Presentation on the topic: "What is a rainforest? A rainforest is a very special forest. In such a forest it is always very humid and warm. It is very dense, often intertwining." Download for free and without registration. Deforestation of tropical forests Where are the

A tropical forest- a forest distributed in the tropical, equatorial and subequatorial zones between 25 ° N. sh. and 30 ° S. sh. Rainforests are found in a wide belt that surrounds the Earth at the equator and is torn apart only by oceans and mountains.

The general circulation of the atmosphere occurs from a zone of high atmospheric pressure in the tropics to a zone of low pressure in the equator, and evaporated moisture is transported in the same direction. This leads to the existence of a humid equatorial belt and a dry tropical one. Between them is the subequatorial belt, in which moisture depends on the direction of the wind (monsoon), which depends on the season.

The vegetation of tropical forests is very diverse, depending mainly on the amount of precipitation and its distribution over the seasons. In the case of abundant (more than 2000 mm) and their more or less uniform distribution, humid tropical evergreen forests.

With distance from the equator, forests appear, in which moisture depends on the season: the rainy period is replaced by a dry one. This - wintry variably humid tropical forests with leaves falling off during a drought. Further, these forests are replaced savannah forests.

At the same time, in Africa and South America, monsoon and equatorial forests are replaced by savanna forests from west to east. In an even more arid climate, forest stands are thinned, savanna forests are replaced by xerophilic thorny forests and thickets of shrubs.

Humid tropical forests are characterized by the greatest abundance of flora on Earth (over 4/5 of all plant species), the predominance of woody species (about 70% of higher plants), and their diversity (from 40 to 100 species per hectare). Unlike temperate forests, rainforests rarely have two trees of the same species standing side by side.

Distribution of tropical forests

It will immediately become clear where the rainforests grow, if we explain that they seem to "encircle" the planet along the Equator. They are located in the humid equatorial, dry tropical, temperate subequatorial zones, representing a clear line, interrupted only by mountains and oceans.

Vegetation changes depending on the air temperature and the amount of precipitation. Rainy areas are covered with evergreen flora, drier regions are characterized by deciduous plants, followed by savanna forests.

In both South America and Africa, there are monsoon forests in the west, savanna forests in the east, and equatorial forests in the middle.

Rainforest map

Forest levels

The warm, humid climate of the rainforest provides an ideal environment for a vast abundance of amazing plant life. The rainforest is divided into several tiers, which are characterized by their own flora and fauna.

The tallest trees in the tropics receive the most sunlight. This includes, for example, a cotton tree.

Second tier- dome. The level of the crowns is considered the most diverse, about 25% of all insect species live here. It is the habitat for half of the rainforest wildlife -, and. This includes trees below 50 m in height with wide leaves, hiding sunlight from the lower floors.

Scientists agree that 40% of all plant species on the planet are located on this tier, although it has not been fully studied. These are philodendron, poisonous strychnos and rattan palms. Vines usually stretch along them to the sun.

Third tier inhabited by shrubs, ferns and other shade-tolerant species.

Last tier, the lower one, usually dark and humid, since the sun's rays hardly penetrate here. It consists of quail foliage, mushrooms and lichens, as well as young growth of plants of higher tiers.

Rainforest classification

The main groups of rainforest formations are rainforest, or wet, and seasonal.

Tropical rainforest

Distributed in the equatorial belt, characterized by abundant precipitation (2000-7000 mm, sometimes even up to 12000 mm) and their relatively uniform distribution throughout the year at a practically unchanged average air temperature (24-28 ° C). Main regions of distribution: South America, Central Africa, Southeast Asia and Australia. Tropical rainforests are considered the center of evolutionary activity, a place where new species form, spreading to other regions.

They are the most ancient type of vegetation, practically unchanged since the Tertiary period.

The main groups of tropical rainforests are humid evergreen mountain forests, tropical swamp forests, rainforests, tropical lowland forests, mangroves.

Mangroves are common in the tidal zone of tropical coasts and, if warm currents favor this, then along the coast in a temperate climatic zone. They grow in places free of water at low tide and flooded at high tide.

Mangrove forest

Tropical mountain evergreen forests usually grow above 1500-1800 m, where air temperatures drop to 10-12 ° and below, which prevents many organisms from developing. The relative safety of these forests, which are of significant importance in the stabilization of natural conditions (water protection, anti-erosion, etc.), is facilitated by their low economic value associated with the difficulties of development due to relief conditions.

