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A CACTA-like transposon in the Anthocyanidin synthase 1 (Ans-1) gene is responsible for apricot fruit colour in the raspberry (Rubus idaeus) cultivar ‘Varnes’
Get PDFCultivated raspberries (Rubus idaeus L.) most commonly bear small, red, highly aromatic fruits. Their colour is derived predominantly from anthocyanins, water soluble polyphenolic pigments, but as well as red forms, there exist cultivars that display yellow- and apricot-coloured fruits. In this investigation, we used a multi-omics approach to elucidate the genetic basis of the apricot fruit colour in raspberry. Using metabolomics, we quantified anthocyanins in red and apricot raspberry fruits and demonstrated that, in contrast to red-fruited raspberries, fruits of the apricot cultivar ‘Varnes’ contain low concentrations of only a small number of anthocyanin compounds. By performing RNASeq, we revealed differential expression patterns in the apricot-fruited ‘Varnes’ for genes in the anthocyanin biosynthesis pathway and following whole genome sequencing using long-read Oxford Nanopore Technologies sequencing, we identified a CACTA-like transposable element (TE) in the second exon of the Anthocyanidin synthase (Ans) gene that caused a truncated predicted ANS protein. PCR confirmed the presence in heterozygous form of the transposon in an unrelated, red-fruited cultivar ‘Veten’, indicating apricot fruit colour is recessive to red and that it may be widespread in raspberry germplasm, potentially explaining why apricot forms appear at regular intervals in modern raspberry breeding populations.publishedVersio
Elevinteraksjon og matematisk resonnement i matematikklæring på norsk videregående skole: En kvalitativ Design-Based Research studie av Jigsaw-metoden
Get PDFI denne masteroppgaven har jeg satt søkelys på elevers muligheter og utfordringer i samarbeid og utvikling av matematisk resonnement i samarbeidslæringsmetoden Jigsaw i matematikklæring. Arbeidsmåten Jigsaw-metode, også kalt puslespill metoden i Norge, er en arbeidsmåte som fremmer engasjement og ansvar blant deltakerne ved at hver person bidrar med et unikt stykke av hele bilde.
I denne studien har jeg studert en andre års S1-klasse på en videregåendeskole som ifølge matematikklæreren hadde liknende erfaring med arbeidsmetoden Jigsaw. Jeg har benyttet meg av en kvalitativ Design-Based Research (DBR) studie. Jeg laget to Jigsaw-opplegg. Oppleggene innholdet tre faser av den opprinnelig Jigsaw-metoden. I studien observert jeg to faser i klasserommet. De er fase II ekspertgruppe og fase III Jigsaw-gruppe. I tillegg, samlet inn jeg data ved et gruppeintervju med fire elever, individuelle intervjuer med tre elever og videoobservasjon av to Jigsaw-økter.
Data fra intervjuene utgjør en stor del av resultatene. Intervjuene ga elever mulighet til å begrunne og sette ord på hvorfor de gjorde det de gjorde i ulike gruppe faser. Det var viktig for meg å forstå elevers erfaringer med Jigsaw-metoden. Videoobservasjon ga meg muligheten til å gjennomgå opptakene gjentatte ganger og kartlegge handlingene i elevinteraksjon.
Resultatet viser at elevene mestret sitt deltema, men hadde utfordringer med å lære de andre deltemaene i Jigsaw-gruppen. Dette resultatet ligner på tidligere forskningsresultater. Elevene uttrykte at de hadde bedre konseptuell forståelse av sitt eget deltema. Dette resultatet ligner på tidligere forskningsresultater.
Funnene mine fremhever at læringsmiljøet i ulike gruppe faser påvirket elevinteraksjonen og utviklingen av kollektivt matematisk resonnement. Funnene indikerer at elevene må ha tid og rom til å utvikle bevissthet om behovet for hjelp, og læringsmålene må føles relevante og iverksettes på en synlig måte.In this master’s thesis, I have highlighted students’ opportunities and challenges in collaboration and the development of mathematical reasoning in the collaborative and cooperative learning method Jigsaw in mathematics teaching. The Jigsaw method, also called the puzzle method in Norway, is a method that promotes engagement and responsibility among the participants by each person contributing a unique piece of the whole picture.
