In addition to this, deforestation is causing a decrease in the supply of hardwood. Only about one tree in twenty is of economic value to the timber companies, but their machinery, and falling timber, destroys many of the surrounding trees. As a result, some species, such as mahogany, greenheart and rosewood are becoming endangered. A decrease in soil fertility is also an unintended environmental consequence of deforestation. In order to live, trees take nutrients from the soil. Dead trees, and leaves shed from trees, rapidly decompose in the hot, wet climate. This allows the nutrients to be returned to the soil. This process is called the humus, or nutrient, cycle. If trees are removed then the cycle is broken. Humus will not replace nutrients in the soil and will be washed away (leached)-by the heavy rain. Within three or four years the soil becomes infertile. The forest Indians overcame this problem by moving home every few years (shifting cultivation). Cattle ranchers, having cleared vast areas, now have to do the same - leaving large areas scarred and unusable. Former families without land, resettled here by the government, have seen the soil become too infertile to grow sufficient food to feed them. Many have abandoned their new farms and moved to urban shanty settlements.
In spite of this, deforestation has also caused many local benefits such as the fact that more jobs are available like mining, logging and tourism and resettlements provide better quality of life for people living in urban shanty towns. Moreover, most rainforests are located in LEDCs, like Brazil and Indonesia, which means money earned from export of timber and ores will increase GDP (Gross Domestic Product) and lead to economic and social development and improve quality of life.
There are also many global effects of deforestation like the loss of medicine. Over half of our modern medicines come from the rainforests. These include painkillers and quinine (used to treat malaria). Recently one plant, a periwinkle, has proved successful in treating child leukaemia. Perhaps the rainforests may hold cures for cancer and AIDS. Deforestation may prevent the discovery of new plants with possible medical value. Forests absorb a lot of sunlight for photosynthesis, and only about 12 to 15% is reflected. The large amounts of energy absorbed by forests acts to stimulate convection currents in air which enhance the production of rainfall. Tropical rainforests in particular are very wet and humid places. Deforested areas, by contrast, reflect about 20% of incoming sunlight. Deforested areas consequently have unintended environmental consequences and can become drier as a result of the loss of vegetation, increasing the risk of . As the area of deforestation increases, so the impact on climate grows.
Trees also absorb from the atmosphere for photosynthesis, and therefore help to regulate the natural , whereas animals breathe in oxygen and breathe out carbon dioxide. Deforestation takes away a potential sink for the carbon dioxide mankind is pumping into the atmosphere through human activities. In addition, if forests are removed by burning, a lot of extra carbon dioxide locked up in tree wood is returned to the atmosphere. This unbalance of carbon dioxide and oxygen could cause global warming and result in temperatures increasing globally destroying many fragile environments.
However, there are ways of preventing such problems. We can protect core areas of forest free from any human activity and establish a ‘buffer zone’ outside core areas and encourage economical but sustainable use of the forest. For example by extractive reserves for rubber and gathering of fruits/nuts only, timber to be felled in narrow strips and then allowed to regenerate and finally by leaving small arable areas, protected by shading trees. The Forest Stewardship Council also links timber producers to customers and gives assurances that timber and timber products are only from areas of sustainable logging. Finally, the MEDCs have to contribute to share the ‘cost’ of conserving the rainforest, and ensure that the living standards of all people in LEDCs improve!
Evaluation
In this project I have gained knowledge about deforestation and the local and global consequences of it. I have learnt that there are both benefits and problems with deforestation. Some of the benefits include the fact that there are more jobs provided which effectively means more money for the country. This in turn is used to help improve the quality of life of everyone. It also allows more people to resettle which gives a healthier live for people living in urban shanty towns. However, there are more problems with deforestation than benefits like the elimination of traditional groups and their way of life, loss of wildlife and prevention of medicines being discovered. In addition to this, deforestation causes soil erosion and more severe and frequent floods, more carbon dioxide that would result in global warming and climatic change and finally a decrease in the production of hardwood. The fact that more human activities involve giving off carbon dioxide and there are fewer trees to produce oxygen and absorb carbon dioxide, means that there is a strong possibility that there is going to be a short supply of oxygen. Furthermore, our rainforests could even turn into ‘deserts’ as a consequence of a decrease in water vapour because of the greatly reduced number of trees. In order to prevent such drastic consequences we need to manage the rainforest in a sustainable way and use our natural resources more effectively.
