Tropical rainforests of all types are similar not only in ecology, but also in general appearance. The trunk of the trees is slender and straight, the root system is superficial. A characteristic feature of many breeds are board-shaped or stilted roots. The bark is usually light and thin. Trees do not have growth rings, their maximum age is 200-250 years. The crowns are small, branching begins closer to the top. The leaves of most trees are medium in size, leathery, often very hard. Many species (about 1000) are characterized by caulifloria - the formation of flowers, and then fruits on trunks and thick branches. Flowers are usually inconspicuous. The vertical structure of the forest is also peculiar. The tree stand forms a continuous canopy at a height of about 35 m. Individual very tall (up to 80 m) emergent trees rise above it.
The canopy itself is not divided into tiers, the trees that form it have different heights and fill the entire vertical space. The reasons for the poor pronounced layering are the optimal growth conditions and the antiquity of this biocenosis: for a long time, trees of different species have adapted to living together. The number of species of woody plants capable of growing together is large: several tens and possibly hundreds of species can form one association. The shrub layer is absent, the undergrowth is represented by low trees.
Tropical forest animals. Description, names and features of rainforest animals
At the same time, very similar habitat conditions led to the fact that a single type of fauna developed in these disparate territories.
These forests have the greatest biological diversity: over 50% of all species of all life on our planet live here. The main reason for such diversity and richness of nature is the optimal temperature and humidity for life. During the dry season (winter), many trees shed their leaves. Soils are predominantly red. Despite the lush vegetation, the quality of the soil in such forests leaves much to be desired. Rapid decay caused by bacteria prevents the accumulation of the humus layer. The concentration of iron and aluminum oxides due to laterization of the soil (the process of reducing the silica content in the soil with a simultaneous increase in iron and aluminum oxides) stains the soil bright red and sometimes forms deposits of minerals (for example, bauxite).
On young formations, especially of volcanic origin, soils can be quite fertile. Tropical rainforests, evergreen, multi-tiered, impenetrable, are distinguished by an abundance of species, many extra-tiered plant species (lianas and epiphytes). Trees in such forests are slender, reach a height of 80 m and 3-) I in diameter, with underdeveloped bark (smooth, shiny, often green), sometimes with plank-like roots at the base of the trunks. The leaves of the trees are large, leathery, shiny. Trunks of trees are usually densely entwined with vines, which create impenetrable "webs" in tropical forests. The herbaceous cover in humid tropical forests is absent and is developed only along the edges and clearings. Let's bring short description tropical forest on the island of Sumatra according to W. Foltz. “Tall trees are mixed with low ones, thin ones with thick ones, young ones with ancient ones. They grow in tiers, reach a height of 70-80 m or more. Walking through the forest, it is difficult to realize their colossal growth.
Only when a river, meandering through the forest, opens up a gap above, or a tree, falling, makes a hole in the thicket, do you get an idea of the height of the trees. The trunks, towering in slender columns, are so wide that five or six people can hardly clasp them. As far as the eye can see, there is not a single knot, not a single branch on them, they are smooth, like the masts of a monstrous ship, and only at the very top are crowned with a leafy crown. Some trunks, dissected, begin to grow downward again and, leaning on bunched roots, form huge niches ... The leaves are breathtakingly heterogeneous: some are delicate, thin, others are rough, similar to plates; some are lanceolate, others are sharp-toothed. But all have a common feature - all are dark green in color, thick and shiny, as if leather. The ground is densely overgrown with shrubs... It is impossible to get through the dense thicket without the help of a knife. Not surprisingly, most of the soil in the forest is bare and covered with rotten leaves. Dense grass can be seen very rarely, more often mosses, lichens and flowering weeds. The slightest gaps between the trunks are filled with creepers and creepers.
From branch to branch, from trunk to trunk, they stretch, crawl into every crack, rise to the very tops. They are thin, like threads, barely covered with leaves, thick, like ropes, like elastic trunks. They hang from the trees in knots and loops, tenaciously twist the trees in narrow spirals, squeeze them so tightly that they choke them, and, digging deep into the bark, doom them to death. Creeping plants weaved twigs, trunks and branches with solid green variegated carpets. The vegetation of tropical forests on different continents is very different. The tropical rainforests of Africa, for example, are characterized by trees from the legume, combrete, pineapple, and other families. In the undergrowth, there is a coffee tree, as well as medicinal liana - strophanthus, rubber-bearing landolphia, and from epiphytes - ferns. Oil palm, aleurites are widespread; from vines - rattan palm, clematis, jasmine, sarsaparilla, tekoma; from epiphytes - different types orchids and ferns. In the endless sea of green tropical forests, rich in juicy and tasty fruits, there are many extremely diverse animals.
From a gigantic elephant to a barely noticeable insect - everyone finds shelter, comfort and food here.
Geographic distribution of tropical rainforests
In the equatorial regions, where at least 400 mm of precipitation falls and high temperatures are maintained, the richest tropical rainforests are common. In Africa, tropical rain forests grow along the shores of the Gulf of Guinea to the mountains of Cameroon. In Africa, in the western tropical region, moist equatorial evergreen forests are most valuable. They are concentrated in two large areas along the shores of the Gulf of Guinea and occupy the southwestern and southern parts of the territories of Senegal, Gambia, Guinea-Bissau, Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Togo, Benin, Nigeria, Comeroon, Central African Republic, as well as the northern parts of the Congo, Zaire and Angola. According to the studies of A. Obreville, virgin evergreen forests have survived only in the hard-to-reach mountainous regions of Cameroon, in the basins of the upper tributaries of the Congo (Zaire) far from roads. In South and Central America - in the river basin. Amazons. Tropical rain forests are common in the equatorial belt, as well as north to 25 ° N. and south to 30°S.
The largest tropical rainforests are common in the Amazon River basin (Amazonian rainforest or selva), in Central America from Colombia to the south of the Yucatan Peninsula, in the West Indies and some areas in the United States, in equatorial Africa from Cameroon to the Democratic Republic of the Congo, in many areas of Southeast Asia from Myanmar to Indonesia and Papua New Guinea, in the east of Queensland in Australia.
In Asia, these forests are distributed along the valleys of the Ganges and Bramaputra rivers, along the eastern coast of the Bay of Bengal, on the Malay Peninsula, on the islands of Ceylon, Sumatra and Java. In Australia, tropical rainforests are found along the Pacific coast. On the Australian mainland, tropical rainforests grow only north of 20°S, occupying the largest area on the east coast of the Cape York Peninsula, where heavy and regular precipitation falls.
In the north of Australia, along the river valleys, tropical rainforest penetrates into the area of \u200b\u200bdistribution of savannahs and light forests covering watersheds.
Landscape Formation Factors in Equatorial Humid and Permanently Humid Tropical Forests
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 on long distance huge trees grow from each other, which rise above the lower general level vegetation. Such forests are widespread throughout the humid tropics.
Tropical rainforests are characterized by the following geochemical landscape classes:
- sour;
- acidic gley (forest swamps-lapaks);
- sulfate (on rocks with sulfides heavy metals);
- calcium (margalite landscapes) - on calcium-bearing rocks;
- saline-sulfide (mangroves) - brackish water coastal forest swamps.
Acidic rainforest landscapes are the most common. These landscapes are formed on watershed surfaces composed of igneous, metamorphic and sedimentary silicate rocks. Due to the decomposition of a large mass organic compounds soil waters are enriched with CO2 and organic acids. There are not enough cations to neutralize them, ground and soil waters are acidic and vigorously weather rocks, leaching mobile compounds to great depths. Calcium, sodium, magnesium and potassium are removed from soils and weathering crust, rare alkalis are also leached - lithium, barium, strontium, cesium. As a result, they are relatively enriched in elements that are inert in a given environment - iron, aluminum, residual quartz and rare elements from the group of inert ones - tantalum, rare earths, zirconium. Very little calcium - 0.1%. Soils acquire a characteristic red, orange color.
