Mixed and deciduous forests Geographical location n. Plants of broadleaf forests
Climate Mixed forests are characterized by warm summers and relatively cold and long winters. Annual amount of atmospheric precipitation up to mm. The moisture coefficient in mixed forests is usually slightly higher than unity, but varies quite a lot from year to year.
Soils In the north, under coniferous-broad-leaved forests, soddy- podzolic soils, and in the southern part under broad-leaved forests - gray forest soils. There are 3 main horizons: the upper humus horizon (the most fertile), the washout and washout horizon.
Vegetation Flora of broad-leaved and mixed forests diverse. Spruce, pine, linden, maple, birch and aspen. Shrubs grow under the trees: hazel, euonymus, elderberry, raspberry, buckthorn, viburnum, and under them there is an abundance of herbs. Moss grows only in damp, dark places. In such fertile forests there are always a lot of mushrooms and all kinds of berry delicacies. There are many light-loving berry plants: strawberries, raspberries, boneberries, blueberries.
Fauna In the mixed and widespread zone deciduous forests The following animals are found: white hare, elk, squirrel, flying squirrel, capercaillie. The predominant birds here are insectivores and granivores. They also live: forest cat, brown bear, pine marten, black polecat, mink, weasel, squirrel.
Natural area of mixed and deciduous forests occupies a smaller area than coniferous forests. However, this complex, formed in a fairly warm and humid climate, is distinguished by a wide variety of flora and fauna.
Characteristics of the natural zone Mixed forests
Mixed forests are transitional link between the taiga zone and deciduous forests. The name of the natural area speaks for itself: both coniferous and deciduous trees grow here. Mixed forests are found in Russia and the European region, South and North America, and New Zealand.
The climate of this natural complex is quite mild. In winter, the temperature drops to -15 degrees Celsius, and in summer it ranges from +17-24.
Compared to the taiga, summers are warmer and longer. The amount of annual precipitation exceeds evaporation, which gave rise to the appearance of deciduous trees.
A distinctive feature of mixed forests is a well-developed grass cover growing on soddy-podzolic soils.
Rice. 1. In the mixed forest zone, grass cover is very developed.
This natural zone is characterized by a clearly defined layering - a change in the type of vegetation depending on the height:
- the highest tier of coniferous-deciduous forests consists of mighty oaks, pines and spruces;
- below are linden, birch, wild apple and pear trees;
- then the most low trees: viburnum, rowan;
- Below are raspberry, hawthorn, and rose hip bushes;
- The layering of mixed forests is completed by a variety of grasses, mosses and lichens.
The fauna of mixed forests is also diverse. Large herbivores (elk, wild boar, deer and roe deer), rodents (beavers, mice, ferrets, squirrels), and predators (foxes, wolves, lynxes) live here.
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Rice. 2. Lynx is a typical representative of forest predators.
Description of the broad-leaved forest zone
As you move south of the continent, they change climatic conditions, which leads to the change of mixed forests to broad-leaved ones. As a result, there are significantly fewer coniferous trees, and dominance is completely transferred to deciduous species.
For broad-leaved forests it is quite typical warm climate with mild winters and long warm summers. The amount of annual precipitation slightly exceeds evaporation, making wetlands a rarity for these areas.
Typical tree species for this zone are maple, linden, oak, beech, and ash.
In the dense thickets of deciduous forests, dense tree crowns do not provide to the fullest grass cover to develop. The ground in such areas is covered with a layer of fallen leaves. As it decomposes, it contributes to the formation of humus and the enrichment of gray and brown forest soils.
Rice. 3. In the area of deciduous forests coniferous trees- rare.
The fauna of deciduous forests is no different from the mixed forest zone. However, as a result active work human population, the number of wild animals has decreased significantly, and currently they live only in nature reserves or in remote areas.
Mixed forests are characteristic of natural zones with a temperate, more or less pronounced continental climate. Compared to deciduous forests, it is better suited for cold arctic influences and withstands frost and strong winds, withstanding low temperatures(from -16 to -30 degrees). Closer to the north quantity coniferous species increases significantly.
The composition of a mixed forest includes coniferous trees - spruce, pine, fir and broad-leaved species such as birch, poplar, oak, maple and many other trees. In such forests, the soils are not fertile, but are quite suitable for cultivation as meadows and arable lands.
In mixed forests live wolves, bears, moose, beavers, small mammals- squirrels, ferrets, stoats, etc.
