Effects of management on biomass production in Norway spruce stands and carbon balance of bioenergy use

In this study, we analyzed the effects of management on the production of timber and energy biomass, and ecosystem carbon balance in Norway spruce (Picea abies) stands, with impacts on carbon neutrality of the use of biomass in energy production. In simulations, we employed the ecosystem model and life cycle analyses tool with varying management scenarios (thinning, nitrogen fertilization and rotation length) on medium fertile and fertile sites in central Finland. We found that the annual mean timber production could be increased by using longer rotation lengths of 60–80 years. This was opposite to energy biomass production, which was increased the most by using shorter rotations of 30–50 years. On the other hand, both of them could be increased by applying nitrogen fertilization and by maintaining higher stocking over the rotation compared to the current Finnish baseline management. This positively affected both the carbon storage and carbon balance in forestry, as well as the energy carbon balance which takes into account both carbon balance for forestry and the CO2 emissions from the burning of energy biomass. It also decreased the CO2 emissions per unit of energy by approx. 30% compared to baseline management, regardless of site fertility type. Similarly, the carbon neutrality of the bioenergy system could be increased in this way compared to the use of coal instead. To conclude, based on proper management it will be possible to increase simultaneously the production of timber and energy biomass, and carbon stock in the forest ecosystem and to improve the forest ecosystem carbon balance so that in the long-term the CO2 uptake will exceed concurrent emissions.

► Forest management affects biomass production and ecosystem carbon balance.
► Management affects also carbon balance for the use of biomass.
► Use of longer rotation and nitrogen fertilization increases annual timber production.
► By maintaining higher stocking over the rotation timber production can be increased.
► Proper management increases both biomass production and carbon neutrality.