A few million years ago, forests covered about 80% of the Earth's land mass. Over the past 10 thousand years, our planet has lost 2/3 of the forest vegetation that covered it.

Currently, forests cover about a third of the land surface (not including the area of ​​Antarctica). The areas occupied by forests continue to decrease every year.

Geographic feature (meaning forests)

The forest is called natural complex, which consists of woody plants of one or many species growing close to each other and forming a canopy of partially or completely closed crowns, many organisms of other kingdoms in combination with soils, surface waters and the adjacent layer of the atmosphere. All components of the forest ecosystem influence each other and interact with all other ecosystems of the planet, including the human ecosystem.

The forest is of general planitary importance, since it has a significant impact on the Earth's climate, surface and underground water flows and soil formation. Russian scientists G.F. and VN Sukachev were the first to single out the global role of the forest as an accumulator of living matter in the planet's biosphere.

Thanks to photosynthesis, the forest accumulates and transforms solar energy, producing oxygen. It is actively involved in global carbon balance cycles. Earth's climate change and the problem greenhouse gases are largely associated with the destruction of forest ecosystems.

Forest characteristics

There are two world forest belts: Northern and Southern. The North includes Russia, Finland, Sweden, Canada and the United States, and the South includes Southeast Asia, the Amazon and the Congo Basin.

According to natural and territorial characteristics, it is customary to distinguish forests by continents and major regions:
- European,
- forests of Eastern Europe,
- Far East,
- Siberian,
- forests of Southeast Asia,
- forests of North America
and others.

Natural areas and forest types

Within the natural territorial zones use a description of the species composition of trees and climatic characteristics. The forests of the world are divided into forests tropical belts and temperate forests.

tropical moist forests(rain) have lower and mountain belts. Vegetate during the rainy season. These equatorial evergreen forests are distinguished by a huge species diversity of representatives of flora and fauna. These include the forests of the Amazon, the Congo Basin and the jungles of India. The height of the trees here reaches tens of meters. Ficuses and palm trees grow in the upper tier, lianas and tree ferns grow below. More than half of this type of forest has already been cleared.

Dry tropical deciduous and mountain forests fall during drought and vegetate during the rainy season. They are also known under the name "caatinga", which is translated from the Tupi-Guarani language as "white forest".

In temperate forests, broad-leaved, small-leaved, taiga and mixed types the woods.

Temperate broadleaf forests are located in Central Europe, in the east North America, East China, mountainous areas Crimea, Caucasus and Carpathians, Far East Russia, New Zealand, Japan. The species composition of trees includes oak, elm, linden, chestnut, sycamore, hornbeam. From the ancient broad-leaved forests, only small green islands in nature reserves and heavily rugged areas are now left.

Taiga forests with coniferous trees occupy the most extensive area. They include most of forests of Siberia.

Broad-leaved and coniferous forests are usually replaced by small-leaved ones. This type of forest is characterized by various species of birch, alder, poplar, aspen, and willow. Their wood is much softer than that of broad-leaved trees, which is why these forests are also called soft-leaved. They make up a significant part of the forests of Russia, with birch forests predominating.

Mixed forests include broad-leaved, coniferous and small-leaved and coniferous trees and occupy an area in Central and Western Europe.

forest climate

Humid and hot equatorial climate, where all year round the temperature does not drop below 24 - 28 ° C - the conditions for the growth of wet rainforest. Heavy rains come here often, the amount of precipitation is up to 10,000 mm per year. The dry season alternates here with tropical downpours at an air humidity of 80%.

Dry tropical forests have to overcome drought and heat from 4 to 6 months a year. They get from 800 to 1300 mm of precipitation per year.

The climate of the taiga ranges from mild maritime in the west to sharply continental in the east, where frosts can reach -60°C in winter. The amount of precipitation is from 200 to 1000 mm. In conditions permafrost moisture stagnates, which leads to the formation of swampy light forests.

Moderately continental climate mixed and broad-leaved forests are relatively soft and fairly warm in summer, with a long and cold winter. The average annual rainfall is approximately 700 mm. If the humidity is excessive and evaporation is insufficient, waterlogging processes begin.

