Decomposition rate constants of Picea abies logs in southeastern Norway

Decomposition rate constants were estimated from 384 cross sections of Norw ay spruce (Picea abies (L.) Karat.) logs with base diameter >7.0 cm collect ed in open areas at five different study sites in southeastern Norway. Fres h wood core samples were taken from 95 standing trees adjacent to the logs to estimate the initial density of these cross sections. Based on this chro nosequence, a simple negative exponential function of time showed an averag e decomposition rate constant for all cross sections of 0.033 per year. Cro ss-section diameter, ground contact, soil moisture, and aspect were all fou nd to have significant impacts on the decomposition rate constant. For diff erent combinations of these characteristics the decomposition rate constant ranged from a minimum of 0.0165 per year to a maximum of 0.0488 per year.