Tropical Rainforests

Tropical Rainforests

1. Characteristics

   • Rainforests are hot and humid all year and have high rainfall and no distinct seasons.
   • Large biodiversity.
   • Trees are deciduous and have a distinctive vertical stratification and plants that climb trees. They form a dense canopy all competing for light.
   • Soils are iron rich but oddly infertile as nutrient cycling is so quick.
   • Small changes like deforestation and air pollution has a massive knock on effect on entire ecosystem.
   • Layers
     • Emergent layer is the trees that are tallest and stick out and receive most light.
     • The canopy is the most productive layer as each tree spreads its leathery leaves out far for as much sun as possible for photosynthesis. The leaves have drip tips to shed water efficiently.
     • The under canopy is shaded and is less substantial than the canopy with trees waiting for he right opportunity of light to grow to the height of the canopy. Interlocking woody branches and tree climbing lianas form green corridors in which light weigh animals can travel.
     • The shrub and ground layer has limited light and is limited to ferns and woody plants and young trees. Bacteria and fungi rapidly rot the fallen leaves and dead plants and animals. Thick butress roots help to spread the weight of the towering trees above.
     • Soils recycle nutrients to support rapid growth.

2. Deforestation in Malaysia

   • Threats
     • Logging- in the 1980s malaysia became the largest exporter of highly valued tropical wood. Destructive clear felling has now be replaced by selective logging of mature trees.
     • Road building- roads are built for access to logging and mining areas.
     • Energy development- boosts malaysias electricity supplies.
     • Mineral extraction- tin mining is established and drilling for oil and gas has started.
     • Population pressure- transmigration of poor people from cities to the countryside.
     • Commercial farming- malaysia is largest exporter of palm oil in the world. Ten year tax incentives encourage more deforestation for more plantations.
     • Subsistence farming- small scale clearance is sustainable but slash and burn fires can get out of control.
   • Impacts
     • Deforestation destroys ecosystems and many habitats which- reduces biodiversity- exposes ground soil which could lead to desertification- affects local and global climates by reducing photosynthesis, transpiration and evapouration.
     • Economic gains are- jobs created- tax revenue used for public services- improved transport infrastructure and tourism- plantation produce supports other industries- cheap and plentiful- minerals are valuable.
     • Economic losses are- water pollution in increasingly dry climate may limit water supply- fires pollute and destroy vast areas of forest-rise in temperature could devastate established farming- medicinal plants could go extinct- economic costs due to climate change- rainforest tourism could decrease.

3. Management

   • Rates of deforestation in Brazil are now dropping as the government stops illegal deforestation- Brazil leads the world in conservation- Brazil is reducing carbon emissions to reduce climate change- Consumer pressure of not using products from deforested areas has led to a decline in cattle farming.
   • Rainforests should be protected for- their biodiversity- Medicines in the forests- resources like rubber fruit and nuts- water- indigenous tribes- prevent the climate from becoming to hot and dry- produces 28% of the worlds oxygen- absorbs and stores co2.

4. Sustainable Management

   • Need sustainable management to- ensure they remain a lasting resource- harness valuable resources without causing long term damage.
   • Sustainable commercial management is- selective logging and replanting- conservation and education preserves rainforests for scientific research and tourism- ecotourism introduces people to the natural world and provides jobs for locals- international agreements.