A mixed forest is an area in which deciduous and coniferous trees coexist harmoniously. If the admixture of tree species is more than 5% of the total flora, we can already talk about a mixed type of forest.
The mixed forest forms a zone of coniferous-deciduous forests, and this is a whole natural zone characteristic of forests in the temperate zone. There are also coniferous-small-leaved forests that form in the taiga as a result of the restoration of previously cut down pines or spruces, which begin to displace different types of birch and aspen.
Main characteristics
(Typical mixed forest)
Mixed forests almost always coexist with broad-leaved forests in the south. In the northern hemisphere they also border the taiga.
The following types of mixed forests in the temperate zone are distinguished:
- coniferous-deciduous;
- secondary small-leaved with the addition of coniferous and broad-leaved species;
- mixed, which is a combination of deciduous and evergreen species.
Subtropical mixed foxes are distinguished by a combination of laurel leaves and conifers. Any mixed forest is distinguished by a pronounced layering, as well as the presence of areas without forest: the so-called opoles and woodlands.
Location of zones
Mixed forests, a combination of coniferous and broad-leaved species, are found on the East European and West Siberian plains, as well as in the Carpathians, the Caucasus and the Far East.
In general, both mixed and broad-leaved forests do not occupy as large a share of the forest territory of the Russian Federation as coniferous taigas. The fact is that such ecosystems do not take root in Siberia. They are traditional only for the European and Far Eastern regions and at the same time grow in broken lines. Pure mixed forests are found south of the taiga, as well as beyond the Urals to the Amur region.
Climate
Mixed-type forest plantations are characterized by cold, but not very long winters and hot summers. Climatic conditions are such that precipitation falls no more than 700 mm per year. The moisture coefficient is increased, but can change throughout the summer. In our country, mixed forests stand on soddy-podzolic soil, and in the west - on brown forest soil. As a rule, winter temperatures do not fall below - 10˚C.
Broad-leaved forest plantations are characterized by a humid and moderately humid climate, where precipitation is distributed evenly throughout the year. The temperatures are quite high, and even in January it never gets colder than -8˚C. Increased humidity and abundant heat stimulate the work of bacteria and fungal organisms, due to which the leaves quickly decompose and the soil maintains maximum fertility.
Features of the plant world
The peculiarities of biochemical and biological processes determine the consolidation of species diversity as we move towards broad-leaved species. European mixed forests are distinguished by the obligatory presence of pine, spruce, maple, oak, linden, ash, elm, and among the shrubs the leaders are viburnum, hazel, and honeysuckle. Ferns are very common as herbs. Caucasian mixed forests contain large quantities of beech and fir, while the Far Eastern forests contain birch, walnut, hornbeam, and larch. These same forests are distinguished by a variety of vines.
Representatives of fauna
Mixed forests are home to those animals and birds that are generally considered typical for forest conditions. These are moose, foxes, wolves, bears, wild boars, hedgehogs, hares, badgers. If we talk about individual broad-leaved forests, the species diversity of birds, rodents and ungulates is especially striking here. Roe deer, fallow deer, deer, beavers, muskrats and nutria are found in such forests.
Economic activity
The temperate natural zone, including mixed forests, has long been developed by local residents and is densely populated. An impressive part of the forest plantations was cut down several centuries ago, which is why the composition of the forest has changed and the proportion of small-leaved species has increased. In place of many forests, agricultural areas and settlements appeared.
Broad-leaved forests can generally be considered rare forest ecosystems. After the 17th century, they were cut down on a large scale, largely because wood was needed for the sailing fleet. Also, broad-leaved forests were actively cut down for arable land and meadows. Oak plantations have suffered especially badly from such human activity, and it is unlikely that they will ever be restored.
Physiographic characteristics of Russia.
1.Geographical location.
1. Russia is the largest state on the globe, with an area of
17.1 million km 2. Our country is located in the northern part of Eurasia, occupying about a third of it
territories. Russia is located in two parts of the world: about 1/3 of the country lies in Europe,
about 2/3 are in Asia.
2. The entire country is located in the northern hemisphere. The extreme northern mainland point of Russia - Cape Chelyuskin (77° 43'N) - is located on the Taimyr Peninsula. Ostrovnaya is located on Rudolf Island in the Franz Josef Land archipelago, this is Cape Fligeli (81°49'N).
The extreme southern point of Russia is located in the North Caucasus, on the border of the Republic of Dagestan with Azerbaijan, 10 km from the peak of Bazardyuzyu (41° 12’ N).
The easternmost point on the mainland is Cape Dezhnev on Chukotka (169° 40’ W). The eastern island point is located on Ratmanov Island in the Bering Strait (169°
The westernmost point lies on the sandbar spit of the Baltic Bay of Gdańsk
sea in the Kaliningrad region (19° 38 'E)
3. Due to the large extent of Russian territory from north to south (about 4
thousand km) and from west to east (about 10 thousand km) the natural conditions of our country
are exceptionally diverse. Russia is located in the Arctic, subarctic, and mostly temperate climate zones. And only
a small part of the Black Sea coast of Russia is located in the subtropics.
Borders of Russia
The length of Russia's borders is about 60 thousand km. Of these, more than 40 thousand occur on the maritime borders, especially in the north and east of the country. The maritime borders of Russia, like other states, lie at a distance of 12 nautical miles from the coast (nautical mile = 1.8 km), followed by a 200-mile economic zone, where free movement of ships is allowed, but the use of any type of natural resources of water, bottom and subsoil carried out only by Russia.
In the north, Russia is washed by the waters of the Arctic Ocean: Barents, White, Kara, Laptev, East Siberian and Chukotka. Within this ocean, from the coast of the country to the North Pole, is the Russian sector of the Arctic. It is located between the meridians 32° 45’ E. and 168° 40’W.
The western border does not have clearly defined natural boundaries, starting from the Barents Sea, and then along the western edge of the Kola Peninsula. Here lies the border with Norway, to the south with Finland, which follows to the Gulf of Finland in the Baltic Sea. Then follows the border with Estonia, Latvia, Lithuania, Poland, Belarus (Kaliningrad region) and Ukraine.
The southern border first runs along the Black Sea, connecting our country with Ukraine, Georgia, Turkey, Bulgaria and Romania. The sea border with Ukraine runs along the Sea of Azov.
The land border along the Greater Caucasus watershed ridge separates
From Georgia and Azerbaijan, the Caspian Sea connects Russia with Turkmenistan, Iran, Azerbaijan and Kazakhstan. From the Volga delta to Altai it passes
land border with Kazakhstan; A short section of the border with China runs along the southern border with the Altai Republic. Then the border with Mongolia passes through the mountains of southern Siberia. To the east, along the Argun, Amur and Ussuri rivers, Russia borders on China. In the extreme southeast, within the Primorsky Territory, the border with the DPRK follows.
The eastern border of our country runs along the seas of the Pacific Ocean. Here
its closest neighbors are Japan and the USA. Straits separate us from Japan
La Perouse and Kunoshirsky. The border with the United States runs along the Bering Strait, between
The Ratmanov Islands (Russia) and Kruzenshtern Islands (USA). Due to the large distance from West to East, there is a large time difference in Russia: the country lies in 11 time zones.
Climate of Russia
The climate of Russia, like other regions of the Earth, is formed under the influence of a large number of different factors. But the first place among all climate-forming factors should be given to geographic location, one of the elements of which is the latitude of the place, on which the amount of incoming solar heat (total solar radiation) depends. Due to the enormous extent from North to South, the amount of total solar radiation varies from 251.2 kJ/cm2 per year in the Arctic to 670 kJ/cm2 per year in the subtropics.
If the total solar radiation represents the incoming part of the radiation balance, then its outgoing part is the effective radiation of the earth's surface and reflected radiation. In summer, the radiation balance in Russia is positive everywhere; in winter, with the exception of the south of the country, it is negative. In general, for the year the radiation balance of the underlying surface within our country is positive, only in the Arctic it is close to zero.
