The Birch { Study of Trees }-12

Beautiful Birch in winter { December Snow}

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Introduction

This the twelve in the series 'A Study of Trees' is another article aimed at helping those who wish to identify trees,but are unfamiliar with the species, to do so. With the aid of descriptive text and great images, recognition should become somewhat easier.

Most people start their recognition process by their form and colour of the tree's foliage. This is all well and good in the summer months but in winter when the foliage has fallen and the branches are naked and bare it is of little use. Yet every tree has a character{s} which will help the observant to recognize the species even in the depths of winter.

Here we review the Birch which belongs to the order of trees known as the Fagales and the family Betulaceae within that order. The downy birch which is the principle species of this article has been allocated the genus name of Betula alba {or pubescens} the Downy birch.

Birch in woodland Finland.

Originally posted to Flickr ,uploaded by MPF to Commons.
Originally posted to Flickr ,uploaded by MPF to Commons. | Source

Betula pubescens subspecies glutinosa

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General information and background

The Birch dressed in its cloth of silver adorned with emeralds or with 'patines of gold'during the autumn was bound to attract the attention of poets and artists. And although the many uses of its components have now been confined to history its beauty adds to the landscape a picturesque scene,and for this it is still valued. Indeed the very name birch in its identity with 'bark','barque',or 'burge' relates to the time when its silver rind formed the canoes of our ancestors,such have been discovered buried in the gravels of the banks of rivers such as the Clyde in Scotland.

The genus Betula to which are subject belongs includes many species of shrubs and trees of a medium size confined to the northern hemisphere and remarkable for their exhibition into the Arctic latitudes.Our subject Betula alba { sometimes Betula pubescens depending on the author},ascends to 2,500 feet in the Highlands of Scotland,and is widely spread over the continent of Europe,Asia and America,extending further north than any other European tree.

Together with the Alders of which there are also many species, the birches form the natural Order of Betulaceae,catkin bearing trees.The Birches differ from the Alders in the scales of the seed bearing catkins being chaff-like,and falling together with its winged fruits, whilst those of the Alder remain as a woody cone. {see my hub The Elegant Alder Tree}

The white or Silver Birch Betula pendula { see my Hub Silver Birch 'Graceful Lady' of the Woods} ios a short lived tree as a rule 40-50 feet high ,with a trunk seldom exceeding a foot in diameter,conspicuous for its flaking silver white bark.

Betula alba, named by Linnaeus, includes several fairly distinct forms. Of these Betula vernacosa is distinguished by its longer pendulous branches,having white resinous tubercles on the bark and occasionally on the foliage, and by its conical buds, by the reflexed sickle-like shaped side lobes of the scales of the fruiting catkins and by the leaf. This is rhomboidally triangular its long stalk passing abruptly into the blade. The veins project from the upper surface of the blade and its point abruptly acuminate or tapering.

Betula glutinosa,on the other hand is often a mere shrub,its buds are egg-shaped, the side lobes of the scales of the fruiting catkins are erect. The leaf is rounded or almost heart shaped at the base,and its has veins projecting from the under surface,and its points acute but not drawn out.

The northern form Betula alba {our subject} differs mainly in the absence of tubercles and in the downiness of the leaves,stalks and twigs. Birch seedlings soon germinate and spread rapidly. Wherever birch abounds in woods and coppice, a great many seedling plants spring up. In various parts of England they were once collected by country people and sold to the Nurserymen. Indeed this was the main way of the Nursery obtaining trees of every kind until the advent of commercial nurseries.

