    • Betula transcaucasicaV.N.Vassil.
    • Betula tricholepideaKindb.
    • Betula urticifolia(Loudon) Regel
    • Betula virgataSalisb.

Betula pubescens (syn. Betula alba), 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 (B. pendula), but grows in wetter places with heavier soils and poorer drainage; smaller trees can also be confused with the dwarf birch (B. nana).

Contents

Six varieties are recognised and it hybridises with the silver and dwarf birches. A number of cultivars have been developed but many are no longer in cultivation. The larva of the autumnal moth (Epirrita autumnata) feeds on the foliage and in some years, large areas of birch forest can be defoliated by this insect. Many fungi are associated with the tree and certain pathogenic fungi are the causal agents of birch dieback disease.

The tree is a pioneer species, readily colonising cleared land, but later being replaced by taller, more long-lived species. The bark can be stripped off without killing the tree and the bark and the timber is used for turnery and in the manufacture of plywood, furniture, shelves, coffins, matches, toys and wood flooring. The inner bark is edible and it was ground up and used in bread-making in times of famine. The rising sap in spring can be used to make refreshing drinks, wines, ales and liqueurs and various parts of the tree have been used in herbal medicine.

Description

The branches are upward or horizontally spread, but never pendulous (as with silver birch) Niitvalja soo sookask 31-12-2017.jpg
The branches are upward or horizontally spread, but never pendulous (as with silver birch)

Betula pubescens is commonly known as downy birch, with other common names including moor birch, white birch, European white birch or hairy birch. [3] It is a deciduous tree growing to 10 to 20 m (33 to 66 ft) tall (rarely to 27 m), with a slender crown and a trunk up to 70 cm (28 in) (exceptionally 1 m) in diameter, with smooth but dull grey-white bark finely marked with dark horizontal lenticels. The shoots are grey-brown with fine downy. The leaves are ovate-acute, 2 to 5 cm (0.8 to 2.0 in) long and 1.5 to 4.5 cm (0.6 to 1.8 in) broad, with a finely serrated margin. The flowers are wind-pollinated catkins, produced in early spring before the leaves. The fruit is a pendulous, cylindrical aggregate 1 to 4 cm (0.4 to 1.6 in) long and 5 to 7 mm (0.2 to 0.3 in) wide which disintegrates at maturity, releasing the individual seeds; these seeds are 2 mm (0.08 in) long with two small wings along the side. [3] [4]

Species identification

B. pubescens is closely related to, and often confused with, the silver birch (B. pendula). Many North American texts treat the two species as conspecific (and cause confusion by combining the downy birch's alternative vernacular name, white birch, with the scientific name B. pendula of the other species), but they are regarded as distinct species throughout Europe. [4]

Downy birch can be distinguished from silver birch with its smooth, downy shoots, which are hairless and warty in silver birch. The bark of the downy birch is a dull greyish white, whereas the silver birch has striking white, papery bark with black fissures. The leaf margins also differ, finely serrated in downy birch, coarsely double-toothed in silver birch. The two have differences in habitat requirements, with downy birch more common on wet, poorly drained sites, such as clays and peat bogs, and silver birch found mainly on dry, sandy soils. [4]

In more northerly locations, downy birch can also be confused with the dwarf birch (Betula nana), both species being morphologically variable. All three species can be distinguished cytologically, silver birch and dwarf birch being diploid (with two sets of chromosomes), whereas downy birch is tetraploid (with four sets of chromosomes). In Iceland, dwarf birch and downy birch sometimes hybridise, the resulting plants being triploid (with three sets of chromosomes). [5]

Distribution and habitat

Betula pubescens near a path encircling a lake inside the Arctic Circle in Tromso Prestvannet-parkvei.jpg
Betula pubescens near a path encircling a lake inside the Arctic Circle in Tromsø

Betula pubescens has a wide distribution in northern and central Europe and Asia. Its range extends from Newfoundland, Iceland, the British Isles and Spain eastwards across northern and central Europe and Asia as far as the Lake Baikal region in Siberia. The range extends southwards to about 40°N, its southernmost limit being Turkey, the Caucasus and the Altai Mountains. [1] [6] It is a pioneer species which establishes itself readily in new areas away from the parent tree. This allows other woodland trees to become established and the birch, a short-lived tree, eventually gets crowded out as its seedlings are intolerant of shady conditions. [7]

Downy birch extends farther north into the Arctic than any other broadleaf tree. Specimens of the subarctic populations are usually small and very contorted, and are often distinguished as arctic downy birch or mountain birch, B. p. var. pumila. [8] [9] (not to be confused with B. nana ). This variety is notable as being one of very few trees native to Iceland and Greenland, and is the only tree to form woodland in Iceland. At one time the island is thought to have been covered in downy birch woodland, but that cover is reduced to about one percent of the land surface today. [5]

Varieties and cultivars

Arctic downy birch forms the tree line in most of Fennoscandia Betula pubescens subsp. tortuosa Saana.jpg
Arctic downy birch forms the tree line in most of Fennoscandia