The prevailing winds and the surrounding oceans have a huge influence on the climate. In temperate latitudes, in which most of the country is located, westerly transport of air masses predominates. With the westerly transport, sea air of temperate latitudes spreads, which is formed in the North Atlantic region. Its spread far to the east of the country is facilitated by the absence of high mountains. Therefore, the influence of the Atlantic can affect all the way to the regions of Eastern Siberia. In summer, the arrival of Atlantic air causes cooling and precipitation, in winter in the western part of the country it leads to thaws, and in the east - to a significant mitigation of frosts
The influence of air forming over the Arctic Ocean is more pronounced in the summer, when relatively low atmospheric pressure is established over the mainland. The impact of Arctic air is most pronounced within the East European and West Siberian Plains. In winter it causes sharp cooling, in spring and autumn - frosts. In summer, moving south and warming up, it forms cloudless and partly cloudy weather, and in the Volga region and in the south of Western Siberia it can cause drought.
The influence of the Pacific Ocean and the air masses formed above it is limited to the coastal zone and occurs mainly in the summer, during the summer monsoon.
The general nature of the relief is also important for climate-forming purposes: the absence of high mountains in the west does not prevent the penetration of Atlantic and Arctic air into the interior of the country, and, conversely, the presence of mountain ranges in the east weakens the impact of the Pacific Ocean on the climate of the Far East and Eastern Siberia. Due to the large extent of Russia from North to South and from West to East, the climate is extremely diverse. Russia is located in the Arctic, mostly in temperate climatic zones, and the Black Sea coast is in the subtropics. The vast territory of our country and its location in several climatic zones leads to large differences in the temperatures of January and July, and the annual amount of precipitation in its different parts. The change in t° in July occurs in the latitudinal direction, which is determined by the amount of incoming solar radiation at different latitudes.
Winter isotherms over the European part change from West to East from 8 to -18°C, which is determined by the influence of the Atlantic and the westerly transport of air masses. In Eastern and Northeastern Siberia, January isotherms have a closed ring-shaped character, reflecting the continental climate of the given territory. In winter, an area of high pressure is established over the land and a strong cooling of the surface layers of air occurs. Particularly low temperatures are observed in Verkhoyansk and Oymyakon, where the average temperature drops to -50°C, and the absolute minimum of Verkhoyansk (-68°C) is considered one of the lowest temperatures on Earth, with the exception of Antarctica. The emergence of this “pole of cold” is also facilitated by the basin-like nature of the relief: heavier cold air stagnates in the basins and they turn out to be much colder than the surrounding mountain slopes (the phenomenon of temperature inversion).
In the Far East, January isotherms are elongated in the Northeast direction, parallel to the coastline, under the influence of the Pacific Ocean.
The distribution of precipitation across the territory of Russia is extremely uneven and is associated with the circulation of air masses, terrain features and air temperature. The greatest amount of precipitation falls in the Caucasus and Altai mountains (more than 2000 mm per year) and in the south of the Far East (up to 1000 mm per year). The plains receive moderate rainfall. Their annual amount decreases from 600-700 mm in the west of the East European Plain to 200-300 mm in Eastern Siberia.
The minimum amount of precipitation occurs in the semi-desert areas of the Caspian lowland (about 150 mm per year).
In most of Russia, precipitation falls in the form of snow in winter. The summer season sees maximum rainfall.
The distribution of temperature and precipitation has a huge impact
on plant development, soil-forming processes, types of agricultural
activities.
Seas of Russia.
Our country is the largest maritime power in the world. General
the length of its sea borders is over 40 thousand km.
Russia is washed by the waters of twelve moraines belonging to three oceans. These
the seas are very diverse in natural conditions, in resources and in the degree of their
knowledge and mastery.
1. The seas of the Arctic Ocean are the most numerous, there are six of them:
Barents, Beloe, Kara, Laptev, East Siberian and Chukotka. All of them
belong to the marginal type of seas, with the exception of the White Sea (it is
internal). The boundaries with the ocean are not clearly defined, and water exchange with the ocean is completely
free. The shelf position of these seas determined their insignificant depth,
which rarely exceeds 200 m. The salinity of the seas is lower than the oceanic one, since
The rivers flowing into them have a desalination effect.
The seas are separated from each other by islands (Novaya and Severnaya Zemlya, New Siberian Islands, Wrangel Island), and the straits separating them (Kara Gate Strait, Vilkitsky Strait, Dmitry Laptev Strait, Long Strait) connect all the seas through which the Northern Sea passes path. It began operating in 1935 and connected European and Far Eastern ports, as well as the mouths of navigable rivers in Siberia. The distance from St. Petersburg to Vladivostok along it is 14,280 km, while through the Suez Canal the route is 23,200 km. The development of the Northern Sea Route, whose length is 4,500 km, is of great importance for the development of the regions of the Far North.
Almost all seas are within the Arctic belt. The only exception is the Barents Sea, into which the warm Norwegian Current enters. Favorable temperature conditions make this sea extremely important for transport (the ice-free water area of the port of Murmansk) and for fishing, the remaining seas are bound by a thick ice cover for 8-10 months a year, which is the main obstacle to shipping. The seas of the Asian sector are characterized by more severe climatic conditions, which reduces their biological productivity. In the eastern direction, the number of fish species decreases and their species composition changes; in the western seas, cod, haddock, sea bass, herring, flounder, and halibut predominate, and in the eastern seas, smelt and whitefish predominate. In some seas, sea animals are also caught: seals, beluga whales, and seals.
2. Pacific Seas:
The Bering Sea (the largest and deepest in Russia), the Sea of Okhotsk and the Sea of Japan. They wash the eastern coast of the country. On the outer ocean side they are limited by the Aleutian (USA), Kuril (Russia) and Japanese (Japan) islands. Sea basins are formed in the zone of transition of the earth's crust from continental to oceanic. They have almost no shelf zone and the seas have significant depths (2500-4000 m). The eastern shores of Kamchatka and the Kuril Islands are washed by the waters of the Pacific Ocean. Here is one of the deepest oceanic depressions - the Kuril-Kamchatka depression with depths of up to 9717 m. This area is tectonically active, there are frequent earthquakes, volcanism and, as a consequence, the occurrence of tsunamis
The Bering and Okhotsk seas are characterized by a harsh climate; in winter, a significant part of them is covered with ice, and the temperature of surface waters, even in summer, does not rise above +5 + 12 ° C. Dense fogs, storms, and hurricanes often form here, making navigation difficult.
The Sea of Japan is warmer; in summer the surface water temperature reaches +20°C. But in winter, the northern coastal part is still covered with ice.
The salinity of these seas is close to oceanic.
All seas experience high tides. They are especially large in the Penzhina Bay of the Sea of Okhotsk, where the water rises by 11 m.
Due to the low temperatures, the sea waters are rich in oxygen, and numerous rivers bring large amounts of minerals. All this creates favorable conditions for the habitat of marine organisms. The Far Eastern seas are of great commercial importance. Herring, cod, and flounder are caught here. The value of salmon fish (pink salmon, chum salmon, chinook salmon, sockeye salmon) is especially great. In addition to fish, crabs, sea cucumbers, oysters, shrimp, scallops, and squid are caught in the seas. Seaweed (especially seaweed) is also used.
Mineral resources are being mined on the shelf of the Far Eastern seas. Up close
Oil fields have been developed in Sakhalin. It is difficult to overestimate the transport
the meaning of these seas.
3. Seas of the Atlantic Ocean wash the western and southwestern outskirts of Russia. These are the Baltic, Black and Azov seas. They belong to inland seas and are connected to the ocean by narrow straits through neighboring seas. Therefore, they have a number of similar natural features: there are practically no tides, the warm waters of the Atlantic almost do not penetrate into them, low salinity due to the fresh waters of the inflowing rivers (from 17-18 0/00 in the central part to 2-3 0/00 off the coast) .
