About half of all forests on our planet are tropical forests (hylaea) that grow in Africa, South-East Asia, South and Central America. Tropical forests are located between 25°N and 30°S, where heavy rainfall is common. The rainforest ecosystem covers less than two percent of the Earth's surface, but 50 to 70 percent of all life forms on our planet are found here.

The largest rainforests are found in Brazil (South America), Zaire (Africa) and Indonesia (Southeast Asia). Rainforest is also found in Hawaii, the Pacific Islands and the Caribbean.

Rainforest climate

The climate in the rainforest is very warm, characterized and humid. From 400 to 1000 cm of precipitation falls here annually. The tropics are characterized by a uniform annual distribution of precipitation. The change of seasons is almost non-existent, and average temperature air is 28 degrees Celsius. All these conditions have significantly influenced the formation of the richest ecosystem on our planet.

Soil in the rainforest

The soil of the tropics is poor in minerals and nutrients - there is a lack of potassium, nitrogen and other trace elements. Usually it has a red and red-yellow color. Due to frequent precipitation, nutrients are absorbed by the roots of plants or go deep into the soil. That's why the aborigines rainforest a slash-and-burn agricultural system was used: in small areas, all vegetation was cut down, it was subsequently burned, then the soil was cultivated. The ash acts as a nutrient. When the soil begins to turn into infertile, usually after 3-5 years, the inhabitants of tropical settlements moved to new areas for cultivation. Agriculture. It is a sustainable farming method that ensures that the forest is constantly regenerated.

rainforest plants

The warm, humid climate of the rainforest provides the perfect 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 the largest number sunlight, as they reach a height of over 50 meters. Here, for example, include the cotton tree.

The second tier is the dome. It is the habitat for half of the representatives wildlife tropical forests - birds, snakes and monkeys. This includes trees with a height of less than 50 m with wide leaves, hiding sunlight from the lower floors. These are philodendron, poisonous strychnos and rattan palms. Lianas usually stretch along them towards the sun.

The third tier is inhabited by shrubs, ferns and other shade-tolerant species.

The last tier, the lower one, is usually dark and damp, since the sun's rays hardly penetrate here. It consists of overripe foliage, fungi and lichens, as well as young shoots of plants of higher tiers.

In each of the regions where tropical forests grow, there are different types of trees.

Tropical trees of Central and South America:
  • Mahogany (Sweitinia spp.)
  • Spanish cedar (Cedrella spp.)
  • Rosewood and Cocobolo (Dalbergia retusa)
  • Purple Tree (Peltogyne purpurea)
  • Kingwood
  • Cedro Espina (Pochote spinosa)
  • Tulipwood
  • Gaiacan (Tabebuia chrysantha)
  • Pink tabebuya (Tabebuia rosea)
  • Bokote
  • Jatoba (Hymenaea courbaril)
  • Guapinol (Prioria copaifera)
Tropical trees of Africa:
  • Bubinga
  • Ebony
  • Zebrano
  • Pink tree
Tropical trees of Asia:
  • Malaysian maple

In the rainforest, they are widespread, which feed on caught insects and small animals. Among them, it should be noted nepentes (Pitcher Plants), sundew, oilwort, pemphigus. By the way, plants of the lower level, with their bright flowering, attract insects for pollination, since there is practically no wind in these layers.

Valuable crops are grown in the places of clearing of tropical forests:

  • mango;
  • bananas;
  • papaya;
  • coffee;
  • cocoa;
  • vanilla;
  • sesame;
  • sugar cane;
  • avocado;
  • cardamom;
  • cinnamon;
  • turmeric;
  • nutmeg.

These cultures play an important role in cooking and cosmetology. Some tropical plants serve as raw materials for medicines especially anti-cancer.

Adaptation of tropical plants for survival

Any flora needs moisture. There is no lack of water in the rainforest, but often there is too much of it. Rainforest plants must survive in areas where there is constant rainfall and flooding. The leaves of tropical plants help to beat off raindrops, and some species are armed with a drip tip designed to quickly drain rain.

Plants in the tropics need light to live. The dense vegetation of the upper tiers of the forest transmits little sunlight to the lower tiers. Therefore, rainforest plants must either adapt to life in constant twilight or grow rapidly upwards in order to "see" the sun.

It is worth noting that in the tropics trees grow with thin and smooth bark, which is able to accumulate moisture. Some types of plants in the lower part of the crown have leaves wider than at the top. This helps to let more sunlight through to the soil.

As for the epiphytes themselves, or air plants that grow in the rainforest, they get their nutrients from plant debris and bird droppings that land on their roots and do not depend on the poor soil of the forest. In tropical forests, there are such air plants as orchids, bromeliads, ferns, large-flowered selenicereus and others.

