5.5 Deforestation and Land Use

Notes

Deforestation is the permanent clearing of forest for other uses.

• Main causes: agriculture (cattle ranching, soy, palm oil), logging, mining, and urban growth.
• Effects: loss of habitat and biodiversity, soil erosion, flooding, reduced rainfall recycling, and added $CO_2$ to the atmosphere because trees store carbon.
• Clear-cutting removes all trees in an area (cheap but harmful). Selective cutting removes only some trees. Slash-and-burn clears land with fire, and nutrients are depleted after a few years.
• Reforestation replants trees; afforestation plants trees where there were none. Sustainable forestry logs at or below the regrowth rate. Certification (like the Forest Stewardship Council) labels wood harvested with such standards.
• Example: tropical forest cleared for cattle pasture may only support grazing for a few years because the soil is thin.