CARBON DYNAMICS OF LAND-USE IN GREAT-BRITAIN

Aggregate yearly carbon fluctuations from 20 categories of land use are calculated and presented for groupings of these categories by estimating biomass carbon changes in the vegetation associated with the land use category and soil carbon changes for soil types associated with the same land use categories. The results are then compared with an aggregate carbon balance for the land-using sector for one year, by estimating carbon fixations and emissions from agricultural and forestry activities. The results show that conversion of land to arable cultivation leads to medium-term reductions in soil and biomass carbon, when the limits of the study are set to count agricultural and forestry products leaving the sector as having been fixed by that sector. Forestry in the period studied has not fixed large amounts of carbon because new planting initially causes losses of previously fixed biomass and soil carbon. The aggregate estimates of carbon sequestration are critically dependent on the boundaries of the study, but the estimates are still relatively minor in relation to total carbon emissions from other sectors of the economy in Great Britain. © 1992 Academic Press Limited.