The rate of CO2 evolution at 23C and 75% moisture content for a diverse group of coniferous leaf litter samples from Oregon was measured. Significant correlations (1% level) were observed between the rate of CO2 evolution and the activity of amylase, cellulase, and xylanase (r=0.71, 0.58, and 0.44, respectively) in 0.05M potassium acetate pH 5.0 extracts of the litter. The amounts of extractable hexose, phenolics, and reducing substances were also correlated with the rate of CO2 evolution (r=0.74, 0.53, and 0.73 respectively). Peroxidase and invertase activities were not correlated with the rate of CO2 evolution. Litter extracts showed zero-order kinetics for the hydrolysis of carbozymethylcellulose, xylan, starch, and sucrose. All carbohydrase activities were destroyed by a 15 min exposure to a boiling water bath.