The largest forests in the world

Even in authoritative sources there is a statement that the biggest woodlands located in the Amazon basin. But actually it is not. The championship belongs to the taiga. It occupied the boreal zone of Eurasia, Canada and Alaska, was located in North America, in large areas in Finland, Sweden and Norway, stretched across the entire territory of Russia. Its area is 10.7 million square meters. km.

Natural resources are formed in natural environments and in space they form certain combinations that change within the boundaries of natural-territorial complexes. On this basis, they can be divided into 2 groups: resources of natural components and resources of natural-territorial complexes.

Fig.1. Classification of natural resources by origin

1. Resources of natural components. Each kind of this resource usually occurs in one of the components of the landscape shell. It is controlled by the same natural factors that create this natural component and affect its features. By belonging to the components of the landscape shell, resources are allocated:

mineral,

climatic,

vegetable,

land,

soil,

Animal world.

This classification is very often used in domestic and foreign literature. When using the above classification great attention it is worth paying attention to the patterns of spatial and temporal formation certain types resources, their quantitative, qualitative characteristics, volumes of natural replenishment of reserves. Scientific understanding of the whole complex natural processes involved in the creation and accumulation of a natural resource, allows us to more correctly calculate the role and place of a particular group of resources in the process of social production, the economic system, and most importantly, it gives us the opportunity to identify the limiting volumes of the removal of a resource from the natural environment, preventing its depletion or deterioration quality.

2. Resources of natural-territorial complexes. At this level of the subdivision, the complexity of the natural resource potential of the territory is considered, arising from the corresponding complex structure the landscape shell itself. Each landscape has a certain set of diverse types of natural resources. Depending on the properties of the landscape, its place in overall structure landscape shell, combinations of types of resources, their quantitative and qualitative characteristics change very significantly, determining the possibilities for the development and organization of material production. Often there are such conditions when one or several resources determine the direction of economic development of the whole region. Almost any landscape has climatic, water, land, soil and other resources, but the possibilities economic use are quite different. In one case, favorable conditions may develop for the extraction of mineral raw materials, in others - for the cultivation of valuable cultivated plants or for the organization of industrial production, a resort complex, etc. On this basis, natural resource territorial complexes are distinguished according to the most preferred type of economic development. They are divided into:

Mining,

Agricultural,

water management,

forestry,

Residential,

Recreational and others.

It is not enough to use only one classification of resources by their origin, since it does not reflect economic importance resources and their economic role. Among the variety of systems for classifying natural resources that reflect their economic importance and role in the system of social production, classification is more often used according to the direction and forms of economic use of resources.

CLASSIFICATION BY TYPES OF ECONOMIC USE

The main criterion for the division of resources in this classification is their assignment to different sectors of material production. On this basis Natural resources can be divided into divided into industrial and agricultural production resources.

1. Resources of industrial production. This subgroup includes all types of natural raw materials that are used by industry. Due to the very large branching of industrial production, the presence of many industries that consume different types natural resources and, accordingly, put forward various requirements for them. The types of natural resources are divided as follows:

Fig.2. Classification of natural resources by types of economic use

1) energy, these include a variety of types of resources used today in the development of science and technology for energy production:

a) fossil fuels

b) hydropower resources are the energy of freely falling river waters, tidal wave energy sea ​​waters and etc.;

c) sources of bioconversion energy - the use of fuel wood, the production of biogas from agricultural waste;

d) nuclear raw material, it is used to obtain atomic energy;

2) non-energy comprising a subgroup of natural resources that supply raw materials for various industries industry or participate in production due to technological necessity:

a) minerals that do not belong to the group of stobioliths;

b) water used for industrial water supply;

c) land occupied by industrial facilities and infrastructure facilities;

G) forest resources, supplying raw materials for wood chemistry and the construction industry;

e) fish resources are referred to this subgroup conditionally, since at present the fishing and processing of the catch have acquired an industrial character.

2. Agricultural production resources combining types of resources involved in the creation of agricultural products:

a) agro-climatic - these are resources of heat and moisture, they are necessary for the production of cultivated plants or grazing;

b) soil and land resources- the earth and its upper layer - the soil, has unique property, is considered both as a natural resource and as a means of production in crop production;

c) plant food resources - resources of biocenoses that serve as a food base for grazing livestock;

G) water resources- water used in crop production for irrigation, and in animal husbandry - for watering and keeping livestock. Very often, natural resources of the non-productive sphere or direct consumption are also allocated. These are, first of all, the resources withdrawn from the natural environment, as well as the resources of the recreational economy, the resources of protected areas and a number of others.