But the seas of the Atlantic They also have a number of distinctive features. In the Baltic Sea, depths reach several hundred meters, in the Azov Sea no more than 12 m, while the Black Sea has significant depths (over 2200 m), as it arose in connection with tectonic faults and subsidence of sections of the earth's crust. In deep-sea basins at a depth of more than 100-150 m, the water is saturated with hydrogen sulfide and there is no life here. The seas also differ in temperature. The temperature difference is especially large in summer. In the Baltic Sea it is +15+18°C, and in the Black and Azov Seas the temperature is much higher than +22+25°C and +25+30°C, respectively.
All seas of the Atlantic Ocean have large fisheries,
transport and recreational significance.
4. To the largest domestic The closed basin of Russia includes the Caspian Sea-lake, which has no connection with the World Ocean. In the past, it was part of the ancient single Caspian-Black Sea basin. The Caspian is also a warm sea, although in winter its northern part is covered with ice. The salinity of its waters varies from 0.4 0/00 at the mouth of the Volga to 14 0/00 in the southern part.
The Caspian Sea-lake plays a very important role: important transport routes pass through it, valuable sturgeon fish are caught here - beluga, sturgeon, stellate sturgeon (80% of the world's reserves), and there are large offshore oil fields.
There are a number of problems associated with the Caspian Sea. First of all, these are significant long-term fluctuations in water levels, on the order of several meters. As well as environmental problems that have arisen as a result of active human economic activity, mainly related to oil production.
Inland waters of Russia.
Rivers.
Rivers are one of the important parts of landscapes and affect all its components. In addition, rivers are also of great importance in human economic activity. Russia has large reserves of fresh water, including river water. In terms of total runoff, our country occupies one of the leading places in the world. The density of the river network depends on the topography and climate, as well as on the history of the formation of a particular territory, for example, on the legacy of the Ice Age. The bulk of water bodies and fresh water reserves are concentrated in the zone of excess moisture. The water content of rivers is related to the size of surface and underground runoff, which is determined by the ratio of precipitation and evaporation. Therefore, the river flow in the northern part is greater than in the south. All Russian rivers belong to the basins of three oceans, the seas of which wash the country’s shores. The largest river in Europe, the Volga, belongs to the internal drainage basin of the Caspian Sea, which occupies more than half of the European part of Russia.
More than half of Russia's territory belongs to the rivers of the Arctic Ocean basin, which flow through the northern European part and almost all of Siberia. The basins of the Pacific and Atlantic Oceans account for less than 1/4 of the country's area. More than 20 rivers in our country have a length of more than 1000 km. The largest rivers in Russia are.
R. Lena- 4400 km,
R. Irtysh (tributary of the Ob), including Ch. Irtysh- 4248 km,
R. Yenisei (with Bolshaya Yenisei) -4102 km,
R. Ob (from the confluence of Biya and Katun)- 3676 km,
R. Volga- 3531 km,
R. Amur (from the confluence of Silk and Arguni)- 2846 km,
R. Kolyma- 2600 km,
R. Angara (tributary of the Yenisei)- 1780 km.
The deepest river is the Yenisei (annual flow 624 km). A common feature for most rivers in Russia is the presence of seasonal ice cover. Freeze-up time lasts from 220-240 days in the North-East of the country, up to 2 months on the rivers of the southern part of Russia.
The variety of climatic conditions characteristic of our country affects the characteristics of the river regime. In addition, rivers of different climatic regions differ in their food sources.
Within the East European Plain and Western Siberia, most of the rivers are predominantly snow-fed with spring floods. It is in the spring that most of the annual runoff occurs. Flash floods are possible in summer and autumn. In winter, during freeze-up, the rivers switch to ground feeding, so their level and flow rates are low.
For rivers originating from the mountains, for example in the Caucasus (Kuban, Terek), floods are typical in the warm season. The higher the summer temperatures, the more intense the melting of snow and glaciers.
Rivers of monsoon climate areas with summer floods are common in the Amur basin.
In those places where permafrost occurs (in the east and northeast of Siberia) there is a unique type of river. When little snow cover melts, spring floods are weakly expressed, and in summer, during rains, severe floods are observed.
The importance of rivers in human economic activity is difficult to overestimate. Rivers are a powerful source of cheap water energy. Potential hydropower resources account for approximately 11% of the world's hydropower reserves. Powerful hydroelectric power stations have been built on the largest rivers. The flow of these rivers is regulated by reservoirs, the S of which reaches several thousand km 2. Many rivers are used for shipping and timber rafting. In dry areas of the country, river water is used to irrigate agricultural land. Rivers are an important source of water supply to industrial centers.
Lakes.
A significant part of water reserves is concentrated in lakes. There are about two million lakes in Russia. But they are distributed extremely unevenly. This is due to two main factors: climate and terrain. Most of the lakes are concentrated in the northern part of the country. There are significantly fewer of them in the southern zone.
The lakes differ in their origin. In depressions and depressions of the earth's crust in mountainous areas, less often on plains, lakes with basins of tectonic origin are common. They are distinguished by great depths. A striking example of such lakes is Baikal - the deepest lake not only in Russia, but also in the world. Its depth is 1637 m!
In areas of active tectonic activity (the Kuril Islands and Kamchatka), volcanic lakes (Kronotskoye, Kurilskoye) formed in the craters of extinct volcanoes.
A common group is formed of mixed glacial-tectonic origin. Their tectonic basins were processed and deepened by the glacier. This is how lakes Ladoga, Onega and lakes of the Kola Peninsula and Karelia arose. Between moraine hills and ridges (traces of accumulative glacial activity), in the North and North-West of the East European Plain, groups of lakes of glacial origin (Seliger and Valdai Lakes) were formed.
In karst areas there are sinkholes and other karst lakes, which, despite their small area, have significant depth. In the south of Western Siberia there are many saucer-shaped lakes that arose as a result of subsidence of loose rocks.
In the floodplains of lowland rivers there are oxbow lakes. And along the shores of the Azov and Black Seas there are estuary lakes. Each such lake is the result of the interaction of river and sea; The river mouth, flooded by the sea, is separated from the sea by a spit rising between the sea and the river.
The regime of lakes largely depends on whether it is flowing or not. Most often, large lakes in Russia are flowing. Stagnant lakes are typical mainly for the southern part of the country. They are usually located in a drainage basin, collecting atmospheric and groundwater. Due to high evaporation and abundance of salinity sources, stagnant lakes in the southern regions are often saline. The largest such sea-lake is the Caspian Sea. The salinity of its waters is about 13 0/00, the maximum depth is 1025 m. The largest salt lake in Russia is Lake Chany in Western Siberia. Salt lakes are divided into brackish and saline (in the event that the salinity increases to complete saturation and the salts precipitate). Salt lakes are lakes Baskunchak, Kuchuk (deposition of Glauber's salt).
Lakes in the Caspian lowland Elton and Baskunchak, which are the place of extraction of table salt, are world famous.
Economic importance of lakes. All large lakes in Russia are used for farming. Navigation is carried out along them, and fresh water is used to supply water to populated areas and to irrigate fields. The lakes, where valuable species of fish are found, are of great commercial importance. Some lakes have large reserves of salts, and sometimes there are healing muds. The shores of the lakes are places of recreation and tourism.
Groundwater is an important component of inland waters. This is one of the sources of water supply, since they are much cleaner than surface water and their level is less subject to seasonal fluctuations.
In addition to fresh water, groundwater with a high content of salts and gases is of great value. These are mineral waters that are used for medicinal purposes. They are found in Ciscaucasia, Karelia, Transbaikalia, etc.
Swamps. These unique natural landscapes occupy more than 10% of the territory of our country. Swamps are common where precipitation exceeds evaporation. The formation of swamps completes the evolution of small lakes. The north-west of the East European Plain is heavily swamped (up to 20-30%); West Siberian Lowland (mainly south of the Ob) - up to 70%, center and northeast of Yakutia, Amur basin (10-12%). Swamps are an important source of river nutrition. Many of them are rich in peat. This is a place where many healthy berries and medicinal herbs grow. Therefore, the conservation of wetlands is important for the protection and rational use of natural resources.
Thus, Russia is very rich in water resources, but they are distributed extremely unevenly.
Natural areas.