Birch in summer

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Verses to the birch

Professor Wilson gives this beautiful description of the Birch tree in his 'Isles of Palms'

" Oh the green slope

Of a romantic glade we sate us down,

And the fragrance of the yellow broom,

While o're our heads the weeping birch tree stream'd

Its branches,arching like a fountain shower"


And Leyden,


" Sweet bird of the meadow,soft be thy rest;

Thy mother will wake thee at morn from thy nest'

She has made a soft nest,little redbreast, for thee,

Of the leaves of birch,and the moss of the tree"

Components of Betula alba { Pubescens}

Atlas de Plantes de France 1891
Atlas de Plantes de France 1891 | Source

Young birch sapling

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Leaves and Catkins of the Birch

In all forms the branches succeed one another in what is termed in botanical parlance as a Cymose manner,each axis being comparatively short and somewhat thick leaves on slender stalks with broad stipules at the base and doubly toothed margins,appear before the maturity of the catkins may be seen forming on the twigs.

The leaves are oval and acute and somewhat deltoide,and nearly glabrous. The Male catkins are borne at the ends of the shoots of the previous year,and are not protected by any winter bud scales,whilst the female or fruiting catkins terminate lateral dwarf shoots that bear few leaves,and are enclosed by bud scales.

The pollen bearing catkins are shorter and are at first erect. In time the two bracteoles cohere with the bract to form a three lobed scale, which, as previously mentioned fall off with the three fruits that are produced from its base,and the form of the side lobes of which distinguishes the subspecies. The little fruits are furnished with a broad membranous wing, which together with their flattened form,aids their dispersal by the wind.

Their general outline is almost circular,surmounted by tow small styles,an indication of the original two chambers of the ovary,reduced in the fruit stage,by an abortion frequent among trees,to one chamber and one seed.

Catkin and fruits

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The disease known as 'Witches broom' look like old magpies nests

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Roots and wood of the birch

The roots extend themselves horizontally and divide into a great number of rootlets and hair like fibres at their extremities,but they never throw up suckers.

The wood of the birch is diffuse and porous, with minute vessels in groups of as many as eight, with pith rays so fine as to be indistinguishable with the naked eye,and with pith-flecks towards the centre of the trunk,whilst the sapwood id light yellowish brown,the heart wood is slightly tinged with red. Though moderately hard, it is exceptionally porous,and of so even a grain as to be readily turned.

In earlier times not only did the birch provide primitive man with his canoe,but it probably roofed his crude buildings and furnished fibre for his cable, and fishing lines in districts beyond the northern line of the linden {Lime}. It is also probable that man took to tapping the white trunks in spring at a very early stage in our history. He learned that the copious flow of sugary sap made not only a refreshing drink in its own right but also realised that he could ferment the sap into wine, or spirit. { This is now illegal in the UK unless you own the tree,or the tree has been designated for felling.}

Louden,{1894} informs us -" That in Lapland and Kamtshatka, the huts are constructed with bitch branches covered by turf, and bundles of the spray with leaves on, in cases formed of the skin of Reindeer serve for seats during the day,and beds at night"

Owing to the arrangement of the cells in the outer bark the birch is constantly shedding in strips that go right around the stems and thus along with the Plane tree one of the species best adapted to withstand the smoke and smog once so familiar in our cities.

The tree however, is prone to the disease known as 'Witches broom' a contorted mass of twigs that appear like an old Corvid's nest and produced by a fungus, or by a very minute gall mite,which attack the young buds. It is recommended that all parts affected are burned,as the mites can be carried from tree to tree by the wind or by birds. It seems that pendulous species of birch are not as vulnerable to attack. It also attacks trees growing on boggy spoil rather more than those growing on lighter sandier soils.

Birches thrive best in moist situations provided there is good drainage and seems to thrive best on light and even sandy soils.

The distinctive trunk of the birch

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Grey birch against a grey sky

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Related species

In North America one of the native species of birch is Betula populifolia known as the grey {gray] birch.It is a deciduous tree that ranges from south east Ontario east to Nova Scotia and south to Pennsylvania and New Jersey. It is a quick growing species attaining the height of twenty-thirty feet,with an irregular crown of slender branches.

The bark of the species tends to be chalky or greyish white with black triangular patches where the bark meets the trunk. However, the bark of the species does not expoliate in the manner of that of the Paper birch Betula papyifera.

The catkins which are wind pollinated are 5-8 cm long the male catkins pendulous and the female catkins erect.