Even today, vast areas of such forests are not completely developed by humans.
Russian Plain
The zone of mixed (coniferous-deciduous) forests of the Russian Plain is characterized by a mild, humid temperate continental climate due to its close proximity to the Atlantic Ocean, the warm, humid air of which significantly influences the formation of the natural zone. To the north the plain borders on the taiga, where weather conditions more severe, in the south with forest-steppe, and in the west mixed forests smoothly turn into broad-leaved forests of Europe. In the southern and western parts of the plain there is a lot of precipitation - up to 800 mm per year. This balance of heat and humidity allows a wide variety of crops to be grown here: wheat, flax, sugar beets, potatoes, etc.
West Siberian Plain
The West Siberian Plain is a vast lowland up to 1900 km wide and an area of about 3 million km 2. Climate in different parts The plains range from sharply continental to moderately continental. Unlike the Russian Plain, there are no broad-leaved forests here. And the mixed forest zone Western Siberia runs along the Yekaterinburg-Novosibirsk line and is characterized by the highest humidity in Russia. Basically, mixed forests are located in the watersheds of the Yenisei, Ob and Irtysh rivers. Due to the high humidity brought by warm air masses from the Atlantic Ocean, there are many areas of wetlands. in winter average temperature fluctuates from -15 to -30 degrees in the northeast. In July here from +5 to +20 in the south.
Amur region
The mixed forest of the Amur region and the Ussuri region covers the mountains of the region, smoothly turning into broadleaf forests in the lowlands. It prevails here monsoon climate, and cedars, Japanese birches, maples, Manchurian ash trees, lindens, hornbeams and bird cherry trees grow. The dense vegetation is very diverse, there are many creeping plants, such as lemongrass, Amur grape, and actinidia. In the shade of these thickets, mosses and ferns grow luxuriantly. The climate here is characterized by humid and hot summers and harsh winters with dry, cold northwest and north winds. Therefore, it is in summer that up to 95% of annual precipitation falls here.
Primorye Sikhote-Alin
Primorsky Krai occupies the southeastern part of the Far East and is washed by the Sea of Japan.
Mixed and broad-leaved forests occupy almost two-thirds of the entire area of Primorye. The Sikhote-Alin mountains occupy most of territory of Primorsky Krai. South Bank located at the latitude of the Black Sea.
The mixed forest consists of Mongolian oak, birch, spruce, and Korean pine. In the Ussuri taiga, larch neighbors next to the liana. The climate here is temperate, monsoon. In winter, cold air masses predominate, there is very little snow, but the weather is usually sunny. Summer, on the contrary, although warm, is foggy and rainy due to large amounts of precipitation.
Bryansk region
The Bryansk region is located in the west of the Russian Plain and occupies the watershed between the Desna and Oka. The Bryansk region covers two natural zones and is distinguished by a wide variety of vegetation. Coniferous forests here alternate with mixed, broad-leaved and even forest-steppe.
The region's climate is influenced by humid air currents coming from the Atlantic coast. This region is characterized by cool summers and warm winters with thaws. Pine, spruce and birch trees grow in the region. Oak groves are often found in river floodplains. Aspen and alder grow in the eastern part of the region.
Nizhny Novgorod region
Climate in Nizhny Novgorod region temperate continental, which explains the warm summers and snowy winter. Very beautiful oak groves and pine-birch undergrowth are often found here. The soil in the Nizhny Novgorod region is quite fertile, since this natural zone has an almost ideal ratio between humidity and heat, which is generally characteristic of the East European Plain.
In the Left Bank part of the region, taiga and mixed forests grow; in the Right Bank, mostly broadleaf trees. In the region there are such tree species, like pine, fir, spruce. From deciduous trees- oak, elm, ash, willow, rowan, wild apple tree. Shrubs include buckthorn, hazel, etc. The southern zones of forest-steppes are susceptible extreme heat and droughts.
The exception is the Priokskaya part, located in the southwest. Here the climate is milder and humid due to the influence of Atlantic air.
Broadleaf forests
Broad-leaved forests are located in temperate zone and feel familiar in a fairly warm winter (-10 degrees) and cool summer(up to +24 degrees). Therefore, they grow in regions with a temperate maritime or temperate continental climate.
The soils of broadleaf forests are enriched with humus and, in some areas, chernozem, so the vegetation is highly diverse. Tree species are represented by oak, chestnut, beech; bird cherry and hazel are typical for undergrowth. Herbaceous plants include lungwort, sedge, hoofweed, etc.
