In northern coniferous forests nutrient release from litter occurs primarily in late stages of decomposition when mainly extensively lignified parts remain. An important regulating factor in these stages is the turnover rate of lignin and related compounds. Two factors which influence the decomposition rate of lignin are 1) nitrogen concentration which retards decomposition and 2) concentration of celluloses which increase the turnover rate. The amount and composition of humus which is formed may be dependent on the initial lignin concentration of the litter, which in its turn varies among species. These results from studies in northern coniferous forests are discussed in an ecosystem context.