Broad-leaved forests: features, relief, plants and animals. Zones of mixed and deciduous forests The tectonic structure is highly variegated

Zone arctic deserts. This zone includes Franz Josef Land, Novaya Zemlya, Severnaya Zemlya, and the New Siberian Islands. The zone is characterized by a huge amount of ice and snow in all seasons of the year. They are the main element of the landscape.

Arctic air prevails here all year round, the annual radiation balance is less than 400 mJ/m2, and average July temperatures are 4-2°C. The relative humidity is very high - 85%. Precipitation amounts to 400-200 mm, almost all of which falls in solid form, which contributes to the formation of ice sheets and glaciers. However, in some places the supply of moisture in the air is small and therefore, when the temperature rises and strong winds, a large lack of moisture occurs and strong evaporation of snow occurs.

The soil-forming process in the Arctic occurs in a thin active layer and is at the initial stage of development. In the valleys of rivers and streams and on sea terraces, two types of soils are formed - typical polar desert soils on polygonal drained plains and polar desert solonchak soils on saline coastal areas. They are characterized by a low humus content (up to 1.5%), weakly expressed genetic horizons and very low thickness. In the Arctic deserts there are almost no swamps, few lakes, and salt spots form on the soil surface in dry weather with strong winds.

The vegetation cover is extremely sparse and spotty, and is characterized by poverty species composition and exclusively low productivity. Low-organized plants dominate: lichens, mosses, algae. The annual growth of mosses and lichens does not exceed 1-2 mm. Plants are extremely selective in their distribution. More or less closed groups of plants exist only in places sheltered from cold winds, on fine earth, where the thickness of the active layer is greater.

The main background of the Arctic deserts is formed by crustose lichens. Hypnum mosses are common; sphagnum mosses appear only in the south of the zone in very limited quantities. Higher plants include saxifrage, arctic poppy, semolina, chickweed, arctic pike, bluegrass and some others. The grasses grow luxuriantly, forming hemispherical cushions up to 10 cm in diameter on a fertilized substrate near the nesting areas of gulls and lemming burrows. Ice buttercup and polar willow grow near patches of snow, reaching only 3-5 cm in height. The fauna, like the flora, is poor in species; there are lemmings, arctic foxes, reindeer, polar bear, and the most common birds are the ptarmigan and the snowy owl. There are numerous bird colonies on the rocky shores - mass nesting grounds seabirds(guillemots, little auks, white gulls, fulmars, eiders, etc.). The southern shores of Franz Josef Land and the western shores of Novaya Zemlya are a continuous bird market.

Coniferous-deciduous forests of the Russian Plain - natural area temperate zone, characterized by relatively soft, humid climate, growing along watersheds with coniferous-deciduous forests on sod-podzolic soils. It is also called the zone mixed forests, which is not entirely accurate, since taiga forests are often mixed in composition. These two names can apparently be considered synonyms.

In the north, the zone borders on taiga, in the south – on forest-steppe, in the west, outside the USSR, it passes into the zone of deciduous forests Western Europe. The leading role in the formation of the landscape is played by the location of the zone in the southwest of the forest belt of the USSR, in relative proximity to Atlantic Ocean. Compared to the taiga, the climate of mixed forests is warmer and more humid, and in its extreme northwest (Kaliningrad region) it is transitional from maritime to continental.

During the year, about 50-55 cyclones pass through the Kaliningrad region; In winter here almost every second day there is a front passing through. The sum of temperatures for a period with a stable temperature above 10° in the north of the zone is about 1800°, in the south – 2400°. The average duration of the frost-free period increases from 120 days in the northeast of the zone to 165 days in the west Kaliningrad region and in the Kyiv region. There is more precipitation in the zone than in the taiga. Their annual amount varies between 600-700 mm, and on the western slopes of the hills it reaches 800 mm. The moisture balance is positive; in the south it approaches neutral: the amount of evaporation here is almost equal to the annual amount of precipitation. The Vysotsky-Ivanov humidification coefficient, as in the taiga, is greater than one, the Budyko dryness index increases slightly and ranges from 2/3 to 1. There is enough heat and moisture here for the cultivation of a variety of crops: gray bread, wheat, potatoes, flax, sugar beets (southwest), hemp (south zone), forage grasses.