In broadleaf forests, in addition to predators and rodents, there are many birds and ungulates: deer, wild boar, roe deer, and moose.
Kursk region
The Kursk region is located on the Central Russian Upland and its slopes. The nature of the terrain is rugged with many ravines and gullies. The natural zone of the region is forest-steppe. Broad-leaved forests grow in the area between the valleys of the Tuskari and Seima rivers. Large forests are also found on the right bank of the Psel River. The forests mainly consist of oak, linden, pine and ash.
The climate here is temperate continental; in summer there are often heavy rains, in winter there is a lot of snow masses. The largest amount of precipitation, which is approximately 600 mm per year, occurs in the southern and eastern regions of the region.
Moldavian forests
Moldova is located in the southwestern part of the East European Plain between the Dniester and Prut rivers, and also occupies the left bank of the Dniester. The nature of this region is characterized by alternation of forest, forest-steppe and plain areas. About a hundred species of shrubs grow on the territory, including dogwood, hawthorn, hazel, and barberry. Of the trees - oak, as well as oak forests interspersed with elm, maple, hornbeam, poplar.
The climate of Moldova is temperate, continental, characterized by short mild winters and long hot summers.
Tula region
The region is located in the northeastern part of the Central Russian Upland and is a very rugged area with river valleys, many hills and ravines. The territory is characterized by forest and forest-steppe natural zones.
The region is ruled by a moderate, continental climate with a lot of rain at the beginning warm summer, winter is not too cold and dry. Broad-leaved forests are picturesquely located in the river valleys of the Oka, Zushi, Upa and in the upper reaches of the Don. The most common trees in this area are oak, linden, poplar, maple, and birch. In the northern and western parts there are coniferous forests. IN Tula region about 25 species of trees and 50 species of shrubs.
Kazansky district
The Kazan region occupies the Ishim Plain and the banks of the Ishim and Alabuga rivers, and belongs to the forest-steppe natural zone. There are many lakes on the territory, in the floodplains of which birch and aspen forests grow.
The climate in this area is continental with a short summer and quite a long cold winter. The region is often subject to the invasion of cold arctic masses, which can bring significant cold snaps even in summer. But the main influence is still exerted by the Atlantic direction, softening too much severe frosts. As a rule, it becomes cold here already at the end of September, and snowfall is possible in November.
The natural zone of broad-leaved forests has been significantly cultivated, but many human activities have disrupted the natural balance of the environment, causing great damage to the land and many species of plants and animals.
Broad-leaved species are more demanding of heat and moisture than conifers. In summer, trees produce a huge number of leaves with a large surface area, evaporating a lot of moisture. Therefore, an indispensable condition for the growth of broad-leaved forest is an abundance of precipitation in summer period. Broad-leaved forests are located in the west of the European part former USSR, wedging out towards the Urals, and in the Far East in the Primorsky Territory.
Broad-leaved forest is characterized by a complex layered structure of the tree stand. There are usually 3 tiers. In the forests of the European part of the former USSR, the first tier consists of large trees - oak, linden, maple, ash. Under their crowns grow trees of the second size - wild apple and pear trees, bird cherry, hawthorn. Below are large shrubs - buckthorn, euonymus, viburnum, etc. There are almost no mosses or lichens in the ground cover, since a thick layer of fallen leaves interferes with their development. They are replaced by a variety of perennial grasses, usually broad-leaved. The above-ground part of them dies off during the winter, and underground they form rhizomes, tubers, and bulbs, which allows them to quickly bloom in early spring, before there is light in the forest and the foliage of the trees has developed. Wind-pollinated trees and shrubs, such as oak, hazel, and alder, also bloom early, as long as the leaves do not interfere with the flight of pollen. Insect-pollinated plants bloom at different times.
Different parts of plants have medicinal value: in early spring they harvest bark from oak and viburnum, collect primrose and lungwort, in summer - linden and elderflower, hawthorn flowers, in autumn - elderberry and hawthorn fruits.
Almost all herbaceous plants living in oak forests are perennials. Their lifespan is often measured in several decades. Many of them reproduce poorly by seeds and maintain their existence mainly through vegetative propagation. Such plants, as a rule, have long above-ground or underground shoots that can quickly spread into different sides, capturing new territory.
