Broad-leaved and mixed forests make up a much smaller percentage of Russia's forest zone than coniferous taiga. In Siberia, they are completely absent. Broad-leaved and mixed forests are characteristic of the European part and the Far Eastern region of the Russian Federation. Deciduous and coniferous trees form them. They have not only a mixed composition of forest stands, but also differ in the diversity of the animal world, resistance to negative environmental influences, and mosaic structure.
Types and tiers of mixed forests
There are coniferous-small-leaved and mixed-deciduous forests. The first grow mainly in continental areas. Mixed forests have a well-marked tier (a change in the composition of the flora, depending on height). The highest tier is tall spruces, pines, oaks. Slightly lower grow birches, maples, elms, lindens, wild pears and apple trees, a younger oak tree and others. Next are the lower trees: mountain ash, viburnum, etc. The next tier is formed by shrubs: viburnum, hazel, hawthorn, overgrowth of rose hips, raspberries and many others. Next are the shrubs. Grass, lichens and mosses grow at the very bottom.
Intermediate and root forms of coniferous-deciduous forest
An interesting feature is that mixed-leaved massifs are considered only an intermediate stage in the formation of coniferous forests. However, they are also indigenous: massifs of stone birch (Kamchatka), birch chippings in forest-steppes, aspen shrubs and swampy alder forests (south of the European part of the Russian Federation). Small-leaved forests are very light. This contributes to the lush growth of the grass cover and its diversity. Coniferous mixed forest of broadleaf type, on the contrary, refers to sustainable natural formations. It is common in the transitional band between taiga and broad-leaved types. Coniferous-deciduous forests grow on the plains and on the lowest mountain belt with temperate and humid climatic conditions.
Zone of mixed and deciduous forests
Coniferous-deciduous forests grow in warmer regions of the temperate zone. They are distinguished by the diversity and richness of grass cover. They grow in discontinuous stripes from the European part of the Russian Federation to the Far East. Their landscapes are favorable for people. A zone of mixed forests is located south of the taiga. They are spread over the entire area of the East European Plain, as well as beyond the Urals (up to the Amur Region). They do not form a continuous zone.
The approximate border of the European section of broad-leaved and mixed forests in the north lies at 57 ° N. w. Above it, the oak (one of the key trees) almost completely disappears. The southern one is almost in contact with the northern border of the forest-steppes, where the spruce completely disappears. This zone is a triangle-shaped area, the two peaks of which are in Russia (Yekaterinburg, St. Petersburg), and the third in Ukraine (Kiev). That is, as you move away from the main zone to the north, broad-leaved, as well as mixed forests gradually leave the watershed. They prefer warmer and ice-protected river valleys with access to the surface of carbonate rocks. On them, broad-leaved and mixed-type forests in small massifs gradually reach the taiga.
The East European Plain mainly has a low and flat relief, only occasionally there are elevations. Here are the sources, pools and watersheds of the largest Russian rivers: the Dnieper, Volga, Western Dvina. On their floodplains, meadows interspersed with forests and arable land. In some regions of the lowlands, due to the proximity of groundwater, as well as limited runoff, they are extremely marshy in places. There are also areas with sandy soils on which pine trees grow. Berry bushes and grasses grow in swamps and clearings. This area is most suitable for coniferous-deciduous forests.
Human influence
Broadleaf, as well as mixed forests, are exposed to various influences from people for a long time. Therefore, many arrays have changed greatly: indigenous vegetation is either completely destroyed, or partially or completely replaced by secondary rocks. Now the remnants of broad-leaved forests that survived under severe anthropogenic pressure have a different structure of flora changes. Some species, having lost their place in indigenous communities, grow in anthropogenically disturbed habitats or have taken intrazonal positions.
Climate
The climate of mixed forests is quite mild. It is characterized by relatively warm winters (on average from 0 to –16 ° C) and long summers (16-24 ° C) in comparison with the taiga zone. The average annual rainfall is 500-1000 mm. It everywhere exceeds evaporation, which is a feature of a pronounced flushing water regime. Mixed forests have such a characteristic feature as a high level of development of grass cover. Their biomass averages 2-3 thousand c / ha. The level of litter also exceeds the biomass of taiga, however, due to the higher activity of microorganisms, the destruction of organic substances is much faster. Therefore, mixed forests have a smaller thickness and a greater level of decomposition of the litter than taiga conifers.
