Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2024
Sammendrag
Forests play a major role in the mitigation of avalanche risk in Norway, but the regulations surrounding the management of “protection forests” are still being worked out. To promote protection forest management, avalanche hazard indication maps for Norway have been produced with the automated mapping tool NAKSIN in a way that makes it possible to quantity the effects of the current forests in a spatially explicit way. NAKSIN makes use of published relations for forest effects on snow properties and uses national models of forest characteristics to estimate the effects on release probability and runout given local climate and topography. The forest properties contain parameters that are directly measured (canopy cover), and properties that are predicted (tree diameter, number of trees) with approximately 70% precision according to ground truth data. NAKSIN uses these forest properties in long chains of models, comprising of both mechanistic and empirical elements, some of which are iterated over timesteps during avalanche flow. This means that errors could be propagated throughout those model chains in unexpected ways. The aim of this study was to conduct a sensitivity analysis to examine the effects of errors in the forest data for hazard mapping in a relevant case study region in fjordic western Norway. We examined hazard maps produced using 95% prediction errors for tree diameter and the number of trees per hectare to determine if these would dramatically affect the hazard zones. These hazard maps focused on runout properties as common release areas were implied for avalanches through a common forest canopy cover percentage applied across the two extreme scenarios. Across the entire region, the hazard zones were generally stable with respect to potential errors in the forest data, suggesting the approach is robust and the braking effect of forest is not overstated. There was one exception, where the prediction errors could reduce the forest braking function to negligible. This exception was easy to identify from the difference in hazard zones and the process allows us to consider where more precise measurements of forests could be required in areas with high consequences. The implications of various approaches to estimate forest leaf area index, and how this might impact on release probability are illustrated to further consider this in the next steps of this research.
Sammendrag
Forests play a major role in the mitigation of avalanche risk in Norway, but the regulations surrounding the management of “protection forests” are still being worked out. To promote protection forest management, avalanche hazard indication maps for Norway have been produced with the automated mapping tool NAKSIN in a way that makes it possible to quantity the effects of the current forests in a spatially explicit way. NAKSIN makes use of published relations for forest effects on snow properties and uses national models of forest characteristics to estimate the effects on release probability and runout given local climate and topography. The forest properties contain parameters that are directly measured (canopy cover), and properties that are predicted (tree diameter, number of trees) with approximately 70% precision according to ground truth data. NAKSIN uses these forest properties in long chains of models, comprising of both mechanistic and empirical elements, some of which are iterated over timesteps during avalanche flow. This means that errors could be propagated throughout those model chains in unexpected ways. The aim of this study was to conduct a sensitivity analysis to examine the effects of errors in the forest data for hazard mapping in a relevant case study region in fjordic western Norway. We examined hazard maps produced using 95% prediction errors for tree diameter and the number of trees per hectare to determine if these would dramatically affect the hazard zones. These hazard maps focused on runout properties as common release areas were implied for avalanches through a common forest canopy cover percentage applied across the two extreme scenarios. Across the entire region, the hazard zones were generally stable with respect to potential errors in the forest data, suggesting the approach is robust and the braking effect of forest is not overstated. There was one exception, where the prediction errors could reduce the forest braking function to negligible. This exception was easy to identify from the difference in hazard zones and the process allows us to consider where more precise measurements of forests could be required in areas with high consequences. The implications of various approaches to estimate forest leaf area index, and how this might impact on release probability are illustrated to further consider this in the next steps of this research.
Sammendrag
Black scurf and stem canker on potatoes, caused by the destructive soil-borne pathogen Rhizoctonia solani Kühn are a major problem for potato growers worldwide. Biological control agents such as plant leaf extracts can influence the severity of R. solani infection and help to reduce the risks to human health and the environment associated with the use of hemical fungicides. In this study, the inhibitory effect of the secondary plant metabolites aucubin, catalpol (iridoid glucosides) and acteoside (phenylethanoid glycoside) from methanolic extracts of Plantago lanceolata (Ribwort plantain (en), Smalkjempe (no)), a native plant in the Nordic countries, on the growth of R. solani mycelium on potato dextrose agar growth medium will be tested for the first time. Plant extracts will be obtained from plants of different age classes and metabolic profiling will be performed with LC-(HR)MS analyses and the concentrations of identified metabolites will be determined. To analyse whether the inhibitory interactions on fungal growth originate from the known secondary metabolites or are caused by the bulk plant extract, we will first expose the fungus to different concentrations of extracts, redissolved in aqueous solution and added to the growth medium, and in a further step we will carry out the same approach with the isolated secondary metabolites as pure substances. The fugus will be incubated for 5 days and the mycelium growth radius will be measured every 24 hours during incubation. Thereafter a suppression index will be calculated and compared to the untreated control. The results are pending at the time of submission of the abstract but will provide a good initial understanding to determine whether extracts of P. lanceolata can be used as a natural biological control agent as an additional component of a more sustainable strategy to manage the risk of infection of potato with R.solani and to reduce the severity of the disease caused by this pathogen.