As mentioned, the soil in most rainforests is very poor and lacks nutrients. To capture nutrients at the top of the soil, most rainforest trees have shallow roots. Others are wide and powerful, as they must hold a massive tree.

rainforest animals

Animals of the rainforest amaze the eye with their diversity. It is in this natural area that you can meet the largest number of representatives of the fauna of our planet. Most of them are in the Amazon rainforest. For example, there are 1800 species of butterflies alone.

In general, the tropical forest is the habitat of most amphibians (lizards, snakes, crocodiles, salamanders), predators (jaguars, tigers, leopards, cougars). All animals of the tropics are brightly colored, as the spots and stripes are the best camouflage in the dense thicket of the jungle. The sounds of the rainforest are provided by the polyphony of songbirds. In the forests of the tropics, the world's largest population of parrots, among others interesting birds there are South American harpies, belonging to one of the fifty species of eagles and on the verge of extinction. No less bright birds are peacocks, the beauty of which has long been legendary.

More monkeys also live in the tropics: arachnids, orangutans, chimpanzees, monkeys, baboons, gibbons, red-bearded jumpers, gorillas. In addition, there are sloths, lemurs, Malayan and sun bears, rhinos, hippos, tarantulas, ants, piranhas and other animals.

Tropical forest loss

Tropical timber has long been synonymous with exploitation and plunder. Giant trees are the target of entrepreneurs who use them for commercial purposes. How are forests exploited? The most obvious use of rainforest trees is in the furniture industry.

According to the European Commission, about one-fifth of EU wood imports come from illegal sources. Every day, thousands of products from the international wood mafia pass through store shelves. Tropical wood products are often labeled as "luxury wood", "hardwood", "natural wood" and "solid wood". Usually these terms are used to disguise tropical wood from Asia, Africa and Latin America.

The main tropical tree exporting countries are Cameroon, Brazil, Indonesia and Cambodia. The most popular and expensive types of tropical wood that goes on sale are mahogany, teak and rosewood.

To inexpensive breeds tropical tree include meranti, ramin, gabun.

The consequences of deforestation in the rainforest

In most tropical rainforest countries, illegal logging is common and a serious problem. Economic losses reach billions of dollars, and environmental and social damage is incalculable.

Deforestation results in deforestation and profound ecological changes. Tropical forests contain the largest in the world. As a result of poaching, millions of species of animals and plants are losing their habitat and, as a result, disappear.

According to the Red List International Union Conservation of Nature (IUCN), more than 41,000 plant and animal species are threatened, including big monkeys such as gorillas and orangutans. Scientific estimates of lost species vary widely, ranging from 50 to 500 species per day.

In addition, logging equipment used to remove timber destroys sensitive topsoil and damages the roots and bark of other trees.

Mining iron ore, bauxite, gold, oil and other minerals also destroy large areas of tropical forests, for example, in the Amazon.

Importance of the rainforest

Tropical rainforests play an important role in the ecosystem of our planet. Cutting down this particular natural zone leads to the formation of a greenhouse effect and, subsequently, to global warming. The largest tropical forest in the world, the Amazon forest, plays the most important role in this process. 20 percent of global greenhouse gas emissions are attributed to deforestation. The Amazon rainforest alone stores 120 billion tons of carbon.

Tropical forests also contain vast amounts of water. Therefore, another consequence of deforestation is a disturbed water cycle. This in turn could lead to regional droughts and changes in global weather patterns, with potentially devastating consequences.

The rainforest is home to unique flora and fauna.

How to protect tropical forests?

To prevent Negative consequences deforestation, it is necessary to expand forest areas, strengthen control over forests at the state and international levels. It is also important to raise people's awareness of the role forests play on this planet. Ecologists say it is also worth encouraging the reduction, recycling and reuse forest products. Switching to alternative energy sources such as fossil gas can in turn reduce the need to exploit forests for heating.

Deforestation, including tropical deforestation, can be carried out without harming this ecosystem. In Central and South America and Africa, trees are cut down selectively. Only trees that have reached a certain age and thickness of the trunk are cut down, and the young ones remain untouched. This method causes minimal damage to the forest, because it allows it to recover quickly.

Rainforests located in the tropical, equatorial and subequatorial belts between 25 ° N.L. and 30 ° S, as if "surrounding" the surface of the Earth along the equator. Tropical forests are only torn apart by oceans and mountains.

The general circulation of the atmosphere originates from the zone of high atmospheric pressure in the tropics to the zone low pressure at the equator, evaporated moisture is transported in the same direction. This leads to the existence of wet equatorial belt and dry tropical. Between them is the subequatorial belt, in which moisture depends on the direction of the monsoons, depending on the time of year.

The vegetation of tropical forests is very diverse, depending mainly on the amount of precipitation and its distribution over the seasons. With abundant (more than 2000 mm), and relatively uniform distribution develop humid tropical evergreen forests.

Further from the equator, the rainy period is replaced by a dry one, and the forests are replaced with leaves falling during the drought, and then these forests are replaced by savannah forests. At the same time, in Africa and South America, there is a pattern: from west to east, monsoon and equatorial forests are replaced by savanna forests.

