1. Ecosystems: Nutrient Cycles

2. Let’s review

3. Causes of Deforestation
Population explosion
Large areas of forest have been cleaned for:
Agriculture
Factories
Roads and rail tracks
Industries
mining/quarrying

4. Causes of Deforestation
FIRES
Forest fires destroy trees, seeds, and the animal life

5. Causes of Deforestation
Pests
Many kinds of insect pests destroy forests by eating shoots and spreading diseases.

6. Causes of Deforestation
Grazing and gnawing animals
Animals eat, trample the young plants, and damage their trunks and roots.

7. Other Causes of Deforestation:
Weather: storms and snow damage the forests.
Dams: Barriers constructed across rivers to prevent floods submerge and kill large tracts of forests.

8. How does deforestation affect the carbon cycle?
Climate has become warmer in the deforested region due to lack of humidity added by the plants.
Consumption of CO2 and production of O2 is adversely affected.

9. How does deforestation affect the water cycle?
First lets talk about transpiration: Loss of water vapor through leaf stomata

10. How does deforestation affect the water cycle
Trees store and transpire a lot of water (which is why rainforests remain humid)
Take away trees- water is lost
Moisture can’t be returned to atmosphere without plants
Extensive cutting can turn forests into deserts
Erosion occurs due to increased Runoff