CLASSIFICATION ON THE BASIS OF EXHAUSTIBILITY

Fig.3. Classification of natural resources on the basis of exhaustibility

When taking into account the reserves of natural resources and the volumes of their possible economic withdrawal, they use the concept of the depletion of reserves. A. Mints proposed to call the classification according to this criterion ecological. All natural resources are depleted into two groups: exhaustible and inexhaustible.

1. Exhaustible Resources. They are formed in the earth's crust or landscape sphere, but the volumes and rates of their formation are measured on the geological time scale. At the same time, the need for such resources on the part of production or for the organization favorable conditions a habitat human society in many respects exceed the volumes and rates of natural replenishment. As a result, depletion of natural resource reserves inevitably occurs. The exhaustible group includes resources with different rates and volumes of formation. This allows them to be further separated. Based on the intensity and speed of natural formation, resources are divided into subgroups:

1. Non-renewable natural resources are resources that cannot be restored after their complete exhaustion (minerals). Some of the non-renewable resources may be replaceable (eg mineral fuel resources - nuclear and solar energy).

2. Renewable natural resources are resources that, as they are spent, are reproduced under the action of natural processes or conscious human effort ( solar energy, the water cycle in nature, the maintenance of oxygen levels in the atmosphere by vegetation). Soil fertility requires human effort, in particular fertilization

3. Relatively renewable soils are, first of all, soils partially out of agricultural circulation as a result of water and wind erosion, or radioactive contamination, forest stands, peat used as fuel. After a certain interval time (from hundreds to several thousand years), these resources can be used again.

The fact of the practical inexhaustibility of water resources on a planetary scale is well known. However, on the land surface, reserves fresh water concentrated unevenly, and in vast areas there is a shortage of water suitable for use in water management systems. Arid and subarid areas are particularly affected by water shortages, where irrational water consumption is accompanied by rapid and often catastrophic depletion of water reserves. Therefore, it is necessary to accurately record the amount of allowable withdrawal of water resources by region.

2 Inexhaustible resources. Among the bodies and natural phenomena of resource significance, there are those that are practically inexhaustible. These include climatic and water resources.

BUT) climate resources. The most stringent climate requirements are Agriculture, recreational and forestry, industrial and civil construction, etc. Usually under climate resources understand the reserves of heat and moisture that a particular area or region has. Since these resources are formed in certain links of the thermal and water cycles, constantly operating over the planet as a whole and over its individual regions, reserves of heat and moisture can be considered as inexhaustible within certain quantitative limits, precisely established for each region.

B) Water resources planets. The earth has a colossal volume of water - about 1.5 billion cubic meters. km. However, 98% of this volume is made up of salty waters of the World Ocean, and only 28 million cubic meters. km - fresh water. Since technologies for desalination of salty sea waters are already known, the waters of the World Ocean and salt lakes can be considered as potential water resources, the use of which is quite possible in the future. Subject to the principles of rational water use, these resources can be considered as inexhaustible. However, if these principles are violated, the situation can sharply worsen, and even on a planetary scale, there may be a lack of clean fresh water. In the meantime natural environment annually "gives" humanity 10 times more water than it needs to meet a wide variety of needs.

A forest is a natural complex, which includes, as its main part, woody plants growing close to each other (forming a more or less dense forest stand). The forest is characterized by stability, the interaction of all plant, animal, soil and other components, a certain impact on the surrounding area.

The microclimate of the forest differs from the microclimate of open spaces in increased air humidity, lower daytime temperature, different wind strength, retention of precipitation, uniform and slow melting of snow, etc.

Every year and for a long period, forests accumulate a large plant mass (phytomass). Leaves, twigs and branches, falling to the ground, rot, forming forest litter, the decomposition of which proceeds with different speed(depending on the climate) and ends with the transformation of organic substances into minerals.

