Title
The Latin generic name was borrowed from the Gaulish language.
The Russian word "birch" comes from praslav. *berza, dating back to the Great I.E. *bheros (compare lit. beržas, Latvian. bērzs, oset. bærž, etc.-ind. bhurjah, etc.-English beorc, English birch, German. Birke, Netherlands. berk, norv. bjørk, Sweden. björk), from the root *bherĝ- "to glow, to whiten".
In other Slavic languages: belor. byarosa, Ukrainian birch, bolg. breza, Serbo-Croatian breza, Slovene. brėza, Czech. bříza, Polish. brzoza, v.-luzh. brěza, N.-luzh. brjaza. Examples of names in other languages: French Bouleau, Yakut. For more information about the genus names in other languages, see the Betula page of the Wikivida project.
The word "birch" is related to the words "birch bark" (Latin Ulmus), "birch bark".
Botanical description
Main source:
Cherry birch
Botanical illustration from the book Köhler's Medizinal-Pflanzen, 1887
Most birch species are trees up to 30 and even 45 m high, with trunk girth up to 120-150 cm, some species are shrubs from large to small, up to creeping, barely rising above the ground. All representatives of the genus are monoecious bisexual wind-pollinated (anemophilic) plants.
The root system of birch trees is powerful, depending on the type and growing conditions, either superficial, or, more often, goes obliquely deep. The taproot of the seedling dies very quickly, but the lateral roots develop powerfully and are rich in thin mochkovidny roots. Birch grows slowly only in the first years. Then, on the contrary, it begins to grow quickly, and this ensures its victory over competing herbaceous vegetation.
Bark of flat-leaved birch (Betula pumila)
A branch of the marsh birch (Betula pumila)
Radde birch Earrings (Betula raddeana)
From left to right: bract scale, coplodium and fruit of the fluffy birch (Betula pubescens)
The bark of most birches is white, yellowish, pinkish or reddish-brown, in some species it is gray, brown or even black. The cavities of the cork tissue cells on the trunks are filled with a white resinous substance - betulin, which gives the bark a white color[9]. The outer part - birch bark - is usually easily peeled off with ribbons. In old trees, the lower part of the trunk is often covered with a dark crust with deep cracks.
Birch leaves are alternate, whole, toothed along the edge, ovate-rhombic or triangular-ovate, monosymmetric, with a wide wedge-shaped base or almost truncated, smooth, up to 7 cm long and 4 cm wide, turn yellow before falling off. Young leaves are sticky. The venation of the leaf blade is perfect pinnate-nervous (pinnate-kraebezhnoe): the lateral veins end in the teeth.
The kidneys are alternate, sessile, covered with spirally arranged, often sticky scales; the lateral kidneys are slightly spaced.
Male flowers in complex inflorescences - catkins - appear in summer on the tops of elongated shoots, usually 2-3; at first they are erect and green, then gradually turn brown. Their length is 2-4 cm . Male catkins consist of numerous thyroid stalked integumentary scales fused with a central flower rod, expanded to the top, provided with two smaller scales from below and containing three flowers on the inside. Each flower is also covered with a scaly perianth, in which the organs of fertilization — stamens are placed. Outside, the entire earring is covered with a resinous substance impervious to moisture. In this form, the earrings overwinter. In spring, in March - May (depending on the climate), the stem of the male earring lengthens, as a result of which the scales surrounding the flower open, and yellow stamens become noticeable between them, liberally releasing flower pollen. At this time, the earrings that used to stand straight, first tilt, and then completely hang. Female catkins grow on the tops of shortened shoots (brachiblasts) developing from the lateral buds of last year's shoots, and therefore always sit on the side of the branch. Simultaneously with the blooming of male earrings, leaf buds and female earrings bloom. During flowering, they are always shorter and already male, which immediately fall off after pollination. The bract (fruit) scales of female catkins are deeply three-lobed; the lateral lobes are usually shorter than the average. Female flowers (that is, only one ovary) sit three under each bract scale; in each ovary there are two hanging ovules, of which one dries up after pollination, and the second grows, occupying the entire cavity of the ovary. The female fertilized earring lengthens at this time, often it grows a leg, and it thickens itself due to an increase in the volume of scales, gradually turning into an oval or oblong-cylindrical "bump". After the fruit ripens, which occurs quite soon - depending on the climate, in July - September - the fruit earring (cone) crumbles and only the core remains from it. .
