Rainforests

• Climate in tropical rainforests

  • No seasons
  • Average temperature between 21° and 30° all year
  • Lots of rain/precipitation (e.g. 2000 mm yearly in Amazon)
• Soil in tropical rainforests

  • Heavy rainfall washes away minerals and nutrients, making soil infertile
  • Nutrient-rich layer on forest floor but does not extend deep underground
• Plants in tropical rainforests

  • Evergreen, don't shed leaves
  • Battle for sunlight, trees can grow up to 46 metres high
  • Interdependence between plants, e.g. epiphytes
• Animals in tropical rainforests

  • Mammals (e.g. gorillas, jaguars, sloths)
  • Reptiles and amphibians (e.g. chameleons, frogs, snakes, crocodiles)
  • Diverse birds and insects
• Life in tropical rainforests

  • Many uncontacted tribes dependent on land, animals and plants for food
• Layers of the rainforest

  • Emergent layer (top)
  • Canopy
  • Understory
  • Forest floor (bottom)
• Tropical rainforests are highly interdependent ecosystems
• Climate and soil in tropical rainforests

  Rapid decomposition in warm, moist climate creates nutrient-rich soil, allowing fast plant growth
• Plants and animals in tropical rainforests

  Animals get nutrition by eating plants, then other animals eat those plant-eating animals, creating a cycle
• Vegetation density in tropical rainforests

  Supports large animal populations by providing abundant food for plant-eaters
• Effects of deforestation


  • Fewer trees to absorb carbon dioxide, contributing to climate change
  • Soil erosion reduces soil quality and ability to support ecosystems
• Plant adaptations in tropical rainforests

  • Buttress roots for stability
  • Waxy leaves to shed rain
  • Lianas and climbing vines to reach sunlight
  • Tall trees to reach sunlight
• Animal adaptations in tropical rainforests

  • Chameleons change colour to camouflage
  • Sloths are nocturnal to conserve energy
  • Flying squirrels have skin flaps to glide between trees
• Tropical rainforests are highly biodiverse, containing 50% of the world's plant and animal species on just 6% of the land surface
• Endemic species


  Species that only live in one specific area, making them more vulnerable to extinction
• Endangered animals in tropical rainforests

  • Giant otter
  • Poison dart frog
  • Jaguar
• Reasons for deforestation


  • Timber sales
  • Road construction
  • Expanding agriculture and cattle farming
  • Building renewable energy infrastructure
  • Expanding housing and mining
• The world's population has grown from 2.5 billion in 1950 to 7.7 billion in 2019, increasing demand for resources from rainforests
• Economic impact of deforestation in the Amazon rainforest for Brazil

  • Fuels the country's economy, provides food and jobs
  • Hydropower provides over 50% of Brazil's energy
• Environmental impact of the Amazon rainforest

  • Absorbs 4% of the world's carbon dioxide yearly
  • Selective logging preserves rainforest structure
• Importance of rainforests


  • Hold valuable products like medicines
  • 50% of all animal and plant species
  • Maintain water cycle stability
  • Act as a carbon sink
• Strategies to manage rainforests sustainably

  • Selective logging
  • Replanting trees
  • International agreements
  • Ecotourism
• Biodiversity


  the variety of life in the world or a particular ecosystem
• Canopy


  the continuous layer of branches in a forest, which in tropical rainforests hosts the majority of plant and animal species
• Carbon sink


  the removal of CO2 from the atmosphere
• Climate


  the average weather over a long period of time
• Climate change


  a long-term change in the earth's climate, especially a change due to an increase in the average atmospheric temperature
• Conservation


  managing the environment in order to preserve, protect or restore it
• Debt reduction


  countries are relieved of some of their debt in return for an agreement that they preserve and protect their natural environments
• Deforestation


  the cutting down and removal of forest
• Ecotourism


  nature tourism usually involving small groups with minimal impact on the environment
• Equator


  an imaginary line that divides Earth's surface into a northern and southern hemisphere
• Global warming


  the increase of global temperatures
• Hardwood


  important resource provided by tropical rainforests
• Indigenous tribes


  native to a particular place, usually living in harmony with the natural environment, using resources without causing long-term harm
• Infertile soil


  soil which is unable to reproduce or sustain life
• International agreements


  promises made between countries and/or organisations to mitigate the destruction of natural habitats
• Leaching


  heavy rainfall quickly dissolves and carries away nutrients in rainforest soils, leaving behind infertile red, iron-rich soil called latosol
• Mineral extraction


  the removal of solid mineral resources from the earth
• palm oil

  raw material extracted from tropical rainforests