FEAT ACCUMULATION AND PEAT DECOMPOSITION AFTER HUMAN DISTURBANCE IN FRENCH AND FINNISH MIRES

The primary production of two pristine Sphagnum-Carex peatlands in Fra nce and Finland were 274 and 629 g C (carbon) m(-2) yr(-1), respective ly and accumulation/productivity ratios were 0,10 and 0,03 yr(-1) whic h represent 28 and 20 g C m(-2) yr(-1). The natural processes of pear accumulation were altered by human activities, i.e. forestry in Finlan d and agricultural use in France. At the French site, the main changes processes in the managed site were Sphagnum reduction and an increase in grasses. These changes diminished the C-Aux to the litter while a parr of the stock in the pear was released with the increase of decomp osition of accumulated peat. Ar the Finnish sire, the main changes in the managed site were the development of tree layer after drainage and an increase in pear respiration. Although litter production was incre ased, the increased decomposition also resulted in the cessation of pe at accumulation and decomposition of earlier accumulated peat.