Threats to the Tropical Rainforest (Cambridge (CIE) IGCSE Geography) : Revision Note

The main threats to the tropical rainforest

• There are six main human causes of deforestation

• Wildfires are a natural cause of deforestation:

  • However, the frequency and severity of wildfires have increased this has been linked to human-induced climate change

Destruction of the tropical rainforest

Environmental impacts of deforestation

• Many of the impacts of deforestation are environmental, including:

  • Areas that have been deforested are planted with monoculture, which reduces biodiversity

  • Interception and infiltration decrease which reduces evapotranspiration and as a result precipitation decreases

  • This also increases overland flow which leads to soil erosion and sedimentation of the rivers

  • Sediment builds up on riverbeds reducing their capacity and increasing the flood risk

  • Lack of interception increases the leaching of nutrients

  • Fewer trees increase the amount of CO₂ in the atmosphere, adding to the enhanced greenhouse effect

  • Soils become less fertile and drier

  • They may turn reddish brown due to increased iron oxide

Impact on the nutrient cycle

• The majority of nutrients in the tropical rainforest are held in the biomass 

• When trees and vegetation are cleared by deforestation, the main store of nutrients is removed 

Social impacts of deforestation

• Indigenous communities have less land to sustain their traditional way of life. This means:

  • Land does not get the opportunity to recover

  • Less food is available 

  • Improved quality of life for some people due to increased income and jobs

  • Indigenous communities may give up their way of life, leading to a loss of culture and traditions

  • Increased risk of landslides which can destroy homes and block roads

  • Loss of potential medicines 

  • Increased risk of flooding settlements

Economic impacts of deforestation

• More jobs available in mining, forestry, agriculture and HEP

• Increased income for the country through the export of goods from the forest – minerals, timber, crops

• Almost a quarter of Brazil's GDP comes from activities in the deforested areas of the Amazon

Managing the tropical rainforest

• Concerns about the rapid deforestation of tropical rainforests have led to a range of sustainable management strategies

• Strategies can be on an international, national or local level

International strategies

• UN Forum on Forests was established in 2000 and is committed to the management, conservation and sustainable development of all types of forests

• The UN Sustainable Development Goals include the sustainable management of forests

• International treaties protect certain areas such as the Central Amazon Conservation Complex (CACC), which is a World Heritage Site. This means hunting, logging, fishing and access are limited

• Trade restrictions on endangered species and timber have been imposed

  • The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) aims to ensure that international trade in specimens of wild animals and plants does not threaten the survival of the species

  • The International Tropical Timber Agreement (ITTA) promotes sustainable forest management and restricts the trade in rainforest hardwood timber

  • The Forest Stewardship Council (FSC) approves wood from sustainable sources 

• Debt reduction – countries are relieved of some of the debt in return for protecting rainforests 

  • Debt-for-nature swap. In 2010 the USA converted US$13.5 million of debt from Brazil into a fund to support the protection of the rainforest

• International organisations such as Greenpeace and WWF monitor deforestation 

National strategies

• Brazil's Forestry code requires landowners to maintain a proportion of their land as forests. However, the amount they need to maintain was reduced from 80% to 50% in 2012

• The DETER satellite was launched in 2004. It:

  • Started by sending reports every two weeks to rangers 

  • In 2011 began sending daily reports, meaning that patrols could target areas of suspicious activity but it only detects areas over 250 m² so people clearing simply reduce the size of the area they clear

  • It was estimated in some areas this led to a 60% decrease in large-scale deforestation

• There are 68 national parks in Brazil. These are protected areas where the aim is to conserve the ecosystem

• The reforestation project is a part of the Amazonia Sustainable Landscapes Project. It aims to:

  • Restore 30,000 hectares of land to the forest by 2023, which will involve planting 73 million trees.

• The Amazon Region Protected Areas (APRA) resulted in a 68% increase in protected areas and Indigenous territories from 2004 to 2012

• Selective logging is where trees to be felled are selected, felled and removed, causing the least possible damage to surrounding trees

• Afforestation to plant new trees replacing those which have been felled

Local strategies

• Agroforestry combines agriculture with forestry, which means some trees remain, which:

  • Decreases deforestation

  • Provides shade as well as increases infiltration and interception, which reduces soil erosion

  • Provides organic matter from the trees and adds nutrients to the soil

  • Increases biodiversity due to the variety of plants grown

• Education of people involved in the exploitation and management of the rainforest

• There are small-scale projects like the Marajo Project, which preserves almost 90,000 hectares of Amazon forest. It includes:

  • A tree nursery to grow saplings to be planted in areas which have been cleared

  • The new trees help to bind the soil, reducing soil erosion and increasing infiltration

  • Agroforestry is encouraged, reducing the need to over-cultivate and clear areas. It includes:

    • A cooperative to support 49 local producers growing açai berries

    • Building of natural fish tanks to improve food security 

  • School-based agricultural education and scholarships

• Ecotourism is becoming widespread. It includes:

  • A focus on the natural environment

  • Low impact on the environment – using materials from the local area and buildings to blend in with the environment

  • Supporting local communities – using locally grown food and employing local people 

  • Education – to inform tourists about the local environment and wildlife

  • Gaining income which can be used for conservation

• Ecotourism rewards the local community for maintaining the rainforest rather than for cutting it down