Read the passages and number them in the correct order. Choose the best title to the text.

Soil Conservation / Ecosystem Management / Man’s Impact on the Environment / The Conservation Movement

A) A second element of ecosystem management, one which has come much more to the fore in recent years, is that of maintaining sustained yield from organic resources. This idea was first applied to the maintenance of the breeding stocks of marine animals and to forestry practice. It is also implicit in the principles of soil conservation, the aim of which is to sustain agricultural fertility. Many authorities would maintain that this is by far the most important aspect of ecosystem maintenance, and that in the face of growing pressure on food resources, the protection of wild life for non-productive reasons is a luxury we can ill afford.

B) In summary, there clearly is a need to ensure that environmental management permits the maximum use of biological resources consistent with the maintenance of the greatest diversity of organic life.

C) As applied to organic resources, one aspect of environmental management is the preservation and protection of wild life or of natural habitats from modification and depletion by man. This may be carried out for a combination of ethical, scientific or aesthetic reasons. To this end, nature reserves, wildlife refuges and similar controlled areas have been set up all over the world, designed to protect a particular habitat and its communities. These have not always been entirely successful. A classic example of the lack of understanding of ecological principles occurred with the establishment of National Parks in East Africa: these were designed originally to protect game animals, man being excluded except as a sightseer. But as a result, animals such as elephant, hippo and buffalo, whose populations had formerly been kept in check by hunting, increased to an extent that widespread devastation of their habitat resulted. What has been often overlooked in the past in environmental management is, first, that ecosystems cannot simply be “preserved”, but are dynamic in character, and second, man is an important habitat factor in many cases: the ecological niche occupied by him cannot suddenly be left vacant.

D) The widespread current concern over the status of ecosystems is the product of a movement that has slowly been gathering momentum over the last hundred years or so. Early efforts at the conscious management of biological resources often arose out of economic necessity: the imminent disappearance of the last forests in Britain and central Europe in the eighteenth century prompted landowners to adopt methods designed to save the last remaining forests and to stimulate forest productivity. The conservation movement as such was born in the United States. The ruthless clear-felling of great stands of forest in the western states and the experience of the Kansas dustbowl in the 1930s served to focus attention on the problem. Currently, of course, conservation has become a much wider issue than the maintenance of natural biological systems.

E) Modern environmental management policies attempt to reconcile these apparently conflicting aims – namely, preservation and productivity. Multipurpose schemes are often now attempted. This is most successfully applied to management of forests, which because of their size are often well suited to a variety of uses – for timber, wildlife conservation, water supply and recreation. In Britain, National Reserves are now managed as multiple resource units.

Model: 1 – D

9.6 Read the text “Environmental Factors” through and make the review of it.

ENVIRONMENTAL FACTORS

Factors which have some effect on the life of an organism at some stage in its development are called environmental factors. These can be divided into groups as follows: first, a climatic group, which includes conditions of light, temperature, water availability and wind; second, topographic influences of slope angle, orientation and altitude; third, edaphic (soil) factors, especially pH and fertility; and fourth, biotic controls, such as a competition between species and the effects of grazing.

These groups are themselves interrelated so that it is extremely difficult to isolate the influence of individual factors. For example, topography and climate will influence soil development; and climate and soil will influence the pattern of biotic controls by determining the species which may inhabit a particular place and compete there for survival.

Light is extremely important environmental factor because it is the vital source of energy for ecosystems and it can also act as a control of functions such as reproduction and migration. Excess light can be a limiting factor in ecosystem development by damaging plant tissues and decreasing productivity.

The influence of light varies with its three main aspects: its quality (that is, wavelength composition), its intensity and its duration (day length).

Temperature is a universally important environmental factor both for its direct effects on organisms and for its indirect effects in modifying other factors such as relative humidity and water availability. Each species has its own minimum, maximum and optimum temperatures for life but the actual limits at any time vary with such things as the age of the individual and water balances in the body. Generally, aquatic plants and animals have narrower tolerance ranges for temperature than those which live on land. This is mainly because there is far more temperature variation in terrestrial ecosystems.

