Influence of climate change, fire and harvest on the carbon dynamics of black spruce in Central Canada

The results of EFIMOD simulations for black spruce (Picea mariana [Miller]) forests in Central Canada show that climate warming, fire, harvesting and insects significantly influence net primary productivity (NPP), soil respiration (Rs), net ecosystem production (NEP) and pools of tree biomass and soil organic matter (SOM). The effects of six climate change scenarios demonstrated similar increasing trends of NPP and stand productivity. The disturbances led to a strong decrease in NPP, stand productivity, soil organic matter (SOM) and nitrogen (N) pools with an increase in CO2 emission to the atmosphere. However the accumulated NEP for 150 years under harvest and fire fluctuated around zero. It becames negative only at a more frequent disturbance regime with four forest fires during the period of simulation. The results from this study show that changes in climate and disturbance regimes might substantially change the NPP as well as the C and N balance, resulting in major changes in the C pools of the vegetation and soil under black spruce forests.