In this study, I studied a second-year S1 class at a high school that, according to the mathematics teacher, had similar experience with the Jigsaw method. I have used a qualitative Design-Based Research (DBR) study. I created two Jigsaw lesson plans. The programs contained three phases of the original Jigsaw method. In the study, I observed two phases in the classroom. They are phase II expert group and phase III Jigsaw group. In addition, I collected data through a group interview with four students, individual interviews with three students and video observation of two Jigsaw sessions.
Data from the interviews constitute a large part of the results. The interviews gave students the opportunity to justify and articulate why they did what they did in different group phases. It was important for me to understand students’ experiences with the Jigsaw method. Video observation gave me the opportunity to review the recordings repeatedly and analyze the actions in student interaction.
The result shows that students mastered their subtopics. However, they had challenges learning the other subtopics in the Jigsaw group. This finding is similar to previous research results. Students expressed that they had a better conceptual understanding of their own subtopics. This finding is similar to previous research results.
My findings highlight that the learning environment in different group phases influenced student interaction and the development of collective mathematical reasoning. The findings indicate that students must have the time and opportunity to develop awareness of the need for help. And the learning goals must feel relevant and be implemented in a visible way
Galleri Åsgårdstrand : et mulighetsstudium av sentrumskjernen
No full textÅsgårdstrand sitt karakteristiske bygningsmiljø og sin rike kunsthistorie gjør den lille byen til en av Vestfold sine store kystperler. Det selvgrodde, historiske gatenettverket med historiske torg og byrom er i dag dekket med asfalterte flater og mye biltrafikk. Resultatet er et sentrum som oppleves oppstykket og udefinert, og det er vanskelig å orientere seg for de som ikke kjenner byen godt.
Byen omtales i dag som en kunstnerby, og gjennom tidene har flere kjente kunstnere som Edvard Munch foreviget Åsgårdstrands vakre landskap og unike atmosfære i sine malerier. Gjennom å bruke kunst som et virkemiddel og verktøy innenfor landskapsarkitektur, ønsker vi i denne masteroppgaven å definere sentrum av Åsgårdstrand, og gi byen en sterkere identitet.
Oppgaven er et mulighetsstudie med bakgrunn i teori, stedsanalyser og metoder fra landskapsarkitektur. Vi ønsker å forsterke Åsgårdstrand som kunstnerby ved å skape levende byrom som inviterer til opplevelser og samtaler for innbyggere og besøkende. Gjennom tydeliggjøring av eksisterende og nye forbindelser, ønsker vi å skape trygghet for de myke trafikantene og en større sammenheng i sentrum.Åsgårdstrand's characteristic built environment and rich art history make the small town one of Vestfold's great coastal gems. The self-grown, historic street network with historic squares and urban spaces is today covered with paved surfaces and a lot of car traffic. The result is a city center that is perceived as fragmented and undefined, and it's difficult to find your way around for those who don't know the city well.
Today, the town is referred to as an artist's town, and over the years, several famous artists such as Edvard Munch have immortalized Åsgårdstrand's beautiful landscape and unique atmosphere in their paintings. By using art as an instrument and tool in landscape architecture, in this master's thesis we want to define the center of Åsgårdstrand and give the city a stronger identity.
The thesis is a feasibility study based on theory, site analysis, and methods from landscape architecture. We want to strengthen Åsgårdstrand as a city of artists by creating vibrant urban spaces that invite experiences and conversations for residents and visitors. By clarifying existing and new connections, we want to develop a sense of security for pedestrians and a greater coherence in the city center.M-L
Ecological and social barriers to nature restoration within a land degradation neutrality framework in Nordre Follo, Norway
Get PDFAnthropogenic land-use change is a major driver of ecosystem degradation and global biodiversity loss. Simultaneously, humans depend on fully functioning ecosystems for survival and well-being. As a result, land degradation neutrality (LDN) has emerged as a policy framework to promote more sustainable land-use practices. LDN requires ecological compensation in the form of restoration or financial contribution to restoration initiatives when nature is degraded in development projects. The first ecological restoration project used as compensation under the LDN framework in Norway is being implemented in Nordre Follo municipality, linked to the construction of the Skotbu elevated water reservoir. This thesis evaluates the Skotbu project as a case study to explore how ecological restoration decisions are made within a Norwegian LDN context.
