as the 'lungs (polmoni) of the earth' and convert large amounts of the greenhouse gas carbon dioxide back into oxygen. It is estimated that the Amazon rainforest alone produces about 20% of the earth's oxygen. Flood control (part of the precipitation that is temporarily stored in the top layer of the forest floor and successively evaporated within a few hours or days during and after the rainfall event Rainforests are an excellent natural measure to reducing flooding. There is leaf cover in rainforests all year so interception continually happens, extending rivers lag time (scarto temporale). grazing (pascolo). Farming: Because of the large amounts of poor people that still live in tropical areas, farming is still Because rainforest soil loses its fertility quickly after the most common form of farming is slash and burn. With growing this method of farming can cause HEP (global power): Many of the world's great rivers flow through e.g. the Amazon. These bird extinction can be extrapolated to approximately 23,000 extinctions. Reduced photosynthesis: As more and more trees are removed the rate of photosynthesis reduces, releasing more carbon dioxide into the atmosphere and contributing to the greenhouse effect. Silting (riempirsi di of rivers: With increased flooding and surface run-off moil soils and silt is washed into rivers, this can not only change local ecosystems (water temperature and clarity) but can also reduce the depth of rivers making navigation harder. Silting of seas and oceans: With the increased frequency of flooding and landslides more silt gets washed into the oceans. The increased amount of silts reduces the transparency of the sea reducing the light reefs receive and the temperature of the water. Increased silt can also block important shipping lanes. Breaking of nutrient cycle: The top soil of rainforests is very thin an receives the majority of its nutrients from rotting flora and fauna. Be removing trees you also remove animals and therefore the source of the soils nutrients. With increased erosion the top soil (humus) layer is quickly washed away. Because rainforest soil its fertility very quickly after deforestation it quickly becomes hard to grow any vegetation on it, leading to sandification and possibly desertification. e e
All vegetation uptakes water and transpires it. Control of soil erosion: The root systems of trees and shrubs hold the very thin soil of rainforest in place. If trees are removed then both erosion of topsoil and landslides are more likely Source of nutrients to humus layer in soil: The topsoil in rainforests is very thin and relies (contare su) on the nutrients provided by rotting plants and animals. Because of the rainforests climate, there is a constant supply of leaf litter. Medical remedies: Rainforests have been the source of many of today's drugs, including the basic ingredients for the hormone increasing great rivers often have the most HEP potential. when a dam (diga) and reservoir are built it causes damage during but also floods large areas. Mining: With an ever increasing demand for the world's natural resources, countries and are looking at isolated locations, places like and The are believed to have many resources including metals and fossil fuels beneath their soils. Gold mining can be particular damaging as Loss of indigenous homes: By clearing rainforests you are obviously destroying the homes of indigenous groups. But also moving close to indigenous groups can spread disease and alter local culture and traditions. Reduced rainfall: Deforestation can lead to reduction in local rainfall because less water is intercepted and transpired from vegetation into the atmosphere reducing the formation of clouds and rainfall. rainforest Antarctica
pill, quinine (a anti-malaria drug) and curare (a paralysing drug). Cash and products: Yam, coffee, rubber, mango, banana, sugarcane, cocoa and avocado were all first discovered in rainforests. With people becoming ever more conscious and looking for adventures, ecotourism to rainforests is increasing. This not only helps protect rainforests, but creates income for locals. Ecotourism is an important income to countries like Costa Rica and Belize. Home to indigenous groups: Although the number mercury is used in its extraction and often runs off into rivers. Road building: Building new roads like Trans Amazon highway from Brazil to Bolivia not only causes itself, but its also opens up new areas to mining and farming causing further growth: With the world increasing as well as rates of increasing many cities like Manaus in Brazil are growing rapidly causing growth: As grow,
of indigenous groups and people have declined rapidly since in South America, it is estimated that there are still over 200,000 people that consider the Amazon their home. in countries like Brazil, Peru, India and Vietnam that contain the demand for land increases, both to grow food and to live). Primary products are often seen as an income source for LEDCs, many of who have large areas of rainforest. At the same time with fossil fuels running out, fuels sources are been searched for including biofuels e.g. Palm oil. This has lead to in countries like Malaysia and Indonesia to plant cops like palm oil. rainforest
Human Causes of Desertification Physical Causes of Desertification Allowing too much livestock to graze on a piece of land which means all the vegetation is eaten making the ground susceptible to wind and water erosion. If you farm land to intensively and don't have fallow periods then all the nutrients in the soil get used. Cutting down trees which not only means the land will be receiving less nutrients, but it also means it is more vulnerable to erosion because there is no and less stability because the root systems have been removed. As the world population Rising As global increase it is becoming hard for to grow thus reducing cover and the risk of wind and water erosion. Falling Rainfall: As the amount of rainfall reduces in some areas like the Sahel, then it is hard for to grow again making the ground more to wind and water erosion. Flash floods: Intense periods of rainfall can also cause erosion of topsoil which leads to
scale dust storms. Northern China is suffering from an increased of dust storms as takes place south of the Gobi Desert. Reduced Crop Yields As the soil becomes less fertile the amount of crops that it can support will reduce. The falling crop yields can lead to famine and Conflict: With soil and reduction in output and available land conflict can arise over so that soil can regain its fertility. Shelter Belts: Shelter belts called wind breaks) are areas of forest or hedge that are left untouched to protect farmland from the affects of water and wind erosion. Shelter belts will often appear around the outside of fields. and By or areas you can help return land to its natural state, making it more fertile and stable, thus reducing wind and water erosion and ultimately land
Famine: If the soil become degraded and cops begin to fail or the yields reduce in quantity then famine can happen. Famine is normally caused by a of factors, soil drought and possibly a natural disaster or conflict, so if soil degrades it increases the potential of famine. Irrigation: It is possible to water areas of land that have become arid to try and improve the of the soil. However, if water is not used then irrigation can cause water shortages and land Grazing Quotas: Placing limits on the number and types of animals that can graze on land, reducing the of vegetation and eventual Control: The main reason we are putting more pressure on the earth's resources (including