Swamp forests occupy a noticeably smaller area than non-flooded plain forests. According to their properties, they are close, although they have enough differences. Distributed in the same plains, they create a landscape mosaic of tropical forests.

Seasonal rainforest

They grow in areas where, despite good moisture (2500-3000 mm), there is a dry period. The amount of precipitation and the duration of the dry period in different forests is not the same, among them there are

• evergreen seasonal forests(e.g. Australian eucalyptus),
• semi-evergreen forests(deciduous species are presented in the upper tier, in the lower tier - evergreens)
• light sparse forests(The floristic composition is poor, sometimes it is represented by one breed).

Deciduous seasonal rainforests are divided into monsoon forests and savanna forests.

Monsoon forests grow in the area of ​​monsoon action, the dry period lasts about 4-5 months. They are located in South and Southeast Asia, including Hindustan, Indochina, the Malacca Peninsula, in the northeast of Java. Forests of this type also grow in the West Indies and Central America (Trinidad Island, Costa Rica) and West Africa.

In monsoon forests, three main groups of plant communities can be distinguished.

• The mixed forests are dominated by terminalia, dalbergia, albicia and others, and the undergrowth consists of bamboos and small palms.
• In teak forests - teak tree (large tectone), deciduous Acacia lencophloea and Albizzia procera and evergreen Butea frondosa, Scheichera trijuda, etc.
• Forests from Shoreya gigantic, undergrowth from Terminalia, Sterculia, etc.

Ebony trees and Indian laurel grow in India. Lianas and epiphytes, although not as numerous as in evergreens, are more numerous than in savanna forests. The forest canopy in monsoon forests is thinner in comparison with humid tropical forests, therefore, the grass cover in them is closed. The grasses are mostly annual, with wild sugarcane prevailing in the driest areas.

Triplochiton (Triplochiton scleroxylon) is especially characteristic of the upper layer of forests of this type in West Africa.

Savannah forests distributed in tropical regions with a pronounced dry season and less annual precipitation than in the belt of closed forests. Distributed over most of Cuba and other islands of the Caribbean Sea, in many regions of South America, East and Central Africa and here and there in India, China and Australia.

For savannah forests, deciduous trees from the legume family are typical, the crown of which is usually flat, umbrella-shaped. The trees are up to 18 m high. In places where the trees are 3-4.5 m high, during the rainy season, the grasses may be higher than the trees. Grains form the basis of the herbaceous cover.

In thorny xerophilous forests, there are trees with scaly leaves and shrubs with green stems without leaves. Plants are often covered with thorns, and stem and root tissues are capable of storing water.

Rainforest herbs

Where tropical forests grow, two groups of grasses prevail: shade-loving and shade-tolerant. The former prefer to grow in significantly shaded areas, while the latter are able to develop normally under a closed forest canopy. It should be borne in mind that even in the daytime twilight reigns here, since the sun's rays are unable to break through the crowns of numerous trees.

In the American tropics, you can find tinama - a poorly flying bird with short but very strong legs.

Well, how can you not remember the bright, funny and talkative, without which the tropics are not tropics. In addition, variegated pigeons, trogons, woodpeckers, flycatchers, hornbills and others live on the equator.

In terms of the number of species, tropical forests significantly exceed the forests of temperate and cold countries, the fauna of tropical rain forests is the richest, nevertheless, the number of representatives of each individual species is small.

Typically, tropical forest animals live in trees and in crowns. Representatives of mammals are monkeys, flying squirrels, sloths, spiny-tailed squirrels, needle-hairs, some insectivores, carnivores, and so on.

Birds are represented by parrots, woodpeckers, toucans, hummingbirds, craxes, hoatsins and others; examples of reptiles are chameleons, tree snakes, some geckos, iguanas, agamas; amphibians - some frogs. Many reptiles are poisonous.

In humid tropical forests, due to a lack of light, the undergrowth and grass cover are poor, so there are few terrestrial species in them. They are represented by tapirs, rhinos, bakers, hippos. The habitat of large mammals, including elephants, giraffes, buffaloes, is the seasonal rainforest.

Invertebrates are very diverse, they can be quite large, stand out for the richness of shapes and colors, among them ants, centipedes, butterflies and others.

