Causes & Impacts of Deforestation Flashcards
All 11 cards in this deck
How does subsistence farming cause deforestation?
Local families clear small plots of forest by slash and burn to grow food for themselves.
What are the steps of slash-and-burn (shifting cultivation)?
e.g. a farming family clearing a plot in the Amazon
- Cut down and burn a small area of forest — the ash fertilises the soil.
- Grow crops for about 3–5 years until soil fertility falls.
- Move to a new plot and let the old one regrow.
How does commercial farming cause deforestation?
Huge areas are cleared for cattle ranching and soya plantations to sell for profit — the biggest cause in the Amazon.
How does logging cause deforestation?
Trees are felled for valuable hardwoods such as mahogany, and clear felling plus logging roads destroys large areas.
How does road building cause deforestation?
Roads such as the Trans-Amazonian Highway are cut through the forest and open up the interior to loggers, miners, farmers and settlers.
How does mineral extraction cause deforestation?
Forest is cleared for mines such as the Carajás iron ore mine and for gold mining, which also pollutes rivers.
How does energy development cause deforestation?
Hydro-electric dams, e.g. Belo Monte, flood large areas of forest, and oil and gas extraction clears more land.
How do settlement and population growth cause deforestation?
A growing population and government resettlement schemes need land for homes, farms and towns, which is cleared from the forest.
Why does deforestation lead to soil erosion?
With no canopy to intercept rain and no roots to bind the soil, heavy rainfall washes the thin topsoil away.
How does deforestation contribute to climate change?
Burning and decaying trees release stored carbon dioxide, and the lost carbon sink absorbs less CO2 — adding to the greenhouse effect.
Give one way deforestation can bring economic development.
It creates jobs and export earnings from timber, minerals, beef and soya, providing tax income to pay for schools, roads and hospitals.