A test and application of the model ForNBM in a northeastern Ontario jack pine (Pinus banksiana lamb.) stand

The model, ForNBM, was used to simulate biomass growth, soil temperature, hydrology, and nutrient cycling in a jack pine forest in northeastern Ontario. Simulated forest biomass growth, water, and nutrient fluxes were compared with up to 9 years of field measurements. The results show that r^2-values between predicted and measured monthly soil leaching of five main nutrient ions (NO3- -N, NH4+-N, Ca, Mg, and K) range from 0.65 to 0.98, with the best simulation for Ca and the worst for NO3- -N. Predicted biomass growth, biomass nutrient content, and cumulative nutrient leaching strongly agree with measurements (all r^2-values >0.9). For the given jack pine stand, the model predicts that N and K supply for jack pine uptake mainly came from soil organic matter mineralization (61 and 60%, respectively). Ca supply is mainly from soil mineral weathering (50%) and K supply from both soil mineral weathering and organic matter mineralization (30 and 30%, respectively). As such, clear-cutting of the jack pine forest may result in a minimal overall degradation of nutrient supply, especially for N and K, for future forest biomass growth.