Ecology

Tropical forests are extremely important for the biosphere of the planet; they are the habitat of almost half of all biological species inhabiting it, over 80% of all plant species. The area of ​​tropical forests is half of the forest area of ​​the Earth. They produce 69% of all net primary forest production in the world. Rainforests evaporate about 9% of the water entering the atmosphere.

Despite the high biological productivity (up to 3500 g / m² per year) and large leaf litter, the stock of litter in them is much less than in temperate forests. This is due to both the intensity of leaching in rain forests and the general intensity of decomposition, with fungi and termites processing over 90% of the annual increase in plant matter. The rest is eaten by herbivores, which, in turn, serve as a food source for predators.

Half of the primary rainforests have disappeared - either secondary forests have grown, or grassy communities remain, which may turn into deserts. The greatest concern is the decline in rainforest rainforests. Ecosystems of the seasonally humid tropics have adapted to both seasonal changes and interannual differences in the duration of dry and wet periods; therefore, they are more resistant to anthropogenic impacts. The process is aggravated by the fact that when deforestation occurs in just 1-2 years, nutrients are washed out from the soil into the subsoil.

The main reasons for the decline in tropical forest area are:

• slash and burn agriculture,
• burning forests for pastures,
• logging.

Many international organizations, for example IUCN, UN FAO, UNEP, recognize the importance of tropical forests for the planet's biosphere and contribute to their conservation. About 40 million hectares of protected areas have been created here, including the Salonga and Maiko National Parks (Zaire); Jau, Amazonian (Brazil); Manu (Peru), Canaima (Venezuela). It is believed that in order to preserve tropical forest ecosystems, protected areas should cover at least 10% of the forest area.

Tropical rainforests stretch over large areas on both sides of the equator, but do not go beyond the tropics. The atmosphere here is always rich in water vapor. The lowest average temperature is about 18 °, and the highest is usually not higher than 35-36 °.

With abundant warmth and moisture, everything grows here with remarkable speed. Spring and autumn are invisible in these forests. Throughout the year, some trees and shrubs bloom in the forest, others fade. Summer is all year round and the vegetation turns green. There is no leaf fall in our understanding of the word, when the forest is exposed by winter.

The change of leaves occurs gradually, and therefore it is not noticed. On some branches young leaves bloom, often bright red, brown, white. On other branches of the same tree, the leaves were fully formed and turned green. A very beautiful range of colors is created.

But there are bamboos, palms, some types of coffee trees, which bloom all at once in one day over an area of ​​many square kilometers. This striking phenomenon makes a stunning impression with the beauty of the bloom and the aromas.

Travelers say that in such a forest it is difficult to find two neighboring trees belonging to the same species. Only in very rare cases are tropical forests of uniform species composition.

If you look at the rainforest from above, from an airplane, then it will appear surprisingly uneven, sharply broken, not at all like the flat surface of a forest of temperate latitudes.

They are not similar in color. Oak and our other forests, when viewed from above, seem to be monotonous green, only with the arrival of autumn do they dress up in bright and variegated colors.

The equatorial forest, when viewed from above, seems to be a mixture of all tones of green, olive, yellow, interspersed with red and white blooming crowns.

Entering the rainforest is not so easy: usually it is a dense thicket of plants, where, at first glance, they all seem entangled, intertwined. And it is difficult to immediately figure out which plant this or that trunk belongs to - but where are its branches, fruits, flowers?

A damp twilight reigns in the forest. The rays of the sun weakly penetrate into the thicket, so trees, shrubs, all plants here stretch upward with amazing strength. They branch little, only three to four orders of magnitude. One involuntarily recalls our oaks, pines, birches, which give five to eight orders of branches and widely spread their crowns in the air.

In equatorial forests, trees stand in thin, slender columns and somewhere at a height, often 50-60 meters, carry small crowns to the Sun.

The lowest branches begin about twenty to thirty meters from the ground. You need good binoculars to see leaves, flowers, fruits.

Palm trees, tree ferns do not give branches at all, throwing out only huge leaves.

Column giants need good foundations, like the buttresses (slopes) of old buildings. And nature took care of them. In African equatorial forests, ficuses grow, from the lower parts of the trunks of which additional - plank - roots develop up to a meter or more. They hold the tree firmly against the wind. Many trees have such roots. On the island of Java, the inhabitants make table covers or cartwheels from board roots.

Between the giants, trees are densely growing trees of lesser height, in four to five tiers, even lower - shrubs. Fallen trunks and leaves rot on the ground. The trunks are entwined with vines.