On flat plains, where the infiltration of atmospheric waters is slow and their stagnation is possible, gleying processes develop and redox zoning occurs: the red oxidation zone is replaced downward by a white or variegated gley zone. In relief depressions, in the lower parts of slopes, river valleys and lake basins, groundwater stagnates close to the surface and superaquatic landscapes are formed - forest swamps with acidic gleying (H-Fe - class). Tropical swamps have a low pH - less than 4 (up to 2), they contain a concentration of siderite and other iron minerals. Moist equatorial forests develop in a humid greenhouse climate, which is characterized by a constant abundance of moisture and an even temperature background. Solar radiation is reduced due to thick cloud cover, but the radiation balance is high. Part of the radiation balance is spent on evaporation. The average monthly temperature is 27-28 C, the daily amplitude is 10-12 rad.
The average annual rainfall is high, reaching 1000-1200 mm or more. Differs in uniform distribution. Humidity is also very high, 60-70%, (especially under the forest canopy). Tropical rainforests, like no other landscape, change climatic conditions, forming their own phytoclimate under the forest canopy. Lighting is less than 1% of the daily value. Forests are saturated with phytoncides. The air contains a lot of gaseous decay products. Up to 50-70% of precipitation is spent on runoff, the annual layer of which is more than 1000 mm. The river network is dense, the rivers are full-flowing with an even regime. The activity of denudation processes is restrained by forest vegetation. The stable hydrothermal regime during the last geological periods with an abundance of heat contributed to the formation of a thick 15-40 (up to 120 m) acidic ferralitic weathering crust. Yellow and red-yellow ferralitic soils are formed on it, they are characterized by: (small humus content, strong leaching, acid reaction, lack of Ca, P, K, accumulation of Fe and Al sesquioxides. Soils have a poorly differentiated profile and clay composition.
Formed by evergreen large-leaved trees, tropical rainforests are distinguished by an amazing density and diversity of the floristic composition of tree species. In Kalimantan, at least 10-11 thousand species of plants are known, in Malacca - about 7.5 thousand. In total, there are up to 40 thousand species of higher plants. In a systematic sense, the trees of the humid tropical forest are mainly represented by legumes, myrtle, malgipium, palm trees and tree ferns are also found. The abundance of vines and epiphytes is combined with the absence or weak development of grass cover, the trees form up to 5 tiers, the top of which has a height of 35-45 m, but some reach 60 m in Eurasia, up to 80 m in Africa, in South America- up to 90 m. The upper tier is not closed, they begin to branch at a height of 25-30 m, the branches do not grow horizontally, but stretch upwards. Trees have plank roots. Trees of the middle tier form a continuous canopy of narrow closed crowns at a height of 20-40m.
It is dominated by fast-growing species with soft wood. The lower tier is represented by slow-growing shade-tolerant trees 10-15 m high, often with hard and heavy wood - ebony, sandalwood, rubber trees, oil and wine palms, coffee trees (Africa).
In South America, the lower layer is represented by dense, up to 2-4 m high thickets of pineapple, banana ferns and other plants. The equatorial forest zone is a natural zone of the equatorial belt, in the natural landscapes of which forests predominate. It occupies mainly lowlands on both sides of the equator (in the Amazon basin, in Equatorial Africa, on the islands of the Malay Archipelago and in New Guinea). Characterized by a little changing day length, the absence of seasonal rhythms of the development of nature, the equatorial climate, a powerful weathering crust. Dense evergreen forests with a rich species composition, an abundance of palm trees, lianas and epiphytes. In the outer parts of the zone, there are forests with an admixture of deciduous trees. Two subzones are sometimes distinguished in the hyla zone: permanently humid equatorial forests and equatorial forests with a short (2-3 months) dry period; the latter is common in the outer (from the equator) parts of the belt and in the eastern sectors that fall under the influence of continental trade winds. Chemical composition tropical plants is very specific.
More carbohydrates accumulate in the tissues of plants in the tropics than in plants of the temperate zone. An abundant accumulation of carbohydrates is known in the trunk of the sago palm, in the fruits of bananas, breadfruit. There are few proteins in the seeds and fruits of tropical plants. Plants of autonomous landscapes contain few mineral substances, the ash content of growth ranges from 2.5 to 5% (in the taiga 1.6-2.5%). In the leaves of tropical trees, among water migrants, silicon occupies the first place - in bamboos, the ash contains up to 90% silicon dioxide. Therefore, tropical rainforests are classified as silicon-type chemistry. The humid and hot climate determines the very rapid decomposition of plant residues and the intensive removal of the main biophilic elements: potassium, silicon, calcium against the background of the relative accumulation of iron and manganese.
The most important water migrants of the BIC (biochemical cycle) are silicon and calcium, the second group includes potassium, magnesium, aluminum, iron, and the third group includes manganese and sulfur. Above-ground parts of plants can absorb ammonia and nitrogen oxides released by above-ground vegetation and entering the surface atmosphere. Under the forest canopy, an almost closed circulation of gaseous nitrogen compounds is thus created. The ground waters of tropical rainforest landscapes belong to the gley class, they are enriched in iron and manganese migrating in the form of bicarbonates or organic complexes. In places where such waters come to the surface or where they meet with oxygenic waters, an oxygen geochemical barrier arises, on which iron hydroxides are deposited and the famous cuirasses (iron shell) are formed. Although the plants of the humid tropics contain a lot of iron, but people do not absorb this element from plant foods well, therefore anemia caused by a lack of iron in food is widespread in these landscapes. The lack of calcium probably affects the growth of animals. So, the okapi in equatorial Africa has a height of 1.5-2 m, and the giraffes of the savannas (calcium landscapes) related to it are about 6 m. The hippopotamus is 1.5 in length, and in the savannas - 4 m. , chickens, dogs, other wild and domestic animals. Thus, there is an adaptation of organisms to calcium deficiency. But due to the large amount of ultraviolet radiation, the formation of vitamin D occurs in sufficient quantities and calcium and phosphorus are fixed in the body and rickets is rare. Another adaptation to calcium deficiency is "calcephobia" in a number of plants. These plants are content with very small amounts of calcium and avoid soils containing a lot of calcium (eg tea).
Peculiarities natural conditions tropical rainforest regions
Tropical rainforests are found mainly on both sides of the equator. They cover vast territories - especially in South America, Southeast Asia and Africa. The largest of these areas is the lowlands of the Amazon basin and its tributaries. This vast area, which Alexander Humboldt called hylaea (a forested area), is considered a kind of model, a model of a tropical rainforest. From west to east it stretches for 3600 km, and from north to south - for 2800 km. Another major area of tropical rainforest is on the east coast of Brazil. In Asia, tropical rainforest extends from Burma and Thailand through Malaysia, Indonesia and the Philippines to northern Australia. In Africa, a continuous array of such forests stretches along the coastal territories from Guinea to the mouth of the Congo. It is very difficult for people who are accustomed to the changes of the seasons to imagine that somewhere on Earth there are places where winter and summer, autumn and spring do not exist. Meanwhile, the tropical rainforest is just such a place. Unusually even, slightly fluctuating temperatures throughout the year, as well as abundant rainfall, the amount of which almost does not change regardless of the seasons - these are the conditions in which tropical rainforests grow. However, it would be misleading to believe that the climate in these areas is extremely hot. The absolute temperature maximums (their highest marks) are between 33º and 36° С, i.е. barely exceed those characteristic of our middle latitudes. But it is especially characteristic that here throughout the year the average monthly temperatures remain practically unchanged: 24 ° - 28 ° C. Almost the same can be said about precipitation. Near the equator there are no seasonal differences in the length of the day, where every morning the sun rises at about 1 o'clock and rises in a brilliant blue sky to the zenith. In the morning, cumulus clouds appear, and then, usually in the afternoon, a thunderstorm breaks out with heavy rain.
