8 | Forests under Threat - Tropical Rainforests

Question 1

What is the biggest store in the TRF?

Answer 1

Biomass store

Question 2

Describe the nutrient cycle in the TRF.

Answer 2

• When leaves or branches fall they drop into the litter store.
• They decompose very quickly as the conditions are hot and wet.
• The nutrients are then released into the soil store and plants then absorb those nutrients.

Question 3

Give 2 reasons for high TRF biodiversity.

Answer 3

1) Conditions for growth are good (warm, wet), so thousands of different species can be supported.
2) The TRF is ancient, so evolution has allowed many species to be formed through evolution and natural selection.

Question 4

What is the function of the drip-tip leaf adaptation?

Answer 4

The canopy layer of the forest is extremely humid, so leaves have thick waxy layer and a tip that allows water to drip off, otherwise it would form algae and moss on the leaf blocking its access to life and hindering photosynthesis.

Question 5

What is the function of the buttress roots adaptation?

Answer 5

Rainforest trees have buttress roots, they are shallow as the nutrients are in the top layer of soil. The buttresses have evolved to keep the tree upright and structurally support it.

Question 6

Adaptations of evergreen hardwood trees.

Answer 6

Slender trunks with no branches, leaves and branches only at the top as that is where the sunlight is. They are situated in the emergent layer.

Question 7

Adaptations of Epiphytes.

Answer 7

Epiphytes live in the canopy and their roots dangle mid-air as they get their water from the air, not the soil as the soil is 10 metres below.

Question 8

Adaptations of Lianas.

Answer 8

Lianas “climb trees” and are wrapped around the tree trunks, they get water and nutrients from the soil and extend to the emergent layer to gain sunlight.

Question 9

Adaptations of monkeys.

Answer 9

• Prehensile hands, feet and tails for balance and grip, colour vision to see fruits.

Question 10

Adaptations of birds.

Answer 10

• Loud calls as it is easier to hear a mate rather than see them as the TRF is too dense.
• Powerful beaks (parrots) to break open nuts.
• Eagles have clawed talons and powerful legs to grab monkeys.

Question 11

What is the size of the litter store and why?

Answer 11

• Large biomass store
• Small litter store and large decay transfer as in hot, wet conditions bacteria and fungi decay dead matter quickly, returning nutrients to the soil.

Question 12

What is leaching and why is it prevalent in the TRF?

Answer 12

When it rains, the top layer of soil is taken away reducing the amount of nutrients, the water does bring some new nutrients though. This happens because there is heavy rainfall all year round.

Question 13

How does weathering contribute to the nutrient cycling?

Answer 13

Chemical weathering processes (solution) are faster n hot wet climates, so release nutrients from the soil into rocks.

Question 14

What is commercial agriculture and how does it affect the TRF?

Answer 14

• Deforestation allows for land to be used for commercial farming.
• E.g. in Brazil 75% of deforestation was for cattle farming as beef is its main export.
• Some forests have been lost for palm oil plantations as those crops are in high demand for biofuels in order to reduce reliance on fossil fuels.

Question 15

What is subsistence agriculture and how does it affect the TRF?

Answer 15

• If locals own land, they they farm to feed their families.
• ‘Slash-and-burn’ - trees are cut, undergrowth burned, crops planted, nutrients in the soil are leached and weed growth occurs, they then deforest a little more and do this again.

Question 16

Give 3 reasons for commercial hardwood logging (and a description).

Answer 16

• Commercial hardwood logging is when rainforest timber is sold for money. Although it is illegal, it still happens.
  1) High demand for tropical timber such as rosewood, dense, pink and fragrant.
  2) People living in poverty will illegally log as it pays well.
  3) Police and government officials allow illegal logging for money.

Question 17

How are minerals exploited and how do they affect the tropical rainforest?

Answer 17

E.g. coltan mining in the Congo, coltan is used in mobile phones, forests have to be cleared to mine for it, sold on to TNCs, for little money, who make money off of it.

Question 18

How does the development of HEP affect the TRF?

Answer 18

In Brazil a dam opened to generate electricity, the dam ended up flooding 1750 square km’s of TRF.

Question 19

Give an example of an indirect threat to TRF (and its effects).

Answer 19

Global warming is heating the world up, an increase in temperature by 2 degrees Celsius could result in 15-40% of land species extinction.
Extreme weather may occur, heat waves for example, and some species aren’t adapted to that (e.g. flying fox bats).

Question 20

Who are CITES and what do they do?

Answer 20

• Convention on International Trade in Endangered species of Wild Fauna and Flora.
• They aim to prevent trade of endangered animal and plant species that threat TRF biodiversity.
• They have 35,000 species under their production
  Countries sign up to monitor trade over borders and punish legal breaches.

Question 21

Who are REDD and what do they do?

Answer 21

• Reducing Emissions from Deforestation and forest Degradation.
• It is a UN project that wants to stop deforestation (accounts for 20% of all CO2 emissions)
• It also aims to replant forests. Arranges large sums of money such as the Brazil scheme which has 1bn dollars in it.

Question 22

Advantages of CITES

Answer 22

• Many countries have signed up - 181.
• Protects a large variety of species.
• Has had some success, reduced Ivory trade, halting the decline of African Elephants.

Question 23

Advantages of REDD

Answer 23

• Large TNCs are involved.
• Funding they access is attractive to governments.
• There is international expertise.

Question 24

Disadvantage of CITES

Answer 24

• Global warming can undermine its success.
• Illegal trade in rainforest products is increasing, this is because demand is high so the risk of illegal trade is profitable.
• CITES can’t monitor 181 countries at once, it’s impossible.

Question 25

Disadvantages of REDD

Answer 25

• Deforestation is still rapid, despite countries signing up to the scheme.
• They are vague about what replanting is, some forests have been made to be oil palm trees.