Climate effects of improved growth increments and changing utilization strategies for birch ( <i>Betula spp.</i> ) in Southern Sweden – impact assessment in a life cycle perspective

Abstract The short-term effects of alternative forest production and utilization systems in Sweden are of significant interest for climate change mitigation. For that, fast-growing broadleaved tree species, such as birch ( Betula spp. ), represent one possible avenue because they are already adapted to (hemi)boreal latitudes. Currently, non-improved birch is used as a source for fuelwood and pulpwood, whereas developing improved genotypes with better wood quality could deliver long-lived wood products. However, there is still a lack of climate impact assessments regarding the increments of improved birch and changing uses of birch wood. The aim of this work was to investigate and compare the climate impact of ‘traditional/non-improved’ birch versus ‘improved’ birch systems, characterized by a 20% total volume gain through time-dependent life cycle assessment methodology. Changes in the product portfolio from short-lived to long-lived wood products were evaluated. The assessment included biogenic carbon dynamics in living biomass and soil, as well as carbon stored in harvested wood products, greenhouse gas emissions from fossil fuels process in value chains, and potential substitution effects, considered over a fixed rotation length of 50 years at the stand level. A shift towards more long-lived wood products could result in more mitigation potential compared to changing birch genotypes. However, these measures may be combined to achieve additional climate cooling effects as compared to the current use of birch in Southern Sweden.