Halvor Solheim
Seniorforsker (pensjonistavtale)
Forfattere
Volkmar Timmermann Isabella Børja Nicholas Clarke Rune Eriksen Jostein Gohli Gro Hylen Jane Uhd Jepsen Paal Krokene Holger Lange Helge Meissner Nina Elisabeth Nagy Jørn-Frode Nordbakken Sverre Solberg Halvor Solheim Ole Petter Laksforsmo Vindstad Bjørn Økland Wenche AasSammendrag
Skogens helsetilstand påvirkes i stor grad av klima og værforhold, enten direkte ved tørke, frost og vind, eller indirekte ved at klimaet påvirker omfanget av soppsykdommer og insektangrep. Klimaendringene og den forventede økningen i klimarelaterte skogskader gir store utfordringer for forvaltningen av framtidas skogressurser. Det samme gjør invaderende skadegjørere, både allerede etablerte arter og nye som kan komme til Norge i nær framtid. I denne rapporten presenteres resultater fra skogskadeovervåkingen i Norge i 2021 og trender over tid for følgende temaer: (i) Landsrepresentativ skogovervåking; (ii) Skogøkologiske analyser og målinger av luftkjemi på de intensive overvåkingsflatene; (iii) Overvåking av bjørkemålere i Troms og Finnmark; (iv) Barkbilleovervåkingen 2021 og mulig overgang til to generasjoner; (v) Asiatisk askepraktbille – en dørstokkart? (vi) Overvåking av askeskuddsyke; (vii) Andre spesielle skogskader i 2021.
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The genus Ceratocystiopsis (Ophiostomatales, Ascomycota) includes 21 species, which can be found mainly in association with bark beetles in the Northern Hemisphere. A survey of Ceratocystiopsis species associated with bark beetles infesting Picea abies and Pinus sylvestris in Norway yielded 126 isolates, representing Ceratocystiopsis neglecta and Ceratocystiopsis rollhanseniana, and four species described herein as Ceratocystiopsis chalcographii, Ceratocystiopsis debeeria, Ceratocystiopsis norroenii and Ceratocystiopsis troendelagii. The new taxa were morphologically characterised and phylogenetically analysed on the basis of sequence data of multiple loci (ITS, LSU, beta-tubulin (TUB2), calmodulin (CAL) and translation elongation factor 1-alpha (TEF1) genes). Ceratocystiopsis norroenii and C. rollhanseniana were the most frequently isolated species, and the latter species had the wider vector range.
Forfattere
Y. P. Tan S. L. Bishop-Hurley R. G. Shivas D.A. Cowan G. Maggs-Kölling Sajeewa S.N. Maharachchikumbura U. Pinruan K.L. Bransgrove S. De la Peña-Lastra E. Larsson T. Lebel S. Mahadevakumar A. Mateos E. R. Osieck A. Rigueiro-Rodríguez S. Sommai K. Ajithkumar A. Akulov F. E. Anderson F. Arenas S. Balashov Á. Bañares D.K. Berger M.V. Bianchinotti S. Bien P. Bilański A. G. Boxshall M. Bradshaw J. Broadbridge F.J.S. Calaça C. Campos-Quiroz J. Carrasco-Fernández J.F. Castro S. Chaimongkol S. Chandranayaka Y. Chen D. Comben J.D.W. Dearnaley A.S. Ferreira-Sá K. Dhileepan M.L. Diaz P.K. Divakar S. Xavier-Santos A. Fernández-Bravo J. Gené F.E. Guard M. Guerra S. Gunaseelan J. Houbraken K. Janik-Superson R. Jankowiak M. Jeppson Ž. Jurjević M. Kaliyaperumal L.A. Kelly K. Kezo A.N. Khalid P. Khamsuntorn D. Kidanemariam M. Kiran E. Lacey G.J. Langer L.V. López-Llorca J. J. Luangsa-ard P. Lueangjaroenkit H.T. Lumbsch J. G. Maciá-Vicente L.S. Mamatha Bhanu T.S. Marney J.E. Marqués-Gálvez A. Morte A. Naseer A. Navarro-Ródenas O. Oyedele S. Peters S. Piskorski L. Quijada G.H. Ramírez K. Raja A. Razzaq V.J. Rico A. Rodríguez M. Ruszkiewicz-Michalska R.M. Sánchez C. Santelices A.S. Savitha M. Serrano L. Leonardo-Silva Halvor Solheim S. Somrithipol M.Y. Sreenivasa H. Stępniewska D. Strapagiel T. Taylor D. Torres-Garcia J. Vauras M. Villarreal C.M Visagie M. Wołkowycki W. Yingkunchao E. Zapora J.Z. Groenewald P.W. CrousSammendrag
