Decomposition of Scots pine litter and the fate of released carbon in pristine and drained pine mires

A field experiment was carried out to validate the results of a previous la boratory experiment showing that part of the carbon released from decaying Scots pine (Pinus sylvestris L.) needle and fine root litter was retained i n the peat soil. C-14-labelled litter was incubated for up to 1.5 years in pristine and drained pear soils. During this period, 40-60% of the: initial C-14-activity was lost from the litter and 10-30% of the lost activity was retained in the soil. Needle litter decomposed faster than fine root litte r. On average, drainage increased the mass and C-14 losses from the needle litter in Carex-peat but not in Sphagnum-peat. Losses from the fine root li tter were not clearly affected by drainage. Drainage did not significantly affect the relative proportion of C-14-activity found in the peat. The resu lts support the earlier hypothesis that a flow of organic C from decaying t ree litter contributes to C storage in drained peatlands. (C) 2000 Elsevier Science Ltd. All rights reserved.