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Mapping pathogenic fungi in decayed Norway spruce stands: Insights from harvester positional data
Full text link1. Root and butt rot caused by pathogenic fungi in the genera Heterobasidion and Armillaria is a pressing issue in managed Norway spruce forests. The disease results in financial losses for the forest owners and reduces the volume of wood that can be used in long-lived products. Pathogenic wood decay fungi spread either with the aid of airborne spores or via mycelial growth among neighbouring trees, the latter leading to clustering (tendency of decayed trees to be in close proximity relative to their neighbouring trees) of decay-affected trees in forests. Understanding the spatial patterns of the decay-affected trees at the forest stand level is vital for designing management strategies to address this problem. 2. We examined decay clustering in 273 clear-cut Norway spruce stands in Norway using harvester-recorded data on spatial occurrence of decayed and healthy Norway spruce trees. We tested clustering using three global-cluster tests that account for population density and distribution, evaluating clustering without identifying specific cluster locations. 3. The proportions of clustered and non-clustered stands differed depending on the statistical test used for clustering assessment, resulting in overall agreement of 32.8% for clustered and 36.9% for non-clustered. Clustered stands exhibited a median cluster distance (maximum distance between the decay-affected trees within a cluster) of 12 m (Inter-Quantile Range, IQR, 6–20 m) and a median of 6 (IQR 3–16) nearest neighbour trees (number of decayed trees forming a cluster), estimates comparable with prior studies focused on assessment of trees infected by mycelial spread of the same fungal individual. The decay incidence in the clustered stands was 16.24%, while the non-clustered stands had a butt-rot incidence of 20.97%. In clustered stands the average number of trees per hectare was higher (693) than in non-clustered stands (553). 4. Synthesis and applications: Our study demonstrates that Norway spruce stands display a diverse range of spatial patterns of butt rotted trees. We found that higher densities of Norway spruce trees probably facilitate the vegetative spread of pathogenic wood decay fungi, leading to clustering of decay-affected trees. To disrupt the spread of decay fungi between tree generations, precision planting of trees other than Norway spruce around infested stumps of prior generation trees has been recommended by earlier studies. We discussed the potential of using harvester-derived geoposition data for butt-rotted trees upon planning and execution of forest regeneration.publishedVersio
Impact of Cellulose Modification by Expandable Graphite and Carbon Nanotubes on Flammability and Thermal Properties
Full text linkThe flammability of cellulosic material restricts its use in insulation and packaging applications. This study examined carbon-based additives to protect cellulose paper against thermal degradation. Carbon nanotubes (CNT) and expandable graphite (EG) were used to modify paper material. Thermal analysis was performed to examine the different modification systems. Our results showed consistently that the addition of EG resulted in an increased fire resistance in the mini fire tube (MFT) test, limited oxygen index (LOI) measurements, and mass loss calorimeter (MLC). In combination with CNT, the heat-release rate could be drastically reduced. Thermal analysis (DSC with TG analysis) revealed that EG had a longer resistance to thermal degradation. The developed composite material can be used, depending on the needs of the industry, as part of thin panel material, partition, or fireproof cladding in construction, railways, transport, automotive, and shipbuilding industries.publishedVersio
Trade-offs and synergies of soil carbon sequestration: Addressing knowledge gaps related to soil management strategies
Full text linkSoil organic carbon (SOC) sequestration in agricultural soils is an important tool for climate change mitigation within the EU soil strategy for 2030 and can be achieved via the adoption of soil management strategies (SMS). These strategies may induce synergistic effects by simultaneously reducing greenhouse gas (GHG) emissions and/or nitrogen (N) leaching. In contrast, other SMS may stimulate emissions of GHG such as nitrous oxide (N2O) or methane (CH4), offsetting the climate change mitigation gained via SOC sequestration. Despite the importance of understanding trade-offs and synergies for selecting sustainable SMS for European agriculture, knowledge on these effects remains limited. This review synthesizes existing knowledge, identifies knowledge gaps and provides research recommendations on trade-offs and synergies between SOC sequestration or SOC accrual, non-CO2 GHG emissions and N leaching related to selected SMS. We investigated 87 peer-reviewed articles that address SMS and categorized them under tillage management, cropping systems, water management and fertilization and organic matter (OM) inputs. SMS, such as conservation tillage, adapted crop rotations, adapted water management, OM inputs by cover crops (CC), organic amendments (OA) and biochar, contribute to increase SOC stocks and reduce N leaching. Adoption of leguminous CC or specific cropping systems