Tropical Rainforests

• LOW AND HIGH PRESSURE

  • low pressure is caused by warm air rising
  • high pressure is caused by air cooling and sinking
  • winds move from HIGH pressure to LOW pressure
  • all these pressure systems create loops forming CELLS around the earth
• AT THE EQUATOR

  • the sun heats the earths surface, causing the air to heat and rise
  • this creates a low pressure belt
  • As the air rises it cools and moves out, away from the equator to 30 degrees north and south
• • 30 degrees north and south of the equator, the cool air sinks, creating a high pressure belt
  • once the cool air reaches the ground it moves as the surface winds blowing either towards the poles or the equator
• • At 60 degrees north and south of the equator, the warmer surface winds meet the cool polar winds. The warm air is less dense so rises, creating low pressure
  • Some of the air moves back to the equator, some moves towards the poles
• • At the poles the warm air sinks, creating high pressure. The high pressure is drawn back towards the equator
• WHAT IS ATMOSPHERIC CIRCULATION?

  The atmospheric circulation model suggests how air moves from the equator to the poles around the planet. It moved int these cells because, the insolation (energy from the sun) is unevenly distributed, it is higher at the equator than it is in the poles
• PLANTS AND ANIMALS

  • The climate provides ideal conditions for plant growth, creating extremely lush and dense vegetation.
  • The is a great biodiversity (variety of life) up to 100 in a single hectare. It supports the largest number of plant and animal species of any biome
  • Most animals are found in the canopy where there is maximum light (monkeys are well adapted to living in trees). Animals such as wild boars, live on the forest floor eating seeds and berries
• STRUCTURE OF A RAINFOREST

  • emergents
  • canopy
  • under canopy
  • shrub layer
  • soils
• SOILS IN A RAINFOREST

  • Red colour due to high iron and aluminium content and infertile
  • Thick layer of leaf litter and decomposing organic matter on the surface
• RAINFOREST NUTRIENT CYCLE:

  • The rainforests nutrients cycle is quick
  • Hot, damp conditions on the ground allow the dead plant material (e.g. leaves) to rapidly decompose
  • This provides rich nutrients, which are absorbed by the plants shallow roots, however these are in high demand, they don’t stay in the soil for long and stay close to the surface
  • If the vegetation is removed, heavy rainfall can dissolve and carry away nutrients from the soil(leaching creating latosol (infertile, iron rich, and very acidic red-coloured soil). The rain can also erode the soil away
• RAINFOREST WATER CYCLE

  1. Heavy daily conventional rain
  2. Trees intercept rain
  3. Some rain reaches the ground
  4. Trees take up water
  5. Water evaporates
• RAINFOREST NUTRIENT CYCLE

  1. Trees shed leaves all year round
  2. Decaying vegetation decomposes rapidly
  3. Nutrients enter the soil
  4. Shallow roots take up the nutrients
  5. Trees grow rapidlya
• PLANT ADAPTATIONS

  • drip tips
  • thin, smooth bark
  • lianas
  • buttress roots
  • epiphytes
• LIANAS

  Woody creepers rooted to the ground but carried by trees into the canopy where they have leaves and flowers (maximise sunlight they receive)
• EPIPHYTES

  Plants which live on trunks and branches of other plants, allows them to make the most of the sunlight in the canopy layer
• DRIP-TIP LEAVES

  Allow the heavy rain to drip off the leaf. This prevents algae growing which could block sunlight and stop photosynthesis
• THIN SMOOTH BARK

  Allows water to flow down the tree easily and stops other plants from growing on the trees surfaces
• LEAVES WITH FLEXIBLE BASES

  Flexibility in their base helps leaves turn to face the sun
• BUTTRESS ROOTS

  Massive ridges to help support the base of the tall trees and help transport water. May also help oxygen/carbon dioxide exchange by increasing surface area
• SELECTIVE LOGGING

  The most damaging form of deforestation is clear felling. All trees, big and small, are chopped down in the area being cleared. This is completely destroys the ecosystem. A more sustainable approach is selective logging. Loggers remove the most valuable trees in the forest, without damaging the surrounding trees. Where trees are removed, the area is replanted as secondary forest. This cycle lasts up to 40 years
• CONSERVATION AND EDUCATION

  The rainforest can be preserve d in conservation areas such as national parks or nature reserves. These areas can be used for education, scientific research and tourism.

  Recently, large international businesses have supported conservation projects in exchange for carrying out scientific research or the provision of raw materials
• ECOTOURISM

  Ecotourism aims to introduce people to the natural world, to benefit local communities and protect the environment, for the future. Through income generates by ecotourism, local people and government benefit from retaining and protecting the rainforest trees. This is a more sustainable option then cutting them down for short term profit.

  Ecotourism earns money, while providing an incentive for forest preservation. Ecotourism developments are small scale to minimise environmental damage. They employ local people and management decision are based on community agreement
• INTERNATIONAL AGREEMENTS

  The international tropical Tiber agreement came into force in 2011. It ensured wood from tropical areas is legally sources and sustainable. The New York declaration on forests, signed by companies such as barclays aims to halve forest loss by 2020 and halt it by 2030. The UN sustainable development goals were established at the end of 2015 - these targets relating to future international development and the protection of forests is a key priority
• DEBT REDUCTION

  Countries can be encouraged to conserve areas of rainforest in exchange for a reduction of their national debt