Spruce volume increases across Sweden–despite decreasing future climate suitable areas

Abstract

Climate change is shifting the suitable habitats for many tree species northwards. Large parts of southern Sweden are projected to become unsuitable for Norway spruce by the end of this century. With the majority of forests in Sweden under management, spruce plays an important role, both economically and in natural ecosystems. Despite its significance, there is limited understanding of whether current trends in spruce prevalence align with the projected changes in habitat suitability. In this study, we addressed this gap by analysing projected range shifts for Norway spruce between 2005 and 2095 under two climatic scenarios (RCPs) and compared them with long-term forest inventory data. Our results show that: (1) In southern Sweden (Götaland), large parts (59.1% for RCP 4.5 and 85.7% for RCP 8.5) of current spruce stands (as by 2005), are projected to fall into areas unsuitable for spruce by 2095. (2) Observed trends in growing stock between 2005 and 2020 are often opposite to those projected for changes in suitability, though trends varied between counties. (3) The growing stock of young trees is increasing across all regions. Combined, these results show a clear mismatch between projected spruce habitat suitability under climate change and current management practices.