Betula pendula
Silver birch (Betula pendula ), illustration: A branch with male catkins, B branch with knospigen female catkins, 1 2 3 male flowers 4 female catkins with pollination prepare flowers. 5 6 female flowers 8 nut winged fruit
The silver birch (Betula pendula ) ( Syn: B. alba, B. verrucosa ), also called silver birch, white birch or birch warts, is a deciduous hardwood tree species in the genus of birch (Betula ). Her slender, elegant stature, their white bark and her delicate spring green make it a spring symbol. In Scandinavia and in Russia it has a role similar to the lime tree and the oak in Germany in the folk traditions. As a "Sand - Birch " named the Silver Birch in 2000 Tree of the Year was.
In the dictionary and in general German dictionaries this tree is written to the German spelling Hängebirke. Referring, however, to scientifically based botanical works, the spelling Silver birch is now standardized as German botanical name, see standard list of ferns and flowering plants in Germany.
Description
The silver birch is 15 to 25 meters high. It reaches a maximum height of 30 meters and a maximum trunk diameter of 0.9 meters. The maximum age is 150 years. The species has a multi-layered crown. The branches are from an acute angle, the branch ends hanging over. The silver birch has a white smooth bark. This is formed by a Oberflächenperiderm, which is not, however, live long active. It bursts borkig and is then replaced by a Tiefenperiderm. The oldest layers of smooth white bark can abringeln large area or replace in narrow strips, more or less. The white color of the bark comes about by deposition of betulin. This reflects the light completely, leaving the bark appears white. The white-colored bark is interpreted as a protective mechanism against fire beef (beef damage caused by intense sunlight).
The silver birch is a not very deep, but intense heart root system. The alternate, stalked leaves are 4-7 inches long, they are arranged spirally. They are diamond-shaped, with long tapered end, her double edge is serrated.
The silver birch is monoecious. Female and male flowers are in drooping catkins isolated on a plant. Flowering time is from April to May, and the seeds ripen in August to September. The seeds are about 3 millimeters long nutlets, which are winged thin-skinned. The light seeds are spread by the wind and germinate when sufficient moisture immediately.
Distribution and ecology
The Silver Birch is a light tree. In Central Europe it is the most important pioneer tree species that inhabited the first fallow, debris and cleared areas. It is undemanding relative to the ground, but because of the growing competition from other tree species mainly on acidic soils; she avoids doing pure limestone soils, but occurs on gypsum. It grows mainly on dry sites, but has a high water consumption. While young birches always need a lot of water, old trees on very dry sites can adapt. ( However, if a previously wet standing tree suddenly dried up, he dies. ) The Silver Birch is to find due to their undemanding on peat soils and on the other extreme locations to which it is displaced due to their competitive weakness. She avoids heat and is moderately frost hardy, their photosynthetic optimum is below 20 ° C and it is adapted to their early foliation at short growing seasons. On heavily waterlogged soils it is replaced by the downy birch, with which it forms also bastards (Betula x aurata ), however, these are sterile.
Main occurrence in the boreal mixed forests of Siberia and Scandinavia on poor, dry sandy soils with pine and oak. The silver birch is found throughout Europe, with the exception of northern Scandinavia, North America and Asia. Their range extends east to the Yenisei, Altai Mountains, Caucasus and Northern Persia. In the Southern Alps, it rises up to 1900 m.
The White Birch comes in many forest communities as pioneer species after disturbances such as Storm damage or clear-cutting before, but will usually rapidly displaced by stronger competitive species. A forest community with permanently higher Birch participation is the birch oak forest, rare it is involved in natural pine forests on sand as the white moss pine forest. As a pioneer species it occurs primarily in the reforestation of open vegetation types and Gentiles (together with the Scots pine ) that she is not here so strongly bound to acidic sites and occurs, for example regularly together with the willow to rubble on.
Birch trees are not capable of coppicing and vegetative reproduction. The very light, capable of flying seeds ( " Flügelnüsschen " ) allow their rapid generative propagation, per catkins develop about 450 seeds. The seeds mature in mid-summer and be scattered in the winter, they germinate the following spring. Birch can start seeds already at the age of 5 years.