Water availability may often restrict ecosystem development because most organisms need large amounts of water to survive. It not only forms a large percentage of the tissues in plant and animal bodies but it is also essential for transport and cooling. In plants, water provides support and is essential for photosynthesis.

Distributions of plants may largely depend on the effectiveness of precipitation; this will be a function of the kind of precipitation, the type of vegetation present and the rate of evaporation. In many areas fog or dew is important in providing essential moisture for plant growth and thus extending the distribution ranges of species.

In the case of animals, water usually only acts as a limiting factor when it is in short supply. There is a great variation in the amounts of water needed different species but usually cold-blooded animals require less than warm-blooded ones, which use it for heat regulation. Some animals display specific adaptations for survival in arid habitats. Desert animals may avoid the hottest and driest season by becoming inactive – that is, aestivating.

Wind can act as an environmental factor either directly by causing mechanical damage to plants or indirectly by affecting relative humidity and evaporation rates. High wind velocities can cause an appreciable increase in the rate of transpiration and limit plant growth. In very exposed situations such as mountain summits, coasts and open plains vegetation may be dwarfed as a result of wind action.

Topography can influence ecosystem development in three major ways. First, by the direct effects of altitude on temperature. Temperature decreases as altitude increases either at the dry adiabatic lapse rate (10°C/km) or, more usually, at a lower rate than this, approximately 6°C/km. Second, topography can act indirectly, since temperature changes affect relative humidity. The combination of changes in temperature and relative humidity leads to the development of an altitudinal zonation of ecosystems. At a low level, desert merges into pine forests, which are succeeded by fir and spruce, and then by alpine communities at the highest altitude.

The third way in which topography can influence ecosystem development is by local variation in slope orientation and angle. South-facing sides of valleys receive strong incident light (in the northern hemisphere) and are therefore warmer and drier than north-facing slopes which are in the shadow for a lot of the time. This leads to great contrasts in species structure and productivity between sides of valleys. Angle of slope will be a critical factor in soil formation and drainage.

The soil is a vital component of terrestrial ecosystems, particularly in cycling nutrients without which all life would cease. Soil and the rest of the ecosystem are closely related; one will influence the workings of the other. Particular attributes of soils, such as texture, pH, soil climate and organic content operate in a closely interrelated fashion to exert control on rates of decomposition, nutrient cycling and plant distribution and productivity.

Soil texture is very important in determining the soil climate, since it affects aeration, drainage and ease of root penetration.

Biotic factors are the interactions that occur between living things. Biotic factors are usually far more diverse and intricate than other environmental controls because they rely on the activities of a wide variety of organisms.

Most habitats can be occupied by many different types of plants and animals. The success of a particular species will depend on its ability to obtain its requirements for life. Competition arises if the resources of a habitat are insufficient to meet the demands of all the organisms living there. Generally competition is most intense between individuals of the same species or of different species that have similar ecological niches, especially at young stages in the life cycle.

Man is by far the most important biotic factor. He has caused fundamental modifications of ecosystems by fire, hunting and agriculture, man has obliterated large areas of natural systems and caused pollution of both terrestrial and aquatic habitats.

9.7 Read the passage about the ozone layer and answer the questions (1-14) by writing a word or a short phrase. The first one is done for you as an example.

Model: 1 Where is ozone found? the Earth’s stratosphere

2 What does ozone filter out?

3 Where is there a high level of concentration of ozone?

4 What was London known as in the past?

5 What was the major cause of London’s smog?

6 What does sunlight encourage to turn into ozone?

7 Give two examples of crops affected by too much ultra-violet radiation.

8 What are malignant melanomas?

9 Give one of the two vital properties of CFCs.

10 About how long does it take СFСs to break down?

11 When does chlorine become an ozone destroyer?

12 What do the scientists compare with the area of the United States and the height of Mount Everest?

13 Do governments ban CFCs?

14 Is CFC a ‘greenhouse’ gas?

Ozone, spread thinly in the Earth’s stratosphere, about 10 km to 50 km above ground level, is essential to all forms of life. The molecules of ozone at that level ‘filter out’ high energy ultraviolet (UV) radiation from the sun, and in doing so protect plants and animals from harmful UV rays. Many scientists believe that certain forms of life were unable to live on land before the ozone layer had formed. But, nearer the ground, ozone is a problem, and by the sea it may even damage your health. Scientists now believe that the invigorating effect that comes from being near the sea is not caused by ozone in the atmosphere, but instead is a result of ions (electrically charged particles) in the sea air. Similarly, the distinctive smell of the sea probably comes from old fish and rotting seaweed, rather than ozone. But even more serious than the effect of ozone by the sea is its high level of concentration in polluted cities all over the world.