A mixed methods approach was applied to assess both ecological and social dimensions of the site selection in the Skotbu project. Three proposed restoration sites (a deciduous forest, a pine forest, and a semi-natural grassland) were evaluated for ecological and social barriers, as well as potential trade-offs. Vegetation analyses revealed ecological barriers including invasive species, grazing maintenance, and informal road networks. Stakeholder interviews identified limited public participation as a significant social barrier. Although stakeholders expressed strong ambitions for biodiversity conservation, the final site selection was primarily driven by socio-economic interests of feasibility, costs, and access to private land. This trade-off underscores the need for increased support from government agencies in LDN restoration projects administered at the municipal level. Municipalities are the primary land-use authority in Norway and have a key role in restoration efforts required to safeguard biodiversity and reach the global goal of restoring 30% of degraded land by 2030. As Norway’s first LDN restoration case, the Skotbu project provides important insights into how the LDN framework should be developed and implemented in Norway in the future
Studies of antimicrobial resistance patterns in bacteria isolated from farmed tilapia in Zambia
Get PDFAntimicrobial resistance is an increasing problem in both human and veterinary medicine worldwide. In this study, bacterial samples were collected from tilapia at six different fish farms in Zambia. A standardized questionnaire was used to interview all producers about their operations and potential use of antibiotics. No farmers reported using antibiotics. The locations ranged from the Copperbelt region in the north to the Siavonga region in the south. Bacterial samples were taken from the skin, vent, and kidneys of ten fish per location, for a total of 60 fish. Bacteria isolated from these fish were further identified through 16S sequencing. Bacterial isolates of the genera Aeromonas, Lactococcus, and Plesiomonas were analysed for antimicrobial resistance using disk diffusion. Standardized zone diameters from CLSI and EUCAST were unavailable for some bacteria. Therefore, adjustments were made to the interpretations of the results. Some level of resistance was detected in the bacteria. P. shigelloides were the most frequent bacteria and were spread across all locations. The bacteria showed resistance to all the different types of antibiotics tested. For Aeromonas spp. and Lactococcus spp., the number of samples was limited, making it challenging to draw conclusions based on the findings. Lactococcus spp. showed a high degree of resistance, while Aeromonas spp. exhibited an expected pattern of resistance.VE
Landscape Justice: Landscape Architecture at the Intersection of Nature and Migration in Peri-Urban Areas
Get PDFMigration has been a constant in human history; however, in contemporary contexts, it presents challenges for urban spaces. As cities expand and urban sprawl increases, particularly into peri-urban areas, marginalized populations — including migrants — are often displaced to less desirable, environmentally degraded, and poorly serviced regions in the outskirts of the cities. This contributes to spatial segregation, reflecting broader social inequalities that are deeply embedded in the landscape. While segregation has been widely studied in relation to housing and urban inequality, there is limited scholarship addressing its spatial implications on landscape, particularly in relation to migration.
This thesis investigates how spatial segregation affects migrants in peri-urban contexts, focusing on two cases: Piraquara, in Brazil, and Oslo, in Norway. Through comparative analysis, the study examines how the landscape reflects and reproduces spatial segregation across different socio-economic and political settings. Methodologically, the research relies on field observations, aerial imagery, land cover data, and document analysis to explore the relationship between migration and landscape transformation. By identifying how segregation manifests spatially and environmentally in these contexts, the study contributes to the discourse on inclusive landscape planning and calls for more integrative approaches that address the intersection of migration, segregation, and urban development.
Keywords: migration, spatial segregation, landscape, peri-urban area
Utfordringer for Marker og Eidsberg Sparebank i implementeringen av CSRD: Løsninger for en vellykket tilpasning
Get PDFDenne studien undersøker hvilke utfordringer Marker og Eidsberg Sparebank møter i implementeringen av EUs bærekraftsdirektiv, Corporate Sustainability Reporting Directive (CSRD), og hvilke løsninger som kan bidra til en vellykket tilpasning. Direktivet stiller betydelig strengere krav til bærekraftsrapportering enn tidligere, og representerer en omfattende endring i hvordan banker må rapportere på miljømessige, sosiale og styringsmessige forhold (ESG). For små og mellomstore banker representerer dette en særlig stor utfordring.
