Effects of fertilization on decomposition rate of Populus tremuloides foliar litter in a boreal forest

Rates of mass loss of foliar litter of trembling aspen (Populus tremuloides Michx.) were measured for 4 years after a single fertilization with N at 200 kg N/ha or a mix of N, P, K. Ca, Mg, S, and B. Foliar litter from fertilized plots had higher N concentrations than litter from control plots; Litter from the nutrient-mix plots had higher concentrations of N, P, and Ca. The average rate of mass loss of aspen foliar litter was 60% after 4 years. The higher concentrations of nutrients in litter from fertilized plots did not affect the rate of decomposition. There was some difference in rates of decomposition of litter incubated in plots of the three treatments. Mass loss was significantly slower in the nutrient-mix plots after 12 and 18 months compared with control plots. This experiment provided no evidence that fertilization of boreal aspen forests will increase rates of litter decomposition.