Explain why deforestation in theamazon rainforest is a continuing concern.

Explain why deforestation in the amazon rainforest is a continuing concern.

Deforestation is a major global problem with serious consequences to the planet. These consequences have a negative effect on the climate, biodiversity, the atmosphere and threatens the cultural and physical survival of life.

Deforestation is the permanent destruction of indigenous forests and woodlands. It has resulted in the reduction of indigenous forests to four-fifths of their pre-agricultural area, so that now indigenous forests cover only 21% of the earth's land surface.

CAUSES

Commercial logging, clearance for agriculture, roads and railways, forest fires, mining and drilling, fuel wood collection and clearance for living space are all intimately connected with deforestation. Tropical forests are destroyed for several reasons, each of which have both similar and differing ecological consequences, none of which are beneficial. There is an ever increasing demand for both farm and grazing land which results in the burning and clearing of rain forests for agriculture production.

Another cause of deforestation is the continued urbanization of the world and thus the need for construction of roads and industrialization. The need for fuel and timber for construction is another major factor leading to the destruction of the rain forest. The two most commonly causes of deforestation are shifting cultivation and commercial logging for teak, mahogany, rosewood and other timber for furniture, building materials, charcoal and other wood products. In the past, local peoples have farmed the rain forests, cutting down trees to allow cultivation of crops and grazing space for animals, and moving on when the soil becomes less fertile. This is no threat to the forests, provided that it is carried out sensibly, and used areas are left to regenerate for long periods before repeating the process. Problems arise when the land is not allowed sufficient time to recover and intensive farming results in irreversible soil degradation. This is the present situation, due to the needs of the growing population - and some sources identify shifting cultivation as the cause of 70 per cent of the deforestation in Brazil.

In the last two centuries populations have expanded, requiring more and more space for housing and agriculture. Before intensive mechanized logging took over from the use of handsaws, axes and animal power, it could be argued that the timber trade posed little threat to tropical rain forests, but the arrival of chainsaws, tractors, roads and railways had a much greater impact.

Also the Brazilian government, they want to exploit the rainforest so that all debts can be wiped. Their plan is to build roads, dams, power lines and gas lines, and although they claim that it would not destroy much of the rainforest, the new roads would allow illegal loggers and hunters into the area to clear the land. The huge multi-national logging companies and the smaller logging companies would like these new roads in the Amazon basin to be built as it would make the transport of timber easier. suppressed discogal_87's structuration .

EFFECTS

Deforestation leads to animal extinction because the forest is a shelter to many animals as well as a source of food for them. A 10 square kilometre (4 square miles) area of tropical rain forest contains about 700 animal species and thousands of insect species. Scientists estimate an average of 137 species of life forms are driven to extinction every day. Animals that live under the canopy of trees in the rainforests have adapted to survive in the humid, tropical environment so when deforestation claims the natural habitat of these animals, they are forced into more open areas ...

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EFFECTS

Rainforests are also home to many undiscovered plants that could be used to treat diseases. It is said that a 10 square kilometre (4 square miles) area of tropical rain forest contains more than 1500 plant species. Twenty-five percent of the medicines prescribed in the United States today come from tropical forest plants. Currently, about 120 prescription drugs that are used worldwide contain plant-derived ingredients from the rainforests. It is estimated that only 10 of tropical plants have been tested by scientists for medical uses. This should be a strong incentive to protect what remains of this potential medical resource. For example, no US pharmaceutical manufacturers were involved in research programs to discover new drugs or cures from plants in 1983; today, more than 100 pharmaceutical companies and several branches of US government are involved in research projects that hope to develop cures for Viruses, infections, cancer, and AIDS from plants. If this resource is destroyed, the cures for many diseases might not be discovered.