In the past, London was so famous for its smogs that the city was commonly known as ‘the Smoke’. These smogs were thick, smoky fogs which enveloped the city, and they persisted until the early 1960s. Coal-burning fires were the major cause of this health hazard, which was not eradicated until legislation was enacted in the late 1950s, setting up ‘smokeless zones’ and controlling the types of fuel that could be burned. But recently, a new type of smog has hit the headlines – of which one of the constituent parts is ozone. The combination of exhaust gases from cars and factories, still air, warmth and clear sunshine, has resulted in a highly poisonous form of ozone. Sunlight encourages a chemical reaction which changes oxygen in the air to ozone – hence the name ‘photochemical smog’; even small amounts of ozone can irritate people’s eyes, give them headaches and affect their breathing. Higher concentrations can also damage plant tissues, and may have other, more severe, consequences. In short, ozone is best kept at a distance from plants and animals.

So when does ozone become a friend to life on earth? Well … the molecules of ozone ensure that a good deal of UV radiation is prevented from reaching people and plants on Earth (and within 10 km of the earth). This is good news for plants – because crops such as maize, wheat and rice give lower and poorer quality yields if too much UV radiation reaches them.

It is good news for human beings too – high levels of UV radiation can cause malignant melanomas, or skin cancers, some of which may be capable of spreading to other parts of the body if they are not treated at an early stage. Why is it that ozone has become so well-known in the last decade? The answer involves ozone itself, UV radiation, and a family of chemicals called chlorofluorocarbons (or CFCs).

CFCs were first demonstrated by the American inventor Thomas Midgley when he inhaled a lungful of CFCs gas and used it to blow out a candle. This showed two vital properties of CFCs: they do not burn and they are not poisonous. For this reason they became the ideal replacement for ammonia in refrigerators: ammonia is toxic, inflammable, and has an unpleasant smell.

The CFC family of chemicals has many other uses, for example, inside aerosols. Within a can, the CFC is a liquid; when the pressure is released it becomes a gas. Other uses are as cleaning solvents.

In Thomas Midgley’s time, CFCs seemed the answer to many problems. Unfortunately, each time they are used some of the gas escapes into the atmosphere. CFCs are very stable – it takes perhaps 75 years before they break down. They remain in the air and reach high into the atmosphere.

This is where the problems begin. Up in the stratosphere, conditions seem to be perfect for breaking down CFCs and releasing chlorine. This is especially true during the cold winters above the South Pole in Antarctica. In temperatures of below –80°C, atoms of chlorine are formed. When the sun returns in spring, the chlorine becomes an ozone destroyer.

Just one chlorine atom can destroy thousands of ozone molecules.

The scientist Joe Farman, until recently head of the British Antarctic Survey team which has been carrying out research in the Antarctic for the past 20 years, first reported the ‘hole’ above Antarctica in 1985. Experts think that the hole is as big in area as the United States (approximately 9,500,000 sq km) and as deep as the height of Mount Everest (nearly 8,850 m). Every southern summer – early in November – the Antarctic hole breaks up into blobs of ozone-reduced air that drift around in the southern hemisphere.

Why do governments not just ban CFCs? The United States banned their use in aerosols five years ago, since when few countries have followed. Manufacturers have been working to find a replacement for CFCs which will not damage the ozone layer, and which does not have other harmful properties.

Some scientists believe that we should not have been so quick to condemn CFCs. They argue that gases from burning vegetation and wood-rotting fungi do far more damage to the ozone layer.

Even so, the effect of CFCs as a ‘greenhouse’ gas in warming the Earth is significant. The search to replace CFCs continues.