The above-ground part of many representatives of oak groves dies off in the fall, and only the rhizomes and roots in the soil overwinter. They have special renewal buds, from which new shoots grow in the spring. However, among the species of oak groves there are also those in which the above-ground part remains green even in winter time. Plants of this kind include hoofweed, hairy sedge, and green grass.
IN coniferous forests big role shrubs play, especially blueberries and lingonberries. In a broad-leaved forest, on the contrary, there are usually no shrubs at all; they are completely unusual for our oak forests.
Among the herbaceous plants growing in Central Russian oak forests, the so-called oak forest ephemeroids are of particular interest. An example of them could be various types corydalis, goosebumps, buttercup anemone, spring guillemot. These are small, relatively low growing plants surprise us with their extraordinary “haste”. They are born immediately after the snow melts, and their sprouts sometimes even break through the snow cover that has not yet melted. It is quite cool at this time of year, but the ephemeroids nevertheless develop very quickly. A week or two after birth, they already bloom, and after another two to three weeks, their fruits and seeds ripen. At the same time, the plants themselves turn yellow and lie down on the ground, and then their above-ground part dries out. All this happens at the very beginning of summer, when, it would seem, the conditions for the life of forest plants are the most favorable - enough heat and moisture. But ephemeroids have their own special “development schedule”, not the same as that of many other plants - they always live only in the spring, and by summer they completely disappear from the vegetation cover. Early spring is most favorable for their development, since at this time of year, when the trees and shrubs have not yet put on leaves, it is very light in the forest. There is quite enough moisture in the soil during this period. And ephemeroids do not need high temperatures, such as in summer.
All ephemeroids - perennials. After their aboveground part dries out at the beginning of summer, they do not die. Living underground organs are preserved in the soil - some have tubers, others have bulbs, and others have more or less thick rhizomes. These organs serve as receptacles for reserve nutrients, mainly starch. It is precisely due to the previously stored “building material” that stems with leaves and flowers develop so quickly in the spring.
Ephemeroids are characteristic of our Central Russian oak forests. There are a total of up to ten species. Their flowers have a bright, beautiful color - purple, blue, yellow. When there are many such plants and they all bloom, you get a motley colorful carpet.
In addition to herbaceous plants, mosses are also found on the soil in oak forests. However, in this respect, oak forests are very different from taiga forests. In the taiga we often see a solid green carpet of mosses on the soil. This never happens in oak forests.
Here the role of mosses is very modest - they are occasionally found in the form of small spots on piles of earth thrown out by a mole. It is noteworthy that special types of mosses are common in the oak forest - not at all those that form a continuous green carpet in the taiga. Why is there no moss cover in the oak forest? One of the main reasons is that mosses are depressingly affected by leaf litter, which accumulates on the soil surface in a broad-leaved forest.
Broadleaf plants
Broad-leaved forest is characterized primarily by a wide variety of tree species. This is especially noticeable if you compare it with a coniferous forest, with the taiga. There are much more tree species here than in the taiga - sometimes there are up to a dozen of them. The reason for the species richness of trees is that broad-leaved forests develop in more favorable natural conditions than taiga. Tree species that are sensitive to climate and soil and cannot tolerate harsh conditions taiga regions.
A good idea of the diversity of tree species in a broad-leaved forest can be obtained by visiting a famous forest area, which is called Tula Zaseki (it stretches like a ribbon from west to east in the southern part of the Tula region). In the oak forests of the Tula Zaseks there are trees such as pedunculate oak, small-leaved linden, two types of maple - Norway maple and field maple, common ash, elm, elm, wild apple tree, wild pear.
What is characteristic of a broad-leaved forest is that the various tree species that make up it have different heights, forming, as it were, several groups in height. The most tall trees- oak and ash, lower ones - Norway maple, elm and linden, even lower ones - field maple, wild apple and pear. However, trees, as a rule, do not form clearly defined tiers well delimited from each other. Oak usually dominates, with other tree species most often playing the role of satellites.
The species composition of shrubs is also quite rich in the broad-leaved forest. In the Tula abatis, for example, there are hazel, two types of euonymus - warty and European, forest honeysuckle, brittle buckthorn, rose hips and some others.
Different types of shrubs vary greatly in height. Hazel bushes, for example, often reach a height of 5 - 6 m, and honeysuckle bushes are almost always shorter than human height.
