Tropical Rainforests

• Where are rainforests located?

  Between the Tropic of Cancer and Tropic of Capricorn
• What are the characteristics of rain in tropical rainforests and why?

  Very high average rainfall with over 2000 mm a year due to an area of low pressure, high transpiration and high humidity
• What are the characteristics of temperature in tropical rainforests and why?

  Very high and around 26 to 28 degrees celsius with a low diurnal range. This is due to the sun shining on the equator continuously
• What are the characteristics of soil in tropical rainforests and why?

  Very nutrient poor and infertile. This is because of leaching which quickly washes away and dissolves the nutrients from organic decomposing matter
• What happens to the soil after leaching?

  Leaves an infertile soil called ‘latosol’ with high levels of aluminum and iron oxide
• Describe the nutrient cycle in tropical rainforests.

  Organic decomposing matter from dead organisms release nutrients back into the soil through decomposition. This process is quick due to the hot and humid conditions. The nutrients are then absorbed by plants and continues the nutrient cycle.
• What is meant by leaching?

  The process of nutrients becoming washed away in the soil due to heavy and continuous rainfall
• • All parts of the tropical rainforest are interdependent
  • A change in one factor affects other factors
  • Deforestation leads to the loss of trees and reduction in biodiversity
  • This then impacts the nutrient cycle
• The tropical rainforest in layers are:

  • Forest floor
  • Understorey
  • Canopy
  • Emergent
• Define ‘deforestation’

  Deforestation is the felling and clearance of trees
• Define the term ‘felling’

  The cutting down of trees
• Define ‘commercial farming’

  Farming of goods and services intended to be exported and make a profit
• Define ’subsistence farming’

  The farming of agriculture intended for the farmer and their family
• What is a cause of human deforestation in terms of hydropower?

  Hydropower, such as dams, generate electricity like Bakun Dam in Malaysia which is one of Asia’s largest dams. In 2010, it flooded and destroyed over 700 km$^2$ of land
• What is a cause of human deforestation in terms of population pressure?

  As the population in Malaysia increases, more housing is needed so the Malaysian government resorted to transmigration, moving its citizens from populated urban areas into underpopulated areas. Between 1956 and 1980’s, about 15000 hectares of rainforest land was felled and cleared for settlers
• What is a cause of human deforestation in terms of logging?

  Trees are used for timber, mahogany and other goods. Malaysia became the world’s largest exporter of tropical wood in the 1980’s and clear felling was common which led to large areas of rainforest land becoming destroyed
• What is a cause of human deforestation in terms of mining?

  Rainforests are rich in valuable products like iron, aluminum, gas and oil. In 2021, an iron ore mine was planned in the Som Forest reserve which has many endangered species including the famous Malayan tiger. The mine would also lead to the destruction of over 60 hectares of rainforest land.
• What is a cause of human deforestation in terms of commercial farming?

  Malaysia has many resources of the palm plant and is one of the world’s largest exporter of palm oil and the second largest producer. In the 1970’s, many areas of rainforest land were felled and cleared into palm oil plantations and farmers received 10 year tax incentives which encouraged the growth of these plantations
• What is a value of tropical rainforests in terms of resources?

  Around 25% of Western pharmaceutical drugs come from rainforest plants, such as novocain from the coca plant used as a local anaesthetic. It is also full of timber, bananas, sugar, cocoa and vanilla
• What is a value of tropical rainforests in terms of water?

  Rainforests provide fresh water to millions of people, for example 20% of the world’s fresh water comes from the Amazon Basin
• What is a value of tropical rainforests in terms of carbon sink?

  Rainforests absorb high levels of carbon dioxide. In fact, the Amazon rainforest alone absorbs about 5% of the world’s carbon emissions yearly
• What is a value of tropical rainforests in terms of atmosphere?

  Rainforests produce about 28% of the world’s oxygen supply. They also provide moisture to areas around the world via atmospheric circulation which prevents many places becoming arid
• What is an impact of deforestation in Malaysia in terms of climate change?

  Malaysian rainforests are estimated to absorb 30% of its carbon dioxide emissions in the country. When trees are felled, more carbon dioxide is left in the atmosphere contributing to the enhanced greenhouse effect. Additionally, the lack of trees decreases transpiration rates and produces more arid land. For example, commercial slash and burn occurred across 10000 square miles in 2015
• What is an impact of deforestation in Malaysia in terms of soil erosion?

  When trees are felled and cleared, the heavy and continuous rain will more easily wash away the nutrients in soil, leaving a latosol behind. Without tree roots binding soils together and humus collecting on the floor, the soils quickly erode away. Annually, 883 tones of soil is eroded in Malaysia
• What is an impact of deforestation in Malaysia in terms of indigenous people?

  Indigenous people lose access to their homes, have less animals to hunt for and catch diseases from the outside world. For example, in the Batek tribe in Kuala Koh village in 2019, 15 people were killed from a disease possibly transmitted by foreign loggers
• What are economic gains of deforestation in Malaysia?

  • Products like rubber, palm and timber provide raw materials for industries and exports
  • Hydroelectric power supplies plentiful and cheap energy
  • Improved transport infrastructure connects more areas easily
  • Development of land for mining and farming produces more jobs, directly and indirectly
• What are economic losses of deforestation in Malaysia?

  • Plants with important medicinal features can become extinct
  • Climate change can alter the growth of crops like palm, vanilla and bananas
  • Pollution of water sources
  • Ecotourism rates decrease
  • Fires from wildfires or slash and burn can lose control and damage huge areas of land
• What are international strategies to manage tropical rainforests?

  • Debt reduction - countries are relieved of some or all debt in return for protecting the rainforest, referred to as debt for nature swaps. In 2010, the US declined 14 million USD from Brazil as debt and instead put it in a rainforest fund
  • The Forest Stewardship Council (FSC) is an international organization that promotes sustainable forestry and hardwood use
• What can ecotourism be used as to manage tropical rainforests?

  • This is a form of sustainable tourism that aims to have reduced environmental impact and support conservation efforts and indigenous people. The Chalalan ecolodge in Bolivia is ran by indigenous people and attracts over 1600 people a year
• How can selective logging be used to manage tropical rainforests?

  • This is the felling of specific trees to reduce the environmental effect of logging. Only mature trees are used so younger ones are left to grow and develop. Additionally, trees are marked to track illegal logging and cut away from other trees to prevent damage to them. An example of this is Malaysia’s Selective Management System (MSMS)
• Label the parts of a rainforest

  A) Emergent

  B) Canopy

  C) Understorey

  D) Forest floor