Tropical forest classification

tropical rainforest, tropical rain forest these are forests with specific biomes located in equatorial (moist equatorial forest), subequatorial and humid tropical areas with very humid climate(2000-7000 mm of precipitation per year).

Tropical rainforests are rich in biodiversity. This is the most livable natural area. It is home to a large number of its own, including endemic species of animals and plants, as well as migratory animals. Tropical rainforests are home to two-thirds of all animal and plant species on the planet. It is assumed that millions of species of animals and plants have not yet been described.

These forests are sometimes referred to as " jewels of the earth" and " the largest pharmacy in the world”, since a large number of natural medical supplies. They are also called " lungs of the earth”, however, this statement is debatable because it has no scientific justification, since these forests either do not produce oxygen at all, or produce very little of it.

But it should be borne in mind that a humid climate contributes to effective air filtration, due to the condensation of moisture on the microparticles of pollution, which has a generally beneficial effect on the atmosphere.

Understorey formation in tropical forests is severely limited in many places due to lack of sunlight in the lower layer. This allows man and animals to move through the forest. If for any reason the leafy canopy is missing or weakened, the lower tier is quickly covered with a dense thicket of vines, shrubs and small trees - this formation is called the jungle.

The largest areas of tropical rainforests are found in the Amazon basin (“Amazonian rainforests”), in Nicaragua, in the southern part of the Yucatan Peninsula (Guatemala, Belize), in most of Central America (where they are called “selva”), in equatorial Africa from Cameroon to the Democratic Republic of the Congo, in many parts of Southeast Asia from Myanmar to Indonesia and New Guinea, in the Australian state of Queensland.

For tropical rainforests characteristic:

  • variety of flora
  • the presence of 4-5 tree tiers, the absence of shrubs, a large number of vines
  • the predominance of evergreen trees with large evergreen leaves, poorly developed bark, buds, unprotected bud scales, deciduous trees in monsoon forests;
  • the formation of flowers and then fruits directly on the trunks and thick branches

Trees in tropical rainforests have several general characteristics, which are not observed in plants of less humid climates.

The base of the trunk in many species has wide, woody ledges. Previously it was assumed that these ledges help the tree to maintain balance, but now it is believed that water with dissolved nutrients flows down these ledges to the roots of the tree. Wide leaves of trees, shrubs and grasses of the lower tiers of the forest are characteristic. The wide leaves help the plants absorb sunlight better under the tree edges of the forest, and they are protected from the wind from above.

Tall young trees that have not yet reached the topstory also have broader foliage, which then decreases with height. The leaves of the upper tier, which form the canopy, are usually smaller and heavily cut to reduce wind pressure. On the lower floors, the leaves are often tapered at the ends so that this allows the water to drain quickly and prevents microbes and moss from growing on them that destroy the leaves.

The tops of the trees are often very well interconnected with creepers or epiphytic plants attached to them.

The trees of the humid tropical forest are characterized by unusually thin (1-2 mm) tree bark, sometimes covered with sharp thorns or thorns, the presence of flowers and fruits growing directly on tree trunks, a wide variety of juicy fruits that attract birds and mammals.

Insects are very abundant in tropical rainforests, especially butterflies (one of the richest fauna in the world) and beetles, and fish are abundant in rivers (about 2000 species, approximately one third of the world's freshwater fauna).

Despite the stormy vegetation, the soil in tropical rainforests is thin and with a small humus horizon.

Rapid decay caused by bacteria prevents the accumulation of the humus layer. The concentration of iron and aluminum oxides due to laterization soil (the process of reducing the silica content of the soil with a simultaneous increase in iron and aluminum oxides) turns the soil bright red and sometimes forms deposits of minerals (for example, bauxite). But on rocks of volcanic origin, tropical soils can be quite fertile.

Tropical rainforest levels (tiers)

The rainforest is divided into four main levels, each of which has its own characteristics, has a different flora and fauna.

The topmost level

This tier consists of a small amount of very tall trees towering above the forest canopy, reaching a height of 45-55 meters (rare species reach 60-70 meters). Most often the trees are evergreen, but some shed their foliage during the dry season. Such trees must withstand harsh temperatures and strong winds. Eagles live on this level the bats, some species of monkeys and butterflies.

Crown level (forest canopy)

The crown level is formed by the majority of tall trees, usually 30-45 meters high. This is the densest layer known in all terrestrial biodiversity, with neighboring trees forming a more or less continuous layer of foliage.

According to some estimates, the plants of this tier make up about 40 percent of the species of all plants on the planet - perhaps half of the entire flora of the Earth can be found here. The fauna is similar to the upper level, but more diverse. It is believed that a quarter of all insect species live here.

