Vital Forest Graphics

Historical forest carbon balance, 1855-1995

Gigatonnes (Gt) of carbon

Tropical Africa

Gigatonnes (Gt) CO 2

Emissions of carbon from changes in land use

Tropical America

Tropical Asia

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Non-tropical regions

Eastern Europe Central Asia

Canada

Europe

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United States

North Africa Middle East

East Asia

Tropical America

South Asia

Tropical Africa

OECD Pacific

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Forests and the carbon cycle

J hrough processes of respiration and through the decay of organic matter or burning of biomass, for- ests release carbon. A carbon ‘sink’ is formed in the forest when the uptake of carbon is higher than the release. Carbon stocks in forest areas com- prise carbon in living and dead organic matter both above and below ground including trees, the understorey, dead wood, litter and soil. On a global scale, vegetation and soils are estimated to trap 2.6 gigatonnes (Gt) of carbon

Forests play a vital role in the global carbon cycle. Forests absorb carbon through photosynthesis and sequester it as biomass, thus creating a natural storage of carbon

annually. Yet there are still many uncer- tainties about the workings of the car- bon cycle: the Intergovernmental Panel on Climate Change (IPCC) estimates that the amount of carbon absorbed in the soil and vegetation amounts to any- thing between 0.9 and 4.3 Gt annually. Carbon stocks in land based ecosys- tems are distributed irregularly between tropical and northern latitudes but are mostly concentrated in forest ecosys- tems and wetlands. Recent research suggests tropical forests play an even more important role in absorbing car- bon than previously thought, taking up 1 Gt of carbon every year, or about 40 per cent of the total for land based absorption (Britton et al . 2007). The conversion of forested to non- forested areas in developing countries has had a significant impact on the accumulation of greenhouse gases in the atmosphere, as has forest degradation caused by over-exploitation of forests for timber and woodfuel and intense graz- ing that can reduce forest regeneration. Scientists are continuing to investi-

Forest carbon stock per region

Carbon in tree and plant biomass Giga tonnes (Gt)

50 25

Europe

North America

West and Central Asia

East Asia

5

North Africa

Caribbean

South and Southeast Asia

West and Central Africa

Central America

East and South Africa

South America

Oceania

91 Gt

Source: FAO 2006a. Map produced by Emmanuelle Bournay.

36 VITAL FOREST GRAPHICS