Effects of climate change and management on net climate impacts of production and utilization of energy biomass in Norway spruce with stable age‐class distribution

Abstract

We studied the effects of climate change and forest management scenarios on net climate impacts (radiative forcing) of production and utilization of energy biomass, in a Norway spruce forest area over an 80-year simulation period in Finnish boreal conditions. A stable age-class distribution was used in model-based analyses to identify purely the management effects under the current and changing climate (SRES B1 and A2 scenarios). The radiative forcing was calculated based on an integrated use of forest ecosystem model simulations and a life cycle assessment (LCA) tool. In this work, forest-based energy was used to substitute coal, and current forest management (baseline management) was used as a reference management. In alternative management scenarios, the stocking was maintained 20% higher in thinning compared to the baseline management, and nitrogen fertilization was applied. Intensity of energy biomass harvest (e.g. logging residues, coarse roots and stumps) was varied in the final felling of the stands at the age of 80 years. Also, the economic profitability (NPV, 3% interest rate) of integrated production of timber and energy biomass was calculated for each management scenario. Our results showed that compared to the baseline management, climate benefits could be increased by maintaining higher stocking in thinning over rotation, using nitrogen fertilization and harvesting logging residues, stumps and coarse roots in the final felling. Under the gradually changing climate (in both SRES B1 and A2), the climate benefits were lower compared to the current climate. Trade-offs between NPV and net climate impacts also existed.

Increased forest biomass production in the Nordic and Baltic countries – a review on current and future opportunities

“…The mean annual carbon stock and carbon sequestration of forests may be increased over a rotation by maintaining a high stocking, which results in lower harvesting frequency and somewhat lower timber production than in the business-as-usual management (Garcia-Gonzalo et al 2007a, 2007bNunery and Keeton 2010;Alam et al 2010;Torssonen et al 2016). In Finland, for example, maintaining high stocking of stands after thinning enhanced carbon stocks and energy wood production at final felling compared with business-as-usual thinning over a 90-year period (2010-2100) according to Alam et al (2010).…”

Climate impacts of carbon sequestration of forests and material substitution by energy biomass and harvested wood products under boreal conditions

“…Over a stand rotation, carbon sequestration, stocks, and energy biomass can be increased by using higher stocking in forests than currently recommended in thinnings (Garcia-Gonzalo et al 2007a;Nunery and Keeton 2010;Alam et al 2012;Kilpeläinen et al 2016a). However, the delayed thinnings, and a consequent decrease in the share of sawlogs, may decrease the economic profitability of forest production (Torssonen et al 2016). Conversely, annual timber production could be increased by using lower thinning thresholds, regardless of species, but this may decrease carbon sequestration and stocks (Alam et al 2008).…”

“…The impacts of climate change on carbon sequestration in forests and consequent effects on mitigation were excluded from the analysis. The LCA tool (Kilpeläinen et al 2011) has previously been used to study the Cnet of forest biomass production and utilization, inside and outside forest ecosystems (Routa et al 2011a;Alam et al 2012Alam et al , 2013Alam et al , 2017Kilpeläinen et al 2012Kilpeläinen et al , 2014Kilpeläinen et al , 2016bTorssonen et al 2016). In this work, the ALCA (Papers II, III) utilized all the flows of ecosystem and technosystem carbon in calculating Cnet for management and harvesting scenarios.…”

Climate Change Mitigation Potential in Boreal Forests: Impacts of Management, Harvest Intensity and Use of Forest Biomass to Substitute Fossil Resources

“…The available nitrogen for growth is determined by the amount of nitrogen released and immobilized in the decomposition of the soil organic matter (i.e., litter and humus layer). The soil moisture is described by using precipitation, evaporation and physical properties of soil (i.e., wilting point and field capacity of soil) [22]. The competition for light is determined by the tree species on the stand and their height distribution.…”

“…Instead, the amount of harvested timber can be increased in thinnings by leaving lower stocking than recommended [18], but this may decrease carbon sequestration of forests [19,20]. However, increased harvests from thinnings and final fellings may increase the potential of wood-based products and energy biomass to substitute fossil-intensive materials (e.g., concrete, steel and plastic) and fuels [3,12,21] and economic benefits as well [22]. The capability of the management measures to enhance carbon sequestration and amount of harvestable biomass within a certain time period will also depend on the initial forest structure [23][24][25][26][27].…”