Scientists have long suspected the diversity of life at this level, but only recently developed practical methods research. It wasn't until 1917 that the American naturalist William Bead stated that "another continent of life remains unexplored, not on Earth, but 200 feet above its surface, spreading over thousands of square miles."

True exploration of this layer only began in the 1980s, when scientists developed methods to reach the forest canopy, such as shooting ropes at the treetops with crossbows. The study of the forest canopy is still in progress. early stage. Other research methods include travel on balloons or aircraft. The science of access to the tops of trees is called dendronautics.

Average level

Between the forest canopy and the forest floor there is another level called the undergrowth. It is home to a number of birds, snakes and lizards. Insect life at this level is also very extensive. The leaves in this tier are much wider than at crown level.

forest floor

In Central Africa, in the tropical primary forest of Mount Virunga, the illumination at ground level is 0.5%; in the forests of southern Nigeria and in the area of ​​Santarem (Brazil) 0.5-1%. In the north of the island of Sumatra, in the dipterocarp forest, the illumination is about 0.1%.

Away from the banks of rivers, swamps and open spaces where dense undersized vegetation grows, forest floor relatively free from plants. On this level, rotting plants and animal remains can be seen, which quickly disappear due to the warm, humid climate that promotes rapid decomposition.

Selva(Spanish " selva" from lat. " silva"- forest) is humid equatorial forests in South America. It is located on the territory of countries such as Brazil, Peru, Suriname, Venezuela, Guyana, Paraguay, Colombia, etc.

Selva is formed on vast lowland areas of land under conditions of constant freshwater moisture, as a result of which the soil of the selva is extremely poor in minerals washed out by tropical rains. The selva is often swampy.

The flora and fauna of the selva is a riot of colors and a variety of species of plants, birds and mammals.

The largest selva in terms of area is located in the Amazon basin in Brazil).

In the Atlantic Selva, the level of precipitation reaches two thousand millimeters per year, and the humidity fluctuates at the level of 75-90 percent.

The selva is divided into three levels. The soil is covered with leaves, branches, fallen tree trunks, lichens, fungus and moss. The soil itself has a reddish color. The first level of the forest consists of low plants, ferns and grass. The second level is represented by shrubs, reeds and young trees. On the third level there are trees from twelve to forty meters high.

Mangroves - evergreen deciduous forests, common in the tidal strip of sea coasts in tropical and equatorial latitudes, as well as in temperate zones, where this is favorable warm currents. They occupy the strip between the most low level water at low tide and highest at high tide. These are trees or shrubs that grow in mangroves, or mangrove swamps.

Mangrove plants live in coastal sedimentary environments where fine sediments, often with a high organic content, accumulate in places protected from wave energy.

Mangroves have an exceptional ability to exist and develop in a salty environment on soils deprived of oxygen.

Once established, the roots of mangrove plants create a habitat for oysters and help slow down the flow of water, thereby increasing sediment deposition in areas where it is already occurring.

As a rule, fine, oxygen-poor sediments under mangroves play the role of reservoirs for a wide variety of heavy metals (traces of metals) that are captured from sea water by colloidal particles in sediments. In areas of the world where mangroves have been destroyed during development, the disruption of these sedimentary rocks creates the problem of heavy metal contamination of seawater and local flora and fauna.

It is often claimed that mangroves are of significant value in the coastal zone, acting as a buffer against erosion, the onslaught of storms and tsunamis. While there is some reduction in wave height and energy as seawater passes through mangroves, it must be recognized that mangroves usually grow in those areas of the coastline where low wave energy is the norm. Therefore, their ability to withstand the powerful onslaught of storms and tsunamis is limited. Their long-term impact on erosion rates is also likely to be limited.

The many river channels meandering through the mangroves actively erode the mangroves on the outside of all river bends, just as new mangroves appear on inside the same bends where precipitation occurs.

Mangroves are a habitat for wild animals, including a number of commercial species fish and crustaceans, while at least in some cases exports of mangrove carbon have importance in the coastal food web.

In Vietnam, Thailand, the Philippines and India, mangroves are grown in coastal areas for coastal fisheries.

Despite ongoing mangrove breeding programs, More than half of the world's mangroves have already been lost.

The floristic composition of mangrove forests is relatively uniform. The most complex, high and multi-species mangrove forests of the eastern formation (the shores of the Malay Peninsula, etc.) are considered.

Foggy forest (moss forest, nephelogilea) – humid tropical montane evergreen forest. It is located in the tropics on the slopes of mountains in the fog condensation zone.

The foggy forest is located in the tropics on the slopes of mountains in the fog condensation zone, usually starts from an altitude of 500-600 m and reaches a height of up to 3500 meters above sea level. It is much cooler here than in the jungle, located in low-lying places, at night the temperature can drop to almost 0 degrees. But here it is even more humid, for one year square meter up to six cubic meters of water falls. And if it doesn't rain, then the moss-covered trees stand shrouded in fog caused by intense evaporation.