9.8 Read the text “How Are People Affected by a Volcano Eruption?” and answer the questions after it.

HOW ARE PEOPLE AFFECTED BY A

VOLCANO ERUPTION?

In 1990 the US Geological Survey claimed that there were 540 active volcanoes in the world. Three-quarters of those were in the Pacific Ring of Fire. The list did not include a little known volcano in the Philippines which had not erupted since 1380. On 9June 1991, Mount Pinatubo hit the headlines. It became one of the three largest eruptions in the world in the 20^th century.

The Philippines lie on a destructive plate margin. The Philippines Plate, composed of oceanic crust, moves north-westwards towards the Eurasian Plate, which is continental crust. Where they meet, the Philippines Plate is forced to dip steeply down under the Eurasian Plate. The oceanic crust is turned into magma, rises, and erupts on the surface. The Philippines owe their existence to the almost constant ejection of lava over a period of several million years. Even before Pinatubo erupted, there were over 30 active volcanoes spread across the country’s many islands.

Fortunately there were several advance warnings of a possible eruption. On 7 June the Americans evacuated all 15,000 personnel from their nearby airbase, From 9 June there were many eruptions, but none matched that of 12 June. An explosion sent a cloud of steam and ash 30 km into the sky. As the ash fell back to earth, it turned day into night. Up to 50 cm of ash fell on nearby farmland, villages and towns. Over 10cm fell within a 600 km radius, and some even reached as far away as Australia. The eruptions continued for several days. They were accompanied by earthquakes and torrential rain – except that the rain fell as thick mud. The weight of the ash caused buildings to collapse, including 200,000 homes, a local hospital, most of the schools and many factories. Power supplies were cut off for three weeks and water supplies were contaminated. Roads became unusable and bridges were destroyed making relief operations even more difficult.

The area surrounding Mount Pinatubo was excellent for rice growing. The thick fall of ash, however, ruined the harvest in 1991, and made planting for 1992 impossible. Over one million farm animals died, either through starvation (no grass to eat) or from drinking contaminated water. Hundreds of farmers and their families were forced to move to cities to seek shelter and food. Huge shanty-type refugee camps were set up. Disease spread rapidly, especially malaria, chicken-pox and diarrhoea. Within a few days the monsoon rains started. Normally these rains are welcomed as they bring water for the rice crop. In 1991, and again in 1993, they were so heavy that they caused flooding and lahars (mud flows). Lahars form when heavy rain flows over, and picks up, large amounts of volcanic ash. Lahars and landslides covered many low-lying areas in thick mud. Finally, ash ejected into the atmosphere encircled the earth within a few days. It blocked out some of the sun’s heat for several months, and lowered world temperatures. Scientists believe the eruption may delay global warming by several years. The eruption and after effects caused the deaths of about 700 people. Only six died as a direct result of the initial eruption. Over 600 died later through disease, and another 70 were suffocated by lahars.

► Answer the questions.

1 Why did so many people live on the slopes of Mount Pinatubo in June 1991?

2 Do you believe that eruptions can be a considerable hazard to human activity and, sometimes, to human life?

3 What caused the eruption of Mount Pinatubo?

4 Is it true that the most violent volcanic eruptions occur at destructive plate margins?

5 List the:

a) immediate effects

b) long-term effects of the eruption of Mount Pinatubo.

9.9 A) Read the text “Shenandoah National Park” and answer the questions given before each part of the text.

SHENANDOAH NATIONAL PARK

Why is the park called Shenandoah National Park?

Shenandoah National Park lies astride a beautiful section of the Blue Ridge, which forms the eastern rampart of the Appalachian Mountains between Pennsylvania and Georgia. In the valley to the west is the Shenandoah River, from which the parks gets its name, and between the north and south forks of the river is Massanutten, a 40-mile-long mountain. To the east is the rolling Piedmont country. Providing vistas of the spectacular landscape is Skyline Drive, a winding road that runs along the Blue Ridge through the length of the park.

When did the first people inhabit this land?