In every forest grow certain types trees, shrubs, herbs. The natural combination of plants in the forest is forest phytocenosis, or a plant community of a given forest (spruce, pine, oak forest, birch grove, etc.). Crowns of trees, shoots, leaves of forest plants are located at different vertical levels - the forest has tiered structure vertically. The first, main, tier includes tall trees of forest-forming species; the second tier is made up of less tall (not higher than 10 m) tree species; the third tier - tall shrubs, crowns of low trees, undergrowth of the main tree species. Next come tiers of low shrubs (up to 1 m) and shrubs, tiers of tall and low grasses; the last layer consists of ground mosses, fungi and lichens. Along with the aboveground, there is also an underground layering. In most forests total weight underground organs of plants naturally decreases from top to bottom (Fig. 47).

Plants of different aboveground tiers live in different lighting conditions, gas composition of air, humidity, temperature, etc.

Of great importance in the life of the forest are the species composition, the age of the main forest-forming species, the height of the trees, and the density of the crowns.

Plants living together in a forest phytocenosis are not similar to each other not only in appearance and structure, but also in the requirements for the environment, and this latter contributes to their life together. For example, the vast majority of our tall trees are wind-pollinated plants: their crowns are well blown by the wind. Low trees and shrubs, covered with crowns of tall trees, are mostly insect-pollinated plants, and those that are pollinated by wind bloom before the leaves unfold on tall trees when the wind is still freely penetrating into the forest community (for example, a hazel in a broad-leaved forest).

The complex tiered structure leaves its mark on the location of light-loving and shade-tolerant plants in the forest. This factor external environment(light) has to combine forest plants greater value than for plants in open spaces.

The largest group in the forests - autotrophic plants- active producers organic matter. Smaller in volume, but significant in terms of the degree of participation in the cycle of substances, the group heterotrophic plants(mushrooms, soil algae, bacteria) incorporates higher plants - saprophytes, which are much less common in other phytocenoses (see p. 89).

The long-term existence of the forest on the territory depends on the renewal of tree species. With natural renewal, young trees grow to replace the older generation of trees under the forest canopy from seeds or from stumps (“stub shoots”). In a dense forest, such undergrowth often looks oppressed (for example, spruce undergrowth in a spruce forest), but as soon as the tree of the upper tier dies, a new one, which has grown in the vacant space from among the undergrowth trees, takes its place. Often, undergrowth of one tree species appears in mass under the canopy of another. Over time, this leads to a change in species in the forest, as a result of which one type of forest is replaced by another (for example, changing from birch to spruce).

With artificial reforestation, a person plants seedlings or seeds of tree species in new places or clearings and grows forest crops.

For each region in our country, types of forest crops have been developed and published in the form of instructions (located in the regional forestry), which indicate the selection of species, the scheme for mixing plants in rows and between rows, planting density, soil preparation, plant care, etc.

Many forest grasses and shrubs are currently protected plants, the lists of which should be known to the inhabitants of the forest belt.

The abundance of plant foods and shelters in the forest creates conditions for large numbers and diversity of species composition of animals, and also provides a close connection between the flora and fauna.

Birds living in the forest are characterized by adaptations for flight that requires active maneuvering: shortened wings with blunt tops, a well-developed wing, and a large tail.

In some species of birds, moving along branches and trunks is characterized by a special arrangement of fingers (three forward, one back), rough, soft thickenings on the lower surface of the fingers, and a special arrangement of plantar tendons.

To hang from the ends of branches, many small passerine birds use prehensile flexible fingers, strong leg flexors, and a special position of the hip joint (near the center of gravity).

In birds that lead a predominantly terrestrial lifestyle (a detachment of chickens), thanks to the powerful pectoral muscles, it is possible to quickly take off, escaping from a predator.

For many mammals, life in forest conditions has made it necessary to climb trees. Movable limbs ending in crooked tenacious claws, special pads on the feet and extensions at the ends of the fingers provide climbing animals with a strong grip on tree branches. A long fluffy tail, which acts as a rudder, helps them when jumping from tree to tree. For quick orientation when jumping, well-developed vibrissae serve.

The forest is rich in various shelters for animals. They find them in the crowns and roots of trees, hollows, rotten stumps, under windbreak. Many birds build their nests on the branches of trees and shrubs, on the ground. Hollow-nesting birds arrange their nests in hollows.

Some animals have also adapted to making nests in trees. Widely used by animals are natural or woodpecker hollows.