Foggy forest formed by trees with abundant vines, with a dense cover of epiphytic mosses.

Tree-like ferns, magnolia, camellia are characteristic, the forest may also include non-tropical vegetation: evergreen oaks, podocarpus, which distinguishes this type of forest from plain hyla

Variable rainforests- forests common in tropical and equatorial zones, in a climate with a short dry season. They are located south and north of the humid equatorial forests. Variable rainforests found in Africa (CAR, DR Congo, Cameroon, northern Angola, extreme south of Sudan), South America, India, Sri Lanka, Indochina.

Variable rainforests are partially deciduous dense rainforests. They differ from tropical rainforests in lower species diversity, a decrease in the number of epiphytes and lianas.

Dry tropical evergreen forest. They are located in areas with an arid climate, while remaining dense and evergreen, becoming stunted and xeromorphic.

HUMAN IMPACT ON TROPICAL FORESTS

Contrary to popular belief, tropical rainforests are not major consumers of carbon dioxide and, like other established forests, are neutral to carbon dioxide.

Recent studies show that most rainforests, on the contrary, are intensively produce carbon dioxide, and swamps produce methane.

However, these forests play a significant role in the turnover of carbon dioxide, since they are its established basins, and the cutting down of such forests leads to an increase in the carbon dioxide content in the Earth's atmosphere. Tropical rainforests also play a role in cooling the air that passes through them. So tropical rainforests - one of the most important ecosystems of the planet, the destruction of forests leads to soil erosion, the reduction of species of flora and fauna, shifts in the ecological balance in large areas and on the planet as a whole.

Tropical rainforests often reduced to plantations of cinchona and coffee trees, coconut palms, and rubber plants. In South America, tropical rainforests are also seriously threatened by unsustainable mining.

A.A. Kazdym

List of used literature

  1. M. B. Gornung. Constantly humid tropics. M.:, "Thought", 1984.
  2. Hogarth, P. J. The Biology of Mangroves. Oxford University Press, 1999.
  3. Thanikaimoni, G., Mangrove Palynology, 1986
  4. Tomlinson, P. B. The Botany of Mangroves, Cambridge University Press. 1986:
  5. Jayatissa, L. P., Dahdouh-Guebas, F. & Koedam, N. A review of the floral composition and distribution of mangroves in Sri Lanka. Botanical Journal of the Linnean Society, 138, 2002, 29-43.
  6. http://www.glossary.ru/cgi-bin/gl_sch2.cgi?RSwuvo,lxqol!rlxg

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Tropical rainforests stretch over large areas on both sides of the equator, but do not go beyond the tropics. Here the atmosphere 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 heat and moisture, everything here grows with remarkable speed. Spring and autumn are imperceptible in these forests. All year long, some trees and shrubs bloom in the forest, others fade. It is summer all year round and the vegetation is 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, palm trees, some types of coffee trees, which, over many square kilometers, bloom all at once in one day. This amazing phenomenon makes a stunning impression of the beauty of flowering and aromas.

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

If you look at the rainforest from above, from an airplane, 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 uniformly green, only with the advent of autumn 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 spots of flowering crowns.

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

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

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

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

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

Giant columns need good foundations, like buttresses (slopes) of ancient buildings. And nature took care of them. Ficuses grow in the African equatorial forests, from lower parts trunks of which develop additional - plank - roots up to a meter or more in height. They hold the tree firmly against the wind. Many trees have such roots. On the island of Java, residents make table covers or cart wheels from plank roots.

Trees of smaller height, four or five tiers densely grow between giant trees, bushes even lower. Fallen trunks and leaves rot on the ground. The trunks are twined with vines.

Hooks, spikes, mustaches, roots - by all means, creepers cling to tall neighbors, twist around them, crawl along them, use devices known to the people as "devil's hooks", "cat's claws". They intertwine with each other, sometimes merging into one plant, then separating again in an unstoppable desire 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, through the valleys of the Amazon, in virgin tropical rainforests creepers, like ropes, are thrown from one tree to another, climb up the trunk to the very top and settle comfortably in the crown.

Fight for the world! In a tropical rainforest, there are usually few grasses on the soil, and shrubs are also few in number. Everything that lives must receive some share of the light. And many plants succeed in this because the leaves on the trees are almost always located vertically 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 impacts of rain showers. Yes, and 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, fungi would populate them immediately.

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

Many tropical plants have nothing to do with the soil at all. These are epiphyte plants - lodgers. They don't need soil. Trunks, branches, even tree leaves give them an excellent shelter, and everyone has enough heat and moisture. In the axils of the leaves, in the crevices of the bark, a little humus forms between the branches. Wind, animals will bring seeds, and they germinate and develop perfectly.

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

In the Botanical Gardens in Calcutta, they show such a huge fig tree that they mistake it for a whole grove. Its branches have grown above the ground in the form of a green roof, which is supported on 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 entwined her with her roots and strangled her.