Soon the sky clears again, the sun shines brightly, and the temperature rises. Such a change of weather can be repeated again before sunset, which at about 6 pm quickly slides below the horizon. And so day after day, almost without exception, every month, every year. Tropical rainforest soils are the "patriarchs" of soils, exceptionally ancient formations that often date back to the Tertiary period. For thousands of years, water, air, plant roots and the paws of animals have destroyed parent rocks. Hence such a high degree of their destruction: the thickness of the layer ground by them (weathering crust) in some places reaches 20 meters. Plentiful rains combined with year-round warmth contribute to the instant washing out of part of the chemical substances from the soil, as a result of which the soil is saturated with iron oxides. The fauna of the humid equatorial forests is distinguished by a huge variety of species. For example, in the African rain forest, the main life is concentrated in the crowns of trees, and animals live on different "floors" without interfering with each other. Termites, ants and other insects live in all tiers. Loose soil and forest floor contain many invertebrates and shrews. In the terrestrial layer, snakes, lizards, and rodents are found; among mammals, the brush-eared pig, African deer, and duikers are common. On the edges of the forest there is a relative of the giraffe - okapi. Great apes live here - gorillas and chimpanzees, and from large predators - only a leopard. Colobus monkeys, monkeys, rodents (spintails, squirrels, dormice), bats (bats) and birds (bananas, turaco, hornbills) live in the crowns of trees. Many species of frogs, geckos, chameleons and snakes find shelter in a dense mass of foliage and epiphytes. Sunflowers flutter among flowering plants. The crowns of the trees are inhabited by viverras and mongooses, ants and termites are hunted by tree pangolins. The African oil palm, up to 30 m high, is the most productive of all oil plants in the world.
Sunbirds - very small birds (weighing up to 20 g) - have an arched beak that helps them extract nectar and pollen from flowers. They live in tropical forests and savannahs of the Eastern Hemisphere, and hummingbirds similar to them live in the Western Hemisphere.
Tropical rainforest, or hylaea, which is not entirely correct for us to call the jungle. They stretch in a wide ribbon along the equator and once circled the world, and now they are preserved mainly in the Amazon basin, in Central America, on some islands of the Caribbean Sea, in the Congo basin, on the coast of the Gulf of Guinea, on the Malay Peninsula, in New Guinea, Sunda , Philippine and some other islands of the Indian and Pacific Oceans.
Remains of the hylaea still exist in East India, Indo-China and Sri Lanka.
Tropical rainforests have a very constant climate. The most remarkable feature of these forests is high humidity. It is created by daily rains, in other places bringing up to 12 meters of annual precipitation. This is a lot. After all, the plants growing here are able to assimilate only from 1/12 to 1/6 of the water falling on the forest. Part of the precipitation is temporarily accumulated in the axils of the leaves, various epiphytes and mosses. The rest of the moisture leaves the trees evaporate into the air, or it goes deep into the soil.
Usually in the morning the jungle is enveloped in thick fog. Only about nine o'clock the sun's rays drive him off the "forest roof" and disperse the clouds. It was then that many animals rise into the crowns to take a sunbath, which is so necessary for most inhabitants of the forest jungle.
In the Asian jungle, the great apes-gibbons, living in small families, are the first to appear here. Sitting on the branches facing the sun, resting their heads on their knees and, just in case, clinging their hands to the nearest branches, they begin their amazing morning choral singing. Both respectable heads of families and foolish children take part in the concert. Monkeys sing selflessly and often bring themselves to ecstasy. Hymns to the sun sound for 1.5-2 hours. When it gets hot, gibbon families hide in the dense foliage.
Under the burning rays of the sun, evaporation rapidly increases, the humidity of the air above the forest canopy increases rapidly, and by two o'clock in the afternoon, when a lot of water vapor accumulates, they thicken into thunderclouds, and at five another downpour falls on the green roof, which will rage the rest of the day and maybe all night. Hurricanes are not uncommon here, when 150 millimeters of water falls in an hour. That is why, under the canopy of the equatorial forest, the air humidity is kept at the level of 90 and even 100 percent, and the jungle itself is called the humid forest. True, in many areas of the jungle at least once a year there is a short dry period when there is little rainfall, but even during this time the humidity of the air never drops below 40 percent.
Constantly wet ground and humid air allowed some invertebrates to move from the water bodies where they usually live to land. Of these, the most unpleasant leeches, which, having settled on the branches, patiently wait for the victim.
Other characteristic equatorial forest - constantly high air temperature. It should not be thought that it reaches extreme values here. Heat over 50 degrees, which happens, for example, in deserts, is impossible here, but the temperature never drops low and it is never cold in the jungle. In the surface layer of the Congolese wilds, it never rises above 36 and does not fall below 18 degrees. The average annual temperatures on the first floor usually range from 25-28, and the monthly averages differ by only 1-2 degrees. A little more, but also small daily fluctuations, usually not exceeding 10 degrees. In the jungle, the pre-morning hours are cooler, and the hottest time of the day is the end of the first half of the day. Sharper fluctuations in temperature and humidity are observed in the "attic" and on the "roof" itself.
The length of the day in the equatorial belt is very constant. It ranges from 10.5 to 13.5 hours, but under the canopy of the rainforest, twilight reigns even at noon. The luxuriantly overgrown foliage of tree crowns uses most of the energy of the daylight for the needs of photosynthesis and almost does not let the sun's rays to the ground. After all, the total area of leaves is 7-12 times greater than the area of the forest itself. On its first floor, there is clearly not enough ultraviolet light, which is why the inhabitants of the jungle have such a need for sunbathing.
Down here, in the darkest places, the light intensity is only 0.2-0.3 percent of the intensity of full daylight. This is very little. In order for green plants to survive, it must be significantly lighter. Only very few of them are able to be content with 0.8 percent of the light output. The life of plants under the canopy of a tropical forest would be completely impossible if there were not a rare lace of sun glare, tiny oases of light. There are very few of them. 0.5-2.5 percent of the forest floor area is illuminated, and even then it is usually not for long. Well if 2-3 hours a day. In addition, the intensity of light in them is small, only 10-72 percent.
Rainforest trees in their infancy and adolescence are able to put up with a lack of light, however, having matured, they become the most sensitive plants of the jungle to lack of light. Forest giants are short-lived. The natural duration of their life is not at all great - from 15-20 to 80-100 years. With such a short lifespan and a relatively high need for light, the self-renewal of the jungle would be impossible if the roof of the forest were a little stronger. But it lacks reliability.
Ferocious hurricanes with monstrous destructive power love to walk over the jungle. They not only break the tops of trees rising above the forest canopy, not only break through the "roof", but often uproot giants from the ground, creating huge glades up to 50-80 hectares in size. This is due not only to the crushing force of the wind, but also to the nature of the root system of the trees themselves. After all, the soil layer under them is thin, and therefore their roots do not penetrate deeply. Only 10-30, rarely 50 centimeters and hold loosely. Through the holes in the forest canopy, formed after the hurricane, a stream of light breaks in, and here begins rapid growth.
In such clearings, many new plants grow at the same time. Peer trees reach up and grow in a race, trying to snatch more light. Therefore, they do not have a crown, more precisely, it is narrow and strongly elongated upwards. When the tree reaches maturity and its further growth stops, they begin to gain strength, several large branches grow, and the crown expands, if neighbors - nearby trees allow it.
