MASS-LOSS MEASUREMENTS AND STATISTICAL-MODELS TO PREDICT DECOMPOSITION OF LEAF-LITTER IN A BOREAL ASPEN FOREST

In a southern boreal aspen forest located in Saskatchewan, Canada, we examined decomposition rates of leaf litter from trembling aspen (Popu lus tremuloides Michx.), hazel (Corylus cornuta March.), and a mixture of different species over a six-month period. Mass loss was measured in the field using the litter bag method. The greatest mass losses occ urred during the first month regardless of litter type. On average, ma ss loss during the first 28 days was 3.2 g . kg(-1). d(-1) for the asp en leaves, 4.4 for hazel leaves and 4.9 for the mixture. The initial r apid loss of weight is attributed to leaching and decomposition of wat er soluble material. The decomposition rates of the leaf litter were r elated to water-soluble organic carbon and nitrogen content, and C:N r atio. Several models were used to describe mass loss of the aspen, haz el, and mixed leaf litter at the early stages of decomposition. A sing le model was not found to be appropriate to describe decomposition of all leaf-litter types. A second order model provided the best fit for the aspen litter decomposition, while the logarithmic model best descr ibed the decomposition of hazel and mixed leaf litter.