NAN HUA HIGH SCHOOLSECONDARY 3 PURE GEOGRAPHY NOTES - TOPIC: NATURAL VEGETATION (Chapter 11)_____________________________________________________________________________________________Name: _______________________________________( ) Class:_______________Deforestation defined:Deforestation is the permanent clearing and destruction of forest.CAUSES of Rapid Deforestation in the World:Main cause: Rapid population growth Forests are being deforested mainly because of rapid population growth leading to the increase in demands of forest resource for socio-economic benefits. Rapid deforestation is largely brought about by human activities which are driven by social-economic development factors.Other causes: Social-economic Demand for more land to produce agricultural products mainly food crops Cleared land for new settlements which has been relocated from over-crowded cities New roads to improve transportation and communications Land for industrial development such as logging and mining Valuable timber and other forest products obtained for big profits Clearing for mining of mineral deposits which are found underground in the forested areas[With Reference to Case Study: Kalimantan, Indonesia]Cause 1: Increase in demand for agricultural land Forests are cleared to provide land for increased scale of agricultural activities due to increase population growth. - For example, in Kalimantan under the Indonesian government’s resettlement programme, the resettlement of people from overcrowded Java and Sumatra has created this demand. - Many new settlers permanently clear forests to establish small holdings or farms where crops are grown; some who are motivated by profit from crops has extended their farmland by clearing more forested areas. Deforestation is also caused by the growth of oil palm plantations which is a very lucrative business. - In Kalimantan, extensive areas of the rainforests have been cleared to make way for plantations. - Between 1998 and 2003, about 10000 sq km of the forests were converted to plantations.Cause 2: Growth of settlements More forests are being cleared for housing as population increases and settlements become more crowded. In parts of Kalimantan, the rural-urban migration due to urbanization has led to overcrowding and forests are cleared for the expansion of those towns and cities. - For example, the growth of Balikpapan in East Kalimantan has expanded into the areas of a protected forest and reduced its area by a third.Cause 3: Improved transport networks Forests are cleared to make way for roads, railways and expressways in order to increase accessibility between settlements and cities. (Note: easy access is needed for social-economic activities to be carried out) - For example, the 230 km long Trans Kalimantan highway cuts through the rainforests to link two cities of Banjarmasin and Balikpapan. The transport networks also allow access to previously remote forested areas and this unfortunately has made it easier for people to destroy even more areas of the forest.
NAN HUA HIGH SCHOOLSECONDARY 3 PURE GEOGRAPHY NOTES - TOPIC: NATURAL VEGETATION (Chapter 11)_____________________________________________________________________________________________Cause 4: Growth of industries As forest are rich in natural resources such as wood and minerals, the increase in demand for such resources has led to the clearing of the forests to support industrial activities. The growth of industries such as logging and mining destroys the forest extensively as the sale of timber and minerals are lucrative source of income. Logging: - For example, in West Kalimantan, heavy logging caused an average of 1656 sq km of forests to be lost annually. - The increased pace of wood processing and exports has resulted in heavy logging. Mining: - Mining of minerals such as gold, silver and copper, exposed the grounds and created adverse environment impacts on the quality of water as well as poisoned the animals with chemicals such as cyanide. In addition, illegal logging has worsened the rate of deforestation.Cause 5: Forest fires Forest fires also destroy large areas of the rainforest in Kalimantan. Plantation companies deliberately start fires to clear large areas of forests for growing oil palm as this is cheaper than employing labourers to clear the forest.PROBLEMS of Deforestation:Problem 1: Loss in biomass Tropical rainforests having the highest biomass, the stored energy to support life measured in kilocalories, will suffer much loss due to massive destruction of the rainforest. - Deforestation in Kalimantan has contributed to the reduction of the Earth’s biomass as the rainforests in Kalimantan form a significant proportion of the Earth’s biomass. - This reduction in biomass reduces the ability of the Kalimantan rainforests to support various plant and animal life because the food chain is