As much as the jungle is rich in trees, so they are poor in grass. Here there are from several tens to one and a half hundred species of trees, and grasses from 2 to 20. This is the direct opposite of what we see in the north, where usually forests are composed of two or three or five types of trees, and grasses and shrubs are quite diverse. In tropical rainforests, grass does not form a continuous cover, and the herbaceous plants themselves, in our everyday sense, do not look like grass at all. Some of them are curly and stretch upwards. Others have lignified, like bamboo, and almost no branching stems. These perennial plants can reach a height of 2-6 meters. It is difficult to call such giants grass. Finally, huge bananas with fleshy leaves, and they are not uncommon here, this is also a kind of grass.
Herbaceous plants include ferns and Selaginella, which are slightly similar to them. Usually these are creeping forms with aerial roots, trying to climb as high as possible. There are no bushes here, which we are accustomed to seeing in the north. Downstairs, in the gloom of the rainforest, the plants stretch upwards, not outwards. But this does not mean that the space at the base of tree trunks is free. On the contrary, without an ax or a sharp machete - a long knife that cuts not too thick branches and trunks of young trees, you can’t even take a step here. The main culprits are creepers, as well as aerial and additional supporting roots.
Roots depart from trunks and large branches at a height of 1-2 meters or higher, go down and branch here, going into the ground far from the trunk itself. Columnar roots-supports and board-shaped root outgrowths at the base of tree trunks often grow together.
Aerial roots descending from somewhere above contribute to this chaos. To meet them, vines rush up to the sun, braiding everything and everyone. They stick around the tree trunks so much that they are sometimes not visible, rise into the crowns, densely cover the branches, spread from tree to tree, sometimes descend back to the ground, reach the neighboring tree and again rush to the sky. The length of the vines is impressive: 60-100, and rattan palms stretch for more than 200 meters. Among the vines there are killers. Having reached the top of the giant tree, in a short time they build up such an amount of foliage, which is located here asymmetrically, that the support cannot withstand the exorbitant weight, and the tree falls. Having collapsed to the ground, it also cripples the liana. However, more often the killer survives and, reaching out to a nearby tree, again rushes towards the sun.
Strangler creepers, having wrapped themselves around a tree trunk, squeeze it, stop the movement of juices. Often in the safe embrace of a creeper that has spread to neighboring trunks and strengthened there, dead tree remains standing until it rots and falls apart.
Tropical rainforest features
Some epiphytes have broad leaves. When it rains, water accumulates in their sinuses. Peculiar flora and fauna appear in miniature reservoirs. The owners of the pools send their aerial roots here. The ability to store water allows them to live at high altitude, where it is much drier than at the foot of the trees. Other epiphytes entwine trunks with their roots or dress them in a sheath of tightly fitting leaves. Under it, a soil layer gradually arises, accumulating water and supplying plants with nutrients.
As already mentioned, the trees of the tropical jungle reach a monstrous size. To match the length and thickness of the trunks. Here, giants look quite ordinary, reaching three meters in diameter at a height of human growth, and thicker ones are also found. In the closed wilds everything stretches upward towards the sun. Therefore, the trunks are straight. The lower lateral branches die off early, and in mature trees they start at a dizzying height, by no means lower than 20 meters from the ground.
Rainforest trees often have smooth, light-colored bark. Rainwater drains completely from a smooth one, and too much of it would linger in a rough one, putrefactive processes could occur or fungi that destroy wood could settle. And it is light so that the sun's rays, if they get here, are more fully reflected and do not heat the trunks too much.
Flowers in rainforest plants are usually brightly colored and have a strong fragrance. Interestingly, they are most often located directly on the trunks and large branches. Color, smell, and location are all geared towards making them easier for insects and other pollinating animals to detect. It would be difficult to find flowers in a sea of foliage.
The leaves, especially those of the tallest trees of the tropical rainforest, are large, dense, leathery, with "drip", drawn down ends. They must withstand the force of hurricanes, withstand the onslaught of downpours and not prevent the water from flowing down as quickly as possible. The leaves are short-lived, not many live more than 12 months. Their change occurs gradually and continues all year round. The amount of litter can reach 10 percent of the total forest biomass, but the litter layer is never thicker than 1-2 centimeters, and it is not found everywhere, since decay is intense. However, soil enrichment does not occur, since water flows wash nutrients into the lower horizons inaccessible to roots. A riot of vegetation, which appears to be a tropical rainforest, is created on extremely poor soils.
Whatever hurricanes hit the jungle, at the bottom of the green ocean, air movement is almost not felt. Warm and humid air is not renewed at all. Here, as in a thermostat, there are ideal conditions for the life of all kinds of microbes, especially putrefactive ones. Here everything rots and rapidly decomposes. Therefore, despite the mass of flowering plants, in the depths of the forest it smells noticeably of rot.
Eternal summer creates favorable conditions for uninterrupted growth, therefore, on the cuts of tree trunks, the annual rings so familiar to us are often missing. For the jungle, it is common for the simultaneous coexistence of plants located in different stages fruiting. The fruits on one of the trees may already ripen, and on the neighboring one, flower buds are just being laid. Continuous activity is not characteristic of everyone. Some trees need a short rest, and during this period they can even shed their leaves, which is immediately used by the neighbors who manage to snatch a little more light.
The ability to grow all year round, the ability to “snatch” everything valuable from the soil that water has not yet carried away, allows even on poor soils to create a huge biomass, a record for the earth's biosphere. Usually it is from 3.5 to 7 thousand tons per hectare, but in some places it reaches 17 thousand tons! Of this mass, 70-80 percent falls on bark and wood, 15-20 percent are underground parts of the root system, and only 4-9 percent fall on leaves and other green parts of plants. And there are very few animals, only 0.02 percent, in other words, only 200 kilograms. This is the weight of all animals living on 1 hectare of forest! The annual increase is
6-50 tons per hectare, 1-10 percent of the total jungle biomass. That's what a super forest is - wet tropical wilds!
Tropical rainforest landscapes. Anyone who is lucky enough to fly from Lima to Iquitos, the administrative center of the department of Lorette in eastern Peru, will cross the white peaks of the Sierra Blanca by air and see how a giant green sea suddenly opens up in front of him - a huge area of \u200b\u200bwet (rain) tropical forests of the Amazon basin. Like waves of surf, dark green rises on the eastern slopes of the Andes, forming a border of mountain moist forests, which the Peruvians poetically call Ceja de la montana - "Mountain's Eyebrow".
The green carpet stretches to the horizon; it is torn apart only by light brown winding ribbons of rivers and floodplain lakes covered with aquatic plants floating on the surface.
Tropical rainforests are distributed mainly near the equator, on both sides of it. They cover vast territories - especially in South America, Southeast Asia and Africa. The largest of these areas is the lowlands of the Amazon basin and its tributaries. This vast area, which Alexander Humboldt called hylaea (a forested area), is considered a kind of model, a model of a tropical rainforest. From west to east it stretches for 3600 km, and from north to south - for 2800 km. Another major area of tropical rainforest is on the east coast of Brazil. In Asia, tropical rainforest extends from Burma and Thailand through Malaysia, Indonesia and the Philippines to northern Australia. In Africa, a continuous array of such forests stretches along the coastal territories from Guinea to the mouth of the Congo.
It is very difficult for people who are accustomed to the change of seasons to imagine that somewhere on Earth there are places where winter and summer, autumn and spring do not exist. Meanwhile, the tropical rainforest is just such a place. Unusually even, slightly fluctuating temperatures throughout the year, as well as abundant rainfall, the amount of which almost does not change regardless of the seasons - these are the conditions in which tropical rainforests grow.