Due to the enormous extent of the territory from north to south, within Russia there is a clearly expressed natural zonation, manifested in soil cover, vegetation and wildlife and is represented by a rich range of zones from Arctic deserts in the north to semi-deserts and deserts in the Caspian region. In mountainous areas, altitudinal zonation is pronounced.
Arctic desert zone. Located in the far north of Russia, it covers the northern part of the Taimyr Peninsula and the islands of the Arctic Ocean. The climate of this zone is very harsh: long and frosty winters with strong winds. Temperatures drop below -40°C. Summer is cold and short, with temperatures no higher than 0°...+4°C. Due to such climatic conditions, 85% of the zone is covered with glaciers. Under a very sparse vegetation cover in ice-free spaces, the soils of Arctic deserts are formed. They are thin, often with a thin (1-3 cm) layer of peat. Significant evaporation during the long polar day (about 150 days) and dry air leads to the formation of saline varieties of polar desert soils. The vegetation is represented by mosses, lichens (mainly crustose), algae and a few species of flowering plants and arctic-alpine grasses (poppy, bluegrass, fippsia, etc.). The fauna is also poor. The islands are inhabited by arctic fox, polar bear, and lemming. Reptiles and amphibians are completely absent here. On the rocky shores of the islands there are large colonies of birds, the so-called “bird colonies”; thousands of razorbills, gulls, guillemots, puffins, guillemots, mayweeds and other birds nest here
Tundra zone occupies the coasts of the seas of the Arctic Ocean from the Kola Peninsula to Chukotka. In the north of Kamchatka it reaches the latitude of St. Petersburg. This zone has short, cool summers with temperatures ranging from +4°C in the north to -+11°C in the south. Winter is harsh, like in the Arctic deserts. There is little precipitation - 200 -
300 mm per year, but with a lack of heat, evaporation is low. Permafrost is widespread here, which prevents moisture from seeping deeper. This contributes to the widespread occurrence of swampy landscapes and the formation of numerous shallow lakes. The soils in the tundra in the north are tundra arctic, in the south they are replaced by typical tundra and podzolized soils. They are characterized by low power, low humus content, high acidity and gley content.
The flora of the tundra is heterogeneous: in the north, in the Arctic tundra, moss-lichen groups predominate. Among the herbaceous plants there are many sedges, cotton grass, and polar poppy. To the south there is a typical tundra with moss, lichen and shrub groups, located east of the Kolyma sedge-cotton grass hummocky tundra. The southern part of the zone is dominated by shrub tundra with low-growing species of birch and willow. Among the plants there are many perennials, including evergreen berry plants (lingonberries, cranberries, blueberries, blueberries), cloudberries, dwarf heather, and mushrooms grow here.
The fauna is very poor; its living conditions have much in common with the Arctic: harsh climate, lack of food and shelter. Many animals, especially birds, leave the tundra for the winter. Only the arctic fox, lemmings, snowy owl, tundra partridge remain here, and in the mountains of North-Eastern Siberia - the ground squirrel, marmot, and pika. Numerous herds of deer roam the tundra in search of moss (fruticose lichen). In summer, many birds come: geese, ducks, swans, waders and loons. Due to low temperatures and poor soil minerals, farming is impossible here.
Forest-tundra.
It is a transition zone from tundra to taiga. It is already much warmer here than in the tundra. The average temperature in July reaches +14°C. The annual precipitation reaches 400 mm, which far exceeds evaporation, so the forest-tundra is the most swampy natural zone. It is characterized by a combination of plants, tundra and taiga zones. The most productive reindeer pastures are located here, since moss grows much faster here than in the tundra.
Forest zone.
Forest zone Occupies the largest area of Russia (60%). But the forested part makes up 45% of the country's area. This zone includes three subzones: taiga, mixed and deciduous forests.
In different areas of the vast taiga zone, many natural conditions are not the same - the overall severity of the climate, the degree of moisture, mountainous or flat terrain. number of sunny days, soil diversity. Therefore, the coniferous trees that form the taiga are also different, which changes its appearance in certain areas. Summer here is cool, the average July temperature is no higher than +18°C. The amount of precipitation varies from west to east from 600 to 300 mm, but in most parts it slightly exceeds evaporation. The snow cover is stable and lasts all winter. Coniferous species predominate in the taiga: pine, spruce, fir, larch. There are also small-leaved tree species: birch, aspen, rowan. On the East European Plain, taiga forests are represented by spruce, fir and pine. In Western Siberia - spruce, fir, Siberian pine and Siberian larch. To the east of the Yenisei, larch forests are most widespread, with the predominance of Daurian larch, the horizontal root system of which allows it to grow on permafrost
Every year, coniferous forests form different types of podzolic soils. As a result of the decomposition of pine litter, acids are formed, which, under conditions of high humidity, contribute to the decomposition of mineral and organic soil particles. The leaching regime leads to the leaching of substances from the upper humus layer into the lower soil horizons, as a result of which the upper part of the soil acquires the whitish color of ash (hence “podzols”). In areas of excessive moisture, soils become gleyed and gley-podzolic soils are formed. In Eastern Siberia, slightly podzolized permafrost-taiga soils are developed under larch forests due to less precipitation and the spread of permafrost. In areas where deciduous trees are mixed with coniferous trees, soddy-podzolic soils are formed. All these soils are low-fertile and highly acidic, but with the application of mineral fertilizers and liming they can produce good yields of vegetables, flax, rye, oats, barley and forage grasses.
The fauna is more diverse than in the tundra. This is the kingdom of fur-bearing animals. Here live: squirrel, sable, chipmunk, brown bear, lynx, pine marten, fox, wolf, elk. There are many birds: wood grouse, hazel grouse, woodpecker, nutcracker, owl and others.
Coniferous forests are used for timber harvesting, fur trading and the collection of berries, mushrooms and medicinal plants are carried out here. Subzones of mixed and broad-leaved forests are located south of the taiga on the Russian Plain, are absent in inland areas and reappear in the south of the Far East. Soils and vegetation change as you move from north to south.
In the subzone of mixed forests to coniferous and small-leaved species
broadleaf trees join: oak, linden, Norway maple, ash, elm, hornbeam and
other. But all of them are found only within the East European Plain. Behind
The Ural ridge is crossed only by linden, found occasionally in the south of the forest zone
Western Siberia. They grow on soddy-podzolic soils. Forest in the south
zone of the East European Plain, broad-leaved species are common in
gray and brown forest soils. ","
The forests of the south of the Far East are unique. The already mentioned tree species are mixed with species of East Asian origin: Korean cedar, Mongolian oak, Amur velvet, Manchurian walnut, aralia, hazel, honeysuckle and vines (Amur grape, actinidia, lemongrass).
The fauna of the subzone is very rich. Roe deer are added to the taiga species,
marten, red deer, wild boar, beaver. In the Far East live the harza, the Amur tiger,
badger, otter, Amur snake, Far Eastern tortoise, blue magpie, duck
mandarin duck.
Forest-steppe zone.
This is a transition zone from forest to steppe, so it alternates between areas of forest and steppe vegetation. The soils of the forest-steppes are very fertile, so the nature of this zone has been greatly changed by human economic activity. The Russian steppe zone is small in area. It occupies the south of the European part of the country and Western Siberia. Steppe areas are also found in Transbaikalia and in the basins of the mountains of Southern Siberia. Since the territory of the steppe zone is located south of the paths of cyclones, there is little precipitation (up to 300-450 mm per year). The humidification coefficient varies from 0.6-0.8 at the northern border to 0.3 in the south. Winter is cold, the average temperature is below 0°C. Summer is moderately hot +21°+23°С.
A small amount of precipitation and high evaporation create conditions for the accumulation of humus in the upper soil horizon. Chernozems are distributed here - the most fertile soils, with a very dark color and granular structure.
In the driest parts of the zone, chestnut soils are common. Saline soils are also found.
Most of the steppe zone is plowed. Grains, vegetables and industrial crops are grown here. Remains of natural steppes are preserved only in the reserves of the Central Chernozem zone ("Talichya Mountain" on the Central Russian Upland)
Semi-desert and desert zones. Located in the Caspian region and on the border with Kazakhstan. They have a dry, sharply continental climate. In summer, the average July temperature rises to +23°+25°C, and in January drops to -10°-15°C. The annual precipitation does not exceed 250 mm.