Under conditions of a positive moisture balance, the surface runoff in coniferous-deciduous forests is large (350-150 mm), the river network is well developed, and the rivers themselves are characterized by high water content. The most significant rivers, the basin of which lies entirely within the zone, are the Western Dvina and the Neman. The Western Dvina, despite its small basin area (85,100 km 2), has an average long-term water flow at the mouth of 680 m 3 /sec. Due to the positive moisture balance, groundwater lies close to the surface (from 0 to 10 m) and is quite widely used for various economic needs. The waters of terminal moraine ridges are variable in their distribution and depth. As in the taiga, mineralization groundwater in the zone it is weak, the salt concentration ranges from 100 to 500 mg/l.

The proximity of groundwater in a humid climate causes widespread development of waterlogging processes. Raised and lowland bogs cover most of the lowlands and basins; they are often found on high, but insufficiently drained watersheds. Among the swamps in the north of the zone, high-moor sphagnum peat bogs predominate, sometimes covered with low-growing pine. To the south of Moscow and Minsk, transitional and lowland bogs predominate, containing peat of lower quality compared to the sphagnum peat of raised bogs. Peat from high-moor and transitional bogs in the zone of coniferous-deciduous forests is widely used for fuel and to fertilize fields. Large areas The swamps, after draining, were converted into fertile arable and hayfields. It seems most appropriate to drain transitional and lowland swamps, which are relatively rich in mineral salts. Agricultural development of raised bogs, poor in mineral salts, requires a lot of labor and material resources and doesn’t always bring the right one economic effect. When producing peat in quarries, it is recommended to leave an agricultural protective layer (the lower layer of the peat deposit) 30 cm thick, which is then used as organic matter for the newly created soil.

1) What forest zones do you know from the course on the geography of continents and oceans?

Taiga, mixed and deciduous forests, humid equatorial forests, variable-humid subequatorial forests.

2) What climatic conditions are necessary for the spread of forest zones?

Sufficient moisture is necessary for the spread of forest zones.

Using the maps, determine where the taiga zone is located, what climatic and soil conditions, what kind of relief and inland waters characteristic of her.

Taiga is a natural zone of the temperate zone, characterized by a cool, humid climate and a predominance of vegetation coniferous forests on podzolic soils and sphagnum bogs.

Questions in a paragraph

*Carefully consider the location of coniferous forests in the taiga zone on the vegetation map and think about what explains their growth in certain areas.

Dark coniferous spruce-fir forests predominate in the European part of the zone and in Western Siberia, where they are joined by cedar forests. There is sufficient moisture and small temperature changes. Most of the Middle and Eastern Siberia covered with larch forests. Everywhere on sandy and gravelly soils they grow pine forests. The forests of the Far Eastern Primorye have a very special character, where on the Sikhote-Alin ridge the usual conifers - spruce and fir - are joined by such southern species, like Amur velvet, cork oak, growing in a monsoon climate.

*Indicate the reason for the replacement of taiga by mixed and broad-leaved forests. Tell us about the climatic conditions of the zone. What tree species do mixed forests consist of? What species are classified as broadleaf?

Taiga is replaced by mixed and then broad-leaved forests due to changes in climatic conditions when moving south. The thermal regime of the zone of mixed and deciduous forests and the degree of its moisture content are favorable for Agriculture. Soddy-podzolic and gray forest soils are characterized by high fertility. Vegetation of mixed forests in addition to broadleaf species: oak, maple, linden, poplar, represented by small-leaved and coniferous trees, the percentage of which increases to the north of the natural zone. Birch, alder, willow, rowan, spruce, and pine are common here. Broad-leaved forests are characterized primarily by such tree species as oak, beech, hornbeam, maple, linden, chestnut, ash, and elm.

*Determine the features of the geographical location of the mixed forest zone. Describe its climatic conditions.