adversely affected. When the plants are removed, they affect the survival of animals higher up the food chain, as they are the basic source of food in the ecosystem. In addition, the reduction of the biomass has adversely affected the amount of nutrients in the forest ecosystem, which also reduces the ability of the Kalimantan rainforests to support various plant life. Composition Composition of nutrients in Composition of nutrients when forest vegetation of Nutrients tropical rainforest removed / deforested Biomass High temperatures and rainfall throughout the When some of the vegetation in the tropical year encourage the rapid growth of tall and rainforests are removed, the store of nutrients in dense vegetation, which forms a large biomass. the biomass is reduced. Leaf litter Although leaves continuously fall on the forest The amount of leaf litter is removed and results in a floor, the hot and wet environment results in the much smaller amount of nutrients stored in the leaf rapid decomposition of the leaf litter and the litter. release of nutrients. As the nutrients are quickly absorbed by the soil, the amount of nutrients in the leaf litter is reduced/limited. Soil The rapid breaking down of dead leaves, twigs Consequently, the amount of nutrients stored in the and branches by worms, insects and small soil is reduced and affects the grow of vegetation. organism in hot and wet conditions are returned The nutrient cycle is broken when no as nutrients to the soil, making the soul more decomposition occurs as trees have been removed fertile. or the increase in surface runoff carry the leaf litter away before decomposition. The exposed ground is subjected to leaching, a process which the rain carries the nutrients out of the topsoil into lower layers at it moves down the soil, reducing soil nutrients.
NAN HUA HIGH SCHOOLSECONDARY 3 PURE GEOGRAPHY NOTES - TOPIC: NATURAL VEGETATION (Chapter 11)_____________________________________________________________________________________________Problem 2: Loss of biodiversity The Kalimantan rainforests contain a very high biodiversity of plants and animals. Due to deforestation, the lost of habitats causes the biodiversity of plants and animals in the Kalimantan rainforests to be reduced. As a result, some plants and animals are close to becoming extinct and are therefore endangered, for example the Proboscis monkey in Kalimantan.Problem 3: Changes in the nutrient cycle The removal of vegetation following deforestation results in the loss of leaf litter and affects the nutrient cycle. - Soils are also leached due to the absence of roots, where the absorption of rainwater is reduced. - As a result, the soil becomes infertile and cannot support vegetation growth. - Therefore very little of the original vegetation could be replaced back and the cleared land also becomes unsuitable for cultivation of crops over time.Problem 4: Changes in quantity of water When trees and other plants are removed, less transpiration takes place. This reduces cloud formation and results in low rainfall. - In Kalimantan, deforestation could have a direct impact on the amount of rainfall received during 1997– 1998, which caused droughts or prolonged dry seasons. On the other hand, floods can be triggered by deforestation. In recent years, many floods have occurred in places where deforestation has taken place in Kalimantan.Problem 5: Changes in quality of water In areas where the rainforests are cleared, the water quality in rivers is generally poor because the soil is eroded and washed away easily by rain into the nearby rivers. This, in turn, increases the sediment level of the rivers and makes the water muddy. The increased amount of sediment in the rivers also changes the pH level of the water by making the water acidic. The increased acidity in the water adversely affects the aquatic life in the rivers of the Kalimantan rainforests.Problem 6: Air pollution When trees and other plants are removed by burning, dust and smoke are released into the air, causing air pollution and resulting haze problems. - Since the 1990s, haze has been a recurring problem in the Southeast Asian region due to the widespread burning of rainforests in Sumatra and Kalimantan. - On several occasions, strong winds have blown smoke and dust particles from the forests to nearby countries like Singapore and Malaysia. - As a result, many people in the region suffered from health problems. The haze also caused everyday activities to cease. For example, in September 2002, schools were closed when the Pollution Standard Index in Central Kalimantan reached 1 500, 15 times more than the safe level of 100. The haze also adversely affected the tourism industry in the Southeast Asian region. - For example, flights were cancelled due to the poor visibility and tourists avoided visiting the region in 1997–98.