Hooks, thorns, whiskers, roots - by all means, vines cling to tall neighbors, twine around them, crawl along them, use devices popularly known as "devil's hooks", "cat's claws". They twist with each other, now as if merging into one plant, then again dividing in an irrepressible striving for light.

These thorny barriers terrify the traveler, who is forced to take every step among them only with the help of an ax.

In America, along the valleys of the Amazon, in the virgin rainforests, lianas, like ropes, are thrown from one tree to another, climb up the trunk to the very top and comfortably settle in the crown.

Fight for light! In a humid tropical forest, there are usually few grasses on the soil, and shrubs are also sparse. Everything that lives must receive some amount of light. And many plants succeed in this because the leaves on the trees are almost always perpendicular or at a significant angle, and the surface of the leaves is smooth, shiny and perfectly reflects light. This arrangement of leaves is also good because it softens the force of the blows of rains and downpours. And it prevents stagnation of water on the leaves. It is easy to imagine how quickly the leaves would fail if water lingered on them: lichens, mosses, mushrooms would populate them immediately.

But for the full development of plants on the soil, there is not enough light. How, then, can we explain their diversity and splendor?

Many tropical plants are not associated with soil at all. These are epiphytic plants - lodgers. They don't need soil. Trunks, branches, even leaves of trees give them an excellent shelter, and there is enough warmth and moisture for everyone. A little humus forms in the axils of the leaves, in the crevices of the bark, between the branches. Wind, animals will bring seeds, and they germinate and develop well.

The very common bird's nest fern produces leaves up to three meters long, forming a rather deep rosette. Leaves, bark scales, fruits, animal remains fall into it from trees, and in a humid warm climate quickly form humus: the "soil" for the roots of the epiphyte is ready.

In the Botanical Gardens in Calcutta, they show such a huge fig tree that it is mistaken for a whole grove. Its branches have grown above the ground in the form of a green roof, which is supported by pillars - these are adventitious roots growing from the branches. The crown of the fig tree is spread over more than half a hectare, the number of its aerial roots is about five hundred. And this fig tree began its life as a freeloader on a date palm. Then she braided her with her roots and strangled her.

The position of epiphytes is very advantageous in comparison with the “host” tree, which they use, making their way higher and higher towards the light.

Often they carry their leaves above the top of the "owner" trunk and take away the sun's rays. The "owner" dies, and the "lodger" becomes independent.

For rainforests, the words of Charles Darwin are best of all: "The greatest amount of life is realized with the greatest variety of structure."

Some epiphytes have thick fleshy leaves, some kind of swelling on the leaves. They have a supply of water in case there is not enough water.

Others have leathery leaves, tough, as if varnished, as if they did not have enough moisture. The way it is. In the hot season of the day, and even with strong winds, the evaporation of water sharply increases in a highly raised crown.

Another thing is the leaves of shrubs: they are tender, large, without any adaptation to reduce evaporation - in the depths of the forest it is small. The grasses are soft, thin, with weak roots. There are many spore plants, especially ferns. They scatter their leaves at the edges of the forest and in the rare lighted meadows. Here are brightly flowering shrubs, large yellow and red cannes, orchids with their fancifully arranged flowers. But herbs are far less diverse than trees.

The general green tone of herbaceous plants is pleasantly interspersed with white, red, gold, silvery leaf spots. Whimsically decorated, they are not inferior in beauty to the flowers themselves.

It may seem at first glance that the rainforest is poor in flowers. In fact, there are not so few of them,
they are simply lost in the green mass of foliage.

Many trees have flowers that are self-pollinated or wind-pollinated. Large bright and fragrant flowers are pollinated by animals.

In the tropical forests of America, tiny, shiny plumage, hummingbirds hover over flowers for a long time, licking the honey from them with a long tongue folded in the form of a tube. In Java, birds often act as pollinators. There are honey birds, small, similar in color to hummingbirds. They pollinate flowers, but at the same time they often "steal" honey without even touching the stamens and pistils. In Java, there are bats pollinating vines with brightly colored flowers.

In the cocoa tree, breadfruit, persimmon, ficus, flowers appear directly on the trunks, which then turn out to be completely hung with fruits.

In equatorial humid forests, swamps are often found, flowing lakes come across. The fauna is very diverse here. Most of the animals live in trees, feeding on fruits.