The natural greenhouse effect is the process where gasses in the lower part of the atmosphere trap heat energy leaving the earth, human beings use this heat to survive. Deforestation leads to increasing levels of carbon dioxide in the atmosphere, because there are less plants to use this gas for a process known as photosynthesis, there is a build up. Also the burning of trees releases carbon dioxide into the atmosphere, approximately 10% of the carbon dioxide released into the atmosphere in 1987 was due to fires in the amazon. Carbon dioxide along with water vapour , methane, nitrous oxide, ozone and CFCs make up the greenhouse gasses. An abundance of these gasses in the atmosphere cause an 'enhanced greenhouse effect', which can cause global warming. The average temperature of the Earth's surface has increased by upto 1.2 F since the late 19 century and scientists predict that by the year 2100 will have increased by upto 6.3 F. Global warming rises the Earth's temperature which can result in drought. It can also cause the polar ice caps to melt, which can cause sea levels to rise 2 to 4 cm per year resulting in flooding.

With deforestation comes soil loss. The removal of trees and shrubs exposes the soil which leads to erosion. Erosion leads to the removal of the thin upper soil layers. This, in turn reduces organic matter content and vegetation growth. Soils that lose organic matter can no longer retain moisture between rainy seasons; when precipitation increases, the soil remains unproductive. The most significant type of soil loss is through landslides. Landslides induce soil loss by mass movement, and occur in natural forests and grasslands. Increased frequency of landslides often occurs in areas recently deforested. They remove soil under indigenous forests and that soil is then replaced by new vegetation cover. Another form of soil loss is from intense rain after deforestation. When deforestation takes place the soil is left with nothing to protect it as the trees prevents the rain reaching the soil at full impact, so the soil becomes very loose and can be easily washed away. Silting of water courses, lakes and dams is also a result of soil erosion.

Deforestation also contributes to desertification which is the spread of deserts into semi arid lands. It is said this happens because an increase in the amount of trees being destroyed leads to a loss of vegetation and an increase in soil erosion. The soil erosion leads to greater demands being made on the productive land that is left. As a result, the carrying capacity of the environment is exceeded and the fragile soils of the semi arid regions are destroyed.

Social Effects of Deforestation

The process of deforestation had numerous social effects for the population of Brazil and the world. It is equally important to note that besides the indigenous population, there were also agriculturalists, hunters, and extractives that lived in the rainforests.

The agriculturalists, mostly Portuguese-speaking settlers, occupied the varzeas, the fertile flood plains, for permanent agriculture. This was possible because soil fertility was renewed annually during flooding. In 1990, the flood plains made up about 5 per cent of the Amazon's areas and the flood plains included over half of all the land suitable for permanent agriculture. Their lifestyles were similar to the indigenous population, but unlike the indigenous population, they sold some crops, fish, jute, and the like to local traders.

The third groups are the hunters, agriculturalists, and extractives. Extractives collected rubber, Brazil nuts and other forest product to sell. They used the money to buy necessities, such as tools, guns, and a few staples. Most of the people in this group, like the indigenous people practiced long uncultivated shifting agriculture and kept a few animals.

All three groups and in particular the indigenous population suffered greatly from the process of deforestation. Case studies documented in detail how outside people invaded the indigenous population reserves and how various devices deprived the indigenous people of their traditional lands and forest. Gold prospectors brought diseases that soon wiped out most of the indigenous population. The mercury gold prospectors used to separate gold from sand polluted drinking water and fish. Consequently, the indigenous population suffered greatly from mercury poisoning because fish was the primary source of protein for them. Cattle ranchers, loggers and land speculators also invaded the indigenous lands. Many forests, especially those near navigable steams were cleared. This affected fish reproductions, since most fish species depended on forest sources. Water reserves, hydrologic regime, soils and local climates, and agricultural productivity were also affected.

The other two groups of traditional rainforest dwellers also suffered greatly from the effects of deforestation. There was widespread mercury poisoning, pollution from mine sludge, and the intensive use of herbicides to control the growth of vegetation near power lines and roads. Fish populations and agricultural production was declining. These problems were further compounded by dams. They changed fish migrating patterns and flooded numerous communities.