Mixed forest soils
The soils of mixed forests are diverse. The cover has a rather variegated structure. On the territory of the East European Plain, the most common type is sod-podzolic soil. It is a southern variety of classical podzolic soils and is formed only in the presence of soil-forming loamy rocks. Sod-podzolic soil has the same profile structure and similar structure. It differs from the podzolic one by the lower mass of the litter (up to 5 cm), as well as the more significant thickness of all horizons. And these are not the only differences. Sod-podzolic soils have a more pronounced humus horizon A1, which is located under the litter. Its appearance differs from a similar layer of podzolic soils. The upper part contains the rhizomes of the grass cover and forms a turf. The horizon can be painted in various shades of gray and has a loose structure. Layer thickness - 5-20 cm, humus fraction - up to 4%. The upper part of the profile of these soils has an acid reaction. As it deepens, it becomes even smaller.
Soils of mixed-deciduous forests
Gray forest soils of mixed-deciduous forests are formed in the inland regions. In Russia, they are distributed from the European part to Transbaikalia. Precipitation penetrates into such soils to a great depth. However, groundwater horizons are often very deep. Therefore, soil soaking to their level is characteristic only in highly moistened areas.
Soils of mixed forests are better suited for farming than taiga substrates. In the southern regions of the European part of the Russian Federation, arable land makes up 45% of the area. Closer to the north and taiga, the proportion of arable land is gradually decreasing. Agriculture in these regions is difficult due to the strong leaching, waterlogging and soil overgrowth. Good crops require a lot of fertilizer.
General characteristics of fauna and flora
Plants and animals of the mixed forest are very diverse. In terms of species richness of flora and fauna, they are comparable only with the tropical jungle and are home to many predators and herbivores. Here squirrels and other animals live on tall trees, birds nests are made on crowns, hares and foxes are built at the roots of burrows, and beavers live near rivers. The species diversity of the mixed zone is very large. Here, both the inhabitants of the taiga and broad-leaved forests and the inhabitants of the forest-steppes feel comfortable. Some stay awake all year, while others hibernate for the winter. Plants and animals of the mixed forest have a symbiotic relationship. Many herbivores eat different berries, which are very numerous in mixed forests.
Mixed forest trees
Mixed small-leaved forests consist of approximately 90% of coniferous and small-leaved trees. Broad-leaved species are not many. Together with coniferous trees, aspen, birch, alder, willow, poplar grow in them. Bereznyakov in the composition of arrays of this type the most. As a rule, they are secondary - that is, they grow on forest fires, on clearings and clearings, old unused arable lands. In open habitats, such forests regenerate well and grow rapidly in the early years. The expansion of their area contributes to human activities.
Coniferous-deciduous forests mainly consist of spruce, linden, pine, oak, elm, elm, maple, and in the southwestern regions of the Russian Federation - beech, ash and hornbeam. The same trees, but of local varieties, grow in the Far Eastern region along with grapes, Manchurian nuts and creepers. In many ways, the composition and structure of the forest stand of coniferous-deciduous forests depends on climatic conditions, topography, and soil-hydrological regime of a particular region. In the North Caucasus oak, spruce, maple, fir and other species prevail. But the most diverse in composition are the Far Eastern forests of coniferous-deciduous type. They are formed by cedar pine, white fir, Aiyan spruce, several varieties of maple, Manchu ash, Mongolian oak, Amur linden and the aforementioned local types of vegetation.
Species diversity of the animal world
Of the large herbivores in the mixed forests live moose, bison, wild boars, roe deer and sika deer (the species was introduced and adapted). From rodents there are forest squirrels, martens, ermines, beavers, chipmunks, otters, mice, badgers, minks, black ferrets. Mixed forests abound with a large number of bird species. Many of them are listed below, but by no means all: Oriole, nuthatch, siskin, blackbird, mountain grouse, grouse, grouse, bullfinch, nightingale, cuckoo, hoopoe, gray crane, goldfinch, woodpecker, black grouse, finch. More or less large predators are represented by wolves, lynxes and foxes. Mixed forests are also home to hares (roosters and squirrels), lizards, hedgehogs, snakes, frogs and brown bears.
Mushrooms and berries
The berries are blueberries, raspberries, lingonberries, cranberries, blackberries, bird cherry, wild strawberries, peony, elderberry, mountain ash, viburnum, wild rose, hawthorn. In forests of this type there are a lot of edible mushrooms: boletus, ceps, valui, chanterelles, russula, honey mushrooms, milk mushrooms, butterflies, traps, various rowers, brown boletus, mushrooms, mushrooms and others. One of the most dangerous poisonous macromycetes are fly agarics and pale grebes.
Shrubs
Mixed forests of Russia abound in shrubs. The understory layer is unusually developed. Oak massifs are characterized by the presence of hazel, euonymus, wolf bast, forest honeysuckle, and buckthorn in the northern zone. At the edges and in the woodlands, rose hips are growing. In the forests of coniferous-deciduous type, there are also lianiform plants: pick fence, climbing hop, bittersweet nightshade.