Broad-leaved forests usually have well-developed grass cover. Many plants have more or less large, wide leaf blades. That's why they are called oak broadgrass. Some of the herbs found in oak forests always grow in single specimens, never forming dense thickets. Others, on the contrary, can almost completely cover the soil over a large area. Such massive, dominant plants in oak forests Central Russia The most common species are common sedge, hairy sedge and yellow green grass.
Broadleaf trees have broad, flat leaves—thickness that is much less than length and width—that typically fall once a year. This group includes maples, beeches, ash trees, eucalyptus trees, and various shrubs. In addition to classification according to the type of leaves, trees are divided according to the lifespan of the leaves - into deciduous and evergreen. Deciduous trees have a clear change in leaf cover: all the leaves on the tree lose their green color and fall off, for some time (in winter) the tree stands without leaves, then (in spring) new leaves grow from the buds. Evergreen trees do not have a clear change in leaf cover: foliage is on the tree at any time of the year, and the change of leaves occurs gradually, throughout the life of the tree.
In areas with long, cold winters, deciduous trees shed their leaves in the fall. In the tropics, where the length of daylight hours varies slightly throughout the year, leaves do not fall in the winter.
Dropping leaves helps save energy because there is too little sunlight in winter for leaves to photosynthesize. In autumn, trees go into a dormant state. The movement of water and nutrients through the vessels inside the trees stops, as a result the leaves dry out and fall off. However, by this time the plant has already managed to accumulate enough nutrients to ensure bud break and the growth of new leaves in the spring. The green pigment chlorophyll is destroyed in the fall, and other pigments become clearly visible, which give autumn leaves yellow, red and rusty colors.
Oak
Oak is the main forest-former of broad-leaved forests in Europe. In the European part of Russia, the English oak (Quergus robur) grows - one of our most durable and largest trees. However, in plantings, with the exception of parks, this plant is quite rare, although it has no equal in a number of properties. In particular, pedunculate oak has the highest recreational resistance and is extremely drought-resistant.
In private areas it is used in single plantings. It tolerates moderate pruning, so you can form very beautiful tapeworms with a spherical, obovate and even tent-shaped crown.
Elm
In the forests of the non-chernozem zone, two species from the elm family naturally grow: smooth elm (Ulmus laevis) and c. rough (U. scabra). This large trees, which are part of the dominant tier of broad-leaved and coniferous-deciduous forests. The use of these species for landscaping purposes last decades controlled by a widespread disease - Dutch elm disease.
Common ash
Ash reaches a height of 30-40 m.
Its trunk is straight. The bark is light gray, darkening with age. The crown is very loose, openwork, letting in a lot of light. Root system powerful, highly branched. Ash is very picky about soil, but tolerates salinity better than others. This is one of the main breeds of field-protective breeding, it is light-loving, in youth it is more shade-tolerant, heat-loving and does not tolerate spring frosts, grows almost throughout the European part Russian Federation, often mixed with other species: oak, hornbeam, maple, sometimes forms pure or almost pure stands. Inflorescences are paniculate, dense.
The flowers of these trees are usually dioecious, less often bisexual, but sometimes there are dioecious trees.
Ash blossoms in May before the leaves bloom. Pollinated by wind.
The fruits are single-seeded lionfish, collected in clusters, ripen in October-November and fall in winter or early spring.
Forest beech (there is also eastern beech) is a tree up to 40 meters high and up to one and a half meters in diameter with light gray bark and elliptical leaves. Occupies large spaces in Western Europe, in our country it grows in the western regions of Ukraine, Belarus and in Kaliningrad region. Eastern beech is distributed in the Caucasus at an altitude of 1000-1500 meters above sea level, in Crimea - at a level of 700-1300 meters, forming a belt beech forests.
The main value of beech is its fruits - nuts, which ripen in September - October. They contain up to 28 percent fatty semi-drying oil, up to 30 percent nitrogenous substances, starch, sugars, malic and citric acids, tannins, up to 150 mg% of tocopherols and the poisonous alkaloid fagin, which decomposes when the nuts are fried, which as a result become harmless to humans . A coffee substitute is prepared from the nuts; ground nuts in the form of flour are added to regular flour when baking various baked goods. Beech wood is very valuable and decorative.
