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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2022

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Abstract

Norway’s most common tree species, Picea abies (L.) Karst. (Norway spruce), is often infected with Heterobasidion parviporum Niemelä & Korhonen and Heterobasidion annosum (Fr.) Bref.. Because Pinus sylvestris L. (Scots pine) is less susceptible to rot, it is worth considering if converting rot-infested spruce stands to pine improves economic performance. We examined the economically optimal choice between planting Norway spruce and Scots pine for previously spruce-dominated clear-cut sites of different site indexes with initial rot levels varying from 0% to 100% of stumps on the site. While it is optimal to continue to plant Norway spruce in regions with low rot levels, shifting to Scots pine pays off when rot levels get higher. The threshold rot level for changing from Norway spruce to Scots pine increases with the site index. We present a case study demonstrating a practical method (“Precision forestry”) for determining the tree species in a stand at the pixel level when the stand is heterogeneous both in site indexes and rot levels. This method is consistent with the concept of Precision forestry, which aims to plan and execute site-specific forest management activities to improve the quality of wood products while minimising waste, increasing profits, and maintaining environmental quality. The material for the study includes data on rot levels and site indexes in 71 clear-cut stands. Compared to planting the entire stand with a single species, pixel-level optimised species selection increases the net present value in almost every stand, with average increase of approximately 6%.

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Abstract

Forest management is an important tool for GHG mitigation by representing three carbon pools: living biomass, forest soil, and wood-based products. Additionally, increasing attention has been given to the potential for wood products to substitute fossil-intensive products as a climate mitigation strategy. The goal of this paper is to analyse the theoretical GHG effects of fully replacing four common non-wood products with wood-based products of ‘low’ and ‘high’ technology options that have a similar functionality: (1) Spruce particle board substituting polyurethane (PU) foam insulation board; (2) spruce cross-laminated timber beam (CLT) substituting steel beam; (3) birch energy wood substituting electric heating; and (4) birch plywood substituting plaster board. The analysis was based on forestry in Western Norway as a case study, where forests typically consist of naturally generated birch and expanding areas of planted Norway spruce. In this study we compare wood products derived from paired stands of Norway spruce and downy birch. The analysis showed that spruce gave a higher theoretical substitution effect relative to birch for the selected pairs of woody and non-woody products. CLT substituting steel beam gave the highest substitution effect, approximately 15% higher than particle board substituting PU foam board. The theoretical substitution effect in mass units of carbon per kg wood product for the two spruce wood products was approximately 17 times higher relative to substituting Norwegian hydro energy-based electric heating, whereas plywood substituting plaster board may in fact increase GHG emissions. As the gross emissions were relatively similar for the birch plywood and the spruce particle board, the major substitution effect was related to the avoided emission of the non-woody product rather than to the tree species per se. The paper concludes that the choice of product to be substituted was the key factor that determined the final substitution effects. Furthermore, the study showed that transportation was the single most important factor that affected the emissions between planting and delivery of the timber at production gate. The analysis enables informed decisions related to CO2-emissions at the various steps from tree planting to wood conversion, and underline the importance of informed decision related to the choice of substitution products.

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Abstract

To mitigate climate change, several European countries have launched policies to promote the development of a renewable resource-based bioeconomy. These bioeconomy strategies plan to use renewable biological resources, which will increase timber and biomass demands and will potentially conflict with multiple other ecosystem services provided by forests. In addition, these forest ecosystem services (FES) are also influenced by other, different, policy strategies, causing a potential mismatch in proposed management solutions for achieving the different policy goals. We evaluated how Norwegian forests can meet the projected wood and biomass demands from the international market for achieving mitigation targets and at the same time meet nationally determined targets for other FES. Using data from the Norwegian national forest inventory (NFI) we simulated the development of Norwegian forests under different management regimes and defined different forest policy scenarios, according to the most relevant forest policies in Norway: national forest policy (NFS), biodiversity policy (BIOS), and bioeconomy policy (BIES). Finally, through multi-objective optimization, we identified the combination of management regimes matching best with each policy scenario. The results for all scenarios indicated that Norway will be able to satisfy wood demands of up to 17 million m3 in 2093. However, the policy objectives for FES under each scenario caused substantial differences in terms of the management regimes selected. We observed that BIES and NFS resulted in very similar forest management programs in Norway, with a dominance of extensive management regimes. In BIOS there was an increase of set aside areas and continuous cover forestry, which made it more compatible with biodiversity indicators. We also found multiple synergies and trade-offs between the FES, likely influenced by the definition of the policy targets at the national scale.

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Abstract

The replacement of native birch with Norway spruce has been initiated in Norway to increase long-term carbon storage in forests. However, there is limited knowledge on the impacts that aboveground changes will have on the belowground microbiota. We examined which effects a tree species shift from birch to spruce stands has on belowground microbial communities, soil fungal biomass and relationships with vegetation biomass and soil organic carbon (SOC). Replacement of birch with spruce negatively influenced soil bacterial and fungal richness and strongly altered microbial community composition in the forest floor layer, most strikingly for fungi. Tree species-mediated variation in soil properties was a major factor explaining variation in bacterial communities. For fungi, both soil chemistry and understorey vegetation were important community structuring factors, particularly for ectomycorrhizal fungi. The relative abundance of ectomycorrhizal fungi and the ectomycorrhizal : saprotrophic fungal ratio were higher in spruce compared to birch stands, particularly in the deeper mineral soil layers, and vice versa for saprotrophs. The positive relationship between ergosterol (fungal biomass) and SOC stock in the forest floor layer suggests higher carbon sequestration potential in spruce forest soil, alternatively, that the larger carbon stock leads to an increase in soil fungal biomass.

2021