Forestation and Deforestation Flashcards
Where is deforestation fastest?
In the tropics.
When did deforestation reach a minimum?
In 2012, due to national politics. Dropped to 34% in first 6 months of President Lula.
What is the main driver of deforestation?
Cattle ranching
Also soy agriculture in Amazonia and palm oil in SE Asia
What is the history of agricultural expansion in Crete and China?
Crete: pollen evidence of oil production from 6,000 BC, with declines of oak pollen at the same time
China: evidence of land clearance 5,000 - 3,000 BC
What are the sources of C emissions from deforestation?
What proportion of anthropogenic emissions is this responsible for?
- Decay of felled trees
- Soil disturbance
- Burning to clear felled area.
1/3
What is the relationship between deforestation and albedo?
Deforestation causes increased surface albedo (reflectance) causing a cooling effect on the lands surface.
What are the feedbacks from forest expansion?
- Photosynthesis and tree growth fertilised by increased CO2
- Young trees grow fast in newly established forests
- Lengthening of high latitude growing season
- Poleward expansion of arctic treeline
What is an international commitment to do with forestation / deforestation?
Bonn Challenge: restore 150 million hectares of deforested land by 2020.
What can afforestation lead to and what are the negatives?
Lead to afforesting grassy ecosystems with exotic trees:
- degrades underground carbon stocks
- compromises water sources
How much carbon does an old tropical forest store as a sink?
0.85 pg C/yr
How much carbon does a young mid latitude forest store as a sink?
1.3 pg C/yr
What is the differences between degraded vs native grassy ecosystems?
Degraded: outcome of deforestation, low biodiversity and carbon
Native: maintained by fires, high biodiversity and carbon.
