ELSS Case Study 1: Amazon Rainforest

Question 1

How large an area does the Amazon Rainforest occupy?

Answer 1

6 million km2

Question 2

How much of the Amazon Rainforest is in Brazil, and what other countries does it spread into?

Answer 2

70% of the rainforest is in Brazil, with the remaining 30% split between Peru, Ecuador, Venezuela, Colombia, Bolivia and Guyana.

Question 3

What is the range of average annual temperatures?

Answer 3

25 - 30*C

Question 4

How much rainfall on average does the Amazon Rainforest get in a year?

Answer 4

Over 2000mm

Question 5

How much seasonal variation is there in the Amazon Rainforest?

Answer 5

Little seasonal variation.

Question 6

How much rainfall is intercepted by the trees?

Answer 6

10% around.

Question 7

How much of the rainfall is returned via evapotranspiration, and where is the largest source of this evapotranspiration?

Answer 7

Around half, and most of it is from intercepted moisture on leaf surfaces.

Question 8

What is the NPP of the Amazon Rainforest?

Answer 8

About 2500g/m2/yr, which accounts for 15-25 % of all terrestrial NPP.

Question 9

How much biomass is there per hectare?

Answer 9

Between 400 -700 tonnes/ha

Question 10

How much biomass is stored in trees per hectare?

Answer 10

180 tonnes of C/ha above ground and a further 40 tonnes of C/ha below ground.

Question 11

How much carbon is stored in the Amazon Rainforest overall?

Answer 11

100 billion tonnes of carbon.

Question 12

How much carbon does the Amazon rainforest sequester a year, and how much does it release through decomposition?

Answer 12

2.4 billion tonnes/yr is absorbed, however 1.7 billion tonnes is released through decomposition each year.

Question 13

What is the distribution of geology across the Amazon Basin like?

Answer 13

Large parts of the basin comprise of ancient shield areas, comprising of impermeable, crystalline rocks, with the rest being permeable and porous rocks such as limestone and sandstone, storing rainwater and slowing run-off, which appear towards the Andes mountains in the West.

Question 14

What percentage of carbon is stored above ground in the Amazon?

Answer 14

60% is stored above ground in biomass.

Question 15

What are some physical factors affecting stores and flows of carbon in the Amazon Rainforest?

Answer 15

The density and size of trees, the high temperatures accelerating photosynthesis, high rainfall and intense sunlight, litter and dead organic matter decomposing rapidly, and the geology of the amazon basin, dominated by ancient metamorphic and igneous rocks, with outcrops of limestone towards the Andes in the West.

Question 16

What has the rate of deforestation been per year between 1970 and 2013?

Answer 16

Average around 17,500km2/year

Question 17

How much of the primary rainforest has been destroyed since 1970?

Answer 17

Almost 1 fifth of the primary rainforest.

Question 18

What is an example of the impact of deforestation on stores and flows of water in the Amazon rainforest?

Answer 18

In the Upper Madeira drainage basin, water storage in forest trees, soils, permeable rocks and in the atmosphere has been reduced, and there is increased surface run off and store of water. This resulted in a devastating flood of the Madeira river in 2014, levels reaching 19.68m above normal, inundating vast areas of floodplain, killing 60 people and resulting in the evacuation of 68,000 families; also oubreaks of cholera and leptospriosis.

Question 19

By what factor does deforestation increase run-off?

Answer 19

By a factor of 27, with half of all of it going into rivers.

Question 20

What is a future projected impact of deforestation?

Answer 20

A predicted 20 percent decline in regional rainfall.

Question 21

What proportion of carbon in the ecosystem is stored in trees?

Answer 21

About 60% of the carbon in the entire ecosystem.

Question 22

What is the difference in carbon storage per ha between primary rainforest and grassland and soya cultivation?

Answer 22

Primary rainforest stores about 180 tonnes/ha, whereas grassland stores about 16.2 tonnes/ha, and soya stores around 2.7 tonnes/ha.

Question 23

Why is deforestation so impactful on the soils of rainforests?

Answer 23

Rainforest soils only contain a small resevoir of essential nutrients, as the forest is sustained by a very rapid nutrient cycle, that without new inputs from trees, the little nutrients are washed away by increased run-off, eroding soils.

Question 24

What are some strategies to manage tropical rainforests?

Answer 24

Brazil is committed to restoring 120,000km2 of rainforest by 2030.

Legislation of large areas of currently unaffected primary rainforest.

Reforestation of areas degraded or destroyed by subsistence farming, cattle ranching, logging and mining.

Improving agricultural techniques to make permanent cultivation possible.

Question 25

By 2015, how much of the Amazon comprised of national parks, wildlife reserves and indigenous reserves where farming is banned?

Answer 25

44 percent of the Brazillian Amazon.

Question 26

What is an example of a reforestation project in the Amazon?

Answer 26

The Parica project in Rondonia in the Western Amazon, aiming to develop a 1000km2 commercial timber plantation on government-owned, deforested land. The plan is for 20. million fast-growing, tropical hardwood seedlings planted on 4000 smallholdings to mature over a period of 25 years. This is supported by local authorities, NGOs and businesses.

However this project is a monoculture, and so will never reach the same levels as primary rainforest.