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Read and translate the text 1 using a dictionary.

Tropical rainforests are found in a belt around the equator of the Earth, covering about 54 million km of land. They are found in parts of South and Central America, Asia, Africa and Australia (figure 3.1).

Rainforests are warm, usually between 20-28 degrees Celsius. This is the wettest of all the biomes, with a typical annual rainfall of 1,500 mm (though sometimes exceeding 4,000 mm). The rainfall is not particularly seasonal, and is evenly spread throughout the year. Drought and frost are not a problem in the tropical rainforest. This is also the richest and most productive environment on Earth, due to the constant high temperatures and rainfall.

Rainforests are home to about fifty million people and most of them don’t hurt the forest they live in. They eat the fruits that grow on the forest trees, but they do not cut them down. They kill some animals to eat, but they do not destroy the species. But as important as the people, scientists consider that over 50% of the world’s plant and animal species are found in the rainforest. Many of the plants are endemic to the rainforest, such as in Brazil, where 70% of the plants are found here and nowhere else (figure 3.2).

Madagascar is home to 10,000 species of plants, 80% of which are endemic. Almost 90% of Madagascar’s forests have been destroyed. Every second, nearly two acres of tropical rainforest are destroyed, due to logging and clearing for animal grazing. Many animals are in danger of extinction because we are destroying the rainforests. One hundred species are lost every day. Scientists estimate that at least 30,000 species of plant and animal have not yet been classified, so some species are driven to extinction before we even know of their existence. When we destroy the rainforests, forest people lose their home, and thousands of species of animals and plants disappear.

Today, there are many forest parks in the rainforests of the world. Animals need large parks because some species have to travel many kilometers to find food. The Parc National des Volcans in Rwanda, for example, protects the mountain gorilla and saves it from extinction. Some animals are in danger because people want them as pets. There are only 2,500 hyacinth macaws now living in the forests of Latin America. But in 1989, people caught 500 hyacinth macaws and sold them in pet shops. Zoo in many countries of the world are helping to protect animals in danger.

The rainforests are as rich in plants as they are in animals. The biggest plants are of course the trees. Rainforests trees grow very slowly, and they live for hundreds of years. When a mahogany tree is fifteen years old it is about fifteen metres tall. After fifty years, it is about thirty metres. It goes on growing until it is 150 years old.


As well as their abundance, the plants here grow taller than in most other biomes, sometimes reaching heights of over 45m. In some areas, up to 200 tree species have been recorded per hectare.

There are distinct layers of foliage in the forest, and each of these support their own community of animals. These are: the emergent layer, canopy layer, understory layer and forest floor. At the bottom is the forest floor, which is often teeming with life, particularly insects. Next comes the understorey, a dark and cool environment under the leaves but above the ground. Above this is the canopy, which is the upper parts of the trees, also full of life. At the top are the emergents, which are giant trees that are much higher than the rest of the canopy. Only the emergent layer is unique to tropical rainforests, while the others are also found in temperate rainforests. The emergent layer contains a small number of very large trees which grow above the general canopy, although on occasion a few species will grow to 60 m or 70 m tall. They need to be able to withstand the hot temperatures and dry winds. Eagles, butterflies, bats and certain monkeys inhabit this layer.

Coffee, chocolate, bananas, mangoes, papayas, avocados and sugar cane all originally came from tropical rainforests, and are still mostly grown on plantations in regions that were formerly primary forest. In the mid-80s and 90s, 40 million tons of bananas were consumed worldwide each year, along with 13 million tons of mangoes. Central American coffee exports were worth US$3 billion in 1970. Much of the genetic variation used in evading the damage caused by new pests is still derived from resistant wild stock. Tropical forests have supplied 250 cultivated kinds of fruit, compared to only 20 for temperate forests. Forests in New Guinea alone contain 251 tree species with edible fruits, of which only 43 had been established as cultivated crops by 1985.

Between 25% and 40% of all pharmaceutical products are obtained from the rainforest. The peoples of the rainforest have always used plants to make medicines. Today, all over the world, people use medicines made from rainforests plants. Quinine, the medicine for malaria, comes from the cinchona tree of Peru. The leaves of the rosy periwinkle from Madagascar are used as a medicine for the deadly blood disease, leukaemia. Many new medicines are waiting in the rainforests. If we destroy the forests, we shall never find them. Ranforests trees are used to make things which we use every day. Rubber, for example, is used to make many things. The trees of the rainforests help the Earth’s air because their leaves use carbon dioxide and make oxygen, which we need to live.

Are we going to destroy all the rainforests of the world? Perhaps one day you will travel to a rainforest country; but will you see the wonderful plants and animals of the rainforests?

 

11.2 Find the answers to the following questions in the text 1:

1. Why are the rainforests important?

2. What is the weather like in a rainforest?

3. Why do animals need large parks in the rainforests?

4. Why are the leaves of rainforest trees important?

5. What layer is unique to tropical rainforests? Why?

 

11.3 Give Russian equivalents: destroy endemic, logging, clearing, animal grazing, extinction, existence, hyacinth macaws, mahogany tree, understorey, canopy, emergents, pharmaceutical products, cinchona tree.

 

11.4 Divide the text into the main paragraphs and name each of them.

11.5 Read the text 1 again and say if the statements are false or true. Correct the false ones.

1. Rainforests are in danger.

2. There are rainforests in all parts of the world.

3. Rainforests are very important for us. They give us wood, rubber, fruits, many of our medicines.

4. There are many rainforests in Europe.

5. The trees and other plants in the rainforest help to make the air that we are breathe.

 

11.6 Skim the text 2. Title it. Write down an annotation of the text.

Text 2

There are several common characteristics of tropical rainforest trees. Tropical rainforest species frequently possess one or more of the following attributes not commonly seen in trees of higher latitudes or drier conditions on the same latitude.

Many tree species have broad, woody flanges (buttresses) at the base of the trunk. Originally believed to help support the tree, it is now believed that the buttresses channel stem flow and it’s dissolved nutrients to the roots.

Large leaves are common among trees and shrubs of the understorey and forest floor layers. Young individuals of trees destined for the canopy and emergent layers may also have large leaves. When they reach the canopy new leaves will be smaller. The large leaf surface helps intercept light in the sun-dappled lower strata of the forest and are made possible because the lower layers are largely protected from winds which damage large leaves in the canopy. Canopy leaves are usually smaller than found in understorey plants or are divided to reduce wind damage. The leaves of rainforest understorey trees also often have drip tips which facilitate drainage of precipitation off the leaf to promote transpiration and inhibit the growth of microbes and bryophytes which would damage or smother the leaf.

Trees are often well connected in the canopy layer especially by the growth of woody climbers known as lianas or by plants with epiphytic adaptations, allowing them to grow on top of existing trees in the competition for sunlight.

Other characteristics that are more frequent in tropical rainforest tree species than in temperate forests or drier tropical regions include: exceptionally thin bark, often only 1-2 mm thick. It is usually very smooth, although sometimes covered with spines or thorns. Cauliflory, the development of flowers (and hence fruits) directly from the trunk, rather than at the tips of branches. Large fleshy fruits that attract birds, mammals and even fish as dispersal agents.

 


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