Three varieties are recognised, the nominate Betula pubescens var. pubescens, B. p. var. litwinowii (distributed in the Caucasus and Turkey) and B. p. var. pumila (arctic downy birch or mountain birch, formerly called B. p. subsp. tortuosa). [10] The latter has arisen from the hybridization of var. pubescens and B. nana (dwarf birch) [9] [11] and is characterised by its shrubby habit, smaller leaves, resinous glands and the smaller wings on the fruit. A number of cultivars have been grown but many are no longer in cultivation. They include "Armenian gold", "Arnold Brembo" (scented foliage), crenata nana (shrubby and dwarf), incisa (lobed foliage), integrifolia (unlobed foliage), murigthii (shrubby with doubly serrate leaves), ponitica (hairless), undulata (leaf margins waxy), urticifolia (nettle-leaved), variegata (variegated) and "Yellow wings". [12] Two others, described by the German botanist Ernst Schelle in 1903, are also lost; pendula , a cultivar with a leader and weeping branches, [13] and pendula nana , which grows into an umbrella-shaped tree with weeping branches but no leader. [13] Betula pubescens 'Rubra' has maroon foliage. [14]

Ecology

Scarce dagger larva feeding on the moor birch Acronicta auricoma - Betula pubescens - Niitvalja bog.jpg
Scarce dagger larva feeding on the moor birch

The larva of the autumnal moth (Epirrita autumnata) feeds on the foliage of Betula pubescens and other tree species. In outbreak years, large areas of birch forest can be defoliated by this insect. Damage to the leaf tissue stimulates the tree to produce chemicals that reduce foliage quality, retarding the growth of the larvae and reducing their pupal weights. [15]

In Greenland, about seventy species of fungi have been found growing in association with B. pubescens, as parasites or saprobes on living or dead wood. Some of the most common fungi include Ceriporia reticulata , Chondrostereum purpureum , Exidia repanda , Hyphoderma spp, Inonotus obliquus , Inonotus radiatus , Mycena galericulata , Mycena rubromarginata , Panellus ringens , Peniophora incarnata , Phellinus lundellii , Radulomyces confluens , Stereum rugosum , Trechispora spp., Tubulicrinis spp. and Tyromyces chioneus . [16]

Birch dieback disease, associated with the fungal pathogens Marssonina betulae and Anisogramma virgultorum , can affect planted trees, while naturally regenerated trees seem less susceptible. [17] This disease also affects Betula pendula and in 2000 was reported at many of the sites planted with birch in Scotland during the 1990s. [18]

Uses

Betula pubescens is a pioneering species, seen expanding its altitudinal range here in Norway Warming-Norwaymountains.JPG
Betula pubescens is a pioneering species, seen expanding its altitudinal range here in Norway

The outer layer of bark can be stripped off the tree without killing it and can be used to make canoe skins, drinking vessels and roofing tiles. [7] The inner bark can be used for the production of rope and for making a form of oiled paper. This bark is also rich in tannin and has been used as a brown dye and as a preservative. The bark can also be turned into a high quality charcoal favoured by artists. The twigs and young branches are very flexible and make good whisks and brooms. [7] The timber is pale in colour with a fine, uniform texture and is used in the manufacture of plywood, furniture, shelves, coffins, matches and toys, and in turnery. [19]

The Sami people of Scandinavia used the bark of both B. pubescens and B. pendula as an ingredient in bread-making; the reddish phloem, just below the outer bark, was dried, ground up and blended with wheat flour to make a traditional loaf. [20] In Finland, mämmi, a traditional Easter food, was packed and baked in boxes of birch bark. Nowadays, cardboard boxes are used, but imprinted with the typical bark pattern. [21] Birch bark was used as an emergency food in times of famine; in Novgorod in 1127–28, desperate people ate it along with such things as the leaves of lime trees, wood pulp, straw, husks and moss. [22] In Iceland, trimmings of birch trees are used with birch sap in the making of a sweet birch liqueur. [23] The removal of bark was at one time so widespread that Carl Linnaeus expressed his concern for the survival of the woodlands. [24] The leaves can be infused with boiling water to make a tea, and extracts of the plant have been used as herbal remedies. [3]

Both B. pubescens and B. pendula can be tapped in spring to obtain a sugary fluid. This can be consumed fresh, concentrated into a syrup similar to the better-known maple syrup, or can be fermented into an ale or wine. In Scandinavia and Finland, this is done on a domestic scale, but in the former USSR, particularly Russia, Ukraine, Belarus, Estonia, Latvia and Lithuania, birch sap is harvested commercially and used to manufacture cosmetics, medicines and foodstuffs. [25]

Related Research Articles

<span class="mw-page-title-main">Birch</span> Genus of flowering plants in the family Betulaceae

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.

<i>Betula pendula</i> Species of birch

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.

<i>Betula papyrifera</i> Species of tree

Betula papyrifera is a short-lived species of birch native to northern North America. Paper birch is named after 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. Primary commercial uses for paper birch wood are as boltwood and sawlogs, while secondary products include firewood and pulpwood. It is the provincial tree of Saskatchewan and the state tree of New Hampshire.

