DEFORESTATION

Definition

Cutting down and removal of trees in a forested area

Lead to permanent destruction and eventual disappearance of rainforest

Loss of a renewable resource: trees

Causes of deforestation 1. Agriculturala) Subsistence / commercial farming b) b)Cattle ranching

2. Logging

3. Mining

4. Others

1. Agricultural activities

• Large scale commercial agricultural activities on plantations

• Obtained by burning and clearing large areas of rainforest

Eg. By 2020, about 242,000 sq km of the Amazon rainforest has been converted into soya beans farm. Besides being a main ingredient in food for cattle, soya beans are also processed into products such as soya milk and tofu.

2. Cattle Ranching

• Refers to operating farms to raise cattle

• Cleared to allow cattle to graze

Eg. Eighty percent of deforestation in the Amazon rainforest is caused by land cleared for cattle ranching. In 1986, the Amazon had less than 10 million head of cattle; in 2011, this number increased to 79 million

3. Logging • Refers to the cutting down of trees for

timber• Used to make furniture, building materials

and charcoal • Commercial logging destroyed 50,000 sq

km of tropical rainforest yearly • For every tree removed, 5 are damaged as

well

Eg. China’s huge demand for timber in the making of disposable chopsticks had resulted in heavy logging in the Amazon rainforest.

4. Mining • Precious metals are found beneath

the tropical rainforest • Cleared to establish mines and roads

for transport

Eg. The Carajas Mine in Brazil has a rich variety of mineral reserves. In 2007, 296 million tonnes of iron ore were extracted from the mine, estimating to contain 18 billion tonnes of minerals, including gold and copper.

5. Other reasons

• Meet housing and industrial needs of growing populations

• Develop infrastructure, eg roads, rail to improve accessibility

• Build dams to increase power supply

Impacts of deforestation

Impacts 1. Environmental impacts • Loss of biodiversity • Loss of water catchment area • Enhanced greenhouse effect2. Economic impacts Depletion of natural resource3. Social impacts oEffects on indigenous people

Environmental impacts • Destroys the habitats of plants and animals • Resulting in loss of biodiversity• Causing some plant and animal species to become

extinct.• This would reduce the variety of resources we can

obtain from the forest, eg food, medicine, timber wood, etc

• Increase the occurrence of insect-borne diseases- reduce predators for mosquito-mosquito population increase -malaria and dengue fever cases increase

• Lack of nutrients will not allow biodiversity to grow again LOSS OF

BIODIVERSITY

Environmental impacts

• Disrupts water cycle• Absorbs water via roots, release via

evaporation and transpiration

o Eg. Deforestation in the Amazon rainforest caused by charcoal production is predicted to reduce half of the water catchments by 2020, causing the cost of water to rise by 4 times.

LOSS OF WATER CATCHMENT AREAS

Environmental impacts

• Greenhouse gases traps heat • Without greenhouse gases, the

earth’s average temp would by -18 °C instead of 15 °C

• Deforestation increases CO2 in the atmosphere, as trees are carbon storages

ENHANCED GREENHOUSE EFFECT

Environmental impacts • Increase surface runoff • Exceeds the carrying capacity of

river • Hence floods occur

• Topsoil is washed away• Decreases the pH level • Plants and animals are unable to adapt

FLOODS AND WATER QUALITY

Environmental impacts • Haze will be produced during burning • Causes airport closures and affects

the health of people

Eg. In 1997, 25000 cases of forest fires with large smoke clouds were detected in the Amazon Rainforest.

AIR POLLUTION

Economic impacts

• Timber, food and water • Essential for many industries

Amount of tropical rainforest destoyed yearly = Forest resource valued at US$ 45 billion

DEPLETION OF NATURAL RESOURCES

Social impacts

• Lose their homes • Find other ways of survival • Loss of livelihood

Food for thought -Malaysia’s oil palm currently provides 600,000 jobs

EFFECTS ON INDIGENOUS PEOPLE

SUSTAINABLE MANAGEMENT

CASE STUDY OF AMAZON

RAINFOREST, BRAZIL

What is sustainable management?

Ensures the use of forest and its resources in a way

At a rate that maintains its biodiversity, vitality and regenerative capacity

That allows present consumers to meet their current needs of the forest without compromising on the needs of the future generation.

Measures

1.Selective logging 2.Laws and regulations 3.Afforestation 4.Conservation 5.Ecotourism

1. Selective logging • Allows the cutting of only selected

trees that meet a certain criteria

• Heavy penalties and fines, including imprisonment

Meets a certain circumference Only a certain number of

trees per hectare

Eg. Brazilian institute of environment and renewable natural resources started a programme in which every tree that is logged must be accounted for

2. Establishment of Laws and Policies

• Withdraw the financial help given to land clearance projects

Eg.• In 1988, the Brazilian Govt withdrew the financial support

and tax incentives given to cattle ranches in order to limit forest clearance

• Cancelled 70% of the logging permits and established measures against illegal logging

• Enforcement agents were employed to patrol forests

SUCCESSFUL? Illegal logging remains a problem, accounting

for 80% of logging activities due to weak enforcement and corrupt govt

3. Afforestation • Refers to the planting of trees in

areas which were previously bare or were used for other land uses

Eg. In 2005, a project to grow popular trees like Brazilian Cedar and mahagony was implemented by the Amazon Ecological Research Centre on a deforested area near Manaus. This project involved 10 000 ha of land which turned into a massive tree farm

4. Conservation • Set aside portions of the rainforest as

conservation areas • Ensures that plant species are left

undisturbed and protected Eg. In 2011, only 4% of Amazon Rainforest is protected as environmental reserves. In 2012, the government increased the amount protected by three times.

20% of the Amazon has been set aside as tribal reserves, protecting the Amazonian indians culture and habitat

5. Ecotourism • Provides activities for visitors to

explore and learn more about the forest

• Activities include natural history study, bird watching and kayaking etc

• Funds raised will go back into research and conservation of the rainforest

Eg.A company called MT Amazon Expeditions organises trips to parts of the Amazon rainforest in Peru organising various activities to raise funds for the conservation of the Brazil Amazon Rainforest.

END

Credits to Pearson “All About Geography” Secondary one by Alicia Brown, Audrey Tan, M C Clarke, Shirley Melissa and Dr Wong Poh Poh