• Bark beetle outbreaks in Europe: state of knowledge and ways forward for management 

      Hlásny, Tomáš; König, Louis; Krokene, Paal; Lindner, Marcus; Montagné-Huck, Claire; Müller, Jörg; Qin, Hua; Raffa, Kenneth F.; Schelhaas, Mart-Jan; Svoboda, Miroslav; Viiri, Heli; Seidl, Rupert (Peer reviewed; Journal article, 2021-07-28)
      Purpose of Review Outbreaks of tree-killing bark beetles have reached unprecedented levels in conifer forests in the northern hemisphere and are expected to further intensify due to climate change. In parts of Europe, bark ...
    • Bark Beetle Population Dynamics in the Anthropocene: Challenges and Solutions 

      Biedermann, Peter H.W.; Müller, Jörg; Grégoire, Jean-Claude; Gruppe, Axel; Hagge, Jonas; Hammerbacher, Almuth; Hofstetter, Richard W.; Kandasamy, Dineshkumar; Kolarik, Miroslav; Kostovcik, Martin; Krokene, Paal; Sallé, Aurélien; Six, Diana L.; Turrini, Tabea; Vanderpool, Dan; Wingfield, Michael J.; Bässler, Claus (Journal article; Peer reviewed, 2019)
      Tree-killing bark beetles are the most economically important insects in conifer forests worldwide. However, despite >200 years of research, the drivers of population eruptions and crashes are still not fully understood ...
    • Bark Beetle-Associated Blue-Stain Fungi Increase Antioxidant Enzyme Activities and Monoterpene Concentrations in Pinus yunnanensis 

      Pan, Yue; Zhao, Tao; Krokene, Paal; Yu, Ze-fen; Qiao, Min; Lu, Jun; Chen, Peng; Ye, Hui (Journal article; Peer reviewed, 2018-11-27)
      Yunnan pine is the most important tree species in SW China in both economical and ecological terms, but it is often killed by pine shoot beetles (Tomicus spp.). Tomicus beetles are secondary pests in temperate regions and ...
    • Carbon castles and insect invaders: dissecting physical defences in conifer stems 

      Krokene, Paal (Journal article; Peer reviewed, 2016)
    • Conifer Stored Resources and Resistance to a Fungus Associated with the Spruce Bark Beetle Ips typographus 

      Lahr, Eleanor C.; Krokene, Paal (Journal article; Peer reviewed, 2013-08-13)
      Bark beetles and associated fungi are among the greatest natural threats to conifers worldwide. Conifers have potent defenses, but resistance to beetles and fungal pathogens may be reduced if tree stored resources are ...
    • Convergent evolution of semiochemicals across Kingdoms: bark beetles and their fungal symbionts 

      Zhao, Tao; Ganji, Suresh; Schiebe, Christian; Bohman, Björn; Weinstein, Philip; Krokene, Paal; Borg-Karlson, Anna-Karin; Unelius, C. Rikard (Journal article; Peer reviewed, 2019-02-15)
      Convergent evolution of semiochemical use in organisms from different Kingdoms is a rarely described phenomenon. Tree-killing bark beetles vector numerous symbiotic blue-stain fungi that help the beetles colonize healthy ...
    • Effects of mild drought on the morphology of sun and shade needles in 20-year-old Norway spruce trees 

      Gebauer, Roman; Volařík, Daniel; Urban, Josef; Børja, Isabella; Nagy, Nina Elisabeth; Eldhuset, Toril Drabløs; Krokene, Paal (Journal article; Peer reviewed, 2019-02-28)
      Several studies have looked at how individual environmental factors influence needle morphology in conifer trees, but interacting effects between drought and canopy position have received little attention. In this study, ...
    • Forest damage. A guide to the identification of damage causes - Norwegian national list 

      Hylen, Gro; Krokene, Paal; Larsson, John Y.; Solheim, Halvor; Timmermann, Volkmar (Håndbok fra Skog og landskap;08/2007, Research report, 2007-04)
      The Norwegian Monitoring Programme for Forest Damage (OPS) has since its start registered damage to selected trees. The aim of the registrations has been to explain variations in crown density and crown colour. In answer ...
    • Fra en til to generasjoner granbarkbille i Norge? Statusanalyse med data fra klekking og barkbilleovervåkingen. 

      Økland, Bjørn; Lange, Holger; Krokene, Paal; Buran, Rolf; Finne, Ellen A. (NIBIO-rapport;7(106) 2021, Research report, 2021-06)
      Overgang fra en til to generasjoner av stor granbarkbille med varmere klima vil kunne øke mengden av skader i norske skoger på grunn av to angrepsperioder. Sommertemperaturene i Norge har vært økende siden 1970-tallet og ...
    • Fra en til to generasjoner granbarkbille i Norge? Statusanalyse med data fra klekking og barkbilleovervåkingen. 