The rainforests of different continents have many similarities with each other, and at the same time, each of them is different from the others.

In Asian forests, there are many trees with valuable wood, plants that give spices (pepper, cloves, cinnamon). Monkeys climb in the tree crowns. An elephant wanders on the outskirts of the tropical thicket. The forests are inhabited by rhinos, tigers, buffaloes, poisonous snakes.

The humid equatorial forests of Africa are famous for their impenetrable thickets. It's impossible to get through here without an ax or a knife. And there are many woody species with valuable timber. The oil palm is often found, from the fruits of which butter, coffee tree and cocoa are extracted. In places in narrow hollows, where fogs accumulate, and the mountains do not let them to the sides, tree ferns form whole groves. Heavy dense fogs slowly creep upward and, cooling down, pour abundant rains. In such natural greenhouses, the spore ones feel as good as possible: ferns, horsetails, moss, curtains of delicate green mosses descend from the trees.

Gorillas and chimpanzees live in African forests. Monkeys tumbling in the branches; baboons bark the air. There are elephants and buffaloes. Crocodiles hunt all kinds of living creatures in the rivers. Meetings with a hippopotamus are not uncommon.

And everywhere mosquitoes, mosquitoes fly in clouds, hordes of ants crawl. Perhaps even this "trifle" is more noticeable than large animals. It disturbs the traveler at every step, stuffing itself into the mouth, nose and ears.

The relationship of tropical plants with ants is very interesting. On the island of Java, in one epiphyte, the stem below is a tuber. Ants lodge in it and leave their excrement on the plant, which serves as a fertilizer for it.

In the rain forests of Brazil, there are real ant gardens. At a height of 20-30 meters above the ground, ants arrange their nests, dragging them onto branches and trunks along with the ground, leaves, berries and seeds. Young plants sprout from them, fastening the soil in the nest with roots and receiving soil and fertilizers right there.

But ants are not always harmless to plants. Leaf cutter ants are a real scourge. They attack coffee and orange trees and other plants in hordes. Cutting pieces from the leaves, they load them onto their backs and move in solid green streams to the nests, exposing the branches,

Fortunately, other ant species can settle on the plants, which destroy these robbers.

The rainforests of America along the banks of the Amazon River and its tributaries are considered the most luxurious in the world.

Vast flat areas, regularly flooded with water during flooding, are covered with coastal forests. Above the spill line, there are huge virgin forests. And drier areas are occupied by forests, albeit less dense and lower.

There are especially many palm trees in the coastal forests, forming whole groves, running in long alleys along the banks of the rivers. Some of the palms fan out their leaves, others stretch out feathery leaves 9-12 meters long. Their trunks are straight, thin. In the undergrowth there are small palms with clusters of black and red fruits.

Palm trees give a lot to people: the fruits are used for food, the locals get fiber from the stems and leaves, and the trunks are used as building material.

As soon as the rivers enter their course, grasses develop with extraordinary speed in the forests, and not only on the soil. From trees and bushes hang green garlands of climbing and climbing herbaceous plants, colored with bright flowers. Passion flowers, begonias, "day beauties" and many other flowering plants form draperies on the trees, as if laid out by the artist's hand.

Myrtle, Brazil nut, blooming ginger, cannes are beautiful. Ferns and graceful feathery mimosas maintain the overall green tone.

In the forests above the border of the river flood, trees, perhaps the tallest of all tropical representatives, stand in a dense closed formation on supports. Among them are the Brazilian walnut and the silk cotton with its enormous plank supports. Laurel trees are considered the most beautiful trees in the Amazon. There are many legume acacias, many aroids. Philodendron and Monstera are especially good with fantastic cutouts and cuts in the leaves. There is often no undergrowth in this forest at all.

In less high, flood-free forests, lower arboreal layers of palms, shrubs and short trees appear, sometimes very dense and almost impassable.

The grassy cover cannot be called luxurious: few ferns, sedges. In some places, there is not a single blade of grass in a significant area.

Almost all of the Amazonian lowlands and part of the northern and eastern coasts of the mainland are occupied by humid forests.

The even heat and abundance of rainfall make all days look like one another.

Early in the morning the temperature is 22-23 °, the sky is cloudless. The leaves are shiny and fresh with dew, but the heat is rapidly increasing. By noon and a little later, it is already intolerable. Plants drop leaves and flowers and appear completely wilted. No air movement, animals hid. But now the sky is covered with clouds, lightning flashes, deafening peals of thunder.