Maple
Various types of maples are widespread in deciduous forests. Most often found here is the Norway maple, or common maple - a tree up to 20 meters tall, with gray bark and five-lobed large dark green leaves. Distributed in the European part of the country, mainly in the western and central parts, and in the Caucasus. Its leaves and shoots can be used for medicinal purposes. It has been established that the leaves contain up to 268 mg% ascorbic acid, alkaloids and tannins. An infusion or decoction of the leaves has a diuretic, choleretic, antiseptic, anti-inflammatory, wound-healing, and analgesic effect. In folk herbal medicine it was used for kidney stones, jaundice, as an antiemetic and tonic. Shredded fresh leaves applied to wounds to heal them.
Oak and beech, elm, maple and ash are very valuable species trees whose wood is considered to be of high quality building material, and the bark is used for household and medical needs.
Complex burs
I tier - pine (30-35m), birch, spruce;
II tier - linden, oak;
III tier - less pronounced - hazel, euonymus, honeysuckle;
IV tier - well defined - lichens, blueberries, wood sorrel...
There is no pine regeneration - complete shading:
pine deciduous forest.
Broad-leaved forest - forest-forming species: oak, linden, ash, maple, elm, hornbeam.
The tiered structure is well expressed, the number of tiers is 7-8 and root systems large number; Soddy-podzolic soils.
Broad-leaved forests involve much deeper soil layers in their biological cycle of substances, due to the location of the root system.
In winter there is a lot of snow, melt water is well absorbed by the litter. The soil is moist, rich in minerals and organic substances. Light conditions change throughout the season.
Trees in oak forests are arranged in tiers.
I tier - oak (50m);
II tier - maple, linden, elm, ash;
III tier - wild apple tree;
IV tier - deciduous shrubs and undergrowth.
In early spring in the forest you can see a whole range of colors - yellow, blue, indigo, white.
These are early flowering plants: oak anemone, anemone, buttercup anemone, corydalis, spring guillemot, amazing violet, etc. Then
The trees are blooming, the last to bloom is the oak tree. At the end of May, shrubs begin to bloom, herbaceous plants begin to bloom: nomad, chickweed, lily of the valley, green grass, tenacious, warbler, raven's eye.
In summer, oak forests look the same; in autumn they transform again due to the changing color of the leaves of oak, ash, maple, and linden. Red berries of viburnum and the eyes of euonymus warty stand out against their background.
Birch forests. It is difficult to imagine our forests without birch with its white trunk and fluffy, spreading crown. The most common species is the warty birch (its branches are covered with yellow warts, the leaves are small and slightly pubescent). The breed is light-loving, undemanding to the soil, grows quickly and reaches a height of 30 meters by the age of forty.
Rowan and rose hips are constantly found in birch forests.
Raspberries grow in clearings.
appear in spring yellow flowers rams or primroses, swimsuits. In summer, forest geraniums, spreading and peach-leaved bellflowers, many grasses, and sedges bloom. Meadowsweet is found in damp places.
They occupy eastern North America, Central Europe, eastern China; also form high-altitude zones in the Carpathians, Crimea and the Caucasus. In addition, isolated pockets of broad-leaved forests are found in the Russian Far East, Chile, New Zealand and central Japan.
Climatic features This zone is favorable for the growth of deciduous trees with a wide leaf blade. Moderate continental air masses bring precipitation from the oceans (from 400 to 600 mm), mainly in the warm season. The average temperature in January is -8°0°C, in July +20-24°C. Beech, hornbeam, elm, maple, linden and ash grow in the forests. The broadleaf forests of eastern America are dominated by trees similar to some East Asian and European species, but there are also species characteristic only of this area. In terms of their composition, these forests are one of the richest in the world. globe. Most of them have American types of oaks, along with them chestnut, linden, and plane trees are common. Tall trees with a powerful, spreading crown predominate, often entwined with climbing plants - grapes or ivy. To the south there may be magnolias and tulip tree. For European broadleaf forests, oak and beech are the most typical.
The fauna of deciduous forests is close to that of the taiga, but there are some animals unknown in the forests of the taiga. These are black bears, wolves, foxes, minks, raccoons. The characteristic ungulate of deciduous forests is the white-tailed deer. It is considered an undesirable neighbor for populated areas, as it eats young crops. In the broad-leaved forests of Eurasia, many animals have become rare and are under human protection. The bison and the Ussuri tiger are listed in the Red Book.
Soils in deciduous forests are gray forest or brown forest.
This forest zone is densely populated and to a large extent negated. It has been preserved only in heavily rugged, inconvenient areas for arable farming and in nature reserves.
