Birch, Silver

[[Category:Top30]]
[[Category:Deciduous Trees]]
[[Category:Betulaceae]]
[[Category:Betula]]
[[File:SilverBirchFeb.jpg|right|200px]]

”’Scientific Name”’: ”Betula pendula”

”’Family”’: ”Betulaceae”

”’Also known as”’: warty birch, or East Asian white birch

”’Habitat”’: In forests and woodland throughout its range. Tolerant of a range of temperatures, it grows as far south as Spain and as far north as Lapland. It has been introduced into North America where it is know as European white birch and is considered invasive in some areas.

Forming stands on open hillsides and heath. Can be one of a few, if not the only deciduous tree amongst the needled trees in the north of its range. often hybridises with our other native birch, the downy birch, ”Betula pubescens” which is more common in Scotland. It thrives in dry woodlands, downs and heaths. [[commons:Betula pendula#Trees and Forests|Silver Birch trees and forests]]

”’Description”’: It is a vigorous and fast growing species. Young branches point upwards, but eventually they droop giving the name “”pendula””. Mature trees can be up to 30 meters.

The bark on the trunk and branches is golden-brown at first, but later this turns to white (hence the “silver” part of the name) as a result of papery tissue developing on the surface and peeling off in flakes, in a similar manner to the closely related Paper birch (”Betula papyrifera”). The bark remains smooth until the tree gets quite large, but in older trees, the bark thickens, becoming irregular, dark and rugged. [[commons:Betula pendula#Bark, foliage, flowers, fruit and buds|Silver Birch detailed images]]

Young branches are burgundy coloured with whitish resin warts and the twigs are slender and hairless.

The buds are small (4-5mm), green, pointed egg-shaped and sticky, and development is sympodial, that is to say the terminal bud dies away and growth continues from a lateral bud.

The leaves have short slender stalks and are 3 to 7 cm long, triangular with broad, untoothed, wedge-shaped bases, slender pointed tips and coarsely double-toothed, serrated margins. They are sticky with resin at first but this dries as they age leaving small white scales. The foliage is a pale to medium green and turns yellow early in the autumn before the leaves fall.

Silver birch is monoecious, and catkins appear from April to May. Male catkins are long and yellow-brown, and hang in groups of two to four at the tips of shoots, like lambs’ tails. Female catkins are smaller, short, bright green and erect. In mid-summer, the female catkins mature and the male catkins expand and release pollen, and wind pollination takes place. The seeds are very numerous and are separated by scales, and when ripe, the whole catkin disintegrates and the seeds are spread widely by the wind.

”’Identification Features”’:
*”’Bark”’ – Smooth, silvery white, often peeling away to reveal grey or pinky-orange underneath. More mature trees developing dark, diamond-shaped fissures. The lower part of the trunk typically becomes very deeply fissured, rugged and corky.
*”’Twigs”’ – Fine, delicate, smooth, burgundy colour with many white resin glands. Shoots are pendulous. From a distance, can give the whole tree a pink/purple glow.
*”’Buds”’ – Small (4-5mm), green, egg-shaped and pointed.

==Pictures throughout the year==

File:SilverBirchFeb.jpg|Silver Birch in February
File:Silver_Birch_male_catkins.jpg|Silver Birch male catkins
File:Silver_Birch_tree_male_catkins_closeup.jpg|Silver Birch male catkins
File:Silver_Birch_bark.jpg|Silver Birch bark
File:Silver_Birch_leaf.jpg|Silver Birch leaf

==Uses==
===Food===
”’Birch sap”’. Silver birch can produce a very large amount of sweet water, for a few weeks each year in the spring. As the sap rises, but before the buds open, you can tap the tree for large amounts of sweet, nutrient rich water. Only tap one tree every three or four years so you don’t harm them.
Inner bark – cooked or dried and ground into a meal. It can be added as a thickener to soups etc or can be mixed with flour for making bread, biscuits etc. Inner bark is generally only seen as a famine food, used when other forms of starch are not available or are in short supply.
Young leaves and catkins – raw or cooked.
A tea is made from the leaves and another tea is made from the essential oil in the inner bark.
===Other===
The sap can be drunk as is, reduced to a syrup and used in place of maple syrup, or used to make a wine.

The ”’bark”’ can be used in making containers, historically was used for tanning, it can be heated to produce a resin, or heated further to produce birch tar, and the bark is quite high in resins so will take a spark for fire lighting even when damp.

Dead ”’twigs”’ can be used as kindling for a fire, or for making a besom broom.
===Medicinal===

Anti-inflammatory, cholagogue, diaphoretic. The bark is diuretic and laxative. An oil obtained from the inner bark is astringent and is used in the treatment of various skin afflictions, especially eczema and psoriasis. The bark is usually obtained from trees that have been felled for timber and can be distilled at any time of the year. The inner bark is bitter and astringent, it is used in treating intermittent fevers. The vernal sap is diuretic. The buds are balsamic. The young shoots and leaves secrete a resinous substance which has acid properties, when combined with alkalis it is a tonic laxative. The leaves are anticholesterolemic and diuretic. They also contain phytosides, which are effective germicides. An infusion of the leaves is used in the treatment of gout, dropsy and rheumatism, and is recommended as a reliable solvent of kidney stones. The young leaves and leaf buds are harvested in the spring and dried for later use. A decoction of the leaves and bark is used for bathing skin eruptions. Moxa is made from the yellow fungous excrescences of the wood, which sometimes swell out of the fissures. The German Commission E Monographs, a therapeutic guide to herbal medicine, approve Betula species for infections of the urinary tract, kidney and bladder stones, rheumatism.
In ”’traditional medicine”’, a decoction of the bark or leaves is used as a diuretic and is said to be useful in the treatment of high blood pressure, high cholesterol, obesity, gout, kidney stones, nephritis, cystitis and respiratory diseases.

==Gav notes==
===Known hazards===
The aromatic and aliphatic hydrocarbons in birch tar are irritating to the skin. Do not use in patients with oedema or with poor kidney or heart functions.
===Harvesting===
For 2 – 3 weeks around the end of March/beginning of April. My preferred method (and least damaging), is to gather a lot of thin twigs (living ones, obviously), cut the ends, and put them into the neck of a bottle. Secure the bottle, make sure that it is lower than the branches and leave it to fill up. Using this method will take longer to get as much liquid, but it’s much less likely to cause permanent damage to the tree than drilling a hole in it.
===Potential lookalikes===
Downy birch (Betula pubescens) and the two easily hybridise. New shoots on the silver birch are hairless and warty whereas those of downy are smooth and covered in soft hairs.
Uses for both are similar.
===Fungus===
Dead or dying birch trees are a good place to find the ”’Birch polypore fungus”’ (http://www.foundfood.com/birch-polypore-pitptoporus-betulinus/).

”’Sources”’:
*Tree and Plant ID course from Frontier Bushcraft – http://identificationmasterclass.com/
*Wikipedia – https://en.wikipedia.org/wiki/Betula_pendula
*Woodland Trust – https://www.woodlandtrust.org.uk/visiting-woods/trees-woods-and-wildlife/british-trees/native-trees/silver-birch/
*PFAF – https://www.pfaf.org/User/Plant.aspx?LatinName=Betula+pendula

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