However, it would be misleading to believe that the climate in these areas is extremely hot. The absolute temperature maximums (their highest marks) are between 33 and 36 C, i.e. barely exceed those of the middle latitudes. But it is especially characteristic that here throughout the year the average monthly temperatures remain practically unchanged: 24 - 28 C. Almost the same can be said about precipitation. Near the equator, there are no seasonal differences in the length of the day, where every morning the sun rises around 6 o'clock and rises in the brilliant blue sky to the zenith. In the morning, cumulus clouds appear, and then, usually in the afternoon, a thunderstorm breaks out with heavy rain. Soon the sky clears again, the sun shines brightly, and the temperature rises. Such a change of weather can be repeated again before sunset, which at about 6 pm quickly slides below the horizon. And so day after day, almost without exception, every month, every year.
Tropical rainforest soils are the "patriarchs" of soils, exceptionally ancient formations that often date back to the Tertiary period. For thousands of years, water, air, plant roots and the paws of animals have destroyed parent rocks. Hence such a high degree of their destruction: the thickness of the layer ground by them (weathering crust) in some places reaches 20 meters.
Abundant rains combined with year-round warmth contribute to the instant washing out of some of the chemicals from the soil, as a result of which the soil is saturated with iron oxides.
These oxides color the soil a brick red color, for which it is called silica, or ferralitic soil (from the Latin “ferrum” – “iron”). These soils seem to be fabulously rich in nutrients. After all, heat, moisture, a huge amount of annually dying plant mass are the most Better conditions for the formation of fertile humus. But it's quite the opposite. In these soils there is no (or almost no) calcium, nitrogen, phosphorus, which are so necessary for plants. Over hundreds of centuries, almost all nutrients from the soil passed into vegetation, which became the main storage, accumulator of nutrients in the landscape. And the dead parts of plants disintegrate so quickly in this favorable climate that, without having time to accumulate, they immediately fall into the "paws" of the root systems of trees and re-enter the biological cycle.
A few decades ago, it was believed that a tropical rainforest is always impenetrable thickets of trees, shrubs, ground grasses, lianas and epiphytes (plants living on other plants). Only relatively recently it became known that in some humid tropical forests, the crowns of tall trees form such a dense roof that sunlight almost does not reach the soil, being "entangled" at the very top. Under such an umbrella there are few who want to settle, and through such forests one can pass almost unhindered.
People who have visited a tropical rainforest for the first time often talk with delight about the fact that you can hardly find two specimens of trees of the same species in it. This is an obvious exaggeration, but at the same time, 50-100 species of trees can often be found on an area of one hectare. But there are also relatively species-poor, “monotonous” moist forests, such as in Indonesia or in particularly damp areas of the Congo basin.
The real masters of the tropical rainforest are, of course, trees - of different appearance and different heights; they make up about 70% of all species of higher plants found here. It is customary to distinguish three tiers of trees in a tropical rainforest - upper, middle and lower, which, however, are rarely clearly expressed. The upper tier - giants 50 - 60 m high (two ten-story houses!), Which, like sentinels, rise above the main canopy of the forest, being quite far from each other. On the contrary, the crowns of trees of the middle tier, having a height of 20–30 m, usually form a closed canopy and look like a fluffy thick green carpet from above.
Wet tropical forests. Brief physical and geographical characteristics
The lower, 10-meter tree layer can be developed very poorly, or it can be completely absent - there is not enough sun for everyone, even at the equator.
A subordinate position is occupied by tiers of shrubs and grasses. These are ascetic species capable of developing in very low light conditions. If you swim through the tropical rain forest along the river, the abundance of lianas is striking - plants climbing trees with flexible and winding trunks. They, like a dense theatrical curtain, hang from the trees growing along the banks. Creepers are one of the most amazing creations of nature in the equatorial regions. First of all, 90% of their species are found only in tropical rainforests. They are very ingeniously fixed on other plants with the help of special roots, as well as trunks and leaves. They are sometimes several times longer than their master in length, but, like an overgrown child, they hug him tightly until he falls.
In addition to numerous vines, other cunning people live in the tropical rainforest. They even manage not to take root in the soil - they settle entirely on a tall tree. Moisture and nutrients are sucked directly from the air, while often thrifty plants accumulate them in favorable periods, and then spend them extremely economically. To accumulate moisture, they all developed original adaptations: some have aerial roots, some have a reservoir of leaves like a pool where moisture accumulates after rains, and some have hollow thickenings on the stem for the same purpose.
At the equator there is a wide strip of wet forests. It passes through the territory of Central and South America, Central Africa, Southeast Asia and Northern Australia. These forests are the most complex ecosystem on Earth, with the most diverse and rich resources. However, despite their importance, rainforests are being destroyed and disappearing at an alarming rate. Moist forests grow in areas where it is constantly high and there is a lot of precipitation. Over millions of years, rainforests have become the most populated habitat on our planet. They account for less than 10% of the land area, but from 50 to 70% of all terrestrial plant and animal species live there. The largest wet forests grow in the Amazon (Brazil). We will talk about them on these pages. Local Indians hunt with special blowpipes. The number of Indians in Brazil over the past 400 years has decreased from 5 million to 200 thousand people. Many of these huge trees put out extra shoots for support, as their own roots are empty inside and weak. The soil in the forests is covered with a layer of fallen leaves several centimeters thick. In this layer, necrophages actively process organic matter, and the roots of plants quickly absorb minerals. This process is so active that very few minerals remain in the lower soil layer: their bulk is found in all kinds of vegetation. When forests are cleared and burned, the mineral substances contained in plants turn into ash. The root system is destroyed, and the surface layer of the soil is washed away by heavy rains. becomes infertile, and areas where life was in full swing until recently turn into. It will take many centuries to restore forests on such lands.
Tiers
All moist forests have a similar structure with five main tiers. Each layer has its own plant and animal life. Often the tiers merge. Sometimes one of the tiers (or more) is missing. The top tier is the most tall trees, rising 10-15 m above the main mass of vegetation. From here, American harpy eagles and other raptors stalk their prey. The second tier (canopy) is a strip about 10 m wide at a height of 30-40 m. This is a solid green roof made of intertwining branches and leaves of tree tops. Most plants and animals settle here, attracted by the abundant sunlight. Undergrowth - consists of the tops of small trees that receive less light, such as palm trees, and young trees tending to. It is much rarer than the second tier, and its own community of plants and animals lives here. The undergrowth is shrubs and small trees that receive diffused sunlight through the branches and crowns of the upper tiers. Where the sun almost does not pass, shrubs and grasses grow very poorly. When more sun penetrates through the gaps in the second tier, shrubs and grasses grow faster. Ground vegetation is ferns and grasses. It is inhabited by single species of mammals, such as tapir, and many insects.
Tropical rainforest model
If you have a large aquarium, you can create a miniature rainforest. At the bottom of the aquarium, pour a layer of gravel and charcoal, and on top of it a few centimeters of fertile compost. Lightly tamp it down so that the gravel pebbles show through. Plant various exotic plants. Cover with a glass lid and place in a warm place, but not in the sun. Plants will begin to flourish. will be moist, and will constantly circulate between the compost, plants, air and aquarium. Add some water every few months. Plant exotic plants. They can be bought at the store. small flowering plants, such as orchids, make a colorful variety. Plant plants at some distance from each other: they need space.
forest people
Wet forests are a native scrap for many natives living in harmony with the surrounding world. Their experience of living in the forest is very valuable to us if we want to learn how to use forest resources wisely. However, these days, the natives are constantly driven out and driven from their lands against their will and basic human rights. With the death of forests, wild tribes also perish, taking with them their invaluable experience.