The position of epiphytes is very advantageous compared to 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 "host" trunk and take away the sun's rays from it. The "owner" dies, and the "tenant" becomes independent.

Tropical forests are best described by the words of Charles Darwin: "The greatest sum of life is carried out with the greatest variety of structure."

Some epiphytes have thick fleshy leaves, some swellings on the leaves. They have a supply of water - in case it is not enough.

In others, the leaves are leathery, hard, as if varnished, as if they lack moisture. The way it is. In the hot time of the day, and even with a strong wind, in a highly raised crown, the evaporation of water increases sharply.

Another thing is the leaves of shrubs: they are tender, large, without any adaptations to reduce evaporation - in the depths of the forest it is small. Herbs are soft, thin, with weak roots. There are many spore plants, especially ferns. They spread their sheets on the edges of the forest and in rare lighted clearings. It's bright in here flowering shrubs, large yellow and red cannes, orchids with their intricately arranged flowers. But grasses are much less diverse than trees.

General green tone herbaceous plants pleasantly interspersed with white, red, gold, silver leaf spots. Whimsically patterned, they are not inferior in beauty to the flowers themselves.

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

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

In the rainforests of America, tiny hummingbirds in brilliant plumage hover over flowers for a long time, licking 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 that pollinate vines with brightly colored flowers.

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

In the equatorial humid forests, swamps are often found, flowing lakes come across. The animal world here is very diverse. Most animals live on trees, eating fruits.

Tropical forests of different continents have many common features and at the same time each one is different from the others.

There are many trees in the Asian forests with valuable timber, plants that give spices (pepper, cloves, cinnamon). Monkeys climb in the crowns of trees. An elephant roams on the outskirts of the tropical thicket. Rhinos, tigers, buffaloes, poisonous snakes live in the forests.

The humid equatorial forests of Africa are famous for their impenetrable thickets. Without an ax or a knife, it is impossible to make your way here. And there are many tree species with valuable wood. The oil palm tree is often found, from the fruits of which oil, coffee tree and cocoa are extracted. In places in narrow hollows, where fogs accumulate and mountains do not let them go, tree-like ferns form whole groves. Heavy dense fogs slowly creep up and, cooling down, pour heavy rains. In such natural greenhouses, spores feel the best: ferns, horsetails, club mosses, curtains of delicate green mosses descend from the trees.

Gorillas and chimpanzees live in African forests. Monkeys tumble in the branches; baboons bark in the air. There are elephants, buffaloes. Crocodiles prey on all kinds of animals in the rivers. Frequent encounters with a hippopotamus.

And everywhere mosquitoes, mosquitoes fly in clouds, hordes of ants crawl. Perhaps even this "little thing" is more noticeable than large animals. It disturbs the traveler at every turn, 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 serve as 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 seeds, leaves, berries and seeds onto branches and trunks along with earth. Of these, young plants sprout, fastening the earth in the nest with roots and immediately receiving soil and fertilizers.

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 droves. Having cut pieces from the leaves, they put them on their backs and move in continuous green streams to the nests, baring the branches,

Fortunately, other types of ants can settle on plants, which destroy these robbers.

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

Vast flat expanses, regularly flooded with water during the flood of rivers, are covered with coastal forests. Above the flood line stretch huge virgin forests. And the drier regions are occupied by forests, although less dense and lower.

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

Palm trees give a lot to people: the fruits are used for food, the locals get fibers 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. Hanging from trees and bushes are green garlands of climbing and climbing herbaceous plants, colored bright flowers. Passion flowers, begonias, "beauties of the day" and many other flowering plants form draperies on the trees, as if laid out by the artist's hand.

Beautiful myrtle, brazil nuts, flowering ginger, cannes. Ferns and graceful feathery mimosas support the overall green tone.

In the forests above the flood line, the trees are perhaps the tallest of all tropical representatives, stand in a tight close formation on props. Notable among these are the Brazil nut and the mulberry cotton plant, with its enormous plank poles. Laurels are considered the most beautiful trees in the Amazon. There are a lot of acacias from legumes, a lot of aroids. Philodendron and monstera are especially good with fantastic cuts and cuts on the leaves. There is often no undergrowth in this forest.

In less tall, unflooded forests, lower tree tiers of palms, shrubs and low trees appear, sometimes very dense and almost impassable.

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

Almost the entire Amazonian lowland and part of the northern and east coasts The mainland is occupied by moist forests.

flat heat and the abundance of precipitation make all days look like one another.

Early in the morning the temperature is 22-23°, the sky is cloudless. The leaves are dewy and fresh, but the heat is rising rapidly. By noon and a little later, it is already unbearable. Plants drop leaves and flowers and seem to be completely wilted. No air movement, the animals hid. But now the sky is covered with clouds, lightning flashes, thunder is deafening.

