CARBON ACCUMULATION IN PEATLAND

(1) Models of pear accumulation are developed that include constant, l inear and quadratic decay of dry mass remaining. Profiles of dry bulk density of 795 peatlands distributed over Finland are used to infer cu mulative carbon for each site. These values and basal ages are themsel ves used to infer rates of growth and decay of the peat. (2) A method, 'function parameter fitting' (FPF), is devised to estimate parameter values in non-linear functions when there are uncertainties in both va riables, as there are in cumulative carbon and age. Where the data are highly variable then results with FPF are substantially different fro m those used hitherto that assume uncertainty in only the dependent va riable. (3) For five regions in Finland and in Boreal Canada the infer red rate of addition, p() [M L-2 T-1], is related to degree-days abov e zero, and decay, a() [T-1] is related logarithmically to mean annua l temperature. The present day rate of accumulation of carbon in north ern peatlands is about 5.6 Tmol yr(-1) or, as dry mass, 0.07 Gt yr(-1) . (4) There are difficulties in the interpretation of LARCA (= LORCA = long term average rate of carbon accumulation). Understanding of peat land dynamics may result from the use of intrinsic models allowing dec ay: it is unlikely to emerge from the exotic models in common use.