3.3.2

Tropical Rainforest: Structure

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Tropical Rainforest: Structure

Tropical rainforests have four main layers. Plants and trees have special features that help them survive in hot, humid conditions with low light near the ground.

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Layers of the rainforest

  • Tropical rainforests have four main layers:
    • Emergent
    • Canopy
    • Understorey
    • Ground
  • Each layer has different light, heat, and moisture levels.
  • Different plants and animals live in each layer.
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Trees in the rainforest (1/2)

  • Many trees grow over 30 metres tall and form the canopy.
  • Wide buttress roots help support the tall trunks in shallow soil.
  • Trees grow tall to reach sunlight in the upper layers.
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Trees in the rainforest (2/2)

  • Most trees have smooth bark to help heavy rainwater flow down easily.
  • Smooth bark also prevents vines and epiphytes from growing on the trunks.
  • Trees remain evergreen all year, allowing them to maintain high levels of photosynthesis.
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Soil characteristics

  • Soils are generally thin and nutrient-poor because heavy rain washes nutrients away.
  • Most nutrients are stored in the living plants and decomposing material on the forest floor.
  • Shallow roots, like buttress roots, help trees stay stable in poor soil.
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Plant adaptations

  • Many plants survive in shade with very low light.
    • Some plants have large leaves to catch more sunlight.
  • Tree ferns and herbaceous plants grow beneath the canopy.
  • Epiphytes grow on trees to reach sunlight without rooting in soil.
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Vegetation on the ground layer

  • The ground layer has little light, so few plants grow there.
    • Herbaceous plants with broad leaves grow in small patches on the ground layer.
  • Fallen leaves and branches cover the forest floor.
    • Fungi and decomposers thrive in the warm, damp conditions.
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Wetland, mangrove and rivers

  • Rainforests include wetland areas with flooded ground.
  • Mangrove forests grow in coastal zones with salty water.
  • River ecosystems flow through the forest, shaping the land.

Jump to other topics

1Paper 1 - Changing River Environnments

2Paper 1 - Changing Coastal Environments

3Paper 1 - Changing Ecosystems

4Paper 1 - Tectonic Hazards

5Paper 1 - Climate Change

6Paper 2 - Changing Populations

7Paper 2 - Changing Towns & Cities

8Paper 2 - Development

9Paper 2 - Changing Economies

10Paper 2 - Resource Provision

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