Semi-deserts are characterized by transitional features from steppes to deserts. Here, wormwood-grass vegetation grows on chestnut and brown desert-steppe soils. The grass stand is dominated by feather grass, fescue, and tyrsa. Subshrubs include white wormwood, prutnyak, bugorgun and others.
In deserts, summer is even hotter, the snow cover is thin and unstable. Wormwood and saltwort grow on gray-brown soils. Salts accumulate in the upper soil horizons due to strong evaporation, so salt marshes and solonetzes are widespread in these areas.
The main animals are rodents: gophers, jerboas, voles, and mice. There are the steppe wolf, polecat, corsac fox, long-eared hedgehog, sand cat, and goitered gazelle. There are many reptiles.
In the southern part of Russia, on the Black Sea coast of the Caucasus, there is a small area of humid subtropics.
The change in natural zones in the mountains is determined by altitudinal zonation, which can often be traced even within low mountains.
Ecological problems of landscapes of natural zones of Russia(according to Petrov K.M.)
In the last few decades, the influence has been particularly strong.
human economic activity on natural landscapes, which
are intensively transformed into anthropogenic ones.
Tundra zone: until the second half of the 20th century, everywhere in this zone
indigenous natural ecosystems prevailed. The local population was engaged
nomadic reindeer herding, fur trading, hunting sea animals. Co
second half of the 20th century, economic activity in the harsh conditions of the North
has received particularly great development. This is related to geological exploration, production
oil and gas, construction of roads, oil and gas pipelines, cities and towns. 1The presence of permafrost is the most important factor influencing the technogenic development of the territory.
Vegetation, moss layer and peat are good natural
. heat insulator. Its destruction contributes to the melting of underground ice,
the formation of subsidence and failures.
1) It is necessary to preserve soil and vegetation cover. In a few years, a cleared dirt area can turn into a sinkhole lake, and a tractor track can turn into a ditch, and then a deep ravine.
Oil products entering the soil decompose very poorly, and low temperatures
and min oxygen retains oil contamination for a long time. => Self-cleaning in
almost no frost occurs in the permafrost zone.
Geological exploration works harm reindeer pastures, area
which has been greatly reduced. => Herds concentrate on limited
area. => Overgrazing. => Destruction of soil and vegetation cover. Reindeer moss
grows very slowly (over 50 years - 6 - 8 cm). Now disturbed reindeer moss
pastures are almost never restored. => With this level of exposure
indigenous natural ecosystems of the tundra will become relict.
Taiga zone: characteristic landscapes of the most extensive
The areas of the taiga zone are coniferous forests and swamps. The territory of the middle and especially the northern part of the taiga began to be developed in Russia relatively recently. Features of economic activity: forestry - timber harvesting, collecting herbs, berries, mushrooms, hunting. In the first half of the 19th century, the population was insignificant, settlement was patchy and concentrated mainly in river valleys. => Cattle breeding and agriculture, because The soils of the floodplains are maximally fertile. In place of clearings there are pastures and arable lands.
Particularly strong changes in the structure of the taiga zone occurred in the second half of the 20th century, because IV timber harvesting. Large development areas covered almost the entire European part of the taiga zone, a significant part of the Urals, and vast areas of Western Siberia, Eastern Siberia and the Far East.
1)
Due to geological exploration, production and development of agricultural land, even in
in hard-to-reach places, taiga landscapes began to suffer from economic
development.
2) Fires cause enormous damage to the taiga.
3. Near large cities, forests are replaced by agricultural land.
I. Forests play an important soil and water conservation role: where they
are destroyed, 1 surface runoff, soil loss increases, ravines appear,
IV groundwater, rivers are shallowing.
Taiga plays an important role in O2 saturation and absorption. CO2 (for 1 year »
1 thousand m 3 Og). .
Taiga swamps are a unique natural complex. These are sources of peat, agricultural land (after
dehumidification). Recently there has been a massive attack on the swamps. But
the economic benefit is minimal, but the consequences are enormous. => Natural swamp vegetation dies, the peat layer is quickly removed (from 1-2 to 12 cm is removed in a year). Dust storms occur in Belarusian Polesie, and black clouds of dried peat rise into the air. The filtering role of swamps is great: sphagnum is sterile, purifies water from various substances, including heavy metals (Pb, mercury, etc.). Swamp water has enormous ecological and economic potential. Drainage of swamps leads to disruption of the rivers' feeding regime, because... they are the sources of many rivers and streams; forests are drying out; The diversity of marsh plants and animals is decreasing.
Conclusion: it is necessary to restore the potential of taiga landscapes.
Zone of mixed and deciduous forests: has a soft
climate and fertile soils => the zone has been inhabited for a long time and has a high population density. At the beginning of the 19th century, arable land and pastures occupied a larger area than forests. In the 20th century, the development and destruction of natural landscapes increased, and relics of natural ecosystems were preserved only in nature reserves. In the near future, the main place will be taken by anthropogenic landscapes, performing resource-reproducing and environment-regulating functions. It takes 1 share of economic costs in the economy to maintain a favorable ecological regime in these anthropogenic landscapes.
> Forest-steppe and steppe zones: this is a zone of long-standing agricultural development =>
main areas of pastures and arable land (up to 70%). => The area of indigenous forests has greatly decreased => negative consequences: soil depletion, loss of humus from the arable layer; droughts, dry winds and dust storms; Natural phenomena are characteristic: intensive development of the ravine-beam network.
Relief of Russia
Traits:
Great diversity due to the complex tectonic structure: maximum height - Elbrus (5642 m), minimum - Caspian lowland (-28 m).
2/3 of the territory is occupied by plains of different heights; 1/3 - adjacent mountains.
The Yenisei River is the border between the lower west and the elevated east.
Most of the territory slopes to the north, as evidenced by the direction of the currents
large rivers.
The tectonic structure is highly variegated:
1. The main territory consists of platform structures.
A) Ancient platforms with a Precambrian foundation: The East European platform is located at the base of the European territory of Russia. In its northwestern part there is the Baltic Shield, which corresponds to the elevated relief of the Kola Peninsula and Karelia and the residual Khibiny Mountains. The East European Platform corresponds to the East European Plain with average heights of up to 200 meters, the surface of which is represented by alternating hills and lowlands of various origins. The Valdai, Smolensk-Moscow, Northern Uvaly hills are a consequence of Quaternary glaciations; Privolzhskaya and Pridneprovskaya correspond to uplifts of the platform foundations.
The second ancient platform is the Siberian one, within which there is an elevated (above 500 m), highly dissected Central Siberian Plateau.
The Precambrian foundation of the platform is broken by numerous cracks, along which magma erupted in the Cenozoic and traps were formed. In the northeast and southeast of the platform there are the Anabar and Aldan shields, which correspond to the Anabar and Aldan highlands.
B) Between the ancient platforms there is a young West Siberian plate,
the foundation of which was formed in the Paleozoic. It is covered by a thick cover of sedimentary rocks of marine origin up to 10 - 12 km thick. It corresponds to the flat, heavily swampy West Siberian Lowland with heights of up to 100 m.
2 . Adjacent to the platforms are areas of folding, which correspond to mountains that differ in height, appearance and origin.
A) Within Russia there is an ancient Ural-Okhotsk geosynclinal belt of Paleozoic age, which includes the mountains of Novaya Zemlya, the Urals, Altai, Sayan Mountains, the Baikal region, Transbaikalia, and the mountains of the Sea of Okhotsk coast. These are mountains of folded block and block structures that formed during the Baikal, Caledonian and Hercynian orogenies and were subsequently severely destroyed. In the Cenozoic, they experienced a secondary uplift (rebirth) to a height of 2000 - 3000 m.
B) The highest mountains belong to the Alpine geosynclinal belt, which was formed in the Cenozoic as a result of the interaction of the Arabian and Eurasian lithospheric plates. It includes the Caucasus Mountains, which were formed as a result of the folding of sedimentary rocks and active volcanism. The presence of mineral springs and extinct volcanoes Elbrus and Kazbek indicate the attenuation of tectonic activity in this area.