Mixed forests are a natural zone of the temperate climate zone. The mixed forest usually borders on the south with a zone of broad-leaved forests. Their northern border with the taiga roughly runs through St. Petersburg, Yaroslavl and Yekaterinburg. Mixed forest is much more adapted to cold climatic conditions than broad-leaved forest. Here the vegetation can already withstand cold winters with average temperatures below -16°C and even frosts of -30°C. Summer here is quite warm with average values ​​from +16 to +24°C. The annual precipitation is within 500 mm and decreases inland.

Questions at the end of the paragraph

1. What role does the forest play in human life?

Forests are a source of various valuable raw materials - animals and flora, wood. Wood is used as fuel, for making paper, and in the wood chemical industry. Forests are important recreational resource. Forests influence the climate, prevent soil destruction, and clean the air.

2. What are the reasons for forest diversity?

The reason for the diversity of forests is the diversity of natural conditions.

3. How do the forests of the European part of Russia differ from the Siberian taiga?

Dark coniferous spruce-fir forests predominate in the European part of the zone and in Western Siberia, where they are joined by pine forests. Most of Central and Eastern Siberia is covered with larch forests. Forests differ not only in their species composition, but also climatic conditions, soils, flora and fauna.

4. What are the similarities and differences between forest zones? North America and Eurasia?

Broadleaf forests North America, compared to the forests of Eurasia, is distinguished by the richness of species of trees and shrubs. The forests are dominated by large-leaved beech, reaching 40 m in height and more than 1 liter in diameter. In autumn, its leaves turn red-brown and fall off in October - December. Large-leaved beech is used in gardens and parks in the southern regions of Russia as an ornamental tree. Unlike the forests of North America, the beech forests of Eurasia have almost no grass cover or layer of shrubs. In Eurasia there is no parallel at 40 natural areas mixed and deciduous forests and taiga zones. In North America there is no natural zone of variable-moist monsoon forests.

5. Determine where the southern border of the forests of Russia lies, and think about why forest vegetation is replaced by forest-steppe vegetation.

The forest zone occupies more than half of the territory of Russia. It extends in a wide strip from the western border of Russia with Finland to the river. Lena and Aldan in the east. The width of the forest zone in western Russia is about 2000 km, in Western Siberia about 1300 km, and beyond Lake Baikal about 1800 km. In the north, the zone borders on forest-tundra, in the south - on forest-steppe, and in Eastern Siberia - on the mountain taiga of the Sayan and Transbaikalia. The forest zone is replaced by forest-steppe due to a decrease in precipitation.

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 temperate climatic 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. 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 ones, the grass cover is very well represented. in deciduous forests large leaves trees prevent entry sun rays on the ground, so the grass cover here 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 summer and mild winter. 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.

TOP 4 articleswho are reading along with this

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 broad-leaved 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.

Test on the topic

Evaluation of the report

Average rating: 4 . Total ratings received: 142.

Remember within which natural zones Ukraine lies. What types of trees are common in the forests of Ukraine?

GEOGRAPHICAL POSITION. Forests in the northern and western parts of Ukraine occupy 28% of the territory. The zone of mixed forests (coniferous-deciduous), which is called Polesie, stretches from west to east in a wide strip between northern border Ukraine and a conditional line passing through the cities of Vladimir-Volynsky - Lutsk - Rivne - Zhitomir - Kyiv - Nizhyn - Glukhov. Polesie is amazing land forests and rivers, where there are no crushing droughts, where in some villages in the spring they move along the streets in boats, where the air smells of pine and hops, and it seems that you can drink it like birch sap.

This is how the field pikes poetically describe their region.

In the west of Ukraine, mixed forests are replaced in the south by broad-leaved forests, which extend to the Cis-Carpathian Upland and the border with Moldova.

RELIEF AND MINERAL RESOURCES. The mixed forest zone occupies mainly the Polesie lowland (Fig. 138). Its surface is almost flat, with a slight slope towards the Dnieper and Pripyat. Its absolute heights rarely exceed 200 m; the highest section is the Slovechansko-Ovruch Ridge (more than 300 m). The relief was affected by the influence of the glacier: it brought polished stones and boulders from the north, leaving sediments in the form of sandy fields, moraine hills and ramparts (Volyn ridge). Wind-blown sands form dunes up to 5 km long and up to 18 m high.