The silver birch has developed an aggressive technique to prevail in the competition for sunlight against other tree species: The acting by the Korkwarzenbesatz like sandpaper limply hanging branchlets grind with wind action steadily and effectively regular aisles in the treetops closely adjacent standing trees of other species.
System
The silver birch (Betula pendula) is a species in the genus of birch (Betula ) in the birch family ( Betulaceae ). There she is assigned to the subfamily Betuloideae ( Birch family in the narrower sense ) with the alder ( Alnus ). In the genus of birch trees they will RGL with 22 other species of section Albae. in the subgenus Eubetula RGL. assigned.
From the Silver Birch were in older literature (H. Winkler: Betulaceae, in A. Engler: The plant kingdom, 1904) described several varieties:
- Betula pendula var vulgaris ( usually ) H. Winkl.
- Betula pendula var oycoviensis (owner ) dip with shrub -like representatives in the valleys of Ojcow in Galicia and the north-east of Hungary
- Betula pendula var arbuscula ( Fries) H. Winkl. from Dalarna and Uppsala in Sweden
- Betula pendula var obscura ( Kotula ) Gürke from the Beskids, the Vistula and Silesia
In recent literature, only the variety Betula pendula var oycoviensis is usually specified.
Use
The silver birch is a Splintholzbaum, aged an optional core is sometimes formed. The wood color is white to reddish- yellow. The medium weight wood with a density of 0.61 g / cm ³ is soft but tough and elastic. It can be worked well, but it is difficult to split. Outside, the durability is low. The birch wood is used for furniture and interior design, from him chipboard, plywood and fiberboard and paper are produced. Valuable veneers are made of different grain shapes. The silver birch provides excellent firewood burning due to the high terpene content in the green state. The brushwood is used for brooms.
In phytotherapy ( herbal medicine ) components of the silver birch are also used, mainly leaves, buds and bark. In the spring a bleeding sap is obtained by tapping the trunks, made from the hair tonic and birch wine. From the bark birch tar can be produced, which is used as Pix Betulinae against skin diseases and as a birch bark for treating leather. On further distillation occurs birch pitch, which served in earlier times ( since the Paleolithic to the Middle Ages ) as a universally usable adhesive.
The bark of birch contains as therapeutically active components mainly terpenes, which are particularly important anti-inflammatory and tumor- inhibiting effect, such as anti-viral, such as betulin, betulinic acid and lupeol.
The blood cleansing and diuretic ( diuretic ) effect has been known for centuries. Blättertees be used in renal gravel, kidney and bladder stones and other kidney - bladder diseases and internal use of birch sap is described. Traditionally, the Sandbirke also for arthritis, cholesterol excess, gout or hyperuricemia, used skin and hair problems ( tars from the bark and birch sap ), rheumatism, transpiration and dropsy (edema). The bile is to be encouraged. Side effects are not known. As contraindication edema are due to impaired heart or kidney function.
From the silver birch, there are many garden forms, the weeping birch ( ' Youngii ') that blood - birch (Betula pendula Roth, cultivar 'Purpurea ') and the Cut- birch (Trost 's Dwarf ) and the Örnas birch.
Fauna
The birch species belong to the native tree species with lots of it adapted to invertebrate species, with differences between silver birch and downy birch are obviously low. Brandle and Brandl give 499 phytophagous species on birch in Germany of which 106 beetles, 140 large and 105 small butterfly species. 133 species are more or less specialized heavily on the birches. A specialized beetle species is, for example, the Birch Leaf Roller ( Deporaus betulae, Rhynchitidae ), which remodels the front part of the leaf blade in an artful, bag- shaped " parcel ", in which it deposits its eggs. A striking specialized type is the Great birch sawfly. Although the birch bug also happens on other deciduous trees, but is particularly common on birch. This kind can sometimes be annoying the people in mass flights in the fall. Bird species with a certain (but not exclusive ) binding to the birch are Redpoll Redpoll and Polar.