and adapted water management tend to create trade-offs by stimulating N2O emissions, while specific cropping systems or application of biochar can mitigate N2O emissions. The effect of crop residues on N2O emissions depends strongly on their C/N ratio. Organic agriculture and agroforestry clearly mitigate CH4 emissions but the impact of other SMS requires additional study. More experimental research is needed to study the impact of both the pedoclimatic conditions and the long-term dynamics of trade-offs and synergies. Researchers should simultaneously assess the impact of (multiple) agricultural SMS on SOC stocks, GHG emissions and N leaching. This review provides guidance to policymakers as well as a framework to design field experiments and model simulations, which can address knowledge gaps and non-intentional effects of applying agricultural SMS meant to increase SOC sequestration.publishedVersio
Asynchronous recovery of evaporation and transpiration following extreme snow damage in a subtropical forest
Full text linkStudy region: The Ailaoshan National Nature Reserve forest is a mountainous water catchment area for the Lancang River basin and a subtropical ecological conservation area in southwest China. Study focus: The study aimed to understand how water fluxes in a subtropical forest responds to extreme weather disturbances and their recoveries in the post-damage years. We used eddy covariance data (2010–2019) to investigate the evapotranspiration (ET), transpiration (T), evaporation (E), and canopy conductance (Gc) before and after an extreme snow event in 2015. New Hydrological Insights: In the snow damage year, the leaf area index (LAI) decreased by 49 % compared to the pre-damage levels. The severe vegetation damage caused a significant decrease in ET, T, E, and Gc by 35 %, 36 %, 23 %, and 33 %, respectively, compared to the pre-damage levels. T returned to its pre-damage level in 2016, one year after the snow damage. In contrast, LAI, ET, E and Gc recovered to their pre-damage levels in 2018, four years after the initial damage. Reduced ET caused a strong positive RFET, which diminished forest evaporative cooling and resilience. Our results suggest that the delayed E recovery enables water reserves in the ecosystems to be used through T to support rapid understory vegetation growth. This mechanism plays critical in bolstering ecosystem resilience as it facilitates swift recovery following disturbances in subtropical forests.publishedVersio
Diversity and Chemical Characterization of Apple (Malus sp.) Pollen: High Antioxidant and Nutritional Values for Both Humans and Insects
Full text linkPollen represents a reward for pollinators and is a key element in plant–insect interactions, especially in apples, which are entomophilous species and require cross-pollination to produce economically valuable yields. The aim of this study was to analyze the chemical content of the pollen in 11 apple cultivars (‘Red Aroma’, ‘Discovery’, ‘Summerred’, ‘Rubinstep’, ‘Elstar’, ‘Dolgo’, ‘Professor Sprenger’, ‘Asfari’, ‘Eden’, ‘Fryd’ and ‘Katja’) grown in Norway and try to establish a relationship between them and insect attractiveness. In the applied chemical analysis, 7 sugars and sugar alcohols, 4 organic acids, 65 phenolic compounds, 18 hydroxycinnamic acid amides (phenylamides), a large number of polypeptides with a molecular weight of 300 kDa to 95 kDa, which made them interesting for insect pollenizers. Only the pollen of the crab apples contained quercetin-3-O-(2″-O-malonyl)-hexoside, which can be used as a marker for the apple species Malus sylvestris (L.) Mill. Apple floral pollen is a rich source of bioactive components and can be used to prevent and/or cure diseases or can be included in diets as a “superfood”.publishedVersio
The use of volatile organic compounds in preventing and managing invasive plant pests and pathogens
Full text linkInvasive pests and plant pathogens pose a significant threat to ecosystems and economies worldwide, prompting the need of anticipatory strategies. Preventing their introduction by detection at the ports of entry has been proven extremely difficult. This review explores the potential of biogenic volatile detection as a reliable preventive solution. It underscores the importance of early detection and rapid response as integral components of effective invasive pest management, and it discusses the limitations of current control measures and the increasing globalization that facilitates the spread of pests and pathogens. Through a synthesis of existing literature, this review analyzes the Volatile Organic Compound (VOC) emissions in five invasive model species: three insects, Halyomorpha halys, Spodoptera frugiperda, Helicoverpa armigera, a nematode, Bursaphelenchus xylophilus, and an oomycete, Phytophthora ramorum. The review focuses on the specific volatiles, released by both the invasive organisms and the infested host plants. If available, the volatiles emitted from similar species were considered for comparison. Ultimately, this review highlights specific pest volatile and shared Herbivore Induced Plant Volatiles (HIPVs) as a reliable and innovative solution in pest detection. If possible, candidate compounds are provided, whilst the lack of some emphasizes the urge of expanding the information available.publishedVersio
The relationship between branch scar attributes and knot features in birch (Betula pendula and B. pubescens)