Most of the rocks that form the Blue Ridge are ancient granitic and metamorphosed volcanic formations, some exceeding one billion years in age. By comparison, humans have been associated with this land only about 9,000 years. Primitive food gatherers and, later, Indian hunters used the land for centuries but left little evidence of their presence. Settlements of the Shenandoah Valley began soon after the first expedition crossed the Blue Ridge in 1716. Many of the settlers came “up river”, north to south, from Pennsylvania. By 1800, the lowlands had been settled by farmers, while the rugged mountains were still relatively untouched. Later, as valley farmland became scarce, settlement spread into the mountains. The mountain farmers cleared land, hunted wildlife, and grazed sheep and cattle. By the 20^th century, these people had developed a culture of their own, born from the harshness and isolation of mountain living. However, the forests were shrinking, game animals were disappearing, the thin mountain soil was wearing out, and people were beginning to leave.

When was Shenandoah National Park established?

In 1926 Congress authorized the establishment of Shenandoah National Park. The Commonwealth of Virginia then purchased nearly 280 square miles of land to be donated to the Federal Government. More than half of the population had left the mountain area, and the remaining residents sold their land or were relocated with government assistance. In dedicating the park in 1936, President Franklin D. Roosevelt initiated a novel experiment in returning an overused area to its original natural beauty. Recreational facilities were built by the Civilian Conservation Corps, and in 1939 Skyline Drive was completed. Croplands and pastures soon became overgrown with shrubs, locusts, and pine; these in turn were replaced by oak, hickory, and other trees that make up a mature deciduous forest. Now, more than 95 percent of the park is covered by forests with about 100 species of trees. The vegetative regeneration has been so complete that in 1976 Congress designated two-fifth of the park as wilderness. The largest remaining open area is Big Meadows, which is being kept in its historically open condition by management fire. Here, the abundance of wildflowers, strawberries, and blueberries attract both wildlife and humans.

What are the permanent and rare residents of Shenandoah National Park?

Deer, bear, bobcat, turkey and other animals that were formerly rare or absent have now returned. Deer and such smaller animals as chipmunk, raccoon, skunk, opossum, and gray squirrel are frequently seen. Bear are found mostly in backcountry areas but are occasionally spotted elsewhere. About 200 species of birds have been recorded. A few, such as ruffed grouse, barred owl, raven, woodpeckers, and junco, are permanent residents. Many more are seen during the warmer months. The park is home to several species of salamanders, and two poisonous snakes, the timber rattlesnake and the copperhead, are occasionally reported, as are several harmless species.

What can you admire in the park?

Whatever time of the year you are here, many new sights and discoveries await you. Between the Skyline Drive and the park boundaries are ridges and valleys, hills and hollows, laced with sparkling streams and waterfalls. Trails take you into the forest of Shenandoah where you can see plants and animals and experience the beauty and peace of this vast recycled land.

What recreation activities does Shenandoah National Park provide for its visitors?

By far the greatest number of people enjoy Shenandoah’s scenic beauty from the 105-mile long Skyline Drive along the Blue Ridge. Numerous parking overlooks present panoramas of the Piedmont to the east and Shenandoah Valley to the west. Park visitor centres provide information services, interpretative exhibits, and illustrated programmes. Naturalist programmes, consisting of evening programmes and campfire talks, hikes, and demonstrations, are offered at several locations; so are self-guiding nature trails with interpretative signs. Family campgrounds and picnic grounds are also provided, having tables, fire-places, drinking fountains, and comfort stations. Accommodations include overnight lodging and restaurants, cottages can be rented. Food service, gift shops, service stations, and facilities for campers – such as grocery and camping supply stores, laundry, and ice and wood dales – are at various points along Skyline Drive. Horseback trips are offered at Skyland Lodge and wagon rides at Big Meadows Lodge. Trails totalling more than 500miles make much of the park accessible to hikers. The trails vary in length from short leg-stretchers to 95-mile segments of the Appalachian Trail that runs the entire length of the park. Fishing for native brook trout provides a challenge to those who are willing to hike to streams in the park.

Shenandoah National Park is your park; please take time to enjoy it and to discover some of its many secrets beyond the Drive.