Importance of rainforests
Tropical rainforests play a vital role in regulating our planet's climate: they hold a special position in the oxygen, carbon and water cycles. In addition, tropical forests are the most valuable source of raw materials for medicine and one of the main sources of new types of food (about 1650 plant species growing in them are edible). People have already begun to actively use the vast resources of wet forests. However, this needs to be done more thoughtfully: a balance must be found between the large-scale use of forest resources - such as timber, rubber and nuts - and the conservation of the forests themselves.
On our planet, more than 50% of wet forests have already been destroyed, and their destruction continues. As a result, in the countries where these forests grow, the population is rapidly impoverished, and the vacated land is distributed unequally (see the article ""). The reason for the massive deforestation is the constant demand for timber in developed countries and ineffective reforestation programs. It is necessary to significantly change the approach to solving all these problems.
Tropical rainforest animals and plants of the world where ferns are located
Ecosystems of the humid tropics and subtropics
Wet rainforests distributed on both sides of the equator near the oceans, they occupy large areas in the western and eastern hemispheres - in South America, in the Amazon, in Central America, eastern Mexico and on some Caribbean islands, as well as in Southeast Asia, from India to Thailand, Indonesia and the Philippines, West Africa, northwest Australia. "Rain" forests are characterized by an excess of moisture and heat, which are distributed more or less evenly throughout the year.
Daily and seasonal fluctuations in temperature are small. Summer temperatures drop slightly during the rainy seasons due to cloud cover. Average temperature for the zone rainforest is 26 degrees Celsius. Temperature constancy is one of the fundamental characteristics of tropical and subtropical moist forests. The daily temperature difference between day and night is only 5 degrees Celsius and exceeds monthly fluctuations.
Within each tropical rainforest region, the distribution of rainfall is uneven. Short droughts are replaced by rainy periods. Dry periods in the tropical rainforest are very short-lived, rain falls on average once every three to four days, and the duration of "pauses" does not exceed two to three weeks.
During the rainy season, every day in the afternoon, a downpour falls on the ground for several hours; then the sun usually peeps through, although it happens that heavy rain pours non-stop around the clock. Heavy rain is as much a part of a tropical rainforest as a scorching sun is to a desert. Rain is the most important factor in maintaining a colossal biomass: over 300 liters of water are used to form 1 kg of foliage.
The average annual rainfall for all tropical rainforests in the world is 400 cm. These areas are characterized by exceptionally high humidity and relatively constant precipitation throughout the year. Relative humidity in the forest can reach 90%.
Unlike deciduous tropical rainforests, it remains green and lush during short dry periods.
In tropical rainforests, illumination is low and uneven. There are sharp differences in the illumination of the crowns of trees of the upper tier and plants of the lower tier. Comparatively the same light conditions on the soil surface in a closed forest for grass cover. During the year, the illumination changes slightly, since the fall of leaves does not occur at a certain time of the year, not at once in all species and not simultaneously in all tiers. Inside the forest, the illumination depends on the development of the crown of trees, the density of crowns and the density of vines.
The length of daylight hours in the tropics varies slightly: the day lasts 11-12 hours, twilight is short - about 30 minutes.
The nutrient content of rainforest soils is low. The processes of decomposition and weathering of plant residues are intensive, but due to heavy rainfall, nutrients from the topsoil easily go deep into the soil. Decaying organic matter and ash elements are quickly assimilated by the root system of plants, which ensures their powerful development.
A characteristic feature of tropical rain forests is a complex multi-tiered structure, as well as a huge variety of trees, shrubs, lianas and epiphytes.
rainforest plants
In the plant community, everything is ordered according to a single principle - the need for light. The first tier is made up of giants of the plant world, reaching a height of 40 m or more. These are the most photophilous plants. Lower trees are crowned with a variety of shrubs, tall herbaceous plants and numerous seedlings of various tree species. The third tier is made up of shrubs and herbaceous plants, the species composition of this tier is extremely rich and diverse, shade-tolerant species grow here, which are content with scattered sunlight.
Most herbs can be found under tree canopy breaks caused by falling trees, in clearings and forest edges. The extralayer vegetation of tropical rainforests is represented by lianas and epiphytes.
The tallest trees are usually slender, unbranched: they are palms with spreading crowns and large leathery leaves that are adapted to strong transpiration. Palm trees are very diverse in their own way. appearance- among them there are powerful trees with pinnate or fan leaves, and low shrubs, and lianas. Wild date (Phoenix silvestris) - grows along the banks of rivers and in wet places in northern India and is considered one of the most decorative palms. In the West Indies, there is a low umbrella sabal palm (Sabal umbraculifera). The soft palm (Caryota mitis) is very interesting - a resident of the tropics of Burma and Indochina. The triangular lobes of the leaf with an uneven edge gave reason to call it the “fish tail palm”. In the tropical forests of Sumatra and other islands of the Malay Archipelago, a creeping rattan palm (Calamus) grows with a thin trunk, over 100 m long, spreading from one tree to another. Its trunk and leaf edges are covered with saw-sharp, curved spikes that hurt and cause deep wounds when touched.
Ficus rubbery
Among the most characteristic trees of the rainforest are ficuses, ranging from mighty trees to small vines. Rubber ficus (Ficus elastica) in its homeland - in India and Burma - reaches a height of 30 m and is part of the upper tier of the tropical forest.
Many tropical trees are characterized by powerful adventitious roots, they serve to maintain the vertical position of the trunk. Especially a lot of them are formed in the Bengal ficus, or banyan tree (Ficus benghalensis). The crown of large trees, supported by a large number of thick columnar adventitious roots, gradually expands to the sides in the form of a small grove.
In ficus radicans (Ficus radicans), the leaves have a structure typical of many tropical plants: thin, drawn-out tips - “drip endings” - provide faster water runoff from the leaves during tropical downpours.
Plants of the middle tier, as a rule, have thinner and more delicate leaves than those of trees, since transpiration in the depths of the forest is much lower than in the upper tiers.
In the tropics and subtropics of various continents, cone-bearing cycads (Cycas) have been preserved - direct descendants of plants that made up the vegetation cover of the Earth in remote geological periods.
Representatives of the genus Pandanus (Pandanus) are very interesting. They have narrow green or striped leaves, often with thorns along the edges. Their characteristic feature is the formation of aerial "stilted" roots, which serve as supports for plants on viscous soil. Pandanuses grow in the tropics of the Old World, on the muddy banks of rivers and lakes.
Begonia Bower ‘Cleopatra’ Calathea Makoya
At the very bottom of the rainforest there are countless herbaceous plants - ferns, begonias, arrowroots, calatheas, various aroids. Undergrowth plants often have very beautiful colorful leaves and bizarre shapes. Many beautiful plants are not yet cultivated anywhere in the world, some have not yet been described by botanists.
Often herbaceous plants in the tropics bloom in different time of the year. The leaves of these plants are thin, delicate, often quite large. There are species that live in densely shaded areas, in connection with which they reproduce vegetatively, transpire weakly, and guttate at night, i.e. droplets release water. These include taro (Colocasia).
In the tropical rainforest, not only trees, but also many herbaceous plants reach a great height, 5-7 meters, such as bananas (Musa). The thick shoots of a banana grow very quickly, but in fact they consist only of leaves. The “trunk” of a banana is actually the expanded bases of the leaf petioles that lie tightly on top of each other. Wild bananas are found in the tropical forests of Asia and Africa.
The most striking feature of the rainforest is extra-tiered vegetation, represented by lianas and epiphytes.