IN) The third geosynclinal belt (Pacific) is located in the east of Russia in the subduction zone of the Pacific and Eurasian lithospheric plates (5 - 7 cm per year). This is the most tectonically active region of our country, where mountain building processes continue and there is a zone of active volcanism and earthquakes. Includes: Koryak Highlands, Kamchatka Mountains. Sakhalin, Kuril Islands, coastal zone of Sikhote-Alin.
G) In the northeast of the country there is a vast area of Mesozoic
folding, which includes the Verkhoyansky, Chersky, Kolyma and Chukotka ridges
highlands, the Dzhugdzhur ridge and most of the Sikhote-Alin. In a relatively short time, the mountains did not have time to collapse and have heights ranging from 1000 to 2000 m. Conclusion: the main forms of relief in Russia were formed due to endogenous processes, but the modern relief has also been influenced by external forces.
1) The action of flowing waters: the formation of a ravine-gully network (Central Russian, Volga Uplands), river valleys (modern hydrographic network).
2) Advance and retreat of the sea - Caspian, Azov, Pechora, West Siberian lowlands.
3) Quaternary glaciations: moraine landforms (Northern ridges, Valdai, Smolensk-Moscow uplands); warm glacial water activity: hills and sandy plains.
6)
Permafrost: heaving mounds, ground subsidence (north of the European part,
territory east of the Yenisei).
Minerals
Russia is exceptionally rich in mineral resources, the distribution of which is related to the morphological structure of the territory.
Ore minerals are confined to the crystalline basement of platforms and folded areas. Non-metallic minerals - to a thick layer of sedimentary rocks.
Oil and gas fields are concentrated in the cover of sedimentary rocks of the West Siberian Plate (60% oil and 80% gas); in the Pre-Ural regional trough between the Volga and the Urals in Bashkiria and Tataria; in the northeast of the European part in the Pechora basin; in the Lena basin; in the north of Sakhalin.
The zone of mixed and deciduous forests is located in the western part of the plain between the taiga and forest-steppe and extends from the western borders of Russia to the confluence of the Oka and the Volga. The territory of the zone is open to the Atlantic Ocean and its impact on the climate is decisive.
The zone is characterized by a mild, moderately warm climate. The relief exhibits a combination of hills (200 m or more) and lowlands. The strata plains are overlain by moraine, lacustrine-alluvial, fluvioglacial and loess rocks. Within the zone, under conditions of a moderately humid and moderately warm Atlantic-continental climate, soddy-podzolic and gray forest soils are formed.
Large high-water rivers of the East European Plain - the Volga, Dnieper, Western Dvina, etc. - begin here. Groundwater lies close to the surface. With dissected topography, clay-sand deposits and sufficient moisture, this contributes to the development of swamps and lakes.
The climate of the zone is favorable for the growth of coniferous tree species along with broad-leaved trees. Depending on the relief conditions and the degree of moisture, meadows and swamps are also formed. European coniferous-deciduous forests are heterogeneous. Among the broad-leaved species in the zone, linden, ash, elm, and oak are common. As you move east, due to the increasing continentality of the climate, the southern border of the zone shifts significantly to the north, the role of spruce and fir increases, while the role of broad-leaved species decreases.
The most widespread of the broad-leaved species in the zone is linden, which forms the second tier in mixed forests. They have a well-developed undergrowth with a predominance of hazel, honeysuckle, and euonymus. In the grass cover, taiga representatives - wood sorrel, oxalis - are combined with elements of oak forests, among which the role of sedum, hoofed grass, woodruff, etc. is significant.
The natural complexes of the zone change to the south, as the climate becomes warmer, the amount of precipitation approaches evaporation, dominance passes to broad-leaved species, and coniferous trees become rare. In these forests the main role belongs to linden and oak.
Here, as in the taiga, upland and floodplain meadows are developed on alluvial soils. Transitional and lowland swamps predominate. There are few sphagnum bogs.
In historical times, the zone of mixed and deciduous forests was home to many wild animals and birds. Currently, they are pushed into the least populated areas or are completely exterminated and are only preserved and restored in nature reserves. Nowadays, the typical animals of the zone are wild boar, elk, bison, black or forest polecat, badger, etc. In recent decades, the number of wild boar, river beaver and elk has increased significantly.
The border of the wild boar's range has advanced to the northeast and southeast in some places up to 600 km or more. Coniferous-deciduous forests are characterized by animal species characteristic of Eurasia, but mostly close in origin to the species of Western broad-leaved and mixed forests, for example, European roe deer, European red deer, European mink, marten, dormouse, European forest cat, muskrat. Red deer, sika deer, and muskrat are acclimatized. Of the reptiles in mixed forests, the sand lizard and grass snake are common.
Rice. 7. Geological structure of the Valdai Hills
The zone of coniferous-deciduous forests has long been densely populated and developed, so its nature has been greatly changed by human activity. For example, forests occupy only 30% of the zone's territory; the most convenient areas are plowed or used for pastures; In the fauna there was a change in the species composition - the tarpans and European aurochs that once lived in the forests completely disappeared. Marten, wolverine, muskrat, golden eagle, osprey, white-tailed eagle, white and gray partridge have become rare.
Much work was carried out to restore the river beaver, bison, red deer, increase the number of elk, acclimatize the raccoon dog, American mink and muskrat. Many species of animals and plants are taken under protection. Nature reserves have been created in the zone to protect the most typical natural complexes and especially rare animals and plants. Among them is the Prioksko-Terrasny biosphere reserve, which protects the natural complexes of the center of the zone, which played a large role in the restoration of bison brought from Belovezhskaya Pushcha and the Caucasus in the dense coniferous-deciduous forests.
The Valdai province extends from the upper reaches of the Lovat and Western Dvina rivers north-northeast to Lake Onega. It consists of the Valdai (341 m), Tikhvin (280 m) and Vepsovskaya (304 m) hills, separated by depressions about 100 m above sea level. In the west, the hills abruptly end with the picturesque Valdai-Onega ledge (up to 150-200 m) to the Priilmenskaya lowland. In the east, the hills gradually turn into adjacent low-lying plains.
The province is located on the western flank of the Moscow syneclise, so the thickness of sedimentary rocks composing the cover occurs monoclinally. The Valdai-Onega ledge is usually considered as a Carboniferous cliff (cuesta ledge), fixing the boundary of the distribution of Carboniferous rocks, represented by limestones, dolomites and marls.
The province is located in the marginal part of the Valdai glaciation, therefore, within its boundaries there is a well-preserved glacial-accumulative hilly-moraine relief with terminal moraine ridges (Torzhokskaya, Vyshnevolotskaya, Lesnaya, etc.) and numerous moraine lakes along the basins (Seliger, Volgo, Valdai, Velho, etc.). This strip of young picturesque landscapes is called Poozerie. The thickness of the moraine that covered the pre-glacial relief varies from 1-2 m to 100 meters or more.
Carbonate rocks underlying the moraine determine the development of karst relief forms where the thickness of Quaternary sediments is small - within the carbon ledge itself and in the valleys of the rivers cutting through it. Karst forms are represented by saucers, ponoras, basins, as well as cavities, caverns, and caves.
The sources of the Volga, Dnieper and Western Dvina lie on the Valdai Hills. Many rivers flow in the depressions of glacial melt water, and their valleys are not yet fully formed. Short rivers connect numerous lakes, forming single water systems.
The province's climate is humid with cool summers. The average temperature in July is only 16°C, and the average daily temperature rarely rises above 20°C. Winter is moderately cold. The average January temperature is -9...-10°C. Cyclones that often come here cause thaws. The annual precipitation is more than 800 mm, which is the maximum for the Russian Plain. The maximum occurs in summer.
