Decomposing litter; limit values; humus accumulation, locally and regionally

Decomposition of foliar litter may be complete or proceed at a progressively lower rate to become zero and a limit value for decomposition may be estimated. Limit values for decomposition have been found to range from 100% accumulated mass loss to 42%, resulting in 'stable' fractions of 0 and 58%, respectively. A limit value does not necessarily mean a complete stop in decomposition but litter mass loss may proceed at a very low rate. An asymptotic function is used to estimate limit value/stable fraction, separating a readily decomposed and a stable residue. The stabilized litter fraction defined as (100 - limit value)/100 may be used for estimating the accumulation rate of stable carbon (C) in organic layers.