Location, Vegetation and Climate:
Straddles equator between the tropics. South America – 70% Brazil
Brazilian Shield = large metamorphic field that limits infiltration and encourages surface
flow.
Tall, evergreen, hardwood trees. High NPP, biomass 500 tonnes/ha despite leached acidic
soils (rapid decomposition in top soil layer).
Intense insolation all year (27 degrees). Dry season (shift in tropical rain belt due to Earth’s
shifted axis) and wet season with daily low-pressure cells (rising warm saturated air in
Hadley cell, adiabatic expansion forms tall cumulonimbus clouds).
Early rainy season due to transpiration; delayed onset due to deforestation. +ve feedback
may limit plant growth (NASA, 2017)
Rate of deforestation:
1/5 of primary forest degraded since 1970
190% increase since 2014.
1/3 destroyed in the last 3 decades.
3/4 wood shipped in 2013 illegally felled.
President Bolsonaro = native jungle → soy / cattle industry predicted to increase
deforestation x3. Promised to stop increase in network of indigenous forest reserves
Deforestation Impacts:
Carbon Cycle =
Stores 100 billion tonnes; 60% in biomass
Absorbs 2.4 billion tonnes/year + releases 1.7
High photosynthesis fixation + fast fluxes.
Deforestation = 15% of GG emissions.
5 tonne tree stores 1.5 tonnes carbon.
Water Cycle =
Produces ½ of its own rainfall
Breaks cloud formation cycle; predicted 20% decline in Madeira drainage basin rainfall,
Rondônia.
2014 floods, river 20m above normal.
Grassland increases run off x27; ½ precipitation direct run-off into rivers.
Severe drought in São Paulo Brazil; Droughts not fully attributed to SST also global warming
which increases speed of hydrological cycle. Wildfires release CO2
Management Strategies:
Legislation =
Protection of primary forest unaffected by commercial development
Brazil committed to restoring 120,000km2 by 2030.
Amazon Regional Protected Areas cover 44% of Brazilian Amazon (20x size of Belgium)
Most widely used, weakness in illegal deforestation (Brazil reduced penalties for past illegal
deforestation in 2018)
Reforestation =
Replanting degraded areas
REDD (Reducing Emissions from Deforestation and Forest Degradation) Carbon projects. 1
tonne carbon offset is $10.
Old-growth forests store carbon in biomass, their rate of sequestration from the
atmosphere is much slower than young-growth forests.
Parica Project developing a 1000km2
commercial timber plantation on deforested land for
exportation (monoculture project). Suruí people first indigenous group in Amazonia to join
UN’s REDD scheme and protect primary rainforest on tribal lands from further illegal
logging.
Improving Agricultural Techniques =
Making permanent cultivation possible
Agroforestry- trees grown along agricultural land to combine valuable crop cultivation under
tropical forest canopy (chemical fertilisers unnecessary for high crop yield). Protection by
fast growing timber species enables growth of higher-quality cocoa.