Spruce volume increases across Sweden – despite shrinking areas suited under future climate
Climate projections indicate that large parts of southern Sweden may become unsuitable for spruce by the end of this century. But the current management trends are moving in the opposite direction: spruce volume is increasing.
Using projected habitat suitability for Norway spruce from 2005 to 2095 under two climate scenarios, researchers from Stockholm University and the Swedish University of Agricultural Sciences (SLU) have compared expected range shifts with long-term forest inventory data on spruce growing stock.
The results show that in Southern Sweden (Götaland), a large share of spruce stands that existed in 2005 are projected to end up in areas that are no longer suitable for spruce by 2095.
Increase of spruce in unsuitable areas
Under a moderate emissions scenario, by the turn of the next century 55 per cent of Sweden’s spruce forest will be located in areas not suitable for spruce in terms of climate. In a scenario with high emissions, this figure rises to 84 per cent.
At the same time, observed trends in spruce growing stock between 2005 and 2020 often run counter to the projected changes in suitability, although patterns vary between counties. In addition, the growing stock of young trees is rising across all regions of Sweden, indicating that management practices are maladapted to climate change.
“Norway spruce is the backbone of Swedish forestry, but our analysis shows a growing gap between where spruce is being planted and where climate conditions are projected to support spruce growth in the long term,” says correspondant author Caroline Greiser from Stockholm University.
Need for climate-adaptive forest management
The study highlights a risk that forest landscapes may become more vulnerable to climate-related stress where spruce is expanded or maintained in areas projected to become less suitable. The authors argue that climate-adaptive forest planning needs to be more directly integrated into operational decisions – such as tree species choice, regeneration strategies, and long-term risk management – if Swedish forests are to remain resilient as the climate changes.
“Our findings show that planting new spruce trees in Southern Sweden comes with high ecological and economic risks as trees may face a higher pre-harvest mortality due to climate-driven stressors such as drought, windthrow or attacks from the bark beetle,” says Jeannette Eggers, co-author from SLU.
Read the article: Spruce volume increases across Sweden – despite decreasing future climate suitable areas.
Contacts
Caroline Greiser, Stockholm Universitet. Tel: +46 764 152 485, e-mail: caroline.greiser@su.se
Jeannette Eggers, Swedish University of Agricultural Sciences. Tel: +46 722 035 026, e-mail: jeannette.eggers@slu.se