Amazon Rainforest - Carbon

• What is the background of the Amazon Rainforest regarding the carbon cycle?

  • Humid, tropical climate, creates ideal conditions for plant growth
  • Net primary productivity is high
  • Biomass is high - 400-700 tonnes/ha
• What are the characteristics of the Amazon Rainforest's carbon cycle?

  • Large trees store 180 tonnes C/ha above ground and 40 tonnes C/ha in roots
  • Soils store 90-200 tonnes/ha of carbon
  • The Amazon is a major global carbon store - 2.4 billion tonnes a year absorbed
  • Humid, tropical climates causes rapid decomposition
  • Carbon fixation through photosynthesis is high
  • Rapid decomposition/recycling of organic matter is the reason why there is a high NPP and biomass in a place with poor soil quality
• What are the flows and stores in the carbon cycle?

  • Vegetation
  • Atmosphere
  • Soil/ground
  • Photosynthesis
• How does vegetation affect the Amazon's carbon cycle?

  • High NPP, high biomass, large trees store 180 tonnes C/ha above ground, 40 tonnes C/ha in roots
• How does the atmosphere affect the Amazon's carbon cycle?

  • Rapid exchanges to atmosphere
  • Decomposition is rapid so quick release of carbon
• How does soil/ground affect the Amazon's carbon cycle?

  • Limited stores of carbon as organic matter quickly broken down and recycled
• How does photosynthesis affect the Amazon's carbon cycle?

  • Sequestration of CO2 very high
• How does an individual tree influence the Amazon's carbon cycle?

  • Trees are major stores of carbon (180 tonnes C/ha above ground, 40 tonnes C/ha below ground)
  • Carbon is fixed in the leaves through photosynthesis
• What are the physical factors that influence the Amazon's carbon cycle?

  • Temperature
  • Vegetation/biomass
  • Geology
• How does temperature affect the Amazon's carbon cycle?

  • High temperatures and guaranteed sunlight causes lots of photosynthesis
  • Promotes rapid decomposition
  • Photosynthesis means more carbon intake resulting in growth
• How does vegetation affect the Amazon's carbon cycle?

  • Main carbon store
  • Absorbs 2.4 billion tonnes of CO2 per yr
  • 60% of carbon is stored above ground i.e., trees
  • 40% stored in roots and soils
  • NPP is stimulated by high temperatures/rainfall/sunlight
  • Leaf litter accumulates at the soils surface - rapid decomposition due to humidity
  • Nutrients are then released to soils, taken up by tree roots, emits CO2 which is returned to the atmosphere
• How does geology affect the Amazon's carbon cycle?

  • Dominated by igneous rock and meta-morphic rocks
  • Little storage of carbon in igneous + metamorphic rock
  • Limestone outcrops are significant stores of carbon
• How does deforestation affect the Amazon's carbon cycle?

  • In primary forest (not affected by humans) the biomass of trees represent 60% of all rainforest ecosystem carbon (180 tonnes/ha)
  • Deforestation exhausts carbon biomass stores e.g., land used for soya cultivation stores 2.7 tonnes/ha of carbon
  • Reduces input of organic matter to soils, depletes them of carbon and exposes them to sunlight
  • This means there are fewer decomposers and the flow of carbon from soil to atmosphere is reduced
• What strategies are implemented to manage the tropical rainforest (both water and carbon cycles)?

  • Parica Project
  • REDD Scheme
  • Improved agricultural techniques
• How does the Parica Project help manage the rainforest?

  • Sustainable forestry scheme producing 100km2 commercial timber plantation
  • Fast growing seedlings planted on small holdings and financial assistance provided
  • Despite it being a monoculture (focusing on a single crop or livestock) it's sustainable in sequestering carbon in trees/soil
  • It also reduces the CO2 emissions from deforestation, reduces run-off and re-establishes carbon/water cycles
• How does the REDD Scheme help manage the rainforest?

  • Surui people joined the UN led scheme in 2008
  • Tribe is paid for protecting the rainforest and abandoning deforestation using carbon credits (which companies can buy)
  • 2013 Natura purchased 120,000 tonnes of carbon credits from the Surui
• How does using improved agricultural techniques help manage the rainforest?

  • Farming is the main cause of deforestation
  • Diversification projects - rotational cropping and combining livestock and arable operations allows 5 fold increase in productivity and reduces deforestation
  • This improves soil quality/fertility