The province is characterized by an extraordinary diversity of soil and vegetation cover, which is due to the frequent change of soil-forming rocks and relief forms. Moraine hills and ridges are covered with broad-leaved spruce forests on sod-podzolic and podzolic soils. Pine forests predominate on outwash plains, lakeside sands and sandy hills. On limestones, dolomites and carbonate moraine, dark-colored humus-carbonate soils are common, on which spruce-broadleaf forests grow with a predominance of oak, with linden, ash and elm in the second tier.
Scattered among the forests are damp meadows and pine-sphagnum lowland grass and convex ridge-hollow bogs with cloudberries and cranberries. They are confined to the bottoms of wide valleys, lake shores, and sometimes flat watersheds.
A significant part of the province’s area has long been greatly altered by man, but in some places slightly altered areas still remain. Here in 1931 the Central Forest Reserve was created, which now has biosphere status. Its territory is covered with spruce and spruce-broadleaf forests, typical of the province.
The Meshchera province is located between the Klyazma and Oka rivers. In the north it is limited by the slopes of the Smolensk-Moscow Upland, in the east by the Oka-Tsninsky rampart. The typical landscape of Meshchera is a gently undulating alluvial-outwash forest plain 80-150 m above sea level with lakes and swamps. Along the edges of Meshchera there are moraine-erosive uplifts with average heights of 150-200 m.
This type of landscape is called woodland. Woodland landscapes formed at the edge of the Pleistocene ice sheet, in depressions of the pre-glacial relief, along which glacial melt waters drained. Elevated remnants or “loess islands” - opoles - have also been preserved here. On the East European Plain within Russia, the Polesie type of landscapes forms an entire belt, consisting of the Bryansk-Zhizdra, Meshchersky, Mokshinsky, Balakhninsky, Vetluzhsky, Kama-Vyatka and other woodlands.
Meshchera is confined to the pre-glacial tectonic trough. At its base lie Carboniferous limestones, overlain by Jurassic and Cretaceous sandy-clayey deposits. Quaternary deposits consist of eroded moraine, preserved in the highest areas of the pre-glacial relief (Egoryevskoe plateau, Oksko-Tsninsky swell, etc.), and large layers of sand and loam of water-glacial and alluvial origin. In the central part of Meshchera there is a lowland with peat bogs and lakes (Svyatoe, Velikoye, etc.). Around it stretch wide strips of sandy plains with dunes. Rivers flow slowly in flat, swampy lowlands and drain them poorly.
The climate of Meshchera is moderately humid with cold, snowy and long winters. The average January temperature is -11...-12°C. Snow lies for up to 150-160 days with a maximum snow cover height of 50-55 cm. Winter weather types are unstable - with frosts and thaws. Due to the significant amount of snow, the flood on the Meshchera rivers is prolonged. Summers are warm with maximum precipitation. The average July temperature is 18.5-19°C. The annual precipitation (about 600 mm) exceeds evaporation, so the territory is excessively moist.
The main area of Meshchera is covered with pine forests, in some places with an admixture of oak and swamps. Spruce and birch forests are less common. Under the forests, soddy-podzolic and soddy-podzolic gley soils were formed on sands and sandy-clayey deposits. Light lichen forests are common on sandy ridges, hills and dunes; in the interfluves along the slopes of the valleys, spruce-pine forests with an admixture of oak, maple and linden dominate; on the moraine outcrops grow mixed forests of spruce, oak and linden, with an undergrowth of hazel and a thick herbaceous cover of nymph, hoofed grass, and lily of the valley; There are wet oak forests on the floodplains.
Swamps occupy about 35% of the surface of Meshchera. The main types of bogs are lowland and transitional, among which are sphagnum-sedge, hypno-sedge, sedge and birch-sedge. Raised bogs are less common, but they form large massifs and contain thick peat layers (up to 8 m) of high quality. The Shaturskaya thermal power plant operates on the Meshchersky peat.
Diverse landscapes are located in the south of Meshchera in the wide Oka valley and the strongly meandering valley of the Pra River, as well as in their interfluve. The Oka Nature Reserve was created there in 1935.
Most of the Canadian Arctic Islands and Greenland.
Climate. Arctic. Negative or near-zero temperatures predominate.
Soils. Poor, rocky and swampy.
Vegetation. Mainly mosses and lichens.
Animal world. Muskox.
The northern coast of the mainland with adjacent islands. In the east are the coast of Hudson Bay and the northern part of the Labrador Peninsula.
Climate. Subarctic (partially Arctic) predominates.
Soils. Tundra - gley, with excess moisture.
Vegetation. In the northern part there are mosses and lichens; in the southern part there are marsh grasses, blueberries and blueberries, wild rosemary bushes, low-growing willows, birches, and alders. Woody vegetation appears to the south.
Animal world. Polar wolf, caribou reindeer, arctic fox, ptarmigan and some others. A variety of migratory birds. In coastal waters there are seals and walruses. On the northern coast there is a polar bear.
It stretches in a wide strip from east to west. Difficult coniferous forests.
Climate. Moderate (with increased moisture).
Soils. Podzolics predominate.
Vegetation. Mainly coniferous trees - balsam fir, black spruce, pine, sequoias, American larch. Hardwoods - paper birch, aspen. On the slopes of the Cordillera there are Sitka spruce and Douglas fir.
Animal world. Wolves, bears, deer and elk, foxes, lynxes, sables, beavers, muskrats. In mountain forests there are skunks, grizzly bears, and raccoons. In the rivers there are salmon fish. There are seal rookeries on the islands.
Mixed and broad-leaved forests
South of the tundra zone. (Variable moist forests predominate in the eastern part of the North American continent.)
Climate. Temperate, turning into subtropical.
Soils. Gray forest, brown forest, yellow soil and red soil.
Vegetation. In mixed forests - sugar maple, yellow birch, white and red pine, linden, beech. In the broad-leaved forests there are different types of oaks, plane trees, chestnuts, and tulip trees.
Animal world. Wapiti deer, bears (grizzly), moose, lynx, wolves, wolverines, raccoons, hares, foxes.
Evergreen tropical forests
In the south of the Atlantic and Mississippian and lowlands.
Climate. Subtropical.
Soils. Gray - brown, brown.
Vegetation. Oaks, magnolias, beeches, dwarf palms. The trees are entwined with vines.
Animal world. Diverse.
Forest-steppe
Treeless plains to the west of the forest zone. (In North America they are called prairies).
Climate. Subtropical.
Soils. Chernozems: podzolized and leached. Chestnut, forest gray.
Vegetation. Tall perennial grasses: wheatgrass, feather grass, etc. In river valleys there is woody vegetation. Near the Cordillera there are low cereal grasses (Gram grass and buffalo grass).
Animal world. Diverse and rich.
Desert and semi-desert zone
A significant part of the California coast, the Mexican highlands and the interior plateaus of the Cordillera.
Climate. Moderate (arid).
Soils. Brown and gray desert.
Vegetation. Black wormwood; on salt licks - quinoa solyanka; thorny bushes, cacti.
Animal world. Scarce.
Savannas and evergreen forests
On the slopes of the Caribbean and Central America.
Climate. There is a distinct change between dry and wet seasons.
Soils. Black, red-brown, brown, gray-brown
Vegetation. Tropical types of hard-leaved grasses. Trees with a long root system and umbrella-shaped crowns predominate.
Animal world. Versatile.
Climate zones
North America experiences almost every type of climate known on Earth. The natural change in temperature and circulation conditions from north to south determines the identification of different climatic zones on the continent.
The Arctic belt occupies the northern coast of the continent and most of the Canadian Arctic Archipelago. Cold and dry arctic air dominates here throughout the year. Therefore, even in summer, the air temperature, as a rule, does not rise above +5 °C. In winter, frosts reach –40 °C, and in Greenland –70 °C. There is little precipitation here and mostly in solid form. Low temperatures contribute to the formation of stable snow cover and glaciation.
The subarctic belt is located south of the Arctic (up to 58–60° N latitude). In summer, the climate of the territory is formed by moderate air masses. The air temperature during the warm period averages + 10 °C. In winter, when Arctic air dominates, it is even colder in the central part of the belt than in the Arctic zone. This phenomenon is explained by the remoteness of the territory from the ocean. In the western part of the belt there is more precipitation than in the eastern.
