Hopp til hovedinnholdet

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.

2021

To document

Abstract

For non-native tree species with an origin outside of Europe a detailed compilation of enemy species including the severity of their attack is lacking up to now. We collected information on native and non-native species attacking non-native trees, i.e. type, extent and time of first observation of damage for 23 important non-native trees in 27 European countries. Our database includes about 2300 synthesised attack records (synthesised per biotic threat, tree and country) from over 800 species. Insects (49%) and fungi (45%) are the main observed biotic threats, but also arachnids, bacteria including phytoplasmas, mammals, nematodes, plants and viruses have been recorded. This information will be valuable to identify patterns and drivers of attacks, and trees with a lower current health risk to be considered for planting. In addition, our database will provide a baseline to which future impacts on non-native tree species could be compared with and thus will allow to analyse temporal trends of impacts.

Abstract

Understanding the quality of new raw material sources will be of great importance to ensure the development of a circular bioeconomy. Building up quality understanding of wood waste is an important step in this development. In this paper we probe two main questions, one substantial and one theoretical: What different understandings of wood waste quality exist and what significance do they have for the recycling and re-use of this waste fraction? And, what is the evolution of knowledge and sustainable practices of wood waste qualities a case of? The analysis is based on diverse perspectives and forms of methods and empirical material. Studies of policy documents, regulations, standards, etc. have been reviewed to uncover what kind of measures and concepts that have been important for governing and regulating wood waste handling. Interviews concerning wood and wood waste qualities have been conducted with key informants and people visiting recycling and waste management stations in Oslo and Akershus in Norway. By studying quality conceptions through the social birth, production, life, end-of-life and re-birth of wood products, we analyse socio-cultural conditions for sustainability. Furthermore we show how the evolution of knowledge and sustainable practices of wood waste qualities, in the meeting with standards and regulations, is a case of adaptation work in the evolution of Norwegian bioeconomy.

Abstract

Forests have climate change mitigation potential since they sequester carbon. However, their carbon sink strength might depend on management. As a result of the balance between CO2 uptake and emission, forest net ecosystem exchange (NEE) reaches optimal values (maximum sink strength) at young stand ages, followed by a gradual NEE decline over many years. Traditionally, this peak of NEE is believed to be concurrent with the peak of primary production (e.g., gross primary production, GPP); however, in theory, this concurrence may potentially vary depending on tree species, site conditions and the patterns of ecosystem respiration (Reco). In this study, we used eddy-covariance (EC)-based CO2 flux measurements from 8 forest sites that are dominated by Norway spruce (Picea abies L.) and built machine learning models to find the optimal age of ecosystem productivity and that of CO2 sequestration. We found that the net CO2 uptake of Norway spruce forests peaked at ages of 30-40 yrs. Surprisingly, this NEE peak did not overlap with the peak of GPP, which appeared later at ages of 60-90 yrs. The mismatch between NEE and GPP was a result of the Reco increase that lagged behind the GPP increase associated with the tree growth at early age. Moreover, we also found that newly planted Norway spruce stands had a high probability (up to 90%) of being a C source in the first year, while, at an age as young as 5 yrs, they were likely to be a sink already. Further, using common climate change scenarios, our model results suggest that net CO2 uptake of Norway spruce forests will increase under the future climate with young stands in the high latitude areas being more beneficial. Overall, the results suggest that forest management practices should consider NEE and forest productivity separately and harvests should be performed only after the optimal ages of both the CO2 sequestration and productivity to gain full ecological and economic benefits. How to cite: Zhao, J., Lange, H., and Meissner, H.: Mismatch between the optimal ages for ecosystem productivity and net CO2 sequestration in Norway spruce forests, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4257, https://doi.org/10.5194/egusphere-egu21-4257, 2021.

