BalanC - The impact of increasing spruce plantation area on the carbon balance of forests in Western Norway

Summary

Tree planting and tree species change has been suggested as a government policy to mitigate climate change in Norway. The aim is to increase the annual CO₂ uptake as well as the long-term storage of carbon in forests. The strategy includes replacing native, deciduous species with fast-growing species like Norway spruce in order to rapidly produce biomass and sequester carbon. To focus solely on carbon sequestration in tree biomass will, however, disregard crucial parts of the total carbon sequestration potential of the forest ecosystem, and will give an incomplete picture of the carbon balance of this measure.

In addition to carbon stocks in vegetation, the total carbon balance includes soil carbon, emissions from wood-product life-cycles and climatic feedback through albedo. Forests in western Norway host some of the largest soil carbon pools in Scandinavia, estimated to more than 3 times the carbon stock found in vegetation. Thus, these soils may potentially function as a long-term carbon reservoir as well as a large source of CO₂ through decomposition.

Compared to forests of the cooler and flatter regions of eastern Norway, little is known empirically surrounding the albedo dynamics in coastal forests of western Norway. Whereas a major goal of the tree species change policy is to promote enhanced use of tree biomass for bioenergy, materials, etc., the fate of carbon in the wood-product chain has not yet been accounted for.

The BalanC project aims at providing complete carbon budget for parallel stands of birch and planted Norway spruce in western Norway that comprises carbon stocks in biomass and soils, in-depth studies of soil carbon processes, the carbon budget of the wood product chain and the climatic feedback from albedo. By investigating the responses of these factors to tree species change, we intend to contribute to a complete and solid assessment of the overall effect of the proposed policy on carbon sequestration and climate change mitigation in Norway.