Most of the continent lies in the temperate zone. The significant extension of the belt from north to south (more than 2000 km) determined large differences in surface heating. Within the belt, the amount of precipitation also varies significantly. The difference in moisture allowed us to distinguish three climatic regions here: marine, temperate continental and continental climate types.
The region of marine type climate covers the Pacific coast and the western slopes of the Cordillera. The temperature here varies little throughout the year. Relatively warm winters and cool summers are accompanied by heavy rains. There is 2000–3000 mm of precipitation per year.
On the contrary, the region of continental climate, which occupies the central part of the belt, is characterized by seasonal differences. Truly warm summers (with temperatures from +18 °C in the north to +24 °C in the south) give way to cold winters (with frosts from –20 °C in the north to –6 °C in the south). Precipitation falls significantly less than on the Pacific coast - 400–600 mm per year.
The region of temperate continental climate is located in the eastern part of the temperate zone. Although the winter here is cold, the summer is not so hot. In comparison with the continental climate region, the amount of precipitation also increases - on average up to 1000 mm.
The southern part of the continent lies in the subtropical zone, where winter is just a cool season: the temperature rarely drops below 0 ° C, and snow is a rare occurrence. In winter, cyclones of the polar front dominate here, carrying moist, moderate air masses. In summer they give way to dry tropical air masses. The precipitation regime and amount of precipitation are associated with the identification of three climatic regions in the subtropical zone: Mediterranean, subtropical continental and subtropical monsoon climate types.
The tropical zone occupies a small, narrow part of the continent lying between the Gulf of Mexico and the Pacific Ocean. Throughout the year, hot tropical air dominates here. It is thanks to this that the climate of the zone is figuratively called the “climate of eternal summer”, since it is difficult to distinguish warm and cold seasons here. However, moisture conditions within the belt are different. In this regard, two climatic regions are distinguished. The Mexican Highlands and the California Peninsula are in the desert tropical climate region. There is very little rainfall here. This is caused by two reasons: a high pressure area in the North Pacific Ocean and the cold California Current. The eastern coast of the Gulf of Mexico and the islands of the West Indies lie in a humid climate region. This is explained by the year-round dominance of humid southeastern trade winds.
The tropical latitudes of North America in summer and autumn are subject to the action of powerful tropical cyclones - hurricanes. A squall wind with a speed of more than 100 m/s drives a wall of rain and raises fifteen-meter waves. The energy released by one hurricane could last a country like the United States for 600 years. It is not surprising that tropical cyclones are a constant scourge of coasts and islands. Nowadays, the weather service can predict hurricanes quite accurately, but at times they still cause catastrophic destruction.
The subequatorial belt covers the southernmost, narrowest part of the continent. High temperatures (above +25 °C) remain here throughout the year and experience almost no seasonal fluctuations. Precipitation falls mainly in summer, when moist equatorial air masses arrive here.
Conclusions:
North America is located in all but the equatorial climate zones.
In the temperate, subtropical and tropical zones, climatic regions are distinguished due to different amounts and patterns of precipitation.
25. physical-geographical zoning of North America
The diversity of the natural conditions of the continent allows, first of all, to distinguish two large regions based on differences in geological structure and topography: the Plain East and the Cordillera. At the second stage of zoning, taking into account landscape-climatic zonality and altitudinal characteristics, several natural areas are identified in each of these regions. The East includes the Canadian Arctic Archipelago and Greenland, the Canadian Plains, the Central Plains, the Great Plains, the Appalachians, and the Coastal Lowlands. The Cordillera mountain belt is divided into the following natural areas: the Alaskan Cordillera, the Canadian Cordillera, the Southern Cordillera (USA Cordillera), and the Mexican Highlands. The continental territory located in tropical latitudes - Central America - is considered as a special natural area. It includes a narrow strip of land and islands of the Caribbean Sea.
As an example of a natural area, it is better to consider the plains of Canada. They are in many ways reminiscent of the landscapes of the subarctic and temperate zones of Russia. This vast natural area lies within the Canadian Shield of the North American Plate. The relief is dominated by elevated plains (Laurentine Upland). In the north they turn into flat lowlands, and in the east into the plateaus of the Labrador Peninsula. The relief of the region was formed under the influence of Quaternary glaciation. Therefore, the area is characterized by an alternation of hilly ridges and interridge basins filled with lakes. The crystalline rocks of the Canadian Shield are associated with rich mineral deposits: iron, nickel, copper, platinum, lead, zinc, uranium, and gold. Deposits of oil, natural gas and coal are associated with sedimentary rocks of the marginal foothill trough of the Cordillera.
The climate on the plains of Canada is continental, subarctic and temperate. Winters here are long, cold and snowy. Summer in the north is short and cool, in the south it is warmer and longer. The region is rich in inland waters: many lakes and deep rapids rivers. There are significant reserves of hydropower resources.
The northern part of the plains of Canada is occupied by tundra and forest-tundra zones, turning into coniferous forests. In the southeast of the region there is a zone of mixed forests. Forest and fur are the main natural resources of the taiga.
In the north of the region, the population, mainly Indians, is engaged in hunting, logging, and working in mines and mines. Most of the region's population is concentrated in the southern plains, on the border of Canada and the United States. These are descendants of immigrants from Europe, mainly from France and England. There are large cities with many industrial enterprises here. These are ferrous and non-ferrous metallurgy plants, engineering, chemical, woodworking and pulp and paper mills. Significant areas of land in the south of the plains are plowed and sown with wheat, barley, and forage grasses. Part of the land is used for pastures. On the Atlantic coast the population is engaged in fishing.
In addition to coniferous forests, North America has zones of mixed and deciduous forests. Their formation and features are greatly influenced by the relief and properties of surface rocks.
Mixed forests of North America
The mixed forests of North America are located in the temperate climate zone between the taiga zone and deciduous forests. They are common in the northeastern United States, eastern United States, and the Canadian border. The name of the forests speaks for itself: both coniferous trees and broad-leaved representatives of this species are concentrated here. Winters in this zone are cool (-5-14 degrees), and summers are quite warm (+20 degrees).
Mixed forests are characterized by gray forest and soddy-podzolic soils.
Among the coniferous species, white and red pine, hemlock, fir, and spruce predominate. The most common deciduous trees are birch, sugar maple, American ash, elm, hornbeam, and linden.
Rice. 1. American ash.
The fauna of mixed forests is very similar to the fauna of taiga. Here you can find black bears, badgers, minks, wolves, otters, raccoons and skunks, and Virginia deer.
Rice. 2. Black bear baribal.
In mixed forests, unlike broad-leaved forests, the grass cover is very well represented. In broad-leaved forests, the large leaves of the trees prevent the sun's rays from reaching the ground, so the grass cover is much sparse.
Broadleaf forests of North America
The broadleaf forests of North America are located in the temperate climate zone in the eastern part of the continent, south of the mixed ones. This zone is characterized by long, warm summers and mild winters. The climate here changes to a more humid and warm one, so coniferous trees, characteristic of mixed forests, are practically not found. This area is characterized by gray forest soil rich in iron.
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Because broadleaf forests are found in the Appalachian Mountains region, they are often called Appalachian forests.
The fauna and flora of deciduous forests is rich and diverse. Beech, ash, maple, hornbeam, chestnut and other trees with broad leaves that fall off in the winter grow here. Broadleaf forests contain several species of American oaks that are endemic, meaning these trees are not found anywhere else except North America. Types of American oaks:
- dwarf oak;
- scarlet oak;
- red oak;
- oval oak.
Rice. 3. Red oak.
In the southern part of the broad-leaved forests there are magnolias, hickories, and tulip trees.
Among the representatives of the fauna, it is worth highlighting the mink, bison, black ferret, cuckoo, pheasant, green woodpecker, and hummingbird.
What have we learned?
Mixed and deciduous forests are found in the temperate climate zone. In deciduous forests the climate is milder and warmer than in mixed forests. They have a diverse flora and fauna, and there are also endemic species in this territory that are not found on other continents.
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