Temperate mixed forests climate zone
These are forests with various breeds trees: coniferous
broad-leaved, small-leaved, small-leaved pine. This zone is located in the north of North America (on the border of Canada and the USA), in Eurasia, forming a narrow strip lying between the taiga and the zone of broad-leaved forests, in Kamchatka and the Far East. The climatic features of this zone differ from the zone of broad-leaved forests.
The climate is moderate, becoming more continental towards the center of the continent. This is evidenced by annual amplitude temperature fluctuations, as well as annual precipitation, varying from oceanic regions to the center of the continent.
The diversity of vegetation in this zone is explained by differences in climate: temperature, amount of precipitation and mode of precipitation. On the Russian Plain, where precipitation falls all year round thanks to west winds from the Atlantic, distributed European spruce, oak, linden, elm, fir, beech, that is, coniferous-deciduous forests are located here.
In the Far East, where precipitation is brought only in the summer by monsoons with Pacific Ocean, mixed forests have a southern appearance and are distinguished by a wide variety of species, multi-tiered, abundance of vines, and on the trunks - mosses and epiphytes. In Western Siberia, deciduous forests are dominated by pine, birch, and aspen trees with some spruce, cedar, and fir. In the mixed forests of North America, the most common conifers are white pine, reaching a height of 50 m, and red pine. Among deciduous trees, birch with yellow hardwood, sugar maple, American ash, elm, beech, linden.
The soils in the mixed forest zone are gray forest and soddy-podzolic, while in the Far East they are brown forest. The fauna is similar to the fauna of the taiga and the deciduous forest zone. Elk, sable, and brown bear live here.
Mixed forests have long been subject to severe deforestation and fires. They are best preserved in North America and the Far East, while in Eurasia they are used for field and pasture land. Taiga
This forest zone is located within temperate climate in northern North America and northern Eurasia. There are two types of taiga: light-coniferous and dark-coniferous. Light-coniferous taiga is the least demanding pine and larch forests in terms of soil and climatic conditions, the sparse crown of which allows sun rays to the ground. Pine forests, having an extensive root system, have acquired the ability to use nutrients from infertile soils, which is used to stabilize soils. This feature of the root system of these forests allows them to grow in areas with permafrost. The shrub layer of the light-coniferous taiga consists of alder, dwarf birches, polar willow, berry bushes. Mosses and lichens are located under this layer. This is the main food of reindeer.
This type of taiga is common in Eastern Siberia.
Dark coniferous taiga are forests represented by species with dark, evergreen needles. These forests consist of numerous species of spruce, fir, and Siberian pine (cedar). Dark-coniferous taiga, unlike light-coniferous taiga, has no undergrowth, since its trees are tightly closed with crowns, and it is gloomy in these forests. The lower tier consists of shrubs with hard leaves (lingonberries) and dense ferns. This type of taiga is common in the European part of Russia and Western Siberia.
Peculiar flora These types of taiga are explained by differences in the climate of the territories: average annual temperatures and the amount of precipitation. The seasons are clearly distinguished.
The soils of the taiga forest zone are podzolic. They contain little humus, but when fertilized they can provide a high yield. In the taiga Far East- acidic soils.
The fauna of the taiga zone is rich. Numerous predators are found here - valuable game animals: otter, marten, sable, mink, weasel. Large predators include bears, wolves, lynxes, and wolverines. In North America, bison and wapiti deer used to be found in the taiga zone. Now they live only in nature reserves. The taiga is also rich in rodents. Of these, the most typical are beavers, muskrats, squirrels, hares, chipmunks, and mice. The taiga world of birds is also very diverse: nutcrackers, blackbirds, bullfinches, wood grouse, black grouse, hazel grouse.
Mixed (monsoon) forests subtropical zone
They are located in the southeastern United States and eastern China. These are the wettest of all subtropical zones. Characterized by the absence of a dry period. Annual quantity There is more precipitation than evaporation. Maximum quantity Precipitation usually falls in the summer, due to the influence of the monsoons, which bring moisture from the oceans; winter is relatively dry and cool. Inland waters quite rich, groundwater is predominantly fresh, shallow.
Here, tall mixed forests grow on brown and gray forest soils. Their species composition may vary depending on soil conditions. In the forests you can find subtropical species of pines, magnolias, camphor laurel, and camellia. Swamp cypress forests are common on the flooded coasts of Florida (USA) and in the lowlands of Mississippi.