Crowns are shaken by sharp gusts of wind. And the blessed downpour enlivens all nature. It floats strongly in the air. A sultry, hot, and damp night sets in. Leaves and flowers plucked by the wind fly.

A special type of scaffolding covers in tropical countries 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, bays. The soil here is a swamp with black, foul-smelling silt; in it, with the participation of bacteria, the rapid decomposition of organic substances takes place. At high tide, such thickets appear to emerge from the water.

With the ebb, their so-called roots are exposed - stilts, which stretch far along the silt. From the branches in the silt there are still roots-props.

Such a system of roots well establishes the trees in silty soil, and they are not carried away by the tide.

Mangroves push the coast to the sea, because plant residues accumulate between the roots and trunks and, mixing with silt, gradually form 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, at other times they resemble a bent pipe or stick out of the silt like young stems.

The method of reproduction found in mangroves is curious. The fruit is still hanging on the tree, and the embryo is already sprouting in the form of a long, up to 50-70 centimeters, pin. 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 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. All these are signs of plants of 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, with its saturation 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 exceptionally great, and it is achieved primarily by the fact that the use of space by plants has been brought here by natural selection to the extreme limits.

In the equatorial belt, encircling the entire Earth on both sides of the equator, evergreen, constantly humid tropical forests dominate for thousands of kilometers. These forests are better known to us under the capacious and sonorous name - the jungle. From the Hindi language, the word "jungle" is translated as "dense thickets" or simply "forest".

Jungles occupy vast expanses of Equatorial Africa, Central and South America, southwest coast India, the Indochina peninsula, the islands of Indonesia, the Greater Sunda and Philippine Islands, part of the island of New Guinea.

The equatorial belt of solar energy and heat receives more than other belts of the Earth. Precipitation here falls from 1,500 to 12,000 mm per year. It rains in the afternoon, and most often it is the strongest downpours - a solid wall of water. The air is saturated with water vapor and therefore relative humidity its very high - 80-90%, which at constantly high temperatures (average annual +24 ... +28 ° С with fluctuations between the warmest and coldest month at 2-3 ° С) creates excessive moisture. The air is humid and warm, so it is difficult to breathe, as in the steam bath. There is no cooling evaporation, not even a slight breeze, and the heat of the day does not subside even at night.

Dense vegetation interferes with normal air circulation, and this contributes to the formation of hot and thick, like cotton wool, surface fogs. There is constant damp twilight here, as the dense crowns of trees prevent the sun's rays from penetrating into the soil and drying it out.

As a result of strong putrefactive processes in fallen leaves, the percentage of carbon dioxide in the surface layers sharply increases. Therefore, there is not enough oxygen in the rainforest, and a person who got there constantly complains of suffocation.

Ancient evergreen forests are distinguished by splendor, density, diversity and richness of species composition. The evergreen vegetation of the permanently humid tropical forest consists of several tiers. The first tier is giant trees 30-50 m high with smooth trunks without knots and a wide crown. In the second layer, the trees are 20-30 m high, and the third consists of various palms from 10 to 20 m high. The fourth layer is an undergrowth of bamboo, shrubs, ferns and club mosses. All this wraps around an incredible number of vines intertwined with each other, forming a continuous green, almost impenetrable network.

Tropical rainforests are divided into primary and secondary. The primary rainforest is quite passable, even though there is a wide variety of woody vegetation and vines. But the secondary forests, located along the banks of rivers and in places of frequent fires, form impenetrable thickets from a chaotic heap of bamboo, grasses, various shrubs and trees intertwined with numerous lianas. In the secondary forest, layering is practically not expressed. Here at a great distance from each other grow huge trees, which rise above the lower overall level of vegetation. Such forests are widespread throughout the humid tropics.

The fauna of the constantly wet evergreen tropical forests is very diverse. Of the large mammals, there are many elephants, hippos, crocodiles. Lots of birds and various insects. However, in each specific tropical zone different continents both flora and fauna sometimes differ significantly from each other. Therefore, it is advisable to consider these territories separately, taking into account their potential danger to a person who finds himself in an extreme situation.

The amazing exotic world of the equatorial forest is a rather rich and complex ecosystem of our planet in terms of vegetation. It is located in the hottest climate zone. Trees grow here with the most valuable wood, miraculous medicinal plants, bushes and trees with exotic fruits, fabulous flowers. These areas, especially forests, are difficult to pass, so their fauna and flora are not well understood.

The plants of the equatorial forests are represented by at least 3,000 trees and more than 20,000 flowering plant species.

Distribution of equatorial forests

Equatorial forests occupy a wide strip of territories of different continents. The flora here grows in rather humid and hot conditions, which ensures its diversity. A huge variety of trees of various heights and shapes, flowers and other plants are wonderful world forests stretching in the zones of the equatorial belt. These places are practically untouched by man, and therefore look very beautiful and exotic.

Moist equatorial forests are found in the following parts of the world:

  • in Asia (Southeast);
  • in Africa;
  • In South America.