Effects on Biodiversity

The process of deforestation in various geographical regions is destroying this unique environment. Consequently, many animals and plants that live in the rainforests face extinction. The lack of biodiversity could have many unexpected consequence, some of which could be fatal to the future of humanity. In particular, medicine may benefit from the cultivation of certain plants that grow only in rainforests. The medicines that come from them could cure cancer, AIDS, or other terminal diseases. Preserving the rainforest would leave many opportunities in medicine and many other fields open for future generations to explore and further advance humanity.

There are people that see the forest as sources of money. These people exploit the forest. They cut down trees for rare, exotic timber that sell at high prices. Their primary concern is profits. In the short term, they can make huge profits selling exotic timber. If this is continued for some time, eventually, there will be no more trees to cut down. People who make their living cutting and selling trees will go bankrupt. The same thing applies to gold mining and raising cash crops. In the case of cash crops, what happens is the soil, which is usually poor to begin with, further degrades until the soil is no longer good for agriculture. People who make their living off of raising cash crops are forced to move to other areas until all the soil goes bad.

First of all, clearing the timber exposes the soil to the sun and makes the soil susceptible to erosion. The soil itself is not really good for agriculture, and the soil becomes totally useless in a matter of years so the cycle is started again. This rapid destruction of rainforest has various effects of forest dwellers and animals.

Environmental impacts

When an area of rainforest is either cut down or destroyed, there are various climate changes that happen as a result. The following is a list of the various climate changes with a brief description of why they come about.

1. Desiccation of previously moist forest soil

What happens is because of the exposure to the sun, the soil gets baked and the lack of canopy leaves nothing to prevent the moisture from quickly evaporating into the atmosphere. Thus, previously moist soil becomes dry and cracked.

2. Dramatic Increase in Temperature Extremes

Trees provide shade and the shaded area has a moderated temperature. With shade, the temperature may be 98 degrees Fahrenheit during the day and 60 degrees at night. With out the shade, temperatures would be much colder during the night and around 130 degrees during the day.

3. Moist Humid Region Changes to Desert

This is related to the desiccation of previously moist forest soil. Primarily because of the lack of moisture and the inability to keep moisture, soil that is exposed to the sun will dry and turn into desert sand. Even before that happens, when the soil becomes dry, dust storms become more frequent. At that point, the soil becomes useless.

4. No Recycling of Water

Moisture from the oceans fall as rain on adjacent coastal regions. The moisture is soon sent up to the atmosphere through the transpiration of plants to fall again on inland forest areas. This cycle repeats several times to rain on all forest regions.

5. Less Carbon Dioxide and Nitrogen Exchange

The rainforests are important in the carbon dioxide exchange process. They are second only to oceans as the most important for atmospheric carbon dioxide. The most recent survey on deforestation and greenhouse gas emissions reports that deforestation may account for as much as 10% of current greenhouse gas emissions. Greenhouse gases are gases in the atmosphere that literally trap heat. There is a theory that as more greenhouse gasses are released into the atmosphere, more heat gets trapped. Thus, there is a global warming trend in which the average temperature becomes progressively higher.

6. Soil Erosion

The relationship between deforestation and soil erosion. Deforestation is known to contribute to run-off of rainfall and intensified soil erosion. The seriousness of the problem depends much on soil characteristics and topography.

7. Other Effects

There many rewards such as clean air and clean water, perhaps the two most important, that forests provide. Rainforests also provide many aesthetic, recreational and cultural rewards. If the rainforests are destroyed, then these rewards disappear. This has major social consequence for the entire world.

SOLUTIONS - Sustainable Development

If development in the rainforest is to be sustainable (e.g. although the resources are used to aid development, it/they will still exist for future generations to use) a number of measures must be taken. These include:

Afforestation - Trees should be replanted in areas of deforestation.

Shifting Cultivation - Farmers should move on after 2-3 years to allow the rainforest to recover.

Rubber tapping - More sustainable methods of exploiting the rainforest should be pursued e.g. rubber tapping

Measuring trees - Trees should only be cut down when they reach a certain size. This will ensure younger trees survive longer and will encourage careful management of the rainforest.