      Økland, Bjørn; Lange, Holger; Krokene, Paal; Buran, Rolf; Finne, Ellen A. (NIBIO-rapport;7(106) 2021, Research report, 2021-06)
      Overgang fra en til to generasjoner av stor granbarkbille med varmere klima vil kunne øke mengden av skader i norske skoger på grunn av to angrepsperioder. Sommertemperaturene i Norge har vært økende siden 1970-tallet og ...
    • Fungal associates of the tree-killing bark beetle, Ips typographus, vary in virulence, ability to degrade conifer phenolics and influence bark beetle tunneling behavior 

      Zhao, Tao; Kandasamy, Dineshkumar; Krokene, Paal; Chen, Jingyuan; Gershenzon, Jonathan; Hammerbacher, Almuth (Journal article; Peer reviewed, 2018-07-20)
      The bark beetle Ips typographus carries numerous fungi that could be assisting the beetle in colonizing live Norway spruce (Picea abies) trees. Phenolic defenses in spruce phloem are degraded by the beetle's major tree-killing ...
    • Fungal Interactions and Host Tree Preferences in the Spruce Bark Beetle Ips typographus 

      Tanin, Sifat Munim; Kandasamy, Dineshkumar; Krokene, Paal (Peer reviewed; Journal article, 2021-06-04)
      The spruce bark beetle Ips typographus is the most damaging pest in European spruce forests and has caused great ecological and economic disturbances in recent years. Although native to Eurasia, I. typographus has been ...
    • Fungal symbionts of the spruce bark beetle synthesize the beetle aggregation pheromone 2-methyl-3-buten-2-ol 

      Zhao, Tao; Axelsson, Karolin; Krokene, Paal; Borg-Karlson, Anna-Karin (Journal article; Peer reviewed, 2015-08-25)
      Tree-killing bark beetles depend on aggregation pheromones to mass-attack their host trees and overwhelm their resistance. The beetles are always associated with phytopathogenic ophiostomatoid fungi that probably assist ...
    • Granbarkbillen Registrering av bestandsstørrelsene i 2021 

      Økland, Bjørn; Krokene, Paal; Beachell, Andreas Myki (NIBIO Rapport;7(173) 2021, Research report, 2021-11)
      Nivået av granbarkbiller er økende for alle fylker i 2021, med unntak av Vest-Agder. Vestfold øker mest og har i år over 20 000 biller per felle i snitt, men billenivået er bare 69 % av nivået ved slutten av utbruddet på ...
    • Granbarkbillen. Registrering av bestandsstørrelsene i 2008 

      Økland, Bjørn; Christiansen, Erik; Wollebæk, Gro; Krokene, Paal (Oppdragsrapport fra Skog og landskap;21/2008, Research report, 2008)
      Økningen i barkbillebestandene siden 2002 fortsetter. Alle fylker unntatt ett viser oppgang i 2008; og noen fylker på Østlandet har nær en fordobling fra fjoråret. Økningen settes i sammenheng med de varme somrene, hvor ...
    • Granbarkbillen. Registrering av bestandsstørrelsene i 2022 

      Økland, Bjørn; Krokene, Paal; Gohli, Jostein; Fajardo, Marta Bosque (NIBIO Rapport 8(128) 2022;, Research report, 2022-10)
      Samtlige fylker i barkbilleovervåkingen viser en nedgang i fangstene i 2022. Dette kan skyldes at effekten av tørken i 2018 avtar, men nye vindfellinger og tørkeperioder i 2022 kan bidra til nye økninger i årene som kommer. ...
    • Granbarkbillens utviklingshastighet i liggende grantrær. Prosjekt barkbilleutvikling 2010 

      Krokene, Paal (Oppdragsrapport fra Skog og landskap;17/2011, Research report, 2011)
      Skog og landskap har utviklet en enkel temperaturd0072evet modell som beskriver granbarkbillens utvikling fra egg til voksent insekt (Lange m.fl. 2009). Modellen drives av daglige middeltemperaturer og beregner hvor langt ...
    • A highly-contiguous genome assembly of the Eurasian spruce bark beetle, Ips typographus, provides insight into a major forest pest 

      Powell, Daniel; Groβe-Wilde, Ewald; Krokene, Paal; Roy, Amit; Chakraborty, Amrita; Löfstedt, Christer; Vogel, Heiko; Andersson, Martin N.; Schlyter, Fredrik (Peer reviewed; Journal article, 2021-09-09)
      Conifer-feeding bark beetles are important herbivores and decomposers in forest ecosystems. These species complete their life cycle in nutritionally poor substrates and some can kill enormous numbers of trees during ...
    • Insektskader 

      Krokene, Paal; Økland, Bjørn; Christiansen, Erik (Others, 2007)
      Dersom vi får et varmere klima er noen effekter tilnærmet sikre, slik som at mange insekter vil øke sin utbredelse mot nord, og at utviklingen fra egg til voksent insekt vil gå raskere. På et generelt plan er slike direkte ...
    • Klimavinnerne - blant insektene 

      Krokene, Paal; Økland, Bjørn; Nilssen, Arne C. (Others, 2010)
      Insektene er blant de organismene som reagerer raskest på klimaendringer. De har kort generasjonstid, er svært mobile og utviklingshastigheten deres er direkte påvirket av temperaturen. Dette betyr at utviklingen fra egg ...