Broad-leaved forests cover the hills - Volyn, Rastochye, Podolsk ( western part), Khotinskaya. The hills underwent tectonic uplift at the end Cenozoic era what caused the crash river valleys and the spread of water-erosive landforms.

As a result, the terrain in many places has become hilly, with heights often exceeding 400 m above sea level. At the same time, in the watershed areas of the Podolsk Upland there are flat hills - plateaus (Fig. 139). The Podolsk Upland and the Prut-Dniester interfluve are the largest accumulation in Ukraine karst forms relief. There are more than 100 caves in gypsum deposits. Among them are the longest in the world - Optimisticheskaya (more than 240 km), Ozernaya, Zolushka, as well as Kristallicheskaya, Mlynki, etc.

In places where crystalline rocks occur shallowly, deposits of copper (Volyn region), kaolins, granites, basalts, labradorites, gabbro and semi-precious stones- topazes, jasper, amber (Rivne, Zhytomyr regions), phosphorites (Sumy, Khmelnytsky regions). Everywhere in Polesie there are deposits of peat, and in Podolia - limestone. The Lviv-Volyn coal basin is located on the border with Poland.

CLIMATE AND INTERNAL WATERS. The climate of forest zones is moderate continental. The air temperature varies from west to east in January from -4 to -8 °C, in July - from + 17 to +19 °C. In forest zones there is more precipitation compared to the flat areas of Ukraine (600 -700 mm per year).

With low evaporation, moisture in the mixed forest zone is excessive. That's why characteristic feature Polesie is swampy. Among the swamps, lowland ones prevail, lying along rivers. In the central-eastern part, the zone is crossed by the Dnieper, receiving the tributaries Pripyat, Desna, Teterev, Irpen. A dense river network forms them river systems. Pripyat originates in the north-west of the Volyn region and is located only in the upper and lower reaches in Ukraine. Its numerous branches, straits and old channels are filled with water in the spring and form a continuous body of water. Major tributaries Pripyat - Turia, Stokhod, Styr, Uzh, Goryn (with the Sluch tributary). All rivers have wide valleys with low banks, slow flow. They are deep-water, as they feed mainly on precipitation.

At the extreme

in the west, the Western Bug has similar characteristics. In the south, the zone of broad-leaved forests is outlined by the Dniester; its left tributaries, crossing the Podolsk Upland, form deep, often canyon-like valleys in the lower reaches.

There are many lakes in Polesie. These are mainly small bodies of water with clean running water. In the northwestern part of the zone there are Shatsk lakes (Svityaz, Pulemetskoe, Luka, Pesochnoe, etc.), mainly of karst origin. Small oxbow lakes are common along the rivers. On the Podolsk Upland there are small karst lakes - “windows”.

SOIL-VEGETATION COVER AND LANDSCAPE. In the natural zoning of Ukraine, the zone of mixed forests is identified as the Polesie physical-geographical region (Ukrainian Polesie), and the zone of broad-leaved forests is designated as the Western Ukrainian region.

In the Polesie physical-geographical region, mixed forests are dominated by soddy-podzolic soils. Their fertility is low due to high acidity and excess moisture. Even less fertile are the soils formed in river valleys and lower reaches - meadows, swamps, peat bogs and peat bogs. Compared to other landscapes of the flat part of Ukraine, the vegetation of Polesie (forest, meadow and swamp) is better preserved, but the name “Polesie” itself rather reflects it natural history, how current state. Forests once covered 90% of the territory, but now they occupy only 25%. Another 10% of the area is meadows.

Swamps characteristic of Polesie occupy more than 4% of its territory. In total, more than 1,500 plant species are known in Polesie.

Of the forest communities, the majority are pine-oak forests. The undergrowth in them is formed by hazel, elderberry, willow, euonymus, and numerous herbaceous plants. Sparse pine forests (pine forests) grow on sandy areas.