The mixed forest zone of the subtropical zone has long been developed by humans. In place of cleared forests in America, there are field and pasture lands, gardens, and plantations. In Eurasia - forestry lands with areas of field lands. Rice, tea, citrus fruits, wheat, corn and industrial crops are grown here.
Topic 3. Steppe zone
Steppes- This is a zonal type of landscape of a temperate climate zone and a subtropical climate zone. Atmospheric precipitation here (from 250 mm to 450 mm per year) falls irregularly and is insufficient for tree growth. The steppes are characterized by hot, dry summers (average July temperature +20-24°C), cold winters (frosts down to -20-30°C) with thin snow cover. Inland waters in the steppe are poorly developed, river flow is small, and rivers often dry up. The vegetation in the steppes is herbaceous, drought- and frost-resistant.
Depending on the nature of vegetation in the steppe zone, three subzones are distinguished:
Meadow steppes. They are transitional to forest areas. These steppes are rich in colorful forbs and moisture-loving grasses (bluegrass, bromegrass, timothy). The soils are chernozems, very fertile, with a thick layer of humus;
Cereals. These steppes are located on southern chernozems and dark chestnut soils;
Southern wormwood-cereals. These are steppes with incompletely closed vegetation cover on chestnut soils with the inclusion of solonetzes. (Saline soils are a type of saline soil that when wet does not allow moisture to pass through, as it becomes viscous and sticky, and when dry it is hard as stone.)
Fauna of the steppes rich and diverse, it has changed greatly under the influence of man. Back in the 19th century, wild horses, aurochs, bison, and roe deer disappeared. Deer are pushed into forests, saigas - into virgin steppes and semi-deserts. Now the main representatives of the animal world of the steppes are rodents: ground squirrels, jerboas, hamsters, voles. Birds include the bustard, little bustard, lark and others.
Steppes are confined to various continents. In Eurasia this natural area stretches in a strip from the mouth of the Danube to Altai. In North America, the steppes extend into meridional direction. IN Southern Hemisphere steppes occur in small areas in South America(Chile, Argentina), in the southwest and southeast of Australia.
Fertile soils of the steppes and favorable conditions life contributed to the dense settlement of people. The steppes are the most favorable areas for agriculture, since cultivated plants can develop here for up to nine months a year. Grains and industrial crops are grown here. Unsuitable for arable land in the steppes is used as pasture for livestock. Fishing and hunting resources here are not of great economic importance.
Steppes- more or less flat, dry, treeless spaces covered with abundant herbaceous vegetation. The spaces are flat and treeless, but wet, and are not called steppe. They form either marshy meadows, or, on far north, – tundra. Spaces with very sparse vegetation, which does not form a grassy cover, but consists of individual bushes scattered far from each other, are called deserts. Deserts are not sharply different from the steppe, and often mix with each other.
Hilly or mountainous countries are not called steppe. But they can just as well be treeless and can support the same flora and fauna as flat steppes. Therefore, we can talk about steppe mountains and steppe slopes as opposed to forested mountains and forest slopes. The steppe is, first of all, a primordial treeless space, regardless of the relief.
The steppe is characterized by special climatic conditions and special flora and fauna. The steppes are especially developed in southern Russia, and purely Russian word the steppe has become everything foreign languages. On the distribution of steppe plants on the earth's surface
spaces are undoubtedly influenced by climate. All over the globe, deserts represent spaces with a very hot and dry climate. Territories with a less hot climate and high annual precipitation are covered partly or entirely with steppe. Spaces with more humid climate, temperate or warm, covered with forests.
Typical steppes represent a flat or gently hilly country, completely devoid of forests, with the exception of perhaps river valleys. The soil is chernozem, most often lying on a layer of loess-like clay with a significant lime content. This chernozem in the northern strip of the steppe reaches its greatest thickness and fatness, as it sometimes contains up to 16% humus. To the south, the black soil becomes poorer in humus, becomes lighter and turns into chestnut soils, and then completely disappears.
The vegetation consists mainly of grasses growing in small tussocks, with bare soil visible between them. The most common types of feather grass, especially the common feathery feather grass. It often completely covers large spaces and with its silky white feathery awns gives the steppe a special, undulating appearance. On very rich steppes, a special variety of feather grass develops, which is much larger in size. On the dry, barren steppes, smaller feather grass grows. After the types of feather grass, the most important role is played by the kipets or typets. It is found everywhere in the steppe, but plays a special role east of Ural mountains. Kipets is an excellent food for sheep.