The fruit is a flattened lentil-shaped nut bearing two dried columns at the top and surrounded by a more or less wide thin-skinned membranous wing. The fruits sit three at a time in the axils of three-lobed fruit (bract) scales. The seeds are very light — there are 5,000 seeds in one gram. They are easily carried by the wind (at a distance of up to 100 m from the mother plant), the fruits are not opened.
Distribution and ecological status
The birch is dwarf, creeping over the stones. Greenland
Dwarf birch in the foreground. In the background there is a European white birch
Birch forest in the Inari region (Finnish polar Lapland)
Many birch species are widespread and the most important forest-forming species, largely determining the appearance and species composition of deciduous and coniferous-deciduous (mixed) forests in the temperate and cold parts of Eurasia and North America. There are also shrubs among the birches, the most famous of them is the dwarf birch (Betula nana) is common in the tundras of Europe and North America and the mountain tundras of Siberia. It does not reach even 1 m in height. During the glacial and post-glacial periods, this birch was spread much further south, now it is found there only in swamps as a relic.
Most birches are very frost-resistant, do not suffer from spring frosts, tolerate permafrost, penetrate far beyond the Arctic Circle or form the upper border of the forest in the mountains (for example, birch woodlands in the Caucasus). Birch trees of subtropical regions (Himalayan-Chinese, some Japanese and American River birch (Betula nigra)) are more demanding of heat. The southernmost and thermophilic species of birch on our planet is the alder birch (Betula alnoides), which enters the mountainous regions of the monsoon tropics of Southeast Asia.
Birch is not demanding to the richness of the soil. Birch species grow on sandy and loamy, rich and poor, moist and dry soils. It is found on the damp banks of rivers and seas, in swamps, in swampy tundra, on dry rocky slopes, in hot dry steppes. For example, the Radde Birch (Betula raddeana) forms forests covering gorges in the mountain forest belt in the mountains of Dagestan.
Most birches are light-loving, although there are also quite shade-tolerant (Ribbed birch (Betula costata), Woolly birch (Betula lanata) and Alleghany Birch (Betula alleghaniensis)).
Many species of birch are pioneers in the settlement of cuttings, harems, wastelands and outcrops (such is the hanging birch (Betula pendula)): in these places, pure birch plantations (secondary forests) are often observed mainly of grass type, therefore birch is often referred to as soil-improving rocks. In the future, the composition of the stand changes: birch is displaced by spruce, since spruce growth can exist under a relatively light birch canopy, and young birches are shaded by fir trees and die (see Succession).
In the forest-steppe, in moist places in saucer-shaped depressions, birch (often together with aspen and occasionally with willow) forms small forests called stakes. Spikes are characteristic of the forest-steppe of Western Siberia, they are found on the Oka-Don plain.
The genus Birch in the collections of botanical gardens of Russia as a whole is represented by 92 taxa, exclusively in open-ground collections. The largest collection of the genus is located in the Main Botanical Garden of the Russian Academy of Sciences.
The life expectancy of birch, according to various sources— is 100-120 years, 150 (300) years, 100-150 years, individual trees live up to 400 years or more.
On the birch live, among others, the caterpillar of the linden hawk moth, the birch moth, the common raspberry. The deer beetle, the largest beetle in Europe, lives in the wood of birch and other deciduous trees. Birch leaves are eaten by May beetles, and in some years, when their numbers are especially high, they can cause serious damage to trees.
Birch groves and forests mixed with birch are characterized by mycorrhizal fungal species, many of which live in a community exclusively or predominantly with birch. The most common and well - known of them are:
The wave is pink among the dry birch leaves.
Lithuania common podberezovik and some other species of the genus Obabok - bolotny podberezovik, rosy podberezovik;
white birch mushroom is one of the most valuable edible mushrooms;
some milkweeds (black bunch, pink wave), certain types of cheesecakes - green cheesecake, yellow cheesecake, food cheesecake.
Damaged trees can be affected by parasitic fungi — for example, the mown tinder (Inonotus obliquus), rarely found on other trees. Preparations obtained from the chaga, an infertile form of the mown tinder, are used in folk and official medicine as adaptogens.
Birch is also characterized by specific types of fungi — destroyers of dead wood (saprotrophic), which play an important role in the process of self-cleaning of forests from dead wood, windbreaks, etc. Of these, birch tinder (Piptoporus betulinus) and birch lenzites (Lenzites betulina) are common in birch groves, the first of which does not occur on wood of other breeds, and the second usually prefers birch.
Chemical composition
