Tropical Rainforests Flashcards
Describe the distribution of tropical rainforests across the earth
•Unevenly distributed
•Can be found between Tropic of Cancer 23 ½ degrees N
•and Tropic of Capricorn 23 ½ degrees S
•Mainly concentrated near the Equator / along the Equator 0 degrees
Continent: Asia, South America, Africa
Region: Southeast Asia, Northern areas of South America, Central Africa
Countries: Malaysia, Indonesia; Brazil, Columbia; Congo, Cameroon
What is a climograph?
A graph that shows how mean monthly temperature and mean monthly precipitation vary throughout the year for a particular place.
•The temperature is shown using a line graph while the precipitation is shown using a bar graph.
How do you describe the temperature pattern shown on a climograph?
Are there variations in the temperatures? Are they slight or large?
If there are seasonal variations, when are the summer and winter months?
What is the highest/lowest mean monthly temp recorded? Which months did they occur in?
What is the annual temperature range? Calculate, showing your working.
How do you describe the precipitation pattern shown on a climograph?
Is the mean monthly rainfall evenly distributed throughout the year?
What is the highest / lowest mean monthly rainfall recorded? Which months did they occur in? Are they seasonal?
What is the total annual rainfall received?
Define a water table
The line marking the boundary between saturated and unsaturated soil
Define confluence
The point where two rivers merge
Define percolation
The downward movement of water within the soil, usually entering the ground water
Define infiltration
The process by which water on the ground surface enters the soil
Define water shed
The boundary/divide between two drainage basins
Define overland flow
The flow of water over the earth’s surface; fastest process of water movement
Define groundwater
Water stored underground in the soil or in pores of rocks
Define tributaries
A smaller river or stream flowing into a larger river
Define mouth
Where the river flows into a lake or ocean
Define through flow
Water moving downslope through the soil
Define base flow
Flow of groundwater into the riverbed; the slowest flow of water movement
Define source
Original point from which the river flows/the place where a river originates
Define evapotranspiration
The sum of evaporation of water from the land surface plus transpiration from vegetation
Why are tropical rainforests important to the indigenous people?
Homes for indigenous people Source of timber Medicinal properties Water catchment Habitat for plants and animals Carbon sink
How do tropical rainforests protect the soil layer from erosion?
During heavy downpours, the mass of vegetation in the rainforest catches and holds much of the rain, which is then lost via evaporation and does not reach the ground
The layers of vegetation also break the force of the rain, protecting the top soil layer from direct force
Roots also help to hold the soil together
Where trees are cut down in large numbers, this natural protection is removed, soil erosion increases and minerals are washed away
Define deforestation
Large scale removal of trees; intentional clearing of large areas of forest for human purposes
Why are tropical rainforests important?
The Amazon is home to the world’s largest river by volume. The Amazon River discharges five times the quantity of water of any other river. •Its catchment area encompasses a whopping 2.72 million square miles, which is roughly 40% of the entire continent of South America.
Rainforests play a key role in adding water to the atmosphere through the process of transpiration
Water vapour released contributes to the formation of rain clouds, which release water back onto the rainforest
In the Amazon, 50-80% of moisture stays locked within the ecosystem’s water cycle
What are the main causes of deforestation?
Increased demand for land for agriculture
> Cattle grazing
- Trees are cleared and the land converted to pasture
for cattle to graze
- Cattle ranching is an important revenue-generating
activity –beef is exported to other countries (e.g.
USA, Canada, Japan, France)
> Growing crops
- For commercial purpose (large scale) E.g. Multi-
national companies clear the forest for plantations
to grow cash-crops (pepper, sugarcane, bananas,
coffee)
- For subsistence purpose (small scale) –over a
period of time the land area required will increase
when there is an increase in population
- E.g. Small holding farmers in Indonesia –need land
for cultivation of crops for food, sell surplus to earn
income
Increased demand for natural resources (timber and mineral ores)
> Timber logging
- Due to increased demand for hardwoods from
other countries (e.g. Japan, Germany, USA)
- Use of mechanical, modern equipment such as
bulldozers, chain-saws
> Mining
- Mining for large deposits of gold, bauxite, iron, tin
and diamonds
- Forests are cleared in order to extract these
minerals
- More than 1/6 of the Amazon forest has been
cleared for extraction of iron
What are some minor causes of deforestation?
Increased demand for land for development of the area •To build settlement, transportation networks, transport infrastructure, railway, roads, airports
•Increased demand for land as a result of growing population
•Need land for housing to cater to needs of the growing population
What are some environmental impacts of deforestation?
