Prescott, C.E. and C.M. Preston, 1994. Nitrogen mineralization and decomposition in adjacent plantations of western red cedar, western hemlock and Douglas-fir. Can. J. For. Res. 24:2424-2431.

To determine if western red cedar (Thuja plicata) litter contributes to low N availability in cedar-hemlock forests, measurements were made of concentrations of N and rates of net N mineralization on forest floors from single-species plantations of cedar, western hemlock (Tsuga heterophylla), and Douglas fir (Pseudotsuga menziesii) on the same site in coastal British Columbia. Concentrations of total and extractable N and rates of net N mineralization during laboratory incubations were lowest in the cedar forest floor in Douglas fir. Less C was mineralized in the cedar forest floor during incubation, and the amount of N mineralized per unit C was least in cedar. Rates of mass loss of foliar litter of the three species were similar during the first 50 weeks of a 70-week laboratory incubation, but cedar lost mass more quickly during the final 20 weeks. Rates of net N mineralization in the forest floors were significantly correlated with the initial percentage N, C/N, percentage Klason lignin and lignin/N of foliar litter. Foliar litter of cedar had lower concentrations of N and greater proportions of alkyl C (based on 13C NMR spectroscopy) than Douglas fir litter. These characteristics of cedar litter may contribute to low N availability in cedar-hemlock forest floors. Concentrations of alkyl C (waxes and cutin) may be better than lignin for predicting rates of mass loss and N mineralization from litter.