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Rainforest climate
Rainforest Climate. In an average year in a
tropical rain forest, the climate is very humid
because of all the rainfall, which amounts to
about 250 cm per year. The rain forest has lots
of rain because it is very hot and wet.
This climate is found near the equator.
• The arrangement of plants within a
tropical rainforest is such that there
are different layers and different
microclimates. The diagram shows
the layering of plants from the tallest
emergent trees, down to the lowest
ground flora. A sharp contrast exists
between the two extremes. For
example, the top of the forest has full
light conditions and the temperature
and humidity vary from 10-40oC and
60-90% relative humidity,
respectively.
Buttress roots
• Many trees have buttress roots, which are very large and thick roots. These roots support the tree as it continues to grow and they prevent leaching (when water floods the tree). The enables the trees to cope with heavy rainfall especially during monsoon seasons. Buttress roots also increase the surface area of the tree to allow more carbon dioxide to enter for photosynthesis.
Drip tips
• Leaves have 'drip tips' -this basically means that the leaves are shaped so water can run off them so that unwanted bacteria does not grow on the leaves during the day when it is warmest and most humid. Some leaves are also quite waxy, which means water would run off them more quickly.
• Height: The tallest trees, known as emergents, can grow up to 40metres in order to reach sunlight for photosynthesis.
They have developed a mechanism in order
to eat insects. Venus flytraps snap shut on
any insects that land on them, where they
are then digested by the plant. Some plants
have developed flowers or leaves with
steep sides which means insects slide
down into the plant and cannot escape.
Some flowers produce a sweet nectar
which attracts insects into their trap. This
is ideal for plants who live further towards
the forest floor where there is less sunlight
for photosynthesis.
• Leaves have stomata (holes where carbon dioxide enters for photosynthesis and oxygen and water leaves). These stomata close during extremely hot weather to preserve water and stop it from leaving the plant. This is helpful as a lot of water is evaporated from the leaves during day when it is hottest. However, the environment can also be quite humid during the day, so stomata would then open as there is plenty of water avaliable. Stomata would open during rain.
• Most tropical rainforest soils relatively poor in nutrients. Millions of years of weathering and torrential rains have washed most of the nutrients out of the soil. More recent volcanic soils, however, can be very fertile. Tropical rain forest soils contain less organic matter than temperate forests and most of the available nutrients are found in the living plant and animal material. Nutrients in the soil are often in forms that are not accessible by plants.
• Constant warmth and moisture promote rapid decay of organic matter. When a tree dies in the rainforest, living organisms quickly absorb the nutrients before they have a chance to be washed away. When tropical forests are cut and burned, heavy rains can quickly wash the released nutrients away, leaving the soil even more impoverished.
Tropical RainforestTemperate Deciduous Forest
52% in Vegetation 31% in Vegetation
48% in Soil 69% in Soil
• National:
Deforestation can consume a country's only natural resource. If deforestation is not managed in a sustainable manner a country's only natural resource could be lost forever.
• Global:
Global WarmingRainforest canopies absorb carbon dioxide which is a gas in the atmosphere. When the rainforests are burned and cleared, the carbon is released. Also, when trees are cut down they can no longer absorb carbon dioxide. This means more carbon dioxide is in the atmosphere. Carbon dioxide allows heat through the atmosphere (suns rays). However, it will not allow reflected energy to escape from the atmosphere. This is called the greenhouse effect and causes global warming.
How can the rainforest be managed for sustainable development?
• Afforestation - Trees should be replanted in areas of deforestation.
• Shifting Cultivation - Farmers should move on after 2-3 years to allow the rainforest to recover.
• Rubber tapping - More sustainable methods of exploiting the rainforest should be pursued e.g. rubber tapping
• Measuring trees - Trees should only be cut down when they reach a certain size. This will ensure younger trees survive longer and will encourage careful management of the rainforest.