Abstract

The use of peat as a growing media in horticulture is supposed to be reduced due to negative effects of its production on the environment. Interest in development of alternative growing media is therefore increasing and is enhanced by both political pressure and industry demands. Therefore, the influence of 33 growing media on the performance and productivity of two strawberry cultivars were examined in a polytunnel under Nordic conditions (60.7 N). Alternative substrates including fibers of spruce, birch and flax and coffee grounds were tested standalone or in mixes. Peat and coir were included as controls. Additionally, impregnation of the wood fibers with organic and inorganic substances was examined. All investigated growing media received identical fertigation strategies (EC 1.5). The highest average biomass production was observed for plants grown in bare peat; however, the best yield performance was noted for peat mixed with perlite and for coarse spruce fiber. Strawberries grown in these two best performing substrates showed comparable overall productivity, with 272 and 268 g of berries per plant, respectively. Both peat/perlite mix and the coarse spruce fiber had also a similar weight of berries larger than 25 mm, with 210 and 198 g plant-1, respectively. Moreover, improvement of the substrate structure by adding perlite or wood chips may have had a pronounced effect on fruiting performance. When compared to peat with added perlite (which gave the highest berry yield in the experiment; 272 g plant-1), strawberries grown in pure peat produced only 187 g plant-1. Furthermore, impregnation of spruce fiber with humic acid enhanced fruiting performance by increasing the total yield and number of large berries (≥25 mm). Future prospects for this study include establishment of an optimal structure of spruce fiber substrate suitable for strawberry production and development of the fertigation strategy optimized for the new growing media.

To document

Abstract

This study explores cell wall changes in Radiata pine (Pinus radiata) after modification with acetylation or furfurylation and subsequent prolonged subjection to the brown rot fungus R. placenta with the aim of better understanding the modus operandi of these two modifications. Both modifications have shown good durability in field tests, but in order to learn from their possible limitations, we used optimal environmental conditions for fungal growth, and extended the testing period compared to standard tests. Hyphae were found in acetylated wood after two weeks, and after 28 weeks of decay abundant amounts of encapsulated hyphae were present. In furfurylated wood, mass loss and a few hyphae were seen initially, but no further development was seen during weeks 18–42. The general degradation pattern was qualitatively the same for unmodified, acetylated and furfurylated wood: carbohydrates decreased relative to lignin. Acetyl groups were lost from acetylated wood during decay (earlier results), while the furan polymer did not seem to be altered by the fungus. Based on these findings it is hypothesized that modifications such as furfurylation that enhance moisture exclusion within the cell wall through impregnation polymerization offer better long term protection compared to modifications such as acetylation that depend on the replacement of hydroxyl groups with ether bound adducts that can be removed by fungi.

To document

Abstract

Aims Understanding fine-grain diversity patterns across large spatial extents is fundamental for macroecological research and biodiversity conservation. Using the GrassPlot database, we provide benchmarks of fine-grain richness values of Palaearctic open habitats for vascular plants, bryophytes, lichens and complete vegetation (i.e., the sum of the former three groups). Location Palaearctic biogeographic realm. Methods We used 126,524 plots of eight standard grain sizes from the GrassPlot database: 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 and 1,000 m2 and calculated the mean richness and standard deviations, as well as maximum, minimum, median, and first and third quartiles for each combination of grain size, taxonomic group, biome, region, vegetation type and phytosociological class. Results Patterns of plant diversity in vegetation types and biomes differ across grain sizes and taxonomic groups. Overall, secondary (mostly semi-natural) grasslands and natural grasslands are the richest vegetation type. The open-access file ”GrassPlot Diversity Benchmarks” and the web tool “GrassPlot Diversity Explorer” are now available online (https://edgg.org/databases/GrasslandDiversityExplorer) and provide more insights into species richness patterns in the Palaearctic open habitats. Conclusions The GrassPlot Diversity Benchmarks provide high-quality data on species richness in open habitat types across the Palaearctic. These benchmark data can be used in vegetation ecology, macroecology, biodiversity conservation and data quality checking. While the amount of data in the underlying GrassPlot database and their spatial coverage are smaller than in other extensive vegetation-plot databases, species recordings in GrassPlot are on average more complete, making it a valuable complementary data source in macroecology.