Rainforests

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Cards (30)

Canopy Layer

Many animals live in this area since food is abundant
Understory Layer  
Little sunshine reaches this area, so the plants have to grow larger leaves to reach the sunlight
Forest Floor 
Very dark. Almost no plants grow. Sun hardly reaches forest floor, so things begin to decay quickly.
Why are rain forests important? - MEDICINES
Hundreds of rainforest plants are used in medicines.
Estimated that 25% of all our medicines come from plants growing in the rainforest.
Only about 1% of the plant species have been studied, so potentially there could be more cures to illnesses waiting to be discovered.
Why are rainforests important? - COMPOSITION OF ATMOSPHERE
They regulate the composition of the atmosphere + act as a carbon sink.

Reduces climate change = less extreme weather + less sea level rise.

They absorb about 20% of the world's man-made carbon dioxide emissions.
Why are rainforests important? - HABITATS
Rainforests are habitats for many animals. Leads to an increase in biodiversity.
They have extremely high biodiversity - contain around 50% of the world's plant, animal and insect species, and may contain half of all life on Earth.
Deforestation = extinction of many species and loss of biodiversity.
Why are rainforests important? - EROSION AND FLOODING
Help regulate the climate and water cycle - without them the risks of drought and flooding in certain areas can increase.
Why are rainforests important? - OXYGEN
Give out about 20% of the world's oxygen
Why are rainforests important? - SOIL EROSION
Reduces soil erosion - roots bind the soil. Reduces flooding.
Why are rainforests important? - USEFUL PRODUCTS
Rubber, coffee, chocolate.
Provides income for farmers.
Rainforest Conditions
Hot + humid (constant climate)

Wet

Rich vegetation + tall trees

Soil isn't very fertile as heavy rain washes nutrients away. There are surface nutrients due to decayed leaf fall.

Litter decomposes very quickly

Many indigenous ppl have adapted to life in the rainforests
Adaptations in the rainforest (plants)
Tall trees - competition for light
Buttress roots - support tree, don't need to go very deep as there is lots of water
Large leaves (especially in undercanopy plants) to absorb light
Smooth, thin bark - no need to protect trunk from cold temperatures
Climbing plants, such as lianas, use tree trunks to reach sunlight
More Plant Adaptations
A) buttress roots
B) lianas
C) leaf angling
D) drip tips
E) epiphytes
F) thin bark
G) waxy surface
Swiss Cheese Plant
A) holes in leaves
B) sunlight
C) run-off
D) ripped
Exam Style Qus
A) tall
B) shallow
C) buttress roots
D) thin bark
Jaguar - Adaptations
Camouflaged - prevents prey from seeing them
Move stealthily when hunting
Sloth Adaptations
specialised tendons that allow them to hang upside down for long periods of time
arms are longer than legs - helps them grasp branches
slow moving - green algae grows on fur, helps them camouflage in trees
some are nocturnal - avoids predators
Reasons for deforestation - LOGGING
Amazon is full of valuable hardwood trees such as mahogany, meaning both legal and illegal businesses use it for logging.
Logging is the first step in the conversion of forest land to other uses.
It is estimated that 50% of logging is illegal. (unregulated + ignores environmental laws)
Reasons for deforestation - COMMERCIAL FARMING (CATTLE)
Forest is cleared to make space for cattle grazing.
Cattle ranching is the main cause of deforestation in the Amazon - in Brazil, there are around 200 million cattle on about 450,000 km squared of pasture.
Believed to account for 80% of tropical rainforest destruction in Brazil.
Land can't be used for long. Quality of the pasture quickly declines. Cattle farmers then have to move on and destroy more rainforest to create new cattle pastures.
Reasons for deforestation - COMMERCIAL FARMING (CROPS)
Soy is a commercially farmed crop as well as rice, corn and sugar cane.
Forest is being cleared to make way for vase plantations. Soil won't sustain crops for long. After a few years, farmers have to cut down more rainforest for new plantations.
Reasons for deforestation - MINERAL EXTRACTION
Minerals are mined and exported to help boost countries' development.
Today, over 50,000 hectares of land is being used in the Amazon for gold mining.
Reasons for deforestation - ROAD BUILDING
The 4000km Trans-Amazonian Highway in Brazil was built through the Amazon to connect the Brazilian coast to other countries.
New roads built for logging have opened up areas that were previously hard to get to, destroying and threatening more forest.
Reasons for deforestation - SETTLEMENT + POPULATION GROWTH
Activities such as road building and mining have knock-on effects. They need workers, and workers and their families need homes and services.
This means clearing the forest to build settlements where these people can live.
Puts pressure on rainforest. e.g. Many farmers have settled along the Trans-Amazonian Highway
Strategies for managing rainforests sustainably - ECOTOURISM
Minimises damage to the environment and benefits local ppl.
Tourists bring in money which can be used to protect the environment and is an incentive to keep it.
EXAMPLE - Sukau Lodge in Malaysia. Have set up a foundation to try and protect the rainforest (using income). Are trying to have minimal impact on environment. Pick up litter from riverbank.
Employs local people. Profits stay in local community. Sustainable and profitable.
Can educate people about rainforests.
Strategies for managing rainforests sustainably - SELECTIVE LOGGING
Only cutting down certain trees in an area. Money is still earnt from the rainforest, but in a sustainable way. Less damaging to whole forest. Allows forest to regenerate.
It is better than no deforestation, because people still earn money. Hopefully, habitats are minimally disrupted. Also, this could benefit the rainforest as it makes the forest floor lighter.
75% of Borneo's wild orangutans live in forests that are being logged.
However, very hard to manage, as ppl may chop down more trees than they should.
Strategies for managing rainforests sustainably - REPLANTING
New trees are planted to replace ones that are cut down.

In some countries, there are laws to make logging companies replant trees when they clear a forested area.
Strategies for managing rainforests sustainably - REDUCING DEBT
Many tropical rainforests are found in LICs/NEEs who may have large debts.
Schemes are sometimes arranged where debt is written off in return for protection of the forest (debt-for-nature swaps).
EXAMPLE - In 2010, the USA signed an agreement to convert a Brazilian debt of £13.5 million into a fund to protect large areas of the tropical rainforest.
However, this is hard to manage, and LICs may take money and still chop down trees.
Strategies for managing rainforests sustainably - CONSERVATION and EDUCATION by NGOs
Education may create awareness abt rainforest + stop ppl buying goods like palm oil. Local ppl can be educated to understand importance of forest. May encourage ppl to take action.
EXAMPLE - Prince's Rainforests Project is an example of a charity trying to raise awareness about rainforests.
Impacts of Deforestation - CLIMATE CHANGE
Trees remove CO2. Amazon stores about 140 billion tonnes of carbon. Deforestation releases some of the CO2, causing global warming.
Up to 75% of Brazil's Co2 emissions come from deforestation.
Also, fire is often used in clearing rainforests.
Impacts of Deforestation - SOIL EROSION
Brazil is losing up to 100 tonnes of topsoil per hectare each year because of soil erosion. May lead to landslides and flooding in the future.
If there is less tree canopy to intercept rainfall and fewer tree roots to absorb it, more water reaches the soil. This reduces soil fertility as nutrients in the soil are washed away.
Pastures and plantations have to be abandoned, so more areas of rainforest are cleared.