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Deforestation and Slash and Burn Agriculture

Deforestation and Slash and Burn Agriculture

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Deforestation and Slash and Burn Agriculture

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  1. Deforestation and Slash and Burn Agriculture

  2. Definitions and Introduction -Slash and Burn Agriculture *Slashing and burning of forest vegetation to inject nutrients from ash into soil -Deforestation *Clearing of trees in a forest *Deforestation rates in 2000’s are estimated to have been about 12.9-16.3 million hectares per year (IPCC, 2007; Loarie et. al., 2009)

  3. (Hauser & Norgrove, 2001)

  4. (IPCC, 2007)

  5. Impacts on Biomass -Biomass: mass of living organisms in an area -Biomass as studied by Fearnside (1995) *Primary (original) forest: 463.5 t/ha *Secondary (regenerated) forest: 28.5 t/ha -Loarie, Asner, and Field (2009): *Deforestation is encroaching into more biomass rich areas of Amazon

  6. Impacts on Local Weather -Increase from forest albedo of .11-.13 to grassland albedo of .2 *Less radiation absorbed>evaporation down -Decrease in biomass means less plant transpiration *Less plants transpiring>transpiration down *Less forest to intercept rain>evaporation down -Result: Less evapotranspiration

  7. Impacts on Carbon Stocks and Emissions -Aboveground biomass is the most vulnerable carbon stock (Kotto-Same et. al. 1997) -How much? *Estimates for carbon lost per hectare in Brazilian Amazon: 183-184 t C/ha cleared (Fearnside, 1998; Loarie et. al., 2009) *Up to 201 t C/ha in 2007 because more biomass rich areas being cleared (Loarie et. al., 2009) *Average carbon stock that replaces forest: 12.8 t/ha (Fearnside, 1998)

  8. Impacts on Carbon Stocks and Emissions -IPCC (2007) estimated emissions of 5.8 Gt C/yr in the 1990’s because of deforestation

  9. Relationship to Climate Change -IPCC (2007) is clear about relationship between anthropogenic GHG emissions and global warming -GHG’s reradiate IR radiation. This warms the earth

  10. Relationship to Climate Change -Graphs from IPCC (2007) reporting increases in GHG concentrations and the effects of the increase

  11. Solutions -Framework for understanding options (Tomich et. al., 1998) *Global community: Forest biodiversity and forest as carbon sink *Local users: private interests and extracting living from forest *Alternatives must: 1. be more profitable for farmers. 2. increase food security for farmers. 3. fund any extra labor they require. 4. be sustainable in the long term.