Sammendrag
RIBI Bioenergi har hatt gårdsbiogassanlegg siden 2019. I 2022/2023 har RIBI med støtte fra Innovasjon Norge bygget en egen reaktor for å kunne drive med testing/utprøving for biogass. Dette prosjektet har sett på utråtning av en blanding av husdyrgjødsel fra storfe og gris, og fiskeslam fra Salmon Evolution. Prosjektet har fulgt opp anlegget med en kombinasjon av onsite analyser og analyser ved biogasslaben på Ås. Annet analyseutstyr for fremtidig testvirksomhet har blitt vurdert. Produksjonen med fiskeslam er fulgt i ca. 1 års tid. Egenskapene til gjødsel og fiskeslam er analysert, og påvirkning på gassproduksjon og prosesstabilitet studert. Innhold av nitrogen i fiskeslam er avhengig av avvanningsgrad. Innholdet av nitrogen påvirker igjen grad av inhibering av biogassprosessen og innhold av næringsstoffer i bioresten. Resultatene fra prosjektet har blitt brukt til informasjonsutveksling mellom blå og grønn næring, og nye biogassaktører.
Forfattere
Martin Næsset HillestadSammendrag
Large volumes of Norway spruce (Picea abies (L.) Karst.) in Northern Norway are approaching maturity. Previous studies conducted on Norway spruce from Northern Norway, indicates lower density and mechanical properties than for Norway spruce grown in the rest of the country. This might be critical for use of Norway spruce from Northern Norway as structural timber. The purpose of this study was to assess lumber quality, density, modulus of elasticity and modulus of rupture on a sample of Norway spruce from Northern Norway, and to evaluate whether visual strength grading results in sufficient properties. Density and mechanical properties were compared to values from Southern Norway, and previous studies from Northern Norway. A sample consisting of 109 boards sawn from 12 trees of Norway spruce, collected from 4 trial stands in Northern Norway, was visually strength graded according to NS-INSTA 142, before density, modulus of elasticity and modulus of rupture was tested according to NS-EN 408. Characteristic values calculated according to NS-EN 384 and verified according to NS-EN 14358, were compared to the strength classes of NS-EN 338. Variation in density and mechanical properties were modelled with linear mixed models, where the random variance was separated into tree-variance and residual variance. Variables on board and log level were treated as fixed effects, and used as covariates in the models. Relative height, calculated as each log’s vertical position in relation to total tree height, was the most important variable for density. Density increased with increasing relative height. Density was important for modulus of elasticity and modulus of rupture, and both increased with increasing density. Variation in density between stands seems to be partly attributed to variation in latitude and altitude. Knots affected both modulus of elasticity and modulus of rupture, and differences in average knot diameter seems to coincide with differences in mechanical properties between stands. Differences in average knot diameter and mechanical properties between stands coincides with differences in silviculture. Mean values for density, modulus of elasticity and modulus of rupture were lower than what is observed in the Southern and middle parts of Norway, but higher than previous studies from Northern Norway. The visual grading resulted in most boards sorted as grade T2, followed by T1, T3 and T0. The characteristic values met requirements for all sorting grades apart from density in T3 for C30, and modulus of rupture in T1 for C18. Low numbers resulted in large uncertainties concerning characteristic values. Despite this, sorting grades T2 and T2+T3 met all requirements for C24. The results give positive indications for density, modulus of elasticity and modulus of rupture in Norway spruce from Northern Norway, and the properties as structural timber. The study is based on a limited sample of boards, collected from a limited number of trial stands, and this results in large uncertainties. Further studies are therefore needed, and should gain values more representative for the forest in Northern Norway.
Sammendrag
In Norway, there is political goal to increase the degree of self-sufficiency of fruits. To achieve this goal, the sales period of Norwegian produced apple fruit needs to be extended, and thus, the storage technology improved. Sensory quality is of importance for consumers acceptability of the apple fruit. The aim of this study was to evaluate the sensory properties of the apple cultivars ‘Red Elstar’ and ‘Rubinstep’ treated with 1-methylcyclopropene (1-MCP) in combination with storage in regular and controlled atmosphere. Before storage, the harvested fruit were divided into two parts; half treated with 1-MCP and the other half untreated. A semi-trained sensory panel evaluated selected sensory properties of apple fruit harvested in 2021, 2022, and 2023, and stored in regular or controlled atmosphere at 2°C for 5.5, 5.5, and 4 months, respectively. Treatment with 1-MCP in combination with controlled atmosphere storage resulted in the highest sensory score of firmness, crispiness, and juiciness, and lowest score for mealiness and sweetness. Fruit stored in a regular atmosphere without 1-MCP had less acidity and the fruitiest aroma. How to obtain optimal taste of ‘Rubinstep’ and ‘Red Elstar’ after the different post-harvest treatments will be discussed.
Sammendrag
In Norway, the apple cultivar ‘Red Aroma’ accounts for approximately one third of the Norwegian production. Treatment with 1-MCP has been tested on fruit of different ripening degrees to improve shelf-life and sensory properties. Fruits were harvested and treated with 1-MCP at one-week intervals starting two weeks before optimal harvest time (OHT) and ending two weeks after OHT. Fruits were stored until the end of November in regular atmosphere at 4 °C. A semi-trained sensory panel evaluated selected sensory parameters in addition to measurements of physiochemical parameters using traditional methods. The panel evaluated 1-MCP treated fruit from all harvest times as more acidic, firmer, less mealy, crisper, and juicier than the untreated fruit. The untreated fruit harvested one or two weeks after OHT were more aromatic (floral and fruity aroma), sweeter, and riper. Intensity of grassy flavour was lowest for the untreated fruit after the optimal harvest time. Some of the evaluated sensory properties correlated with measured physiochemical parameters. Optimal sensory quality in relation to harvest time and 1-MCP treatment will be discussed.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Synneva GjellandSammendrag
Det er ikke registrert sammendrag
Forfattere
Helge BerglannSammendrag
Det er ikke registrert sammendrag