Loss of biodiversity
•Unique environment of tropical rainforest
•Over a million species of plants and animals, and many not classified
•Animals forced to migrate, may not be able to adapt
•Plants species are lost before being discovered, such
plants could have been medicinal
• Extinction of plants and animals
Enhanced Greenhouse Effect
•Greenhouse gases in the atmosphere trap heat and
keep the Earth warm
rise in the Earth’s average temperature
•Deforestation > less carbon dioxide absorbed > more stored carbon released
Increase in soil erosion and frequency of landslides
- no trees and leaves to intercept rain, which may wash away soil
- no tree roots to hold soil
- topsoil contains minerals and nutrients essential for plant growth
- loosened slopes will cause landslides
Increased sedimentation and flooding
•Eroded soil washed into rivers > affects water quality > threaten survival of aquatic plants and animals
•Increases chances of flooding as water level rises by the large amount of soil particles deposited in it > destruction to property and lives
What are the economic impacts of deforestation?
Depletion of natural resources
- Rapid deforestation > destroys the tropical rainforest
faster than it can replenish itself
- less supply of resources
What are the social impacts of deforestation?
Indigenous people live as hunters and gatherers & some as shifting cultivators > rely on forest for survival
•Deforestation forces them to move to other areas > losing their homes and ways of life
•Indigenous tribes are also forced to disperse and their culture disappears
•Dwindled from 6 million to less than 200,000 today
How can we classify the impacts of deforestation?
Scale and time (short and long term)
What should the goal of management of deforestation be?
Reducing the impacts of deforestation
•Sustainable resource management: Careful use of resources (e.g. protecting forests) to ensure their availability in the future
•Conservation: Protecting the environment and its natural resources from harm which involves maintenance, restoration and wise management of resources to avoid permanent depletion of resources
Who are the stakeholders in deforestation?
Government; Multi-national companies; Consumers; Indigenous people
What can we do to manage deforestation?
- Protection of forested areas
- Controlled logging
- Public education
- Reforestation
Explain how to manage deforestation through protection of forested areas
Setting of laws to protect an area from
unfavourable activities which might endanger the biodiversity and natural resources found in the area
• Unsustainable logging and agricultural practices are banned
• Indigenous and traditional communities living in these areas are preserved
How does protection of forested areas reduce rate and impacts of deforestation?
Prevent companies from carrying out logging or mining activities in protected area > reduce rate of deforestation
• Useful for educational and recreational purposes, and scientific study > increase awareness of tropical rainforests, reduce rate of deforestation
• Important in the conservation of native biodiversity > reduce loss in biodiversity
• Preservation of indigenous and traditional communities > reduce loss of homes
What are the challenges faced when implementing protection of forested areas?
• Protected areas are not fenced and are still vulnerable
to human impact
• Officers responsible for monitoring the protected areas may give in to corruption and allow loggers and miners to illegally enter protected areas (Amazon)
• Not enough forest rangers to patrol the huge areas of the tropical rainforest (Amazon)
• Difficult to balance between development and biodiversity conservation (Singapore)
Explain how to manage deforestation through controlled logging
- Careful management of forests that are being logged
- Logging has to be done in a sustainable manner
- Determine the extent of logging through certain criteria such as:
- Selected plant species, area, age of trees
- Logging is controlled via:
- Penalties (fines and imprisonment) enforced on irresponsible timber companies that carry out illegal logging
- Education and research programmes
- Inform timber companies of the damage caused
- Discuss measures to manage extent of damage
How does controlled logging reduce rate and impacts of deforestation?
- Decrease the amount of logging being carried out > reduce rate of deforestation
- Reduce amount/area of trees being cut down > reduce loss of biodiversity and soil erosion
What are the challenges faced when implementing controlled logging?
- Identifying and logging selected trees is time-consuming and difficult to implement
- Difficult to track illegal loggers > areas designated for controlled logging in the Amazon still face threats from illegal loggers as the rainforest covers a large area
Explain how to manage deforestation through public education
- Change people’s attitudes and practices towards tropical rainforests
- Inform people of the importance of rainforests and contribute to conserving rainforests
- Ecotourism > organises trips to parts of the tropical rainforest
- Exhibitions > showcase biodiversity of the tropical rainforest and raise awareness of management and conservation strategies
- Produce publications which provide current information about the state of the rainforest
How does public education reduce rate and impacts of deforestation?
- Has far-reaching effects, especially in the long term where it can help to change people’s mindsets, and increase awareness, understanding and appreciation of forests
- Knowledge and awareness can lead to action and participation from the community
- Reduce in rate of deforestation as people are more concerned about protecting the forest > reduce loss of biodiversity, reduce loss of natural resources
What are the challenges faced when implementing public education?
- Turning environmental awareness into personal behaviour and action is difficult
- Raising awareness is difficult in some countries with low literacy rates
- Difficult to balance between development and conservation > countries around the Amazon rely on the rainforest and obtain income from exports derived from the rainforest
Explain how to manage deforestation through reforestation
- Planting of native trees in areas where the original forest has been cleared
- Often involves non-profit organisations, companies and local communities
- Takes a long time – 15 years for a rainforest canopy
How does reforestation reduce rate and impacts of deforestation?
- Reduces soil erosion, maintains the water cycle, and preserves the rainforest habitat and biodiversity
- Soil fertility can be improved in the long term and help sustain plant growth in the area
What are the challenges faced when implementing reforestation?
- Can be expensive and time-consuming
* Depends on the availability of native plants for reforestation