The presence in the forests of a large number of various conditions for hiding and camouflage contributed to the development of adaptations in the behavior of animals. Thus, forest birds lack coloniality. Forest ungulates (red, spotted and reindeer, elk, roe deer, wild boar) prefer to stay alone or in pairs. Only in winter time they gather sometimes in large herds.

A large number of shelters in the forest caused a relatively small number of digging animals compared to open spaces. Rich and varied plant and animal foods provide large numbers and a diverse species composition of animals living in the forest.

The nature of food and the way it is obtained has left its mark on the structure of the beak and tongue in birds, which are very diverse. Some birds have special adaptations for transporting food: a crop, a stretchable esophagus, sublingual throat and neck pouches. So, the nutcracker in the sublingual sac carries nuts with a total weight of up to 35 g. The jay in the mouth and esophagus, which is highly stretched, carries 8-10 medium-sized acorns. However, in general, the storage of food for forest birds is not typical.

The nature of food and the way it was obtained caused a number of adaptations in birds of prey and owls. Predators that beat birds on the fly (peregrine falcon) have a shortened paw with powerful claws, especially the hind ones. On the contrary, predators that forage in dense thickets or grass have long legs, long fingers and sharp saber-shaped claws.

The forests are rich large quantity feed in the form of bark, branches, leaves, seeds, fruits, which are high in calories. It is difficult to overestimate their environmental significance. They are the main supplier of atmospheric oxygen: more than half of the oxygen produced as a result of photosynthesis enters the atmosphere from forests. However, they absorb carbon dioxide in global scale. Forests are natural filters of the atmosphere, purifying the air from microorganisms and dust, act as a regulator of the hydrological regime of rivers and the water balance in general.

Forests protect the soil, preventing blowing, erosion, and are used to fix moving sands. They prevent siltation of rivers, reservoirs and ponds. The role of forests in the protection of agricultural land is great: they create more favorable microclimate, reduce evaporation, retain moisture.

In general, forests play an important role in the conservation of natural territorial complexes. They act as one of critical components landscapes.

Forest protection is carried out on the basis of forest legislation, including whole line laws. Legislation provides for the rational use of forests, measures for the protection of forests and wildlife, rules for the use of forests for hunting, picking mushrooms, berries and other fruits by citizens, administrative, criminal and material liability for forest violations, including for damage caused forest fauna. Special measures are provided for the protection of rare animals and plants that are threatened with extinction. They are listed in the Red Book of Russia.

A significant contribution to the common cause of saving forest resources is made by such forms of work as school forestries and green patrols. Not less than importance has environmental education.

On the territory of Russia, forests are very diverse in terms of conditions of existence (soil, climate, relief, etc.) and tree species. Therefore, forest plants and animals can be characterized with sufficient completeness only on the example of any particular type of forest.

land cover- forests, shrubs, gardens, meadows, gardens, swamps, sands, etc. The main characteristics of the forest are determined by the species of trees, their age, thickness, height and density of planting According to the age of the forest, height and thickness of trees, the forest is usually divided into: young forest - tree height 4-6 m, thickness 5-15 cm - middle-aged forest - tree height 6-10 m, thickness about 20 cm; - on a mature forest - the height of the trees is more than 10 m, the thickness is more than 20-25 cm. According to the density, the forest is divided into dense forest- the distance between the trees is less than 10 m, the forest of medium density is 10-15 m, the sparse forest is 15-30 m.

"Natural zones of the cold belt" - Natural zones of the earth. Natural zones of the temperate zone. Natural zones of the cold zone. Taiga. Tundra zone. tundra ecosystem. Deserts. Taiga mixed broad-leaved forest forests. " Ecological systems". In the direction from the pole to the equator, natural zones replace each other in a certain order. cold moderate hot moderate cold.

"Natural zoning" - Make a description of the natural zone. Agro-climatic resources natural zone Problems of natural zone protection. What is indirect and direct impact on natural areas? Learning new material. Economic activity human in natural areas. Name and geographic location. The doctrine of natural zones.

"Natural complexes and zones" - Equator. Water. Precipitation. Relief. Man has created new natural complexes. Heat. Sea. equatorial forest. Variety of natural complexes. Components of the natural complex. Climate is the leading component of the natural complex. Give examples of natural complexes. Change of natural zones. Plants. Desert.