(Shenandoah NP, Va, National Park Service, US Department of the Interior, 1996)

B) Correspond the facts with the following numbers: 40-mile-long / one billion / 1716 / 1800 / 280 square miles / 1936 / 95% / 100 species / two-fifth / 200 species / 500 miles / 95-mile segments

9.10 Read the text “The Temples of Nature” and fill in the table after it.

THE TEMPLES OF NATURE

When the first miners and hunters returned from the Rocky Mountains, they brought back such marvelous tales of natural beauty that a group of scientists decided to test the truth of their stories. These skeptical scientists, who visited the Rockies in 1870, wrote reports that sounded more like fiction than fact. They described a mountain made entirely of black glass; rivers of ice that were blue-white; magnificent deep canyons; towering white waterfalls; and great caves far beneath the earth.

One night, as the members of the party rested around their campfire, they discussed ways of preserving these magnificent natural scenes. It was finally and enthusiastically agreed that the whole area should be set aside as a great national park for all people to enjoy. This suggestion was accepted by the federal government and, two years later, the Yellowstone National Park came into being. Today some 9,000 square kilometres of this magnificent wilderness are preserved for millions of visitors to enjoy. Since 1872, the system of national parks has grown steadily; by 1981, there were 48 such areas set aside by the national government. State and local governments have added smaller regions.

The land in the national parks belongs to the federal government which bought the areas from the states or private individuals. The government protects the plants and animals native to each national park area. No rancher, miner, hunter or logger may use its meadows, trees or wildlife, except under strict controls.

The parks are under the jurisdiction of the National Park Service, whose rangers protect the areas, guide visitors through the parks, and lecture on the natural phenomena so that the visitor can more fully enjoy the natural monuments, scenery, wild animals and plants. Within the parks, there are campgrounds, cabins and motels available to the approximately 180 million annual visitors.

Yellowstone is still the favourite of tourists. Excellent highways lead into the park; comfortable, inexpensive lodgings are offered. Experienced instructors serve as guides to the famed geysers and hot springs and animals wander about unhunted and unafraid.

Some parks are famous for their scenery; others have special significance for students of geology or cultural anthropology. For example, Mesa Verde National Park is a tableland about 24 kilometres vide, rising 600 metres out of the valley below. It contains the cliff dwellings of some of America’s earliest known Indian tribes. Rocky Mountain National Park is a geological museum which contains the remains of older mountains, canyons, forests and glaciers. Yosemite National Park is famous for its beauty: its waterfalls which cascade 730 metres, and its valleys which have walls over 900 metres high.

But perhaps no scene can equal the Grand Canyon of the Colorado. There, for a million and a half years, the great river has been gouging through the mountain rocks. The most impressive parts of the canyon lie within the 270-square-kilometre Grand Canyon National Park.

More than any other section of the United States, the mountains and deserts are still the country of immense open space. This land, which once barred the way of weary travellers, now has become a land for winter and summer vacations, a land of magic and wonder.

► In what park can you meet: the most impressive parts of the canyon / waterfall cascades / dwellings of some Indian tribes / students studying cultural anthropology / comfortable, inexpensive lodgings / glaciers / valleys with high walls? Fill in the table.

9.11 You are going to read the text “Deforestation” and some quotations from a number of writers around the world. Read and decide how important forests can be in people’s lives. Give reasons.

DEFORESTATION

It has been estimated that an area of tropical rain forest the size of 100 football pitches is destroyed every minute. If this continues the tropical rain forest will have disappeared in about forty years. Forests in more temperate climates are also under threat and you may have read in newspapers about the threat to trees from acid rain. There are many important reasons why we should conserve the forests.

Trees slow down heavy rain before it reaches the soil and their roots help anchor the soil to hillsides. They help to control the amount of moisture in the soil and to maintain its fertility through the rotting of fallen leaves and other fallen vegetation. This natural system of protection fails if the trees are removed.

In every continent of the world soils are being devastated because trees are being cut down, without any regard for the environment, by large timber companies who make huge profits by selling the valuable timber to the richer nations. Some governments encourage the clearing of forests to make more farmland. In many parts of the world local people depend on firewood for fuel for cooking and warmth. They use up trees at an alarming rate and could not afford alternative fuels even if they were available.

