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 typical for the European part and the Far East region of the Russian Federation. They are formed by deciduous and coniferous trees. 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 layering of mixed forests
There are coniferous-small-leaved and mixed-broad-leaved forests. The former grow mainly in continental regions. Mixed forests have a clearly visible layering (changes in the composition of the flora, depending on the height). The uppermost tier is tall spruces, pines, oaks. Somewhat lower grow birches, maples, elms, lindens, wild pears and apple trees, younger oak forests and others. Next come lower trees: mountain ash, viburnum, etc. The next tier is formed by shrubs: viburnum, hazel, hawthorn, rose hips, raspberries and manyother. Next come the semi-shrubs. Grasses, lichens and mosses grow at the very bottom.
Intermediate and primary forms of coniferous-small-leaved forest
An interesting feature is that mixed-small-leaved massifs are considered only an intermediate stage in the formation of a coniferous forest. However, they are also indigenous: massifs of stone birch (Kamchatka), birch pegs in the forest-steppes, aspen bushes 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 grass cover and its diversity. Coniferous-mixed broad-leaved forest, on the contrary, belongs to stable natural formations. It is distributed in the transition zone 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.
Mixed and broad-leaved forest zone
Coniferous-broad-leaved forests grow in the warmer regions of the temperate zone. They are distinguished by the diversity and richness of the grass cover. They grow in intermittent stripes from the European part of the Russian Federation to the Far East. Their landscapes are favorable for people. To the south of the taiga is a zone of mixed forests. They are distributed throughout 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.
Approximate boundary of the European area of broadleaf and mixed forests in the northruns along 57° N. sh. Above it, the oak (one of the key trees) almost completely disappears. The southern one almost comes into contact with the northern border of the forest-steppes, where the spruce completely disappears. This zone is a section in the form of a triangle, two peaks of which are in Russia (Ekaterinburg, St. Petersburg), and the third - in Ukraine (Kyiv). That is, as you move away from the main zone to the north, broad-leaved, as well as mixed forests, gradually leave the watershed spaces. They prefer river valleys that are warmer and protected from icy winds with access to the surface of carbonate rocks. On them, forests of broad-leaved and mixed types gradually reach the taiga in small arrays.
The East European Plain is mostly low-lying and flat, with only occasional uplands. Here are the sources, basins and watersheds of the largest Russian rivers: the Dnieper, the Volga, the Western Dvina. On their floodplains, meadows are interspersed with forests and arable lands. In some regions, the lowlands, due to the proximity of groundwater, as well as the limited flow, are extremely swampy in places. There are also areas with sandy soils on which pine forests grow. Berry bushes and herbs grow in swamps and clearings. This area is the most suitable for coniferous-deciduous forests.
Human Influence
Broad-leaved and mixed forests are subjected to various influences by people for a long time. Therefore, many arrays have changed a lot: native vegetation or completelydestroyed, or partially or completely replaced by secondary rocks. Now the remains of broad-leaved forests, which 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) compared to the taiga zone. The average annual rainfall is 500-1000 mm. It exceeds evaporation everywhere, which is a feature of the pronounced leaching water regime. Mixed forests have such a characteristic feature as a high level of grass cover development. Their biomass averages 2-3 thousand c/ha. The level of litter also exceeds the biomass of the taiga, however, due to the higher activity of microorganisms, the destruction of organic matter is much faster. Therefore, mixed forests are thinner and have a higher level of litter decomposition than taiga coniferous forests.
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 soddy-podzolic soil. It is a southern variety of classical podzolic soils and is formed only in the presence ofsoil-forming rocks of loamy type. The soddy-podzolic soil has the same profile structure and a similar structure. It differs from the podzolic one in the lower massiveness of the litter (up to 5 cm), as well as in the greater thickness of all horizons. And these are not the only differences. Soddy-podzolic soils have a more pronounced humus horizon A1, which is located under the litter. Its appearance differs from the similar layer of podzolic soils. The upper part contains the rhizomes of the grass cover and forms the turf. The horizon can be colored in various shades of gray and has a loose structure. The layer thickness is 5-20 cm, the proportion of humus is up to 4%. The upper part of the profile of these soils has an acidic reaction. As it deepens, it becomes even smaller.
Soils of mixed-deciduous forests
Gray forest soils of mixed-deciduous forests are formed in inland regions. In Russia, they are distributed from the European part to Transbaikalia. In such soils, precipitation penetrates to a great depth. However, groundwater horizons are often very deep. Therefore, wetting the soil to their level is typical only in highly humid 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 to 45% of the area. Closer to the north and taiga, the share of arable land gradually decreases. Agriculture in these regions is difficult due to the strong leaching, waterlogging and bouldering of soils. For good harvestsneeds a lot of fertilizer.
