Carbon storage in forest soils
1995
Harrison, A.F. | Howard, P.J.A. | Howard, D.M. | Howard, D.C. | Hornung, M.
The amounts of carbon stored in soils and vegetation in Britain, and the potential of forestry to influence, whether soils act as sinks or sources, are discussed. Soils are estimated to contain c.22 x 10(9) t carbon, while the amount in vegetation including forests is only 115 x 10(6) t. Some 86 per cent of the soil carbon is present in peats and peaty-surfaced soils, mainly in north-west Britain. Soil carbon content is strongly related to climate and altitude. Conversion of lowland cultivated land to forest can result in carbon accumulation in soils, as it can following the planting of some uplands, but quantities appear to be small in relation to the amounts of carbon released to the atmosphere through fossil fuel use. Forest felling may result in decreases in soil carbon store, due to soil disturbance and changes in microclimatic conditions, but several decades after reafforestation the carbon store may recover to near original levels. Shortening forest rotations may result in long-term declines in soil carbon store. The main concern is the potential for forestry to convert peats, which contain amounts of carbon equivalent to 100 years' fossil fuel use at 1988 levels and which are normally slow sinks for atmospheric carbon, into carbon sources returning it to the atmosphere. The possible impacts of forestry and global warming on rates of carbon loss from upland soils including peats are discussed.
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