Studien bygger på kvalitativ metode, med semistrukturerte dybdeintervjuer av nøkkelpersoner i Marker og Eidsberg Sparebank og én representant fra Eika Gruppen. Datamaterialet er supplert med dokumentanalyse og relevant faglitteratur.
Funnene viser at banken opplever regelverket som komplekst og oppfatter CSRD som lite tilpasset små banker. Manglende ressurser og begrenset intern kompetanse gjør det krevende å etablere nødvendige systemer og rutiner for datainnsamling, analyse og rapportering. Dette forsterkes av manglende standardisering og lav modenhet i kundesegmentet. CSRD medfører at banken får et utvidet ansvar som pådriver for bærekraft i møte med sine kunder.
Oppgaven konkluderer med at en vellykket implementering forutsetter en kombinasjon av intern kompetansebygging, tett samarbeid med kundene og støtte fra Eika-alliansen. Studien peker også på at CSRD kan brukes strategisk. Tilpasningsarbeidet kan styrke bankens interne styring, forbedre risikohåndteringen og gi et konkurransefortrinn i et marked med økende krav til bærekraft. Endringer i CSRD-regelverket våren 2025 fører riktignok til at banken unntas fra rapporteringsplikten i denne omgang, men funnene tilsier at arbeidet med bærekraftsrapportering likevel bør videreføres.
Studien gir innsikt i hvordan en mindre sparebank kan tilpasse seg et krevende regelverk gjennom alliansebasert samarbeid, kompetanseheving og gradvis implementering. Funnene har overføringsverdi til andre små banker i samme situasjon, og peker på behovet for mer proporsjonal regulering og bedre støtteordninger for mindre aktører.This study investigates the challenges faced by Marker og Eidsberg Sparebank in the implementation of the EU’s sustainability directive, Corporate Sustainability Reporting Directive (CSRD), and which solutions may contribute to a successful adaptation. The directive imposes stricter requirements for sustainability reporting and marks a major shift in how banks report on environmental, social, and governance (ESG) matters. For small and medium-sized banks, this presents a particularly major challenge.
The study is based on a qualitative study, using semi-structured in-depth interviews with key individuals in Marker og Eidsberg Sparebank and one representative from Eika Gruppen. The data material is supplemented with document analysis and relevant academic literature.
Findings show the bank sees CSRD as complex and poorly suited to small banks. A lack of resources and limited internal expertise makes it difficult to establish the necessary systems and routines for data collection, analysis, and reporting. This is reinforced by a lack of standardization and low maturity in the customer segment. CSRD entails that the bank assumes an expanded role as a driver of sustainability in its interactions with customers.
The study concludes that successful implementation requires a combination of internal capacity building, cooperation with customers, and support from the Eika alliance. The study also points out that CSRD can be used strategically. The work towards an adaptation can strengthen the bank’s internal governance, improve risk management, and provide a competitive advantage in a market with increasing focus on sustainability. Changes to the CSRD regulation in the spring of 2025 have led to the bank being exempted from the reporting obligation, but the findings suggest that the work on sustainability reporting should still continue.
