European alder - Alnus glutinosa скачать в хорошем качестве

European alder - Alnus glutinosa

What do clogs, leather, and Venice have in common? Alnus glutinosa. Alder is the common name of a genus of flowering plants (Alnus) belonging to the birch family Betulaceae. The genus comprises about 30 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 and the northern Andes. Alnus glutinosa, common alder, black alder, European alder: member of birch family Betulaceae. Medium sized, short-lived, monoecious tree. Although the tree can live for up to 160 years, it is best felled for timber at 60 to 70 years before heart rot sets in. Leaves - short-stalked, rounded. Separate male and female flower in the form of catkins. Both male (pendulous, reddish) and female (upright, broad and green, with short stalks) catkins form in the autumn and remain dormant during the winter. Become dark brown to black, hard, somewhat woody, and superficially similar to small conifer cones (during autumn). Last through the winter and the small winged seeds are mostly scattered the following spring. Small, rounded, cone-like fruits. Seeds are flattened reddish-brown nuts edged with webbing filled with pockets of air. This enables them to float for about a month which allows the seed to disperse widely by wind and water. Adventitious roots at base of trunk. Bark of young trees is smooth, glossy and greenish-brown. Bark of older trees it is dark grey and fissured. Buds are purplish-brown and have short stalks. Thriving in wet locations, the common alder is used as a pioneer species and to stabilise river banks, to assist in flood control, to purify water in waterlogged soils and to moderate the temperature and nutrient status of water bodies. On marshy ground it is important as coppice-wood, being cut near the base to encourage the production of straight poles. It may be cultivated as a fast-growing windbreak. In woodland, the seedlings cannot tolerate dense shade and as the forest matures, the alder trees in it die out. The wood is soft, white when first cut, turning to pale red; the knots are attractively mottled. Under water the wood is very durable and is used for deep foundations of buildings—such as those in Venice. The wood is used in joinery, both as solid timber and as veneer. As the wood is soft, flexible and somewhat light, it can be easily worked as well as split. It is valued in turnery and carving, in making furniture, window frames, clogs, toys, blocks, pencils and bowls. The bark of the common alder has long been used in tanning and dyeing. The bark and twigs contain 16 to 20% tannic acid but their usefulness in tanning is limited by the strong accompanying colour they produce. Depending on the mordant and the methods used, various shades of brown, fawn, and yellowish-orange hues can be imparted to wool, cotton and silk. It is also the traditional wood that is burnt to produce smoked fish and other smoked foods, though in some areas other woods are now more often used. It supplies high quality charcoal. The bark of common alder has traditionally been used as an astringent, a cathartic, a hemostatic, a febrifuge, a tonic and an alterative (a substance able to restore normal health). Alder leaves are consumed by cows, sheep, goats and horses though pigs refuse to eat them. According to some people, consumption of alder leaves causes blackening of the tongue and is harmful to horses. http://en.wikipedia.org/wiki/Alnus_gl...