There are almost no shrubs or grasses in them; low areas are completely covered with moss. Wet areas are occupied mainly by alder and birch forests. Meadows in Polesie are common not only in floodplains, but also in places where forests have been cut down. The greatest diversity of herbaceous plants is in floodplain meadows. They meet here and there

sands covered with thyme or heather. Lowland marshes They are famous for their variety of herbs (yellow killer whale, loosestrife, beaver grass, and swamp beetle). Raised bogs overgrown with moss, cranberries, and sundews are rare. Among the sandy lowlands of Polesie there are large swamps covered with hummocks of grass.

In the Western Ukrainian region, gray forest soils have formed under broad-leaved forests. As we move east, chernozems spread - typical, on which there was once rich meadow and steppe vegetation, and podzolized (formed in the process of natural overgrowing of steppe spaces with broad-leaved forests). Today, broad-leaved forests occupy less than 15% of the region's area. The predominant deciduous species are oak and beech (in the west), oak and hornbeam (in the east). Ash, maple, and linden are also common, with occasional stands of pine and spruce. Steppe vegetation has been preserved in small patches on hillsides or in ravines.

Roe deer live in the forests, raccoon dog, wild boar, wolf, fox, marten, hare, squirrel. Occasionally found Brown bear and lynx. Beavers build their huts along the rivers. There are many birds - black grouse, wood grouse, crane, stork.

So, the physical and geographical diversity of forest zones of Ukraine forms the following natural landscapes: mixed-forest coniferous-deciduous lowland (Polessye), broad-leaved forest upland, floodplain meadow and meadow-swamp. Nowadays, most of the zone’s territory is occupied by anthropogenic landscapes.

NATURE MANAGEMENT AND NATURE CONSERVATION.

The zones of mixed and deciduous forests of Ukraine and the neighboring territories of Belarus and Poland are the ancestral homeland of the Slavs. From here they settled throughout Eastern Europe. For a long time forest zone was sparsely populated natural forests were preserved almost untouched. Intensive destruction of forests due to economic activity man began in the 16th century. Subsequently, agricultural development of land and industrial logging intensified, cities arose, and roads were laid. Currently, agricultural landscapes cover more than 65% of the Polesie area and about 80% of broad-leaved forests. Enormous changes occurred in natural landscapes after the drainage of swamps and straightening of river beds.

In 1986, the Chernobyl accident occurred on the territory of the forest zone. nuclear power plant. People were evicted from the 30-kilometer zone around it, as a result of which natural processes occur there without their participation, but under the influence of a strong radiation pollution. Their progress is monitored in Drevlyansky nature reserve and Chernobyl radiation-ecological biosphere reserve, created in 2016. To preserve the landscapes of Polesie, forest and swamp vegetation in mixed forests, a number of protected areas have been created. In particular, in the Cheremsky, Rivnensky and Polessky natural reserves, swamp-peat massifs, lakes, and pine forests are studied and protected. In Shatsk National natural park There are 22 lakes under protection, in which there are valuable species fish (eel, catfish), and swamps located among pine forests and alder forests.

In the broad-leaved forests in the natural reserve "Raztochye" and the national natural park "Yavorovsky" forest areas of beech and oak are protected, and in the natural reserve "Medobory" and national park"Podolsk Tovtry" - unique natural complexes Tovtr.

REMEMBER

Mixed forests (Polesie) occupy the northern part of Ukraine, and broad-leaved forests occupy the western part.

The mixed forest zone is characterized by swampiness, glacial landforms, soddy-podzolic soils, pine-oak, pine and alder forests.

The broad-leaved forest zone is characterized by elevated terrain, gray forest soils and chernozems, oak-beech and oak-hornbeam forests.

QUESTIONS AND TASKS

1. Describe geographical position zones of mixed and deciduous forests. Find out on the map which administrative regions of Ukraine are completely or partially located in these zones.

2. What are the differences in the topography of mixed and deciduous forest zones?

3. Why are there many swamps in Polesie and a dense river network formed?

4. Name plant communities and representatives of the fauna of mixed and deciduous forests.

5. How is the natural environment protected and preserved in the forest zone?

This is textbook material