The study provides insight into how a smaller savings bank can adapt to a demanding regulatory framework through alliance-based collaboration, competence development, and gradual implementation. The findings are transferable to other small banks in similar situations and highlight the need for more proportionate regulation and better support mechanisms for smaller entities
Return and Volatility Spillovers in the Energy Sector: Dynamics Driven by Financial and Macroeconomic Factors
Get PDFThis thesis empirically investigates return and volatility spillovers in the energy sector and its four subsectors (Oil and Gas, Oil and Gas Equipment and Services, Multiline Utilities, and Renewable Energy). We consider this a broad selection of subsectors that captures most key dimensions within the energy sector. Using daily stock return data for 73 publicly traded firms within these subsectors, the study examines how macroeconomic and financial factors shape these spillovers. We employ a rolling- window vector autoregression model with generalized forecast-error variance decomposition to compute time-varying return and volatility spillover indices. Key macro-financial drivers such as interest rates and an economic policy uncertainty index are included as external variables to assess their impact on connectedness. The results show that Oil and Gas firms consistently act as net shock transmitters, underscoring their leading role in cross-sector risk propagation. Subsector-specific patterns emerge for example, Renewable Energy and Multiline Utilities firms receive disproportionately higher spillovers from other segments, while Oil and Gas Equipment and Services firms exhibit intermediate behaviour. Volatility spillovers react more quickly and with greater magnitude to shocks than do return spillovers, indicating heightened risk sensitivity in the energy complex. Moreover, rising interest rates and elevated policy uncertainty significantly amplify both return and volatility spillovers across all subsectors. These findings highlight the dominant influence of traditional oil and gas companies in propagating shocks and the critical role of macro-financial conditions in energy market interconnectedness.This thesis empirically investigates return and volatility spillovers in the energy sector and its four subsectors (Oil and Gas, Oil and Gas Equipment and Services, Multiline Utilities, and Renewable Energy). We consider this a broad selection of subsectors that captures most key dimensions within the energy sector. Using daily stock return data for 73 publicly traded firms within these subsectors, the study examines how macroeconomic and financial factors shape these spillovers. We employ a rolling- window vector autoregression model with generalized forecast-error variance decomposition to compute time-varying return and volatility spillover indices. Key macro-financial drivers such as interest rates and an economic policy uncertainty index are included as external variables to assess their impact on connectedness. The results show that Oil and Gas firms consistently act as net shock transmitters, underscoring their leading role in cross-sector risk propagation. Subsector-specific patterns emerge for example, Renewable Energy and Multiline Utilities firms receive disproportionately higher spillovers from other segments, while Oil and Gas Equipment and Services firms exhibit intermediate behaviour. Volatility spillovers react more quickly and with greater magnitude to shocks than do return spillovers, indicating heightened risk sensitivity in the energy complex. Moreover, rising interest rates and elevated policy uncertainty significantly amplify both return and volatility spillovers across all subsectors. These findings highlight the dominant influence of traditional oil and gas companies in propagating shocks and the critical role of macro-financial conditions in energy market interconnectedness
Utforsking av utnyttelsen av β-mannaner i tarmmikrobiomer : nøkkelenzymer og gunstige egenskaper
Get PDFβ-Mannans are hemicelluloses that are widely distributed in the human diet,
either as food additives or as constituents in foods like legumes, bananas, coffee
beans, and cereals. These fiber structures are diverse and are subject to
microbial degradation in the gut by specific microbes. Thus, β-mannans may
influence the shaping of the gut microbiota, which is highly important for host
health. Despite their frequent presence in diets, the understanding of microbial
utilization of β-mannans in the gastrointestinal tract is limited. Further
understanding of the breakdown of β-mannans by beneficial microbes in the gut
may highlight the effect these glycans have on the microbiota, with potential
health effects to the host.
In paper I, we demonstrate how the beneficial and major butyrate producer in
the gut, Faecalibacterium prausnitzii, can cross-feed on different β-
mannooligosaccharides (β-MOS) derived from the extracellular mannanase
activity of surrounding gut microbiota. Coculture experiments on polymeric β-
mannan with the primary β-mannan degraders, Bacteroides ovatus and
Roseburia intestinalis, showed syntrophic growth. Biochemical analyses of
proteins in two β-MOS utilization loci (MULs) of F. prausnitzii revealed highly
adapted enzymes for β-MOS degradation. These MULs were found to be highly
conserved and globally distributed by genomic comparisons with F. prausnitzii
strains and analysis of publicly available human metagenomes.
Many β-mannans are acetylated and require carbohydrate esterases for
enzymatic degradation. Deacetylation of β-mannans has been demonstrated for
Bacillota but not for Bacteroidota. Paper II investigates how the human gut
commensal Bacteroides cellulosilyticus deacetylates β-mannans. We used
proteomics and biochemical analyses to examine the role of two carbohydrate
esterases, BcCE7 and BcCExxx, that cooperatively deacetylate β-mannans. The
multifunctional BcCE7 also deacetylates other oligosaccharides, whereas
BcCExxx is most active on the axially oriented 2-O-acetylations on β-mannans.
