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Carbon pool definitions

Carbon pools in a forest are a complex collection of live and dead organic matter and minerals.

Carbon pools in a forest are a complex mix
of live and dead organic matter and minerals.

Carbon cycle

All parts (pools) and fluxes of carbon; usually thought of as a series of the four main pools of carbon interconnected by pathways of exchange. The four pools are atmosphere, biosphere, oceans and sediments. Carbon exchanges from pool to pool by chemical, physical and biological processes.

Carbon pool

A system with the capacity to accumulate or release carbon, expressed in mass units (tonnes C). Examples are forest biomass, wood products, soils, and the atmosphere.

Carbon stock

The quantity of carbon in a pool. Any change may be expressed as 'stock change'.

Definitions of carbon pools: The table provides a generic representation of carbon pools occurring in a terrestrial ecosystem based on IPCC's Good Practice Guidance for Land Use, Land Use Change and Forestry: Table 3.1.2)

Pool Description
Living biomass Above-ground biomass All living biomass above the soil including stem, stump, branches, bark, seeds, and foliage. Where forest understorey is a relatively small component of the above-ground biomass carbon pool, this may be ignored so long as the methodology is used consistently throughout the inventory time series.
Below-ground biomass All living biomass of live roots. Fine roots under, say, 2 mm diameter may be excluded as they often cannot be distinguished from soil organic matter or litter.
Dead organic matter Dead wood All non-living woody biomass not contained in the litter, either standing, lying on the ground, or in the soil. This includes wood lying on the surface, dead roots, and stumps (usually defined as having a diameter of at least 10 cm).
Litter All non-living biomass with a smaller diameter than that used for dead wood (say, 10 cm), lying dead, in various states of decomposition above the mineral or organic soil. This includes the litter, fumic, and humic layers. Live fine roots (of less than the diameter limit for below-ground biomass, say 2 mm) may be included here.
Soils Soil organic matter Includes organic carbon in mineral soils to a specified depth chosen by the country and applied consistently through the time series. Live fine roots (of less than the chosen diameter limit for below-ground biomass) to 30 cm depth may be included here.

Last updated: 3 August 2009