Deforestation
Biology: Edexcel IGCSE, topic 5.2.4
Deforestation
Deforestation is the cutting, clearing and removal of forests in order to free up land for other purposes such as housing, agriculture or logging. Deforestation has a range of negative effects on an ecosystem:
Atmospheric gases
- The burning of trees and decomposition of wood increases the rate of carbon dioxide that is released into the atmosphere.
- As less photosynthesis is taking place, less carbon dioxide can be removed from the atmosphere in the carbon cycle.
Biodiversity
- Deforestation destroys habitats. This causes biodiversity to be lost.
Soil erosion
- Soil covering bare earth (compared to in forests) is more easily washed away by rain, which makes the remaining soil less fertile and harder to grow crops in.
- Soil that erodes away in rainwater runoff can also take fertiliser minerals with it in a process called leaching. This water runoff can then pollute water sources and cause eutrophication.
Water cycle
- Deforestation disrupts the water cycle by reducing evapotranspiration (the combination of transpiration from trees and evaporation from the ground).
- When trees are removed, there is less transpiration.
- Rainwater more easily runs off bare ground (rather than soaking into the soil), so less water stays in the soil and evaporates.
- This means less water then falls as rain and the land can turn into infertile desert.
Test yourself on Deforestation
How does deforestation affect the carbon cycle?