"Geography of natural complexes" - The entire hydrosphere. The relationship of organisms Natural complex Geographical shell and biosphere. Atmosphere. Lithosphere. the entire biosphere. "Component" - translated from Latin means " component the whole." Hydrosphere. The mountains. Large natural complexes - continents and oceans. “Complex” means “combination” in Latin.

"Savannas and woodlands" - In Africa, the most diverse fauna of the savannas. Dry. Soils. Australia. South America. Climatic features. Savannahs and woodlands. Humus accumulates in the soil. Each continent has its own vegetable world savannas and woodlands. Animal world. Definition of a natural area. Climatic features, soils, flora and fauna.

"Natural areas of the world" - Tapir. Define the natural area according to the description. Steppes (pampas). Savannah-. The reason for the change of natural zones? Throughout the year. Lives near the water, swims and dives, feeds on the stems of aquatic plants. natural areas South America. Vnazhlye villages (selva). You need to warn the geography teacher about your delay in the semi-deserts of Patagonia.

The geographic envelope is not tripled in the same way everywhere, it has a "mosaic" structure and consists of separate natural complexes (landscapes). Natural complex - this is part earth's surface with relatively uniform natural conditions: climate, relief, soils, waters, flora and fauna.

Each natural complex consists of components between which there are close, historically established relationships, while a change in one of the components sooner or later leads to a change in others.

The largest, planetary natural complex is the geographic shell; it is subdivided into natural complexes of a smaller rank. Separation geographical shell on natural complexes due to two reasons: on the one hand, differences in the structure earth's crust and the heterogeneity of the earth's surface, and on the other hand, the unequal amount of solar heat received by its various parts. In accordance with this, zonal and azonal natural complexes are distinguished.

The largest azonal natural complexes are continents and oceans. Smaller - mountain and flat territories within the continents West Siberian Plain, Caucasus, Andes, Amazonian lowland). The latter are subdivided into even smaller natural complexes (Northern, Central, Southern Andes). To natural complexes lower rank include individual hills, river valleys, their slopes, etc.

The largest of the zonal natural complexes - geographic zones. They coincide with climatic zones and have the same names (equatorial, tropical, etc.). In turn, geographical zones consist of natural zones, which are distinguished by the ratio of heat and moisture.

natural area called a large piece of land with similar natural ingredients- soils, vegetation, wildlife, which are formed depending on the combination of heat and moisture.

The main component of the natural zone is the climate, because all other components depend on it. Vegetation renders big influence on the formation of soils and wildlife and is itself dependent on soils. Natural zones are named according to the nature of the vegetation, since it most obviously reflects other features of nature.

The climate naturally changes as you move from the equator to the poles. Soil, vegetation and wildlife are determined by climate. This means that these components should change latitudinally, following climate change. The regular change of natural zones when moving from the equator to the poles is called latitudinal zoning. At the equator there are humid equatorial forests, at the poles - ice arctic deserts. Between them are other types of forests, savannas, deserts, tundra. Forest zones, as a rule, are located in areas where the ratio of heat and moisture is balanced (equatorial and most of the temperate zone, east coasts continents in tropical and subtropical zone). Treeless zones are formed where there is a lack of heat (tundra) or moisture (steppes, deserts). These are the continental regions of the tropical and temperate zones, as well as the subarctic climatic zone.

The climate changes not only latitudinally, but also due to changes in altitude. As you climb up the mountains, the temperature drops. Up to a height of 2000-3000 m, the amount of precipitation increases. A change in the ratio of heat and moisture causes a change in the soil and vegetation cover. Thus, unequal natural zones are located in the mountains at different heights. This pattern is called altitudinal zonation.

The change of altitudinal belts in the mountains occurs approximately in the same sequence as on the plains, when moving from the equator to the poles. At the foot of the mountains there is a natural zone in which they are located. The number of altitudinal belts is determined by the height of the mountains and their geographic location. The higher the mountains, and the closer they are to the equator, the more diverse the set of altitudinal zones. Most complete vertical zonality expressed in the Northern Andes. Moist equatorial forests grow in the foothills, then there is a belt of mountain forests, and even higher - thickets of bamboos and tree-like ferns. With an increase in altitude and a decrease in average annual temperatures, coniferous forests appear, which are replaced by mountain meadows, often turning, in turn, into stony placers covered with moss and lichens. The tops of the mountains are crowned with snow and glaciers.

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