The crowns are shaking with sharp gusts of the oncoming wind. And the blessed downpour revives the whole nature. It soars strongly in the air. A sultry, hot and damp night falls. Leaves and flowers torn by the wind fly.

A special type of forest in tropical countries covers the sea coasts, protected from waves and winds. These are mangrove forests - dense thickets of evergreen shrubs and low trees on flat banks near river mouths, in lagoons and bays. The soil here is a swamp with black, foul-smelling silt; in it there is a violent decomposition of organic substances with the participation of bacteria. At high tide, such thickets seem to emerge from the water.

At low tide, their so-called roots - stilts, which stretch far along the silt, are exposed. From the branches into the silt, there are still supporting roots.

Such a root system strengthens trees well in silty soil, and they are not carried away by ebb or flow.

Mangroves push the coast to the sea, because plant residues accumulate between the roots and trunks and, mixing with silt, gradually form dry land. Trees have special respiratory roots, which are very important in the life of these plants, since the silt contains almost no oxygen. Sometimes they are serpentine in shape, in other cases they resemble a cranked tube or stick out of the silt like young stems.

A curious way of reproduction found in mangroves. The fruit is still hanging on the tree, and the embryo is already sprouting in the form of a long pin, up to 50-70 centimeters. Only then does it break away from the fruit, fall into the silt, burrowing into it with its end, and it is not carried away by the water into the sea.

These plants have leathery, shiny, often fleshy leaves covered with silvery hairs. The leaves are arranged vertically, the stomata are reduced. These are all signs of plants in arid places.

It turns out a paradox: the roots are immersed in silt, they are constantly under water, and the plant lacks moisture. It is assumed that sea water, when it is saturated with salt, cannot be easily absorbed by the roots of trees and shrubs - and therefore they must evaporate sparingly.

Together with sea water, plants receive a lot of table salt. The leaves are sometimes almost completely covered with its crystals, isolated by special glands.

The richness of species in tropical forests is extremely great, and it is achieved primarily by the fact that the use of space by plants is brought here by natural selection to the extreme limits.

Rainforests represent more than 50% of all green space on the planet. Over 80% of animal and bird species live in these forests. Today, the deforestation of the rainforest is taking place at a rapid pace. Such figures are terrifying: more than 40% of trees have already been cut down in South America, and 90% in Madagascar and West Africa. All this is an ecological catastrophe of a global nature.

The meaning of the rainforest

Why is the forest so important? The significance of the rainforest for the planet can be enumerated endlessly, but let's dwell on the key points:

• the forest takes a huge part in;
• trees protect the soil from being washed out and blown away by the wind;
• wood purifies the air and produces oxygen;
• it protects territories from sudden temperature changes.

Rainforests are such a resource that renews itself very slowly, but the rate of deforestation is destroying a large number of ecosystems on the planet. Deforestation leads to sudden temperature changes, changes in air speed and rainfall. The fewer trees grow on the planet, the more carbon dioxide enters the atmosphere and. Swamps or semi-deserts and deserts form in place of cut down tropical forests, and many species of flora and fauna disappear. In addition, groups of environmental refugees appear - people for whom the forest was a source of livelihood, and now they are forced to look for a new home and sources of income.

How to save the rainforest

Experts today suggest several ways to preserve the rainforest. Every person should join this: it is time to switch from paper information carriers to electronic ones, to hand over waste paper. At the state level, it is proposed to create a kind of forest farms, where trees that are in demand will be grown. It is necessary to prohibit deforestation in protected areas and to toughen the punishment for violating this law. You can also increase the state duty on wood when exporting it abroad, in order to make the sale of wood impractical. These actions will help preserve the planet's rainforests.

Rainforests are forests that grow in tropical and subtropical regions. Rainforests cover about six percent of the Earth's land surface. There are two main types of rainforest: tropical rainforest (such as those in the Amazon or Congo Basin) and dry tropical forests (such as those in southern Mexico, the plains of Bolivia, and the western regions of Madagascar).

