A comparison of carbon assessment methods for optimizing timber production and carbon sequestration in Scots pine stands

▶ The forest carbon stock was assessed, with three methods: stem carbon, biomass expansion factors (BEFs), and a process-based model. ▶ Changing carbon assessment methods leads to very different optimal thinning regimes and average carbon stocks. ▶ Raising the carbon price resulted in longer rotations and a significantly higher average carbon stock over the rotation. Projected changes in forest carbon stocks and carbon balance differ according to the choice of estimation methods and the carbon pools considered. Here, we compared three carbon assessment methods for optimizing timber production and carbon sequestration in six example Scots pine (Pinus sylvestris L.) stands in Finland. The forest carbon stock was assessed, with three methods: stem carbon, biomass expansion factors (BEFs), and a process-based model. Given a carbon price of 40€t−1 (equivalent to 10.9€t−1 CO2) and a 3% discount rate, the highest average carbon stock and mean annual increment (MAI) were obtained with the BEF method. Increasing the carbon price from 0 to 200€t−1 resulted in longer optimal rotations and higher MAI, and increased the average carbon stock, especially when carbon was assessed by the BEF method. Comparison of these carbon assessment methods, using economic sensitivity analyses, indicated that optimal thinning regimes and average carbon stocks are strongly dependent on the assessment method. The process-based method led to less frequent thinnings and shorter rotations than the BEF method, due to different predictions of biomass production. As a cost-effective option, optimal thinning regimes play a very important role in timber production and carbon sequestration.