Full text linkThere is currently no quality sorting of harvested hardwood timber in Norway on a national scale. Medium- and high-quality logs including those from birch (Betula pubescens Ehrh., B. pendula Roth) are thus not utilized according to their potential monetary value. Increased domestic utilization of quality birch timber requires that the quality of harvested logs be properly assessed for potential end uses. A preferred sorting procedure would use visually detectable external log defects to grade roundwood timber. Knots are an important feature of inner log quality. Thus, the aim of this study was to evaluate whether correlations between branch scar size and knot features could be found in Norwegian birch. Using 168 knots from seven unpruned birch trees, external bark attributes often showed strong correlations with internal wood quality. Both length of the mustache and length of the seal performed well as predictors of stem radius at the time of knot occlusion. The presence of a broken off branch stub as part of an occluded knot significantly increased the knot-effected stem radius, proving that the practice of removing branches and branch stubs along the lower trunk is a crucial measure if quality timber production is the primary management goal.publishedVersio
Kjelle avrenningsforsøk. Årsrapport 2022–2023 for jordarbeidingsforsøk på lav erosjonsrisiko
Full text link‘Ingen jordarbeiding om høsten’ har vært et av de viktigste tiltakene mot erosjon og tap av næringsstoffer fra jordbruksarealer siden begynnelsen på 1990-tallet. Avrenningsforsøk som startet på 1980-tallet viser stor effekt av ‘ingen jordarbeiding om høsten’ på erosjon og næringsstofftap på forholdsvis bratte jordbruksarealer. Det har derimot kun vært få undersøkelser av jordarbeidings-effekter på arealer med liten helling, på tross av at slike arealer utgjør størsteparten av jordbruksarealene der det dyrkes korn. Avrenningsforsøket på Kjelle vgs. i Bjørkelangen ble satt i gang i 2014 for å belyse effekter av jordarbeiding på næringsstoffavrenning fra arealer med liten erosjonsrisiko, det vil si forholdsvis flate arealer. Forsøket består av 9 forsøksruter med målinger av avrenning fra både overflatevann og grøftevann fra hver rute. Det er tre gjentak og behandlingene omfatter 1. høstpløying med vårkorn (havre, bygg fra 2022), 2. vårpløying med vårkorn (bygg) og 3. høstpløying med høstkorn (høsthvete). Resultater fra ni forsøksår (2014-2023), er beskrevet i denne rapporten med fokus på siste året.Kjelle avrenningsforsøk. Årsrapport 2022–2023 for jordarbeidingsforsøk på lav erosjonsrisikopublishedVersio
Etablering av blomsterengarter fra frø
Full text linkErfaring har vist det er krevende å etablere blomsterengarter fra frø både i eksisterende grasmark og ved såing på bar jord. Dette er utfordringer som må løses for en mer målrettet restaurering eller rehabilitering av natur. Tidligere prosjekter har pekt på egenskaper hos planteartene, kvaliteten på frøet, og metoder for etablering som viktige faktorer. I dette prosjektet undersøkte vi 1) om frøplanteegenskaper kan forklare ulike blomsterengarter sine evner til å etablere seg i felt og 2) om bruk av eBeetle frøhøstemaskin til sams høsting av lokalt frø i donorenger kan være et alternativ til frøblandinger basert på håndhøsta og oppformerte frø av enkeltarter. Vi dokumenterte stor variasjon i frøplanteegenskaper for i alt 41 blomsterengarter. Selv om disse egenskapene gav en god prediksjon av plantevekst, men klarte ikke å predikere responser på konkurranse i like stor grad. Vi fant likevel at egenskaper for effektiv ressursinnhenting forklarer etablering for noen av artene. Det er altså noen mekanismer eller faktorer i selve konkurransesituasjonen som ikke er tilstrekkelig undersøkt. Feltetablering av frø samlet med eBeetle ble sammenlignet med håndhøstet frø fra de samme donorengene ved såing i bar jord i tre mottakerenger i Grimstad, Kongsberg og Asker. For utvalgte semi-naturlige arter som ofte er av høy prioritet i restaurering, ga frøblandinger basert på håndhøsta frø vesentlig bedre tilslag enn frø høsta med eBeetle. Frøhøstemaskinen klarte ikke høste en tilstrekkelig mengde av disse utvalgte artene og frøene ble tynnet ut med store mengder frø av vanlige arter og uønska arter som rotugras og grove, kraftigvoksende grasarter. Det var betydelige forskjeller i resultater mellom mottakerengene og arter. eBeetle egner seg for høsting av vanlige arter i enger uten rotugras eller andre problemarter, men må suppleres eller erstattes av tradisjonelt oppformerte naturfrøblandinger for etablering av et større mangfold arter fra semi-naturlige enger.Etablering av blomsterengarter fra frøpublishedVersio
Tapsårsaker hos lam på Høylandet, beitesesongen 2023
Full text linkDødsårsaker hos lam i en tapsutsatt sauebesetning på Høylandet er kartlagt. Av 170 lam instrumenterte med mortalitetssendere (dødsvarslere), døde 27 lam på beite. Ni av de omkomne lammene ble drept av fredet rovvilt (33,3 %), ni omkom som følge av sjukdom (33,3) og to døde i ulykke (7,4 %). De resterende sju kadavrene var det ikke mulig å dokumentere dødsårsaken på, slik at disse har fått status ukjent tapsårsak (25,9 %). Det er for første gang dokumentert kongeørndrepte lam i denne besetningen. Flere tapsforebyggende tiltak er anbefalt.Tapsårsaker hos lam på Høylandet, beitesesongen 2023publishedVersio