Rainforests typically have four distinct layers that define the structure of the forest. The tiers include the forest floor, the undergrowth, the upper canopy (forest canopy), and the upper tier. Forest floor, the darkest place in the rainforest, where little sunlight penetrates. Undergrowth is a layer of forest between the ground and up to a height of about 20 meters. It includes shrubs, grasses, small trees, and large tree trunks. The canopy of the forest is a canopy of tree crowns at a height of 20 to 40 meters. This tier consists of the binder crowns of tall trees, which are home to many animals of the rainforest. Most of the food resources in the rainforest are found in the upper canopy. The upper tier of the rainforest includes the crowns of the tallest trees. This tier is located at an altitude of about 40-70 meters.

Main characteristics of the rainforest

Below are the main characteristics of the rainforest:

• tropical forests are located in tropical and subtropical regions of the planet;
• rich in species diversity of flora and fauna;
• a large amount of precipitation falls here;
• rainforests are threatened with extinction due to logging, farming and grazing;
• the structure of the rainforest consists of four layers (forest floor, undergrowth, canopy, upper layer).

Rainforest classification

• Tropical rainforests, or tropical rainforests, are forest habitats that receive heavy rainfall throughout the year (typically more than 200 cm per year). Humid forests are located close to the equator and receive enough sunlight to keep the average annual air temperature high enough (between 20 ° and 35 ° C). Tropical rainforests are some of the richest habitats on earth. They grow in three main areas around the world: Central and South America, West and Central Africa, and Southeast Asia. Of all the rainforest regions, South America is the largest in the world: it covers about 6 million square kilometers.
• Dry rainforests are forests that receive less rainfall than rainforests. Dry forests tend to have a dry season and a rainy season. Although the amount of rainfall is sufficient to keep vegetation growing, the trees must be able to withstand long periods of drought. Many tree species that grow in dry rainforests are deciduous and shed their leaves during the dry season. This allows trees to reduce their water requirements during the dry season.

Rainforest animals

Examples of several animals that inhabit the rainforest:

• (Panthera onca) is a large feline that lives in the rainforests of Central and South America. Jaguar is the only species of panther living in the new world.
• The capybara, or capybara (Hydrochoerus hydrochaeris), is a semi-aquatic mammal that inhabits the forests and savannahs of South America. Capybaras are the largest living rodents.
• Howler monkeys (Aloautta) are a genus of monkeys that includes fifteen species inhabiting rainforests throughout Central and South America.

You can find out more information about the animals of the Amazon rainforest in the article "".

In countries that are close to the equator and where a huge amount of precipitation falls all year round, the air temperature is high and rich humid forests, or, in other words, tropical forests grow. In Africa, tropical forests grow on the shores of the Gulf of Guinea to the very mountains of Cameroon.

In America (South and Central), the rainforest grows in the Amazon. In Asia, the distribution of tropical forests is typical for the valleys of the Ganges and Brahmaputra rivers, on the Malacca Peninsula and the islands of Sumatra, Java, and Ceylon. In Australia - similar forests can be seen if you walk along the Pacific coast.

Rainforests are evergreen, rugged, multi-tiered forests that differ in species and many non-tiered plant species. In tropical forests, trees grow slender, their height is from 40 to 60 meters, diameter is from 3 to 4 meters. The bark of trees is underdeveloped, it is smooth, shiny. Trees have large, shiny, leathery leaves. Usually tree trunks are densely entwined with vines. These vines make the forest impenetrable.

Description of the rainforest on the island of Sumatra

Trees tall and low grow in a mixture. Grow in tiers. The height is more than 80 meters. If you walk through the forest, it is very difficult to imagine their colossal height. The trunks of the trees are so wide that it takes about five or six people to grasp them. The trunks are very smooth, there are no twigs, branches, only at the very top there are branches with leaves. The leaves are so different. Some are delicate, others are thin, some are coarse, lanceolate, sharp-toothed, etc., but they are all dark green, thick, shiny.

The land is almost invisible, because it is very densely overgrown with bushes. You cannot go through the thickets without a knife. Therefore, most of the land is covered with leaves, which have been cut down and subsequently rotted. Small gaps between trees are filled with vines and growing creepers. Creeping plants stretch from branch to branch, from trunk to trunk. Vines are thin, there are thick. Thin lianas, like threads that are barely covered with leaves. Thick vines are like a rope that is elastic like a trunk.

They hang from trunks, from trees in loops, knots. Vines twine around trees with their narrow spirals so tightly, squeeze them so tightly that they strangle them, penetrating deep into the bark of the tree and thereby dooming it to death. Vines plug all twigs, trunks, branches with their spirals. Rainforest vegetation is very diverse on every continent.