How Forest Management and Climate Change Affect the Carbon Sequestration of a Norway Spruce Stand?( Multipurpose Forest Management)

Mitigation of climate change by forest carbon sequestration is one of the ecosystem services that will be taken into account in future forest planning. The potential capacity of forests to sequester carbon is determined by edaphic and climatic factors, but the actual carbon accumulation is highly controlled by management. The effects of the management practices on stand development are successfully analyzed with traditional stand simulators that rely on empirical data. One of the current challenges is to understand how ecosystem services, such as carbon sequestration and timber production, can be managed in the changing climate, i.e. under conditions of which there are no observations. The objective of this study was to investigate the responses of forest soil and vegetation to a climate change under different management scenarios ranging from intensive thinning to unmanaged stands. The responses of tree growth and forest carbon sequestration to changes in temperature and precipitation (+3℃ and +10%, respectively) under different management scenarios were investigated with a process-based forest model (PipeQual) which was combined to a soil decomposition model (ROMUL) and a soil water balance model. According to our simulations, the growth response of Norway spruce to increased temperature was positive. Carbon stocks of both vegetation and soil were increased with the changing climate in all the simulated management scenarios. In the changing climate decomposition of soil organic matter was accelerated, however, increased litter input resulting from enhanced growth of vegetation compensated this decrease. Intensively harvested stands had a decreased carbon stock in the vegetation, which resulted in low litter production and decline in soil carbon stock after thinnings. The simulations with the process-based forest growth and soil model can guide management by determining a sustainable level of biomass harvest.