Their main share falls on Africa and South America, and in Eurasia they are found to a greater extent on the islands. Unfortunately, the increase in clearing areas drastically reduces the area of ​​exotic vegetation.

Equatorial forests occupy large areas of Africa, South and Central America. The jungle covers the island of Madagascar, the territory of the Greater Antilles, the coast of India (southwest), the Malay and Indochina peninsulas, the Philippine and large Zand Islands, most of Guinea.

Characteristics of tropical moist (equatorial) forests

The humid tropical forest grows in subequatorial (tropical variable-humid), equatorial and tropical regions with a rather humid climate. The annual rainfall is 2000-7000 mm. These forests are the most common of all tropical and rainforests. They are characterized by great biodiversity.

This zone is the most conducive to life. Plants of equatorial forests are represented by a huge number of their own, including endemic species.

Evergreen moist forests stretch in patches and narrow bands along the equator. Travelers of past centuries called these places green hell. Why? Because high multi-tiered forests stand here as a solid impassable wall, and under the dense crowns of vegetation, dusk, high temperature, and monstrous humidity constantly reign. The seasons are indistinguishable here, and terrible downpours with huge streams of water constantly fall. These areas at the equator are also called permanent rain.

What plants grow in equatorial forests? These are habitats for more than half of all plant species. There are suggestions that millions of species of flora have not yet been described.

Vegetation

The flora of the equatorial forests is represented by a huge variety of plant species. The basis is trees growing in several tiers. Their powerful trunks are entwined with flexible vines. They reach a height of up to 80 meters. They have a very thin bark and you can often see fruits and flowers right on it. Various types of palms and ficuses, ferns and bamboo plants grow in the forests. In total, about 700 species of orchids are represented here.

Coffee and banana trees grow here, cocoa (the fruits are used in medicine, cosmetology and cooking), hevea brazilian (from which rubber is extracted), oil palm (oil is produced), ceiba (seeds are used in soap making, and fiber is used from its fruits, used for stuffing furniture and toys), ginger plants and mangrove trees. All of the above are plants of the highest tier.

The flora of the forests of the equatorial lower and middle tiers is represented by lichens, mosses and mushrooms, grasses and ferns. Reeds grow in places. Shrubs are practically non-existent here. These plants have very wide foliage, but as growth increases, the width decreases.

Average monthly temperatures are +24...+29 °C. annual temperature fluctuations do not exceed 1-6 °C. Total solar radiation for the year is more than indicators middle lane 2 times.

Relative humidity is quite high - 80-90%. Up to 2.5 thousand mm of precipitation falls per year, but their amount can reach up to 12 thousand mm.

South America

Equatorial rain forests of South America, especially on the banks of the river. Amazons - 60-meter-high deciduous trees intertwined with dense shrubs. Epiphytes are widely developed here, growing on mossy branches and tree trunks.

In such not very comfortable conditions of the jungle, all plants, as best they can, are fighting for survival. They are drawn to the sun all their lives.

Africa

Plants of the equatorial forests of Africa are also rich in a variety of growing species. Precipitation falls evenly throughout the year, and they amount to more than 2000 mm per year.

The zone of equatorial moist forests (otherwise hyla) occupies 8% of the entire territory of the mainland. This is the coast of the Gulf of Guinea and the river basin. Congo. Ferrallitic red-yellow soils are poor in organic matter, but a sufficient amount of moisture and heat contributes to good development vegetation. In terms of the richness of plant species, African equatorial forests are second only to the humid zones of South America. They grow in 4-5 tiers.

The upper levels are represented by the following plants:

  • giant ficuses (up to 70 meters tall);
  • wine and oil palms;
  • ceiba;
  • cola.

Lower tiers:

  • ferns;
  • bananas;
  • coffee trees.

Among the vines interesting view is landolphia (rubber liana) and rattan (palm liana growing up to 200 meters in length). The last plant is the longest in the whole world.

There are also iron, red, black (ebony) trees, which have valuable wood. Lots of mosses and orchids.

Flora of Southeast Asia

A huge number of palm trees (about 300 species), tree ferns, ramps and bamboos grow in the equatorial zone of Asia. The vegetation of the mountain slopes is represented by mixed and coniferous forests at the foot and juicy alpine meadows on the tops.

Tropical humid zones of Asia are characterized by abundance and species richness. useful plants, cultivated not only here at home, but also on many other continents.

Conclusion

You can talk about the plants of the equatorial forests indefinitely. This article was aimed at making readers at least a little familiar with the peculiarities of the living conditions of representatives of this amazing world.

The plants of such forests are of great interest not only to scientists, but also to ordinary travelers. These exotic places attract attention with their unusual, diverse flora. The plants of the forests of equatorial Africa and South America are not at all like flowers, herbs, trees, familiar to all of us. They look different, and bloom unusually, and the aromas from them come completely different, therefore they arouse curiosity and interest.