Changes in geographical and climatic conditions with increasing altitude in the tropical zone shape the appearance of the forest, its structure and species composition. The regulator of this process is the air temperature. For every 300 m you rise, the temperature drops by 2 °C. As the temperature decreases, biological processes slow down, which manifests itself in a decrease in the height of trees, a decrease in the species composition of flora and fauna, and a transition from a complex multi-tier structure to a simple single-tier structure.
Lowland rain forests are gradually replaced by tropical rainforests of the foothills and mountains. As the altitude increases to 1000-1500 m, the appearance of gloomy forest communities, called cloudy or foggy forests, is observed. Here, the slender tall trees of the lowland areas are replaced by trees of curved, bizarre shapes. Due to the huge humidity in such a forest, the trunks and branches of trees are densely covered with mosses. The forest is shrouded in fog, there is very little light. The grass cover is high, dotted with bright flowers, there are a lot of epiphytes on the trees. The moisture of the clouds condenses on the leaves of the trees, and water constantly flows from them. These forests do not differ in pronounced specificity.
Wind forests form in areas that are exposed to cyclones and hurricanes. In these plant communities, trees are pressed to the ground, take the form of shrubs, dense undergrowths occupy large areas in rainforests. Rattan palms (Calamus) and other climbing plants create dense weaves, firmly binding the crowns of trees.
In those areas where rainfall is seasonal, periods of rain alternate with drought, deciduous tropical forests are common. Many woody plants in these forests lose their leaves during the dry season. The amount of precipitation here is about 250 cm, the difference between the average temperatures of the warmest and coldest periods reaches 8 ?C. Such forests are common in South America, Africa, India, Burma, on the island of Java. In tropical deciduous forests, two types of vegetation can be distinguished:
1. Tropical humid semi-evergreen forests border on evergreen forests and do not differ from them during the rainy season. The blooming of young leaves begins shortly before the start of the monsoon rains and is stimulated by the established high temperature.
2. Tropical forests, green during the rainy season (monsoon forests). Teak (Tectona grandis) is the best known species of these forests.
Acanthostachis cone-bearing Bougainvillea naked
From tropical deciduous forests, some begonias, aroids, bromeliads, bougainvillea, passionflower, krinum, hemanthus and many other plants came to culture.
In the humid tropics, there is a special type of plant formations - mangroves. It is coastal vegetation on muddy shores flooded by the sea, consisting of evergreen small trees and shrubs forming thickets. Mangroves are located directly on the coastline on saline soils. The leaves of mangrove plants are more or less thick, leathery, they have glands that remove excess salt that enters the plant with water.
Many tropical trees that grow along the banks of rivers, in swamps, in mangroves develop aerial, stilted roots that serve as supports for the plant while living on viscous fragile soil. Often the stem of the plant at the bottom dies off and the plant is left standing on stilted roots. Mangrove formations formed by the Nipa palm are common in the eastern tropics. Mangroves are found in the northeastern part of South America, on the western coast of Africa, in Asia and Oceania, where species of the genus Pandanus predominate. The most complex in terms of species composition are the eastern formations, in particular the mangrove forests on the Malay Peninsula.
The subtropical climate is characterized by alternating moderate, cool winters and hot summers. Vegetation of plants here can be year-round.
Humid subtropical forests differ from tropical ones in lower temperatures and more significant seasonal fluctuations. Summer temperature is 18-22 degrees Celsius, winter - 13-18 degrees Celsius, relative humidity in summer is about 80%, in winter - 65-70%. The humid subtropics include monsoon landscape zones and evergreen forests. Humid subtropical forests are found in Brazil, Mexico, Florida, Africa, Madagascar, Australia, New Zealand, the Atil Islands, Japan, China and the southern part of Black Sea coast. They develop outside the tropics and gradually move into the tropics. The species composition of vegetation here is somewhat less than in tropical forests.
Southern cordilina
In New Zealand and the Antilles, special fern forests occupy a large place. The islands of New Zealand have many endemic plants, ie. nowhere else found in the wild. We can note thick-leaved pseudopanax (Pseudopanax crassifolium) with beautiful foliage, corynocarpus, or "New Zealand laurel" (Corynocarpus laevigata) - an evergreen tree with edible fruits, four-winged sophora (Sophora tetraptera) with large yellow flowers, thick-leaved pittosporum (Pittosporum crassifolium) - a tree with dark red flowers and large green fruits - boxes. Eucalyptus forests are found in the humid subtropics of Australia. Eucalyptus trees (Eucalyptus), except for Australia, are found in the wild only on the islands of Kalimantan and New Guinea. Among the eucalyptus trees there are trees up to 100 m tall and low shrubs. On the peat soils of New Zealand, a beautiful shrub grows - southern cordilina (Cordyline australis). Miniature creeping shrub - lying fuchsia (Fuchsia procumbens) - a typical plant of open rocky areas.
Araucaria variegated
In the humid subtropical forests of Australia, there are several species of araucaria (Araucaria) and foot-bearing (Podocarpus) - the original coniferous plants with flat wide needles, southern liviston fan palm (Livistona australis). The woody flora of Australia is characterized by doryphora (Doryphora sassafras), a large tree with white fragrant flowers, Eugenia myrtifolia (Eugennia myrtifolia) with cream flowers and red berries, wavy pittosporum (Pittosporum undulatum). Very elegant bunch-colored albizia (Albizzia lophantha) is a small bean tree from Southwestern Australia. In the mountains of Queensland, the southern cyathea (Cyathea australis) tree fern is common. In Australia, there are two species of the Proteaceae family - strong grevillea (Grevillea nobusta) and notched stenocarpus (Stenocarpus sinuatus).
Feijoa Sellow Psidium Cattley
In the subtropics of South America, a tall deciduous tree from the Myrtle feijoa Sellow family, or acca (Feijoa sellowiana) grows with beautiful white flowers and large edible fruits. Other deciduous fruit tree- Psidium Cattly (Psidium cattlyanum) comes from Brazil, its fruits are the size of a walnut, taste like strawberries. The Brazilian blechnum fern (Blechnum brasiliense) belongs to the herbaceous plants of the humid subtropics of South America. In the forests North America evergreen sequoia coniferous tree (Sequoia sempervirens) surprises with its height. This tree lives up to 250 years, reaches 100 m in height and 5-9 m in trunk diameter. Sequoia forms pure forests along the banks of rivers; it is found singly in mixed forests on mountain slopes. Swamp cypress (Taxodium distichum) is a coniferous tree that grows in swamps and swampy floodplains of Florida. Settling on moist soil, poor in oxygen, swamp cypress forms respiratory roots of pneumatophores vertically sticking out of the soil around the trunk 1 m in height, absorbing oxygen directly from the air. Magnolia grandiflora (Magnolia grandiflora) is one of the oldest plants on Earth. They appeared about 120 million years ago to replace the previously dominant gymnosperms.
Pelargonium fragrant
In the humid subtropics and tropics of Africa, the date rejected (Phoenix reclinata), goblet ficus (Ficus craterostoma) with triangular leaves, plectranthus (Plectranthus), various types of pelargoniums (Pelargonium) are common. In the African subtropics, there are tall grasses, such as banana-like Strelitzia (Strelitzia). Its inflorescences resemble a bright bird's head.
Clivia orange Encephalarthos Altenstein
South Africa is the center of origin for many bulbous plants. This is the well-known clivia with orange flowers, hemanthus. Succulent species of spurges are very interesting, for example, shiny spurge (Euphorbia splendens) - a thorny shrub with bright red bracts. The African cycad encephalartos is represented by two species - wavy and Altenstein (Encephalartos villosus and Encephalartos altensteinii.
A large species diversity is observed in the humid subtropics of Asia: Japan, China, the Himalayas, India, Indochina and Indonesia.