<span class="mw-page-title-main">Autumnal moth</span> Species of moth

The autumnal moth is a moth of the family Geometridae. The species was first described by Moritz Balthasar Borkhausen in 1794. It is found throughout the Palearctic region and the Near East and has a much wider distribution than its two close relatives. In Sápmi (Lapland), in some years, the numerous autumnal moth larvae defoliate square miles of birch forests on mountains.

<i>Betula nana</i> Species of flowering plant

Betula nana, the dwarf birch, is a species of birch in the family Betulaceae, found mainly in the tundra of the Arctic region.

White birch is a common name for Betula papyrifera, a species of tree native to northern North America.

NVC community W11 is one of the woodland communities in the British National Vegetation Classification system. It is one of the six communities falling in the "mixed deciduous and oak/birch woodlands" group.

<span class="mw-page-title-main">Weeping tree</span> Tree with a weeping habit

Weeping trees are trees characterized by soft, limp twigs. This characterization may lead to a bent crown and pendulous branches that can cascade to the ground. While weepyness occurs in nature, most weeping trees are cultivars. Because of their shape, weeping trees are popular in landscaping; generally they need a lot of space and are solitary so that their effect is more pronounced. There are over a hundred different types of weeping trees. Some trees, such as the cherry, have a variety of weeping cultivars. There are currently around 550 weeping cultivars in 75 different genera, although many have now disappeared from cultivation.

<i>Stigmella lapponica</i> Species of moth

Stigmella lapponica is a moth of the family Nepticulidae found in Asia, Europe and North America. It was first described by the German entomologist, Maximilian Ferdinand Wocke in 1862. The larvae mine the leaves of birch.

<i>Betula utilis</i> Species of birch

Betula utilis, the Himalayan birch, is a deciduous tree native to the Western Himalayas, growing at elevations up to 4,500 m (14,800 ft). The Latin specific epithet utilis means "useful", and refers to the many uses of the different parts of the tree. The white, paper-like bark was used in ancient times for writing Sanskrit scriptures and texts. It is still used as paper for the writing of sacred mantras, with the bark placed in an amulet and worn for protection. Selected varieties are used for landscaping throughout the world, even while some areas of its native habitat are being lost due to overuse of the tree for firewood.

<i>Lactarius pubescens</i> Species of fungus

Lactarius pubescens, commonly known as the downy milk cap, is a species of fungus in the family Russulaceae. It is a medium to large agaric with a creamy-buff, hairy cap, whitish gills and short stout stem. The fungus has a cosmopolitan distribution, and grows solitarily or in scattered groups on sandy soil under or near birch.

<i>Acer palmatum</i> Species of maple

Acer palmatum, commonly known as Japanese maple, palmate maple, or smooth Japanese maple (Korean: danpungnamu, 단풍나무, Japanese: irohamomiji, イロハモミジ, or momiji,, is a species of woody plant native to Korea, Japan, China, eastern Mongolia, and southeast Russia. Many different cultivars of this maple have been selected and they are grown worldwide for their large variety of attractive forms, leaf shapes, and spectacular colors.

Betula pubescens 'Pendula', or Weeping Downy Birch, is a weeping tree and a cultivar of Betula pubescens, the Downy Birch. It was first described by Schelle in 1903. No trees are known to survive of this cultivar.

<i>Euceraphis punctipennis</i> Species of true bug

Euceraphis punctipennis, the downy birch aphid or European birch aphid, is a species of aphid in the order Hemiptera. These aphids are tiny green insects with soft bodies and membranous wings. They are found living on downy birch trees where they feed and multiply on the buds and leaves by sucking sap.

Birch dieback is a disease of birch trees that causes the branches in the crown to die off. The disease may eventually kill the tree. In an event in the Eastern United States and Canada in the 1930s and 1940s, no causal agent was found, but the wood-boring beetle, the bronze birch borer, was implicated in the severe damage and death of the tree that often followed. In similar crown dieback occurrences in Europe several decades later, the pathogenic fungus Melanconium betulinum were found in association with affected trees, as well as Anisogramma virgultorum and Marssonina betulae.

<i>Taphrina betulina</i> Species of fungus

Taphrina betulina is a fungal plant pathogen that causes the gall, witches broom, which is a chemical infection of birch buds or the developing shoots, leading to a proliferation of growth. It was first described by Emil Rostrup in 1883 and is found in Europe, New Zealand and North America.

Massalongia rubra is a species of gall midge which forms galls in the leaves of birch. It was first described by the French naturalist and entomologist, Jean-Jacques Kieffer in 1890 and is found in Europe.

References

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  5. 1 2 Thórsson, Æ.Th.; Pálsson, S.; Sigurgeirsson, A.; Anamthawat-Jónsson, K. (2007). "Morphological Variation among Betula nana (diploid), B. pubescens (tetraploid) and their Triploid Hybrids in Iceland". Annals of Botany. 99 (6): 1183–1193. doi:10.1093/aob/mcm060. PMC   3243578 . PMID   17495985.
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