General characteristics of fauna and flora
The plants and animals of the mixed forest are very diverse. In terms of species richness of flora and fauna, they are comparable only to the tropical jungle and are home to many predators and herbivores. Here, squirrels and other living creatures settle on high trees, birds make nests on the crowns, hares and foxes equip holes at the roots, and beavers live near the rivers. The species diversity of the mixed zone is very high. Both the inhabitants of the taiga and broad-leaved forests, and the inhabitants of the forest-steppes feel comfortable here. Some are awake all year round, while others hibernate for the winter. The plants and animals of the mixed forest have a symbiotic relationship. Many herbivores feed on various berries, which are abundant in mixed forests.
Mixed forest trees
Mixed-small-leaved forests are approximately 90% composed of coniferous and small-leaved tree species. There are not many broad-leaved varieties. Together with coniferous trees, aspens, birches, alders, willows, and poplars grow in them. There are the most birch forests in the massifs of this type. As a rule, they are secondary - that is, they grow in forest fires, clearings and clearings, old unused arable lands. In open habitats, such forests regenerate well and grow rapidly in the first years. Human economic activity contributes to the expansion of their areas.
Coniferous-broad-leaved forests mainly consist of spruce, linden, pine, oak, elm, elm, maple, and insouthwestern regions of the Russian Federation - beech, ash and hornbeam. The same trees, but of local varieties, grow in the Far East region along with grapes, Manchurian walnuts and lianas. In many respects, the composition and structure of the forest stand of coniferous-broad-leaved forests depends on climatic conditions, topography and soil-hydrological regime of a particular region. Oak, spruce, maple, fir and other species predominate in the North Caucasus. But the most diverse in composition are the Far Eastern forests of the coniferous-broad-leaved type. They are formed by cedar pine, white fir, Ayan spruce, several varieties of maple, Manchurian ash, Mongolian oak, Amur linden and the above-mentioned native vegetation types.
Species diversity of the animal world
Moose, bison, wild boars, roe deer and sika deer (a species introduced and adapted) live in mixed forests. Of the rodents, there are forest squirrels, martens, ermines, beavers, chipmunks, otters, mice, badgers, minks, black ferrets. Mixed forests abound in a large number of bird species. Many of them are listed below, but not all of them: oriole, nuthatch, siskin, field thrush, goshawk, hazel grouse, bullfinch, nightingale, cuckoo, hoopoe, gray crane, goldfinch, woodpecker, black grouse, chaffinch. More or less large predators are represented by wolves, lynxes and foxes. The mixed forests are also home to hares (hare and hare), lizards, hedgehogs, snakes, frogs and brown bears.
Mushrooms and berries
Berries are represented by blueberries, raspberries,lingonberries, cranberries, blackberries, bird cherry, wild strawberries, stone berries, elderberries, mountain ash, viburnum, rose hips, hawthorn. In the forests of this type there are a lot of edible mushrooms: boletus, porcini, valui, chanterelles, russula, mushrooms, milk mushrooms, boletus, volnushki, various rows, boletus, moss mushrooms, mushrooms and others. Fly agarics and pale grebes are among the most dangerous poisonous macromycetes.
Shrubs
Mixed forests of Russia abound with shrubs. The understory layer is unusually developed. Oak massifs are characterized by the presence of hazel, euonymus, wolf's bast, forest honeysuckle, and in the northern zone - brittle buckthorn. Rose hips grow on the edges and in light forests. In the forests of the coniferous-broad-leaved type, there are also liana-like plants: new fence, climbing hop, bittersweet nightshade.
Herbs
High species diversity, as well as a complex vertical structure, have grasses of mixed forests (especially coniferous-broad-leaved type). The most typical and widely represented category is the mesophilic nemoral plants. Among them, representatives of oak broad grass stand out. These are plants in which the leaf plate has a significant width. These include: perennial forestry, common gout, obscure lungwort, May lily of the valley, European hoof, hairy sedge, yellow greenfinch, lanceolate stellate, nomad (black and spring), amazing violet. Cereals are represented by oak bluegrass, giant fescue, forest reed grass, short-legged pinnate, spreading forest andby some others. The flat leaves of these plants are a variant of adaptation to the specific phytoenvironment of coniferous-deciduous forests.
In addition to the above perennial species, these massifs also contain herbs of the ephemeroid group. They transfer their growing season to spring time, when the lighting is maximum. After the snow melts, it is the ephemeroids that form a beautifully flowering carpet of yellow anemones and goose onions, purple corydalis and lilac-bluish woods. These plants go through a life cycle in a couple of weeks, and when the leaves of the trees bloom, their aerial part dies off over time. They experience an unfavorable period under a layer of soil in the form of tubers, bulbs and rhizomes.