Paper III addresses the influence of acetylated galactoglucomannan (AcGGM)
from Norway spruce on the gut microbiota of pigs in in vitro experiments. We
performed in vitro fermentations inoculated with cecal samples obtained from
pigs either fed a control diet or with a 4% inclusion of AcGGM. Changes in
population abundances were compared between in vitro and in vivo
communities. Gene expression of β-mannan-degrading enzymes during in vitro
growth on AcGGM was investigated using metatranscriptomics. Several taxa,
including species with upregulated genes for β-mannan degradation and
previously unknown to utilize β-mannan, were more abundant in the in vitro
fermentation than observed in vivo in the presence of AcGGM.
Together, these results increase our understanding of how β-mannans are
utilized and enzymatically broken down by specific microbial taxa and how β-
mannans may influence the composition of the gut microbiota.β-Mannaner er en type hemicellulose som er utbredt i menneskets kosthold,
enten som tilsetningsstoffer eller som bestanddeler i matvarer som belgfrukter,
bananer, kaffebønner og kornprodukter. Disse fiberstrukturene er mangfoldige
og kan brytes ned i tarmen av spesifikke mikrober. Dermed kan β-mannaner
påvirke tarmfloraen, som har stor betydning for vertens helse. Til tross for at β-
mannaner ofte forekommer i kostholdet, er kunnskapen om mikrobiell
utnyttelse av β-mannaner i mage- og tarmkanalen begrenset. En bedre
forståelse av hvordan β-mannaner brytes ned av gunstige mikrober i tarmen,
kan belyse hvilken effekt disse glykanene har på mikrobiotaen, og hvilke
potensielle helseeffekter dette kan medføre for verten.
I artikkel I viser vi hvordan den gunstige og viktige butyratprodusenten i
tarmen, Faecalibacterium prausnitzii, kan utnytte ulike β-mannooligosakkarider
(β-MOS) som stammer fra den ekstracellulære mannanaseaktiviteten til den
tilstedeværende tarmmikrobiotaen. Dyrkningsforsøk på polymerisk β-mannan
med de primære β-mannan-nedbryterne, Bacteroides ovatus og Roseburia
intestinalis, viste syntrofisk vekst. Biokjemiske analyser av proteiner i to β-MOS
nedbrytnings locus (MULs) hos F. prausnitzii viste høyt tilpassede enzymer for
β-MOS-nedbrytning. Genomiske sammenligninger mellom F. prausnitziistammer
og offentlig tilgjengelige humane metagenomer viste at disse MUL-ene
viste seg å være svært konserverte og globalt distribuerte.
Mange β-mannaner er acetylerte og krever karbohydrat-esteraser for
enzymatisk nedbrytning. Deacetylering av β-mannaner har blitt påvist for
Bacillota, men ikke for Bacteroidota. Artikkel II undersøker hvordan den
kommensale tarmbakterien Bacteroides cellulosilyticus deacetylerer β-
mannaner. Proteomikk og biokjemiske analyser ble brukt for å undersøke rollen
til to karbohydrat-esteraser som samarbeider om deacetylering av β-mannaner.
Den multifunksjonelle BcCE7 deacetylerer også andre oligosakkarider, mens
BcCExxx er mest aktiv på aksialt orienterte 2-O-acetyleringer på β-mannanene.
Artikkel III tar for seg hvordan acetylerte galaktoglukomannaner (AcGGM) fra
gran påvirker tarmmikrobiotaen hos gris i in vitro-forsøk. Vi utførte in vitrofermenteringer
inokulert med tarmprøver fra griser som enten hadde fått et
kontrollfôr eller et fôr med 4 % innblanding av AcGGM. In vitro-endringene i
populasjonsmengden ble sammenlignet med in vivo-samfunn. Genuttrykk av β-
mannan-nedbrytende enzymer under in vitro-vekst på AcGGM ble undersøkt
ved hjelp av metatranskriptomikk. Flere taxa, inkludert arter med oppregulerte
gener for β-mannan-nedbrytning og arter som tidligere ikke var kjent for å
utnytte β-mannan, var mer tallrike i in vitro-fermenteringen enn det som ble
observert in vivo i nærvær av AcGGM.