In his book Familiar Trees with their Leaves {American} 1896, Ferdinand Mathews states-" The European birch is indeed closely allied to our tree,is certainly very beautiful and is becoming quite common in cultivation. There is a specimen placed in front of a private residence Plymouth N.H., it is a cut leaved variety specifically named Betula alba var laciniata. But when I admit its beauty I must remind those who have studiously observed our own gay birch, that its European relative does not possess the power of flashing that jewel like green light to which I have drawn attention. In a wood the foreign tree possesses a beautifully shaped leaf,without the splendid lively colour of its American relative.

Leaves of Betula populifolia

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Betula papyifera another relative

Betula papyifera has also been referred to as B.alba var commotata and B.alba var cordifolia. It is a medium sized tree reaching sixty feet tall {18m} which live for about one hundred and forty years. It is also known as the canoe birch and is another native of North America. It is the state tree of New Hampshire.

The foliage are arranged alternately they are ovate one point five inches long and two.four inches broad. The margins are furnished with two rows of teeth. The leaf buds are conical and small. The catkins one point five inches long growing from the tips of the twigs. The white birch with all its varieties have a wide distribution in South and central Alaska and throughout Canada with the exception of Nunavut as well as the northern United States south to Pennsylvania and Washington with small isolated populations further south.

The species is considered to be vulnerable in Indiana, imperilled in Illinois,Virginia, West Virginia and Wyoming and critically imperilled in Colorado and Tennessee.

Bark of the Betula papyifera

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The larvae of Camberwell Beauty feeds on birch foliage

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Birch and wildlife

Mr. Westwood {1800's} observed it is a tree upon which a very great number of insects feed,seldom,however, causing any mischief to the tree of any importance. Of these we look at those that seem to feed on the Birch species only,starting with the Lepidoptera, the caterpillars of which exclusively or partially subsist upon its leaves.

Among the butterflies the Camberwell Beauty is a partial birch feeder whilst the Brown Hairstreak seems to be confined to birch woods, they appear as adults in August. The birch leaves are also fed upon by a number of moth larvae. Some beetle larvae also feed on the foliage and in some instances so do the adults, as do the larvae of Sawflies.

When the birch is in decay various fungi root themselves into the wood particularly the bracket fungus Piptoporus betulinus, this species generally grows on the trunks of dead trees On the ground the Fly Agaric, Agarus muscarious, the most poisonous of the genus is generally found especially associated with Birch woods.


Birch polypore Piptoporus betulinus a bracket fungus that grows on the trunks of birch

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6 comments

D.A.L. profile image

D.A.L. 2 years ago from Lancashire north west England Author

aviannovice,

Hi Deb, you are very welcome. I love the bark of birch and the way it stands out on a moonlit night. Best wishes to you.


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aviannovice 2 years ago from Stillwater, OK

Indeed, the birch is a truly remarkable tree. There were many of these wonderful hardwoods on my property in Maine. As a child, I would peel some of the bark to expose the beautiful tan layer underneath. This tree left me in awe, as the bark had a number of layers, as the outer layer would eventually wear away. Thanks for the memories...


D.A.L. profile image

D.A.L. 2 years ago from Lancashire north west England Author

JYOTI KOTHARI,

Hi, my friend thank you too,for your encouraging comments,much appreciated. Best wishes to you.


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JYOTI KOTHARI 2 years ago from Jaipur

This is a beautiful tree and the hub is so. Rated up and funny.


D.A.L. profile image

D.A.L. 2 years ago from Lancashire north west England Author

DDE,

Hello Devika, yes I seem to be on a roll at the moment, and it is thanks to kind and encouraging comments from good friends like you which spur me on. The photographs are really good but I can only be credited for choosing them. Best wishes my friend..


DDE profile image

DDE 2 years ago from Dubrovnik, Croatia

I so enjoyed reading another one of your well-informed hubs. You have such a great display of photos it gives a great image to your writing skills. I see that you are writing more often. Keep up that routine! Voted up, interesting, and useful.

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