Land Cover Change Flashcards
What is the FAO global forest resource assessment and what did they find about net forest change between 1990 - 2020 - including in diff regions?
Compilation of national forest data every 5 or 10 years
- 178 million ha reduction - 13 times the size of england
- Reduction of global forest cover of 4.3%
- Rate of net forest lost appears to be slowing
- Net forest gain in Asia and Europe
- Net forest loss in South America and Africa
What is the net change in forest area?
The sum of forest expansion and deforestation
What are the different ways to monitor forest change?
- Forest Resources Assessment (FRA) - countries submit own data through diff methods: forest inventories, satellite monitoring or extrapolation based on past data - varies in reporting/measuring/definitions by country
- Satellite: consistent across countries
What did Hansen et al., 2010 do and what did they find about forest change?
- MODIS - (coarse resolution) - not capable of seeing fine changes in tree cover
- Couldn’t use Landsat - as you needed to pay
- Found 3% gross. forest loss between 2000-2005
What may drive the differences in satellite sensing and national forest inventories?
Different definitions of forests:
- Canopy cover - FAO: <10% tree canopy cover and area > 0.5 ha
- Forest type: FAO count tree plantations (including rubber and oil palm) as forest - but other studies may not include this as a forest
What was the first study that was able to use Landsat for global forest loss?
Hansen et al., 2013
- Landsat - 30m resolution (higher resolution) - can see fine changes in forest
What are some examples of land cover change having been imprinted seen by satellites?
- Fishbone pattern - due to building of roads and then parallel roads - e.g., amazon
- Checkerboard pattern - policy decision - USA - gave every other square of land to rail companies to build rail
What did satellite data tell us about deforestation in Amazon, Congo and SE Asia - Rosa et al., 2016
Satellites provide annual data on deforestation
- Rapid deforestation of Amazon started in 1970s and in SE Asia in 1990s
- Congo basin experienced lower rates of deforestation until the 2000s
What high level reasons can be the cause of tropical deforestation?
- Underlying causes: e.g., national level policy factors / global economic
- Proximate causes - things happening on the ground - e.g., infrastructure extension / agricultural expansion
How do different drivers of deforestation leave different patterns of deforestation on the ground?
- Commodity driven - straight lines - ordered/structured
- Shifting agriculture - small holders/more sporadic/informal way
- Fire - very different signal
What are the main drivers of forest loss?
- Commodity-driven - 27%
- Shifting agriculture - 24%
- Forestry - 26%
- Wildfire - 23%
- Urbanization - ? minor factor
Percentages from Curtis et al., 2018
- Shows us that agriculture is dominant cause of forest loss globally - both commodity + shift agricultire
What commodity of agriculture is the biggest driver of deforestation?
Goldman et al., 2020 - Globally
- Cattle cause more deforestation than all other commodities combined
Tyukavina et al., 2018 - in Amazon
- Expansion of pasture for cattle is the largest single cause of deforestation in the Amazon
What are some of the different methods for stopping deforestation?
- Protected areas
- Zero deforestation commitments
How do protected areas work and how effective are they?
- E.g., national parks etc - protect biodiversity/habitats etc
- 12.5% of Earth’s land surface covered by protected areas - Europe has lowest amount of protected areas
How effective?
- Effective - clear cut boundaries - no deforestation in protected areas - but not always easy to tell how effective these are
- Problem: protected areas are often put in places that arent of use to humans anyway - so would have lower deforestation rate anyway
- So need to have a more nuanced look - compare rate of deforestation within protected area vs rate of deforestation directly outside - to see how effective protected area is - Spracklen et al., 2015
- Need to understand whats causing these differences - e.g., protected areas are effective at preventing forest loss due to commodity-driven deforestation- as large companies are likely to abide by laws
Give an example of using zero deforestation commitments?
G4 agreement (Brazil) - biggest beef producing companies in Brazil - areas with bigger market share signing up to this agreement had a lower rate of deforestation - relatively effective…