Samlet sett øker disse resultatene vår forståelse av hvordan β-mannaner
utnyttes og brytes ned enzymatisk av spesifikke mikrobielle taxa, og hvordan β-
mannaner muligens kan påvirke sammensetningen av ulike mikrobiotiske
miljøer
Densitet og mekaniske egenskaper av konstruksjonsvirke fra gran i Nordland
Get PDFI denne studien er bøyefasthet, elastisitetsmodul og densitet til konstruksjonsvirke av gran (Picea abies (L.) Karst.) fra i Nordland fylke i Norge undersøkt. Hovedmålene har vært å undersøke om konstruksjonsvirke fra Nordland tilfredsstiller krav gitt i Norsk standard NS-EN 338 etter visuell sortering i henhold til Norsk standard NS-INSTA 142, og studere variasjonene.
Det ble samlet inn tømmer fra 45 trær fordelt på fem bestand i Nordland. Tømmeret ble skåret til 411 planker som ble styrkesortert visuelt i henhold til Norsk standard NS-INSTA 142, og densitet, e-modul og bøyefasthet ble testet i henhold til standard EN 408. Målingene ble korrigert i henhold til Norsk standard NS-EN 384, og karakteristiske verdier ble beregnet etter Norsk standard NS-EN 14358.
Resultatene viste at T1 oppfyller kravene til C18, sorteringsklasse T2 oppfyller kravene til C24, og sorteringsklasse «T2 og bedre» oppfyller kravene til C24. Gran sortert til klasse T3 holdt imidlertid ikke kravene i henhold til Norsk standard NS-EN 338.
Det ble utviklet statistiske modeller som viser at visuelle og posisjonsrelaterte variabler som kvistdiameter, relativ høyde i treet og årringbredde kan forklare de mekaniske egenskapene. Noen av modellene bruker skog-, tre- og stokkvariabler, og det kreves sporing av tømmer fra skog til sagbruk for å bruke disse modellene til sortering på sagbruket.
Gjennomsnittsverdier for densitet, elastisitetsmodul og bøyefasthet i denne studien er lavere enn det som er funnet i studier av gran fra Sør-Norge. Likevel oppfyller gran i denne studien kravene til og med fasthetsklasse C24 med visuell styrkesortering etter Norsk standard NS-INSTA 142, og det viser et potensiale for å bruke gran fra Nordland som konstruksjonsvirke.In this study, the modulus of resilience, modulus of elasticity and density of structural timber from Norway Spruce (Picea Abies) from Nordland in Norway were studied. The main objectives were to assess whether structural timber from Nordland meets the requirements specified in the Norwegian standard NS-EN 338 when graded by using visual grading according to the Norwegian standard NS-INSTA 142, and to examine the variations.
Timber was collected from 45 trees from five stands in Nordland. The logs were sawn into 411 planks, which were visually strength-graded in accordance with Norwegian standard NS-INSTA 142, and density, modulus of elasticity and modulus of resilience were tested following the standard EN 408. The test results were adjusted in accordance with Norwegian standard NS-EN 384, and characteristic values were calculated in accordance with Norwegian standard NS-EN 14358.
The study found that sorting class T1 meets the requirements for strength class C18, sorting class T2 meets the requirements for C24, and class “T2 and better” meets the requirements for C24. However, spruce graded as T3 did not meet the requirements for C30 given in Norwegian standard NS-EN 338.
Statistical models were developed, showing that visual and position- related variables such as knot diameter, relative height within the tree and annual ring width can explain the mechanical properties. Some of the models use forest-, tree-, and log-specific variables, requiring traceability of timber from forest to sawmill for these models to be implemented in sorting at the sawmill.
The average values for density, modulus of elasticity and modulus of resilience in this study were lower than those found in studies of spruce from southern Norway. Nevertheless, the spruce from this study meets the requirements up to and including strength class C24 when visually strength-graded according to Norwegian standard NS-INSTA 142, approving a potential for using spruce from Nordland as structural timber