You may have seen on television the barren landscape in parts of Africa. Ethiopia is often in the news and when we see that dried-up landscape it is difficult to imagine that only 55 years ago half of Ethiopia was forested. Even fifteen years ago many of the hillsides were covered in trees. Today Ethiopia loses one billion tonnes of soil each year because of wind and water erosion. In Nepal about half the forests have been lost since 1950s and about 20 tonnes of soil are lost from every hectare of treeless mountainside. Soil is thus washed down towards the sea causing rivers to rise and floods to become more and more serious among the villages on the river plains.

In South and Central America farmers have been encouraged to clear the forest to make room for growing crops. This has not been particularly successful as the intensive cropping. After two or three crops have been harvested the soil is no longer fertile and becomes suitable only for rough grazing. From 1966 some 50,000 square kilometres of Brazil’s Amazon jungle were cleared to make way for 336 cattle ranches. The intention was to produce a surplus of beef to export to the USA and Europe. Soon it was realized that the amount of beef produced on this cleared land was a lot less than had been expected, as the forest soils were not as fertile as they had hoped. Only 22 kilograms of beef were produced per hectare of land which compares very poorly with 270 kilograms per hectare on European farms. Similarly in Nepal, where large areas of trees have been destroyed, yields of rice have gone down by 20 per cent and of maize by 30 per cent.

When we think of forests we often think of them as being useful only for timber and producing very little in the way of food for people. Yet the tropical forests provide food, shelter and medicines for millions of people. They can be for growing crops. In Brazil it has been calculated that an area of untouched forest could produce ten times more food than the beef cattle that graze there. Fruits, nuts, game and fish are the main foods found in the tropical forest. Many of the remote and almost forgotten peoples of the world, like the Baka people of Cameroon, get all they need to survive from the forest, as do the peoples and tribes of the South American rain forest, such as the Yanomami who are completely in tune with their natural surroundings. In Britain we have now forgotten what our ancestors knew about the productivity of our forests: providing timber for houses and ships; fodder for farm animals and game and berries to eat. In medieval times the forests were regulated and farmed so they would remain productive and be conserved for future generations. Perhaps we should be encouraging this kind of ‘forest farming’ in other parts of the world so that the fragile soils will be protected and people fed.

Malaysia

Deforestation is usually followed by massive soil erosion with valuable topsoil washed away into rivers. This is a loss of a most vital resource required for agriculture and at the same time a siltation of the river systems causes widespread floods.

(Khor Kok Peng, 1989)

Kenya

Kenya fells up to 20,000 hectares of trees a year but … thanks to efforts at grassroots level, encouraged by government, the country now has a record unparalleled in the developing world of efforts to eventually planting more trees than it fells.

(UNEP News, 1987)

South America

In other regions pristine tropical forest has been converted on a massive scale to cattle pasture. Ironically even small farmed plots in cleared tropical forest areas are often converted to pasture after two or three years because of declining yields on poor soils. Perhaps 90% of tropical moist forest soils are completely unsuitable for any kind of annual agriculture. The only people that have evolved sustainable agroecosystems in these areas are the indigenous and tribal peoples who inhabit many of the still intact rainforests.

(Ecoforum, 1988)

India

The variety of forest resources available and used by the rural people are neither recorded nor appreciated by the government foresters. Arttabandhu Mishra, a researcher … in the eastern coast of Orissa, has recorded that rural people in Orissa get almost all their needs in the forest without destroying it. “There are at least 30 to 40 varieties of roots and rhizomes collected by the villagers from the hill slopes and by asking the old ladies in the villages I learned of 40 types of spinaches and edible flowers …”, Mr Mishra reported. So abundant is the resource that in certain seasons people taking cattle for grazing in the forest rarely take lunch with them because fruits, berries, mushrooms etc. Are so readily available.

(Ravi Sharma, Ecoforum, Dec. 1989)

9.12 Read the text “The Greenhouse Effect” and think what consequences of this phenomenon can be. Name them.

Date: 2014-12-22; view: 1381