Estimating carbon accumulation rates of undrained mires in Finland - application to boreal and subarctic regions

Equations based on empirical relationships of peat physical properties were used to estimate the average long-term apparent rate of carbon accumulation (LORCA) in Finnish mire vegetation regions. The results were generalized to the boreal and subarctic regions. Analyses of 1302 dated peat cores were used to infer carbon accumulation for each mire vegetation region of Finland. The area-weighted LORCA for Finnish undrained mire areas was 18.5 g m(-2) yr(-1) and the total carbon sink 0.79 Tg yr(-1) (1 Tg = 10(12)g). The total carbon pool of Finnish undrained mires was estimated as 2257 Tg. The aapa-mire region included 80% of the total net accumulation rate of carbon and 85% of the total carbon reservoirs of Finnish undrained mires. LORCA was significantly higher in the raised-bog region, 26.1 g m(-2) yr(-1), compared with the aapa-mire region, 17.3 g m(-2) yr(-1), and bogs generally had a higher LORCA 20.8 g m(-2) yr(-1), than fens 16.9 g m(-2) yr(-1). The total C sink for boreal and subarctic mires was estimated at 66 Tg yr(-1) which is about 31% lower than the previous estimates. The total C pool of all boreal and subarctic mires was estimated at 270-370 Pg (1 Pg = 10(15)g).