Tropical Rainforests

Question 1

what are the physical characteristics of a rainforest

Answer 1

• climate - high temps high rainfalls
• water - distinct wet season with high rainfall lasting several months
• soils - infertile due to leaching (excess water transporting them away) and also the optimum conditions needed for photosynthesis are present so plants grow very quickly so use up the nutrients quickly too
• people - tribes living in harmony with nature = sustainable, but increasing numbers of outsiders exploiting it for commercial gain
• plants and animals - highest level of biodiversity in the world due to the huge range of habitats available

Question 2

why do plants and trees tend to have shallow roots in rainforests

Answer 2

because the soils are not very rich in nutrients and all the nutrients are concentrated in the upper topsoil

Question 3

how are tropical rainforests interdependant

Answer 3

• climate means high rainfall means more water means more leaching means less soil nutrients
• the canopy of trees act as an umbrella and reduce soil erosion in heavy rainfall
• plants relying on animals to spread their seeds (fruit)

Question 4

how do plants adapt to tropical rainforests

Answer 4

• strong vertical growth to gain access to sunlight
• buttress roots anchor the trees in the shallow rainforest soil
• leaves are often waxy and have tips that allow water to run off them
• leaf stems are flexible to allow them to move with the sun (photosynthesis)

Question 5

how do animal adapt to tropical rainforests

Answer 5

• adapting and specialising to eat what other animals can’t eg toucans with strong beaks for hard nuts
• colour either as camouflage or to warm predators away (poisonous frogs)
• some animals are poisonous

Question 6

what are some issues associated to biodiversity decline

Answer 6

hunting and deforestation have massive knock on effects:
- intricate food web (eg orangutans declining which disperse fig tree seeds so fig tree declining so fig wasps declining so other plants the fig wasp pollinates decline)
- important medical plants may become extinct
- plant and animal species becoming extinct before they are even discovered
- indigenous tribes becoming unable to survive in rainforests and having to abandon their traditional lifestyle

Question 6

why are tropical rainforests very biodiverse

Answer 6

• wet warm climate = wide range of plants and trees = wide range of habitats for animals
• rapid nutrient cycle speeds up plant growth = food for animals
• many parts of the rainforest are untouched by people allowing it to thrive

Question 7

how is the rate of deforestation changing

Question 8

why are rates of deforestation increasing

Answer 8

ecomonic growth and opportunities

Question 9

why are rates of deforestation declining

Answer 9

awareness and education about climate change triggering new laws from governments

Question 10

what are the causes of deforestation in Brazil

Answer 10

• subsistence and commercial farming
• logging
• road building
• mineral extraction
• energy development
• settlement
• population growth

Question 11

Brazil commercial farming as a cause for deforestation

Answer 11

cattle ranching accounts for 80% of deforestation

Question 12

Brazil logging as a cause for deforestation

Answer 12

mahogany and teak are highly valued for furniture and other uses
smaller trees are used for fuel or made into charcoal

Question 13

Brazil road building as a cause for deforestation

Answer 13

roads bring supplies and provide access to new mining areas, settlements, and energy projects (allows easier access to more deforestation)

in Brazil the Trans-Amazonian Highway covers 4,000km through the rainforest

Question 14

Brazil mineral extraction as a cause for deforestation

Answer 14

minerals such as gold, bauxite, copper are mined extensively

this pollutes rivers, causes scars in the landscape

larges iron ore mine in the world is at Carajás which is worked 24 hours a day

Question 15

Brazil energy developmentas a cause for deforestation

Answer 15

high rainfall creates ideal conditions for HEP

Damming of the Xingu River over 40,000 hectares of rainforest was flooded and 20,000 local people displaced

Question 16

Brazil settlement and population growth as a cause for deforestation

Answer 16

the increase in other opportunities has lead to an increase in population

Question 17

what are the impacts of deforestation in Brazil

Answer 17

• economic development
• soil erosion
• climate change

Question 18

Brazil economic development as an impact of deforestation

Answer 18

• mining and commercial farming bring employment and an international income
• taxes can improve education and social conditions
• HEP = cheap, renewable power
• ## loss of biodiversity may reduce tourism

Question 19

how does deforestation cause soil erosion (in Brazil)

Answer 19

once land is exposed by deforestation, the soil is much more vulnerable to the torrential tropical rain. without the roots binding it together, the soil is easily washed away too

Question 20

Brazil climate change as an impact of deforestation

Answer 20

• climate becomes drier as tropical rainforests normally retain and emit moisture
• climate becomes hotter as normally high levels of evaporation from leaves and branches cools the air
• rainforest as carbon sinks so less storage of carbon dioxide = global warming
• when the trees are cleared they are burned, releasing more Carbon = global warming

Question 21

what is the value of rainforests to people

Answer 21

• resources - wood, bananas, sugar, cocoa
• medicine - less then 1% rainforest plants have been tested for medicinal qualities & about 25% of all medicines come from rainforest plants
• indigenous tribes - relying on the rainforest for food, building materials and fuel
• energy - HEP
• employment - in tourism, construction, farming, mining

Question 22

what is the value of rainforests to the environment

Answer 22

• water - about 20% world’s freshwater comes form the Amazon basin
• biodiversity - contain 50% world’s plants and animals
  climate - lungs of the world, its water cycle emitted through transpiration prevents dryness and heat
• climate change - carbon sink, offsets global warming
• soil erosion - shelter and bind the soil, also meaning less silt in the rivers and reservoirs

Question 23

how can tropical rainforests be managed sustainably

Answer 23

• selective logging and replanting
• conservation and education
• ecotourism
• international agreements
• debt reduction

Question 24

what is selective logging and replanting

Answer 24

• trees are selected by professionals, felled and extracted in a way that minimises damage to other trees
• officials monitor logging to ensure it is done legally and correctly
• new trees are planted for sustainability

Question 25

what is ecotourism

Answer 25

a sustainable form of tourism that focuses on the environment and has a low impact

indigenous people are employed as guides, local communities are supported, and there is a focus on nature to financially reward the locals for preserving them rather than cutting them down

Question 26

what does conservation and education involve (tropical rainforests)

Answer 26

• designating rainforests as national parks
• international organisations supporting conservation efforts in exchange for carrying out scientific research
• international charities support education programs, training conservation officers and scientists, and promoting conservation in schools

Question 27

what does debt reduction involve (rainforests)

Answer 27

larger countries reduce the debt of countries such as Brazil so that the money must be used in conservation efforts

Question 28

what do international agreements involve (rainforests)

Answer 28

• suppliers of timber are encouraged to only buy wood with the Forest Stewardship Council stamp. this is a form of environmental quality control
• The International Tropical Timber Agreement restricts the trade of hardwoods by only marking timber with a registration mark if it is from a sustainably managed forest