Novel species of fungi described in this study include those from various countries as follows: Argentina, Colletotrichum araujiae on leaves, stems and fruits of Araujia hortorum. Australia, Agaricus pateritonsus on soil, Curvularia fraserae on dying leaf of Bothriochloa insculpta, Curvularia millisiae from yellowing leaf tips of Cyperus aromaticus, Marasmius brunneolorobustus on well-rotted wood, Nigrospora cooperae from necrotic leaf of Heteropogon contortus, Penicillium tealii from the body of a dead spider, Pseudocercospora robertsiorum from leaf spots of Senna tora, Talaromyces atkinsoniae from gills of Marasmius crinis-equi and Zasmidium pearceae from leaf spots of Smilax glyciphylla. Brazil, Preussia bezerrensis fromair. Chile, Paraconiothyrium kelleni from the rhizosphere of Fragaria chiloensis subsp. chiloensis f. chiloensis. Finland, Inocybe udicola onsoilinmixedforest with Betula pendula, Populus tremula, Picea abies and Alnus incana. France, Myrmecridium normannianum on dead culm of unidentified Poaceae. Germany, Vexillomyces fraxinicola from symptomless stem wood of Fraxinus excelsior. India, Diaporthe limoniae on infected fruit of Limonia acidissima, Didymella naikii on leaves of Cajanus cajan, and Fulvifomes mangroviensis on basal trunk of Aegiceras corniculatum. Indonesia, Penicillium ezekielii from Zea mays kernels. Namibia, Neocamarosporium calicoremae and Neocladosporium calicoremae on stems of Calicorema capitata, and Pleiochaeta adenolobi on symptomatic leaves of Adenolobus pechuelii. Netherlands, Chalara pteridii on stems of Pteridium aquilinum, Neomackenziella juncicola (incl. Neomackenziella gen. nov.)and Sporidesmiella junci from dead culms of Juncus effusus. Pakistan, Inocybe longistipitata on soil in a Quercus forest. Poland, Phytophthora viadrina from rhizosphere soil of Quercus robur, and Septoria krystynae on leaf spots of Viscum album. Portugal (Azores), Acrogenospora stellata on dead wood or bark. South Africa, Phyllactinia greyiae on leaves of Greyia sutherlandii and Punctelia anae on bark of Vachellia karroo. Spain, Anteaglonium lusitanicum on decaying wood of Prunus lusitanica subsp. lusitanica, Hawksworthiomyces riparius from fluvial sediments, Lophiostoma carabassense endophytic in roots of Limbarda crithmoides, and Tuber mohedanoi from calcareussoils. Spain (Canary Islands), Mycena laurisilvae on stumps and woody debris. Sweden, Elaphomyces geminus from soil under Quercus robur. Thailand, Lactifluus chiangraiensis on soil under Pinus merkusii, Lactifluus nakhonphanomensis and Xerocomus sisongkhramensis on soil under Dipterocarpus trees. Ukraine, Valsonectria robiniae on dead twigs of Robinia hispida. USA, Spiralomyces americanus (incl. Spiralomyces gen. nov.) from office air. Morphological and culture characteristics are supported by DNA barcodes.
Forfattere
Ari Hietala Ahto Agan Nina Elisabeth Nagy Isabella Børja Volkmar Timmermann Rein Drenkhan Halvor SolheimSammendrag
The populations of European ash and its harmless fungal associate Hymenoscyphus albidus are in decline owing to ash dieback caused by the invasive Hymenoscyphus fraxineus, a fungus that in its native range in Asia is a harmless leaf endophyte of local ash species. To clarify the behavior of H. albidus and its spatial and temporal niche overlap with the invasive relative, we used light microscopy, fungal species-specific qPCR assays, and PacBio long-read amplicon sequencing of the ITS1-5.8S-ITS2 region to examine fungal growth and species composition in attached leaves of European ash. The plant material was collected from a healthy stand in central Norway, where ash saplings in late autumn showed leaflet vein necrosis like that commonly related to H. fraxineus. For reference, leaflet samples were analyzed from stands with epidemic level of ash dieback in southeastern Norway and Estonia. While H. albidus was predominant in the necrotic veins in the healthy stand, H. fraxineus was predominant in the diseased stands. Otherwise, endophytes with pathogenic potential in the genera Venturia (anamorph Fusicladium), Mycosphaerella (anamorph Ramularia), and Phoma, and basidiomycetous yeasts formed the core leaflet mycobiome both in the healthy and diseased stands. In necrotic leaf areas with high levels of either H. albidus or H. fraxineus DNA, one common feature was the high colonization of sclerenchyma and phloem, a region from which the ascomata of both species arise. Our data suggest that H. albidus can induce necrosis in ash leaves, but that owing to low infection pressure, this first takes place in tissues weakened by autumn senescence, 1–2 months later in the season than what is characteristic of H. fraxineus at an epidemic phase of ash dieback. The most striking difference between these fungi would appear to be the high fecundity of H. fraxineus. The adaptation to a host that is phylogenetically closely related to European ash, a tree species with high occurrence frequency in Europe, and the presence of environmental conditions favorable to H. fraxineus life cycle completion in most years may enable the build-up of high infection pressure and challenge of leaf defense prior to autumn senescence.
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Det er ikke registrert sammendrag
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Det er ikke registrert sammendrag
Forfattere
Kalev Adamson Marili Laas Kathrin Blumenstein Johanna Busskamp Gitta J. Langer Darta Klavina Anu Kaur Tiit Maaten Martin S. Mullett Michael M. Müller Emília Ondrušková Allar Padari Enn Pilt Taavi Riit Halvor Solheim Liina Soonvald Leho Tedersoo Eeva Terhonen Rein DrenkhanSammendrag
Diplodia sapinea is a cosmopolitan endophyte and opportunistic pathogen having occurred on several conifer species in Europe for at least 200 years. In Europe, disease outbreaks have increased on several Pinus spp. in the last few decades. In this study, the genetic structure of the European and western Asian D. sapinea population were investigated using 13 microsatellite markers. In total, 425 isolates from 15 countries were analysed. A high clonal fraction and low genetic distance between most subpopulations was found. One single haplotype dominates the European population, being represented by 45.3% of all isolates and found in nearly all investigated countries. Three genetically distinct subpopulations were found: Central/North European, Italian and Georgian. The recently detected subpopulations of D. sapinea in northern Europe (Estonia) share several haplotypes with the German subpopulation. The northern European subpopulations (Latvia, Estonia and Finland) show relatively high genetic diversity compared to those in central Europe suggesting either that the fungus has existed in the North in an asymptomatic/endophytic mode for a long time or that it has spread recently by multiple introductions. Considerable genetic diversity was found even among isolates of a single tree as 16 isolates from a single tree resulted in lower clonal fraction index than most subpopulations in Europe, which might reflect cryptic sexual proliferation. According to currently published allelic patterns, D. sapinea most likely originates from North America or from some unsampled population in Asia or central America. In order to enable the detection of endophytic or latent infections of planting stock by D. sapinea, new species-specific PCR primers (DiSapi-F and Diplo-R) were designed. During the search for Diplodia isolates across the world for species specific primer development, we identified D. africana in California, USA, and in the Canary Islands, which are the first records of this species in North America and in Spain.
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The relationship between the ecological success of needle pathogens of forest trees and species richness of co-inhabiting endophytic fungi is poorly understood. One of the most dangerous foliar pathogens of pine is Dothistroma septosporum, which is a widely spread threat to northern European forests. We sampled two Pinus sