The natural zones of the Earth are most clearly distinguished by their vegetation cover, therefore, the names of natural zones are given according to the main distinguishing feature - vegetation.
Natural zones of the equatorial and subequatorial geographic zones
The largest areas are in Africa, South America, South East Asia and Oceania. Wet equatorial forests(gileas) are formed in conditions of constantly high temperatures and a large amount of precipitation throughout the year. These are the richest forests on the planet in terms of species composition. They are characterized by density, multi-tiered, abundant lianas and epiphytes (plants growing on other plants - mosses, orchids, ferns).
Forests are one of nature's renewable resources and the largest plantation in the world. They account for about 70% of the organic matter produced by all vegetation on the Earth. The highest degree of forest cover occurs in the equatorial and subtropical regions of Indonesia, the Indochina Peninsula and Japan, where forests cover about 60% of the total area. There are also Asian countries that are almost devoid of forests - Iraq, Saudi Arabia, Uzbekistan and Kazakhstan.
Wet equatorial forests make up only a small part, mostly short-walled forests. The forest of Europe is unevenly distributed. The largest share of forests in the entire country is found in Finland and Sweden. The lowest rate is in the north-western and southeastern European countries: the Netherlands, Denmark and Great Britain do not reach 10%, Ukraine, Moldova and Greece do not exceed 20%. European forests account for only 4.4% of the world's forests. European forests are dominated by the most common types of conifers - mainly pine and spruce, to a lesser extent spruce and larch.
In South America, trees with valuable wood - rosewood and pau brazil, as well as ficuses, hevea grow under the giant trees of seiba and bertolecia; in the lower tiers - palms and a chocolate tree. In Africa grow oil and wine palms, cola, breadfruit, in the lower tiers - bananas and a coffee tree. Valuable wood is possessed by mahogany, iron, ebony, sandalwood. Equatorial forests South-East Asia and about. New Guinea is poorer in species composition: palm trees, ficuses, tree ferns. Gileas form on poor, red-yellow ferralite soils.
Conifers account for 67% of all forests, and in some countries even more than 80%. There are approximately 214 million productive forests in the United States. ha. Of these, 49.7% are conifers and 50.3% are hardwoods.
The largest wooded areas are located in Brazil. The largest forested areas are the Amazon, the Pacific coast of Colombia and Ecuador, in Miedzyzec, Argentina. In Queensland, forests cover less than 7% of the territory, and in Western Australia - 2.5%. There are no forests in South Australia.
Subequatorial forest zone
Previously, the forest area was much larger. The cuts were made by humans, taking over forests to obtain new agricultural land, for fuelwood, housing and industrial needs. Oftentimes, deforestation also led to overgrazing of livestock and goats in the forests. Many forest complexes were damaged and destroyed by fires. Deforestation began in the Neolithic, but size has only grown in the last three hundred years. This process has not gone ahead, and its negative consequences are often irreversible.
Gilea animals are adapted to life in trees. Many have a prehensile tail, like a sloth, a possum, a prehensile porcupine. Only in the gileys of the Old World were the great apes preserved - gorillas, orangutans, chimpanzees. From land animals - forest antelopes, tapirs. There are predators: jaguar, leopard. There are many birds: parrots, guinea fowls, peacocks, toucans, hummingbirds. The transitional zone between equatorial forests and savannas is subequatorial variable moist forests... The presence of a dry period causes the appearance of deciduous trees. Ficuses and palms prevail among evergreen trees.
Natural zones of the equatorial and subequatorial geographic zones
In Western Europe, two thirds of the primary forest has been cleared. The most deprived European countries include the United Kingdom, where forests cover less than 5% of the country's total land area. In the Middle East and Middle East, significant areas are devoid of forests. In the mountains of Lebanon, only the remains of beautiful cedar forests have survived. The heavily deforested countries also include China, although most of the mountains have been inhabited in the past. Deforestation in China has resulted in climate change, increased soil erosion and an expansion of the desert zone.
Savannahs and woodlands are located mainly in subequatorial geographic zones, largest areas concentrated in Africa, South America, Australia and South Asia. Savannahs are predominantly open grass plains with freestanding trees and groves. They are characterized by an alternation of dry winter and wet summer seasons... Depending on the moisture content, wet, typical and deserted savannas are distinguished, under which, respectively, red, brown-red and red-brown soils develop. The herbaceous cover is formed by bearded and feather grass. Of the trees for the savannahs of South America, palm trees (Mauritius, wine, wax) are characteristic. In the African savannas, in addition to palms (olive, dum), baobabs are often found. Casuarins are typical for Australia. Acacias are ubiquitous.
Forestry - industry National economy, including the use of forests and activities related to the maintenance of forest plantations in the conditions of their exploitation: breeding, protection, maintenance and increase of forest resources, as well as the management of forest animals.
Additional elements of forest management are: the collection of forest fleets, trees, medicinal plants and the implementation of non-productive functions of the forest related to the protection of air, water and soil. For the needs of forest management, forests are divided into several types. Depending on the adopted criteria, forests can be divided into different ways, for example, taking into account the climate and zonal planning of vegetation, in a very short time, forests can be divided into.
The African savannah is characterized by an abundance of ungulates (antelope, giraffe, elephant, zebra, buffalo, rhinos, hippos) and predators (lion, leopard, cheetah). For the South American savannas, animals with a protective brown color (spoke-horned deer, maned wolf), rodents (capybara) and edentulous ones (armadillo, anteater) are typical. An integral part of the Australian savannah are marsupials (kangaroos, wombats) and large flightless birds (emu, cassowary).
Cool zone of coniferous forests, forests with temperate climate, humid equatorial forests, tropical rainforests, dry forests. Cold zone coniferous forests, also known as taiga, form the boreal forest belt in Eurasia and North America... They are characterized by a low variety of tree species and resistance to low temperatures and drought. These forests usually contain spruce, spruce, pine and larch. As an admixture there are birch, aspen and alder.
Mixed mixed mixed forests are richer in species than coniferous forests. They are found in the northern part of Asia, in the northwest of North America, in mountainous areas Europe, Mexico and the Himalayas. Wood is used from coniferous and deciduous plantations, mainly beech, oak and birch.
Natural zones of tropical and subtropical geographical zones
Forests form in the eastern oceanic regions of the tropics, and deserts and semi-deserts in the central continental and western oceanic regions washed by cold currents.
Tropical deserts and semi-deserts are the most extensive natural zone of the tropical zones. The largest desert areas are concentrated in tropical latitudes ah Africa, the Arabian Peninsula and central Australia. (Determine from the atlas map which deserts are located inside the mainland, and which ones are on west coasts.) These are very hot and dry areas with poor vegetation and wildlife. By vegetation, deserts are distinguished: gramineous-dwarf shrubs, dwarf shrubs and succulent deserts. Tropical semi-deserts and deserts North Africa- cereal-dwarf shrubs (acacia, tamarisk, wild millet, dwarf saxaul, camel thorn). In the oases, the main cultivated crop is the date palm. For deserts South Africa characteristic succulents storing moisture (aloe, milkweed, wild watermelons), as well as irises and lilies blooming during short rains. Semi-desert soils - gray soils, deserts - stony or sandy.
Wet equatorial forests, inhabited by a large amount of rainfall throughout the year, occupy an area of about 14 million. They are characterized by a rich mosaic of species composition. The humid equatorial forests, which are so poorly managed economically, provide timber, fruit, rubber and resins. However, the natural productivity of tropical rainforests is low.
Equatorial forest and conversion to agricultural land have not produced lasting positive results and have been largely wrong. Leaves-shedding rainforests are planted in areas with more prolonged drought. Depending on the time of their existence, these forests are similar in their appearance and species composition to humid equatorial forests or savannah. Monsoon forests, dominated by medium-sized trees, are found in Africa, South America, Asia and Australia.
For the deserts of Australia, the bushy grass spinifex is characteristic, for the semi-deserts - thickets of swans, salt-tolerant species of acacias. Dry grasses and cacti grow on the gray soils of the coastal deserts of South America, on the gravelly soils of the high-mountainous deserts - creeping and pillow-like grasses, thorny shrubs.
In the well-hydrated east tropical belt moist and variably humid tropical forests develop on red soils. In South America, palm trees, ficuses, mahogany, ceiba grow in them.
Teak wood, valuable for its technical qualities. The dry savanna forest is a transitional form between dense forest and savanna. The advantage of the grass gives this character to the park. Dry forest stands are characterized by a large number of species, and from the economic point of view, by small forest resources. The area of dry, productive forests is growing as a result of the devastation of adjacent, more productive forests.
Due to their composition and geographic location, we can distinguish. Coniferous forests, deciduous forests, mixed forests. ... With regard to forest management, they can be divided into. Protective forests, commercial forests, spatial forests. ... The main tasks of forest management are.
In the humid tropics of Madagascar, there is a "tree of travelers", iron, ebony, rubber plants. Lemurs have survived on the island. For rainforest Australia is characterized by eucalyptus, evergreen beeches, araucaria. Marsupials (tree kangaroo, koala) and "living fossils" - the platypus and the echidna live.
Hard-leaved evergreen forests and shrubs are widespread on the western outskirts of the subtropical geographic zone in a Mediterranean climate. Classically hard-leaved evergreen forests are represented in the Mediterranean: cork and stone oak, alepine pine, pine, Atlas and Lebanese cedars, cypress with a rich undergrowth of wild olive, laurel, pistachio, myrtle, strawberry tree.
The amount of harvested wood cannot exceed the volume of the increase in wood mass; the need for afforestation of areas where logging was carried out; creation of forest reserves and national parks... Forests are managed in accordance with the following principles.
Universal protection of forests, sustainability of forests, continuity and sustainable use of all functions of the forest, increasing forest resources. Forest management is based on. The provisions of the Nature Conservation Law have a significant impact on the conditions of forest management. Wood is a very popular commodity in international trade. The largest wood importers are countries Western Europe and Japan, and some of them also include the United States and Canada. Canada's exports dominate Canada.
The species composition of the vegetation of this natural zone differs on different continents. Fir, cedar, thuja, pine and ancient sequoias grow in North America. In South America - evergreen beeches, teak, perseus. The forests of South Africa are composed of silver wood, Cape olive, African walnut; Australia - from eucalyptus and "herbaceous tree". The natural vegetation of the natural zone has been largely reduced; it was replaced by impoverished thickets of shrubs on gray-brown soils. The brown soils of the forests are highly fertile, therefore they are plowed up for the cultivation of subtropical crops (olive, citrus, vines, etc.). The eastern outskirts of the subtropics are occupied by subtropical variably humid (including monsoon) forests of evergreen deciduous and coniferous species, with an abundance of lianas and epiphytes. Red and yellow soils are formed under these forests.
However, it is more profitable to export wood after processing with pulp and paper, furniture, etc. the United States, as the world's largest paper producer, is also the largest importer. mainly from Canada and Finland. Large exporters of cellulose? a feature of Finland, Sweden, Canada and the United States. Poland is a world exporter of wood and paper products, including sawn timber.
Unfortunately, in most countries, the forest economy is robbery. Rational or robbery of the forest economy is the amount of harvested timber in relation to the total amount of harvested timber - the more timber harvested, the more rational the forest economy is. The collected wood is used in the mining, construction, pulp and paper industries and other processing industries, as well as in the power industry.
The richest forests have survived in East Asia. They are characterized by a mixture of plants of different latitudes. Magnolia, lacquer tree, and even palms and tree ferns grow alongside maple and birch trees. The animal kingdom is also characterized by a mixture of species: lynx, maral, macaque, raccoon dog and the endangered panda. In the continental areas of the subtropics, there are zones of subtropical steppes, semi-deserts and deserts. In Asia, they have a mosaic distribution and occupy the largest areas in the south of Central Asia and in the interior of the highlands of Western Asia. Dry climate with hot summers and warm winter allows growing on gray soils and brown desert soils only drought-resistant grasses and shrubs (caragana, feather grass, wormwood, onions). The unique appearance of the subtropical deserts of North America is given by giant cacti (prickly pear and cereus), yucca and agave. The richest subtropical steppes are found in South America. On chernozem soils, forb-cereal meadows of wild lupine, pampas grass, feather grass grow.
The role of forests in combating the effects of carbon dioxide concentrations in the atmosphere and protecting against the greenhouse effect is emphasized. This is due to the need to reduce the erosion of equatorial forests, mainly in the Amazon and Congo basins, and also accelerates the rotation of trees in temperate zones... It is about rejuvenating forests by creating plantations. Young forests assimilate more and purify the atmosphere better. Until now, such plantations have been established mainly in developed countries, especially in Europe, where fast-growing poplars and willows are grown, and in Australia, where eucalyptus plays a similar role.
The fauna of semi-deserts and deserts of the tropics and subtropics is represented by species that have adapted to high temperatures and lack of moisture. Ungulates (gazelles, mountain rams, antelopes) travel long distances in search of food and water. "Ship of the Desert" - a camel can be without food and water for a long time, storing them in its humps. Rodents dig holes: marmots, jerboas, ground squirrels. Scorpions, phalanxes, geckos, skinks, boas (sandy, steppe), snakes (vipers, rattlesnakes), monitor lizards live.
Location: Equatorial forests lie on either side of the equator. In South America, they occupy the Amazon basin, the Guyana plateau, the north of the Brazilian plateau; in Africa - Congo basin, Gulf of Guinea, east of Madagascar; in East Asia - Malaysia. The river flows are magnificent all year round. In conditions high temperature and moisture, intensive disintegration and chemical change of the rock occurs, which led to the formation of a thick crust of change, rich in iron oxides. Laterite soils are poor in humus due to intense frequent torrent rains.
Natural zones are named according to their main distinguishing feature - vegetation cover. In equatorial and tropical latitudes, the largest areas are occupied by natural zones of humid equatorial forests, savannas and tropical deserts and semi-deserts. Forests form in the eastern oceanic regions of the tropics, and deserts and semi-deserts in the central continental and western oceanic currents washed by cold currents.
Biochemical processes, washing of the soil surface play a significant role in the modeling of the relief, causing the formation of sugar skins. The increased heat and humidity favored the development of the defining element of this type of environment - lush vegetation with a large number of species. Some trees and shrubs in equatorial forests are of great economic importance. The biotic component is especially rich in both species and populations. Equatorial forests are composed of five vertical floors: tall, medium, small trees, gnomes, and grasses.
INTRODUCTION
South America is a continent crossed by the equator, most of which is located in Southern hemisphere... South America is located between By the Pacific Ocean and Atlantic Ocean... It was connected to North America quite recently with the formation of the Isthmus of Panama. The Andes, a relatively young and seismically unstable chain of mountains, stretches along western border continent; the land to the east of the Andes is occupied mainly by tropical forests, the vast basin of the Amazon River. The largest country in South America in terms of area and population is Brazil. Regions of South America include the Andean states, the Guyana Highlands, the Southern Cone, and Eastern South America. South America also includes various islands, most of which belong to the countries of the continent. The Caribbean territories belong to North America. Countries in South America that border Caribbean- including Colombia, Venezuela, Guyana, Suriname and French Guiana - known as Caribbean South America. In this course work we will consider the natural zones and geographic zones of South America, as well as human settlement and its impact on the nature of South America.
The mammalian world is represented, in particular, by those who are adapted to the life of trees: small and large monkeys. On the outskirts of the forests there is a jaguar, a puma, an anthill, etc. these animals have well-developed claws, long tails that help to climb. There are also mammals adapted to flight. The reptile fauna is rich. Bird species with brightly colored plumage are extremely numerous. This environment is specific to spatial, static, dynamic, causal, functional relationships.
Intense manifestation has a relationship characteristic of the living world: parasitism, neutrality, competitive relations, etc. some areas of the equatorial environment are densely populated and intensively exploited. Thus, large areas of forest were plundered in Southeast Asia to expand agricultural land for rice, tea, cassava, cocoa trees, rubber trees, banana trees, etc. as a result, the natural environment of the equatorial forest has changed in these regions in the anthropic environment.
> NATURAL ZONES OF THE EQUATORIAL AND SUB-EQUATORIAL BELT
> Zone of humid equatorial forests
Wet equatorial forests - evergreen forests, mainly in the equatorial, less often in the subequatorial zones in the north of South America, in Central America, in Western Equatorial Africa, in the Indo-Malay region. In the Amazon basin, they are called helium, selva. Distributed in areas with annual precipitation of more than 1500 mm, relatively evenly distributed over the seasons. Characteristically big variety species of trees: from 40 to 170 species are found per hectare. Most trees have straight, columnar trunks, branching only in the upper part. The tallest trees reach heights. 50-60 m, trees avg. tier - 20-30 m, lower - approx. 10 m. Many trees have board-like roots, sometimes rising to a height. 8 m. In swampy forests, trees have stilted roots. Change of foliage different types trees happens in different ways: some shed their leaves gradually throughout the year, others only at certain periods. Opening young leaves initially hang as withered, sharply differing in color, which is characterized by a wide range of colors - from white and pale green to crimson and burgundy. Flowering and fruiting also occur unequally: continuously throughout the year or periodically - once or several times a year. Often on the same tree you can see branches with fruits, flowers and young leaves. Many trees are characterized by caulifloria - the formation of flowers and inflorescences on the trunks and leafless areas of the branches. The dense crowns of trees almost do not allow sunlight to pass through, so there are very few grasses and shrubs under their canopy. In the equatorial forests there are many vines, mainly with woody stems, less often grassy ones. Their trunks reach a diameter of 20 cm, and the leaves are raised to the height of tree crowns. Some lianas, for example, rattan palms, rest on tree trunks with short shoots or special outgrowths; others, such as vanilla, are fixed with adventitious roots; however, most tropical vines are curly. There are often cases when the trunk of a vine is so strong, and the crown is so closely intertwined with several trees that the tree braided by it does not fall after death. Epiphytes are very diverse and numerous - plants growing on trunks, branches, and epiphylls - on tree leaves. They do not suck out nutritious juices from the host plant, but use it only as a support for growth. Epiphytes from the bromeliad family accumulate water in the rosettes of leaves. Orchids store nutrients in the thickened areas of the shoots, roots or leaves. Breeding epiphytes, for example. ferns "bird's nest" and "antlers" accumulate soil between the roots, epiphytes-sconces - under the leaves adjacent to the tree trunks. In America, even some types of cacti are epiphytes. Wet equatorial forests have been predatory and continue to be destroyed. By now, their area has already halved and continues to decrease at a rate of 1.25% per year. They are inhabited by St. 2/3 of all species of plants and animals on Earth, many of which perish, even without being discovered and explored by man. In place of the destroyed primeval forest, low-growing and very species-poor forests of fast-growing trees begin to grow. With regular fires and clearings, secondary forests are replaced by savannas or pure thickets of cereals.
> Subequatorial forest zone
The subequatorial forest zone is located on the outskirts equatorial belt... Subequatorial forests in the inner regions of the subequatorial belt, in the outer - savannahs. Subequatorial forests are divided into 2 late ones: 1. Seasonally humid forests. Dry season 3.5-4 months, ferralite soils. The main background of forests in the north of the Guiana Highlands. 2. Subzone of permanently humid subequatorial forests. Occupies only the North-East of the Guiana Plateau. Dry season less than two months. The soils are ferralite and red-yellow.
> Zone of savannas, woodlands and shrubs
Zones of savannas, woodlands and shrubs are located mainly in the subequatorial and partly in the tropical climatic zones... The savannahs occupy the Orinoco Plain, where they are called Llanos, as well as the interior of the Guiana and Brazilian Highlands (Campos).
Savannah soils are red ferralite and red-brown. In the savannahs of the northern hemisphere, sparsely standing palms and acacias grow among tall grasses. Gallery forests are characteristic along the river banks. In the savannas of the Brazilian Highlands, the grass cover, as in the llanos, consists of tall grasses and legumes. But the woody vegetation is much poorer; mimosas, tree-like cacti, and milkweed predominate. In the northeast of the Brazilian Highlands and the Inner Tropical Plains, in a drier climate (up to 400 mm of precipitation per year), tough grasses, thorny shrubs, bottle trees, low-growing open forests of kebracho - a tree with very hard wood (“kebracho” in translated means "break the ax"). In the fauna of the savannahs of South America, there are few ungulates (small deer); there are peccary pigs, armadillos, anteaters, and of the predators - the cougar. Subzones: 1. Wet savannahs. Orinok lowland (llanos). A clear division into a dry period, 3.5-4 months. The soils are red, there are areas of yellow and red-yellow. Palm vegetation and herbs. 2. Dry shrub savannas and woodlands. central part Brazilian Highlands, North-East of the Orinoco Plain. The amount of precipitation is not more than 700 mm, the soils are brown-red. The grass cover is sparse, represented mainly by grasses, shrubs are characteristic. This type of savanna is called campos. Dry period about 5 months 3. Kaatina (subzone of deserted woodland). North-East of the Brazilian Highlands. Almost complete absence of grass cover, only shrubs and a wax palm grow. The soils are red-brown.