Metasequoia (Metasequoia) is an ancient coniferous tree that was considered completely extinct in the mountains of East Asia.
drooping cycad
Other conifers are cypress trees, tueviki, Japanese cryptomeria (Cryptomeria japonica), Himalayan cedar, or deodar (Ceadrus deodara) are common in the mountain forests of the Himalayas. Gingo biloba (Ginkgo biloba) is the only species from an ancient group of plants close to conifers. In Japan and China, there is a drooping cycad (Cycas revolute), Japanese camellia (Camellia japonica), in the wild it is found only in China and Japan, it is the closest relative of tea.
Trachycarpus Fortune
Among the shrubs, the umbrella-shaped rhaphiolepis (Rhaphiolepis umbellate), nandina domestic (Nandina domestica) with beautiful leaves that change color from green to red in winter are interesting. Very decorative fan palms: squat rapis (Rhapis humilis), Chinese liviston (Livistona chinensis), Fortune's trachycarpus (Trachycarpus fortunei).
Among the herbs of Japan and China, bamboo stands out - a large rhizomatous cereal with woody stems. Some Himalayan species grow to a height of only 15 cm. The stems of Vietnam's tropical bamboos reach 50 m in height and 30 cm in thickness. Bamboo has a very vigorous growth, the growth rate of shoots is unusually high. Japanese bamboo (Pseudosasa japonica) has a daily growth of up to 30 cm. Some species grow up to 90 cm.
Aspidistra high Fatsia japonica Ficus dwarf
Japanese aucuba (Aucuba japonica) and high aspidistra (Aspidistra elation), small herbaceous plants with beautiful hard leaves, are very decorative. The Japanese Fatsia shrub (Fatsia japonica) from the Araliaceae family has very beautiful carved palmate dark green leaves and dark purple fruits. Beautiful and original miniature liana with small leaves - dwarf ficus (Ficus pumila). Rhododendron species (Rododendron) grow wild in the mountains of Southeast Asia. This small tree is covered during the flowering period with a large number of bright large flowers of pink, lilac, white, red, simple or double.
Hello, dear readers of the site "I and the World"! Today we will talk about the so-called lungs of our planet - tropical forests. We will tell you: where they grow, what animals and plants can be seen in these forests, why they are called the lungs of the planet.
What is this?
What is a tropical forest? This is a vast territory in the tropical, equatorial and subequatorial zones, overgrown with evergreen trees, where only their own special plants and animals are found. The green belt of these forests stretches across Asia, Australia, Africa, Central and South America and through many islands of the Pacific Ocean. Quite mild climate without hot and cold weather with temperatures ranging from 20 to 35 degrees.
Different parts of the tropics
Among all tropical forests, wet (rain) and seasonal are distinguished. The former are characterized by a large amount of precipitation per year, while the latter grow where, despite moisture, there are periods of drought. The tropical rainforests of Atsinanana, growing in the east of the island of Madagascar, stand out separately.
These are ancient relic plants, formed about 60 million years ago, but now they are under the threat of destruction. Unique places with more than 12,000 plant species and 78 wingless mammals.
At one of the Chinese resorts of Yalunvan, tropical forests are presented in a huge Botanical Garden. More than 1,200 species of plants grow on its territory, some of which are difficult to find in wildlife.
Another area of the tropical jungle in China is Yanoda, which occupies 123 square meters. km. Madly beautiful orchids, huge trees, exotic birds.
The park is located on the island of Hainan, 35 km from the city of Sanya, from which you can get both by regular bus and tourist bus. Here you can also relax on the beach in Dadonghai.
In one of the tribes of Latin America, local sorcerers pray daily for heaven to send rain to the earth. It would seem, well, why constantly water the already waterlogged soil. There is only one answer: there will be no showers - huge forests will disappear, and without them all of humanity will disappear, because it is not for nothing that the tropics are considered the lungs of the planet.
Flora and fauna
Many types of local vegetation grow only here, and the abundance of insects and snakes is a distinctive feature of these places. Animals mainly live in trees - these are mainly marmosets and cebids. There are quite a few ungulates: baker pigs and undersized pointed deer. Lots of reptiles and amphibians.
- This is a zone of tropical vegetation in 6,700,000 square meters. km, which is located along the river. The jungle is represented by a huge variety of flora and fauna. 40,000 plant species, 1300 birds, 5500 fish, 430 mammals and 1400 amphibians and reptiles.
The largest rodent on the planet, the capybara, lives in the Amazon, as well as the Brazilian otter, giant anteater, spider-like monkeys, howler monkeys, Amazonian dolphins and many other animals, including titan lumberjacks, the largest bugs on the planet that are dangerous to humans. , because with their tongs they can easily break a pencil.
Barriers to Growth
In the Amazon, there is a problem of cutting down trees - since the end of the last century, more than 750,000 square meters have been destroyed here. km. Environmental problems associated with the disappearance of the tropics around the world are shown in feature and documentary films, as well as in cartoons for kids. We recommend watching one of these cartoons, Fern Valley, which is like a manifesto against corporations cutting down ancient trees.
The tropical forest of India is a valuable tree species of more than 20,000 species. And if on other continents slowly, but the vegetation disappears, then India restores its wealth.
The diversity of the animal world is enormous. The inhabitants of only one of the islands of Kalimantan are 7 times more than in the whole of Europe. What are the names of all representatives of the flora and fauna of this beautiful country is difficult to list in one article.
The tropics on the world map are located between 25°N. and 30 ° S, as if encircling the planet with a green ribbon. The names and classification of forests are presented in the description and in the photo.
Video for children
Tropical forests grow in the humid equatorial, subequatorial and tropical zones of the Earth. The main condition for the emergence of tropical forests: high air temperatures and high humidity.
Usually, in a tropical forest, there are several tiers of trees (trees of different heights). The tallest trees have a straight trunk that stretches up, and a wide crown spreads at the very top. the leaves of such trees are dense, shiny (so that they do not burn out in the sun and so that it is not so easy to beat them with rain).
the lower tiers (lower trees) have more delicate leaves, and they themselves are weaker. because they do not have enough light, from which they are covered by the crowns of the tallest trees.
in such a forest there are many vines (they are like loaches with a woody stem). they wrap around everything in their path and make the rainforest impenetrable (jungle).
from an excess of moisture, the soil in such a forest is waterlogged. there are few herbaceous plants due to lack of light.
many bright birds and animals that are able to move through the trees.
a lot of insects - because they love a humid and hot climate.
Where do tropical forests grow?
In the territories located near the equator, it is always warm and humid. Here the seasons do not differ from each other, and eternal summer reigns with frequent showers. Such conditions are very favorable for the growth and life of plants, so tropical forests are lush, impenetrable thickets.
Vegetation in the rainforest is arranged in tiers. The tallest trees reach a height of 60 m. A little lower is the bulk of plant crowns, even lower - growing trees (they are called undergrowth), under them - shrubs. Near the ground it is so gloomy that the plants do not have enough light and there are few of them.
Grasses in the rainforest survive only if they settle directly on the trunks of trees, obtaining nutrients from rainwater. So orchids bloom their outlandish flowers on tree branches. Other plants - creepers - cling to trees, braid their trunks, trying to climb as high as possible towards the light. Lianas can spread to neighboring trees and reach a length of 100 m.
In this exuberant plant kingdom, life is literally teeming; many animals have found refuge here. First of all, these are birds - colorful parrots, hummingbirds, toucans (almost half of all birds known to scientists live in the tropical forests of the Amazon basin in South America).
Most of the animals that inhabit the rainforest spend most of their lives in the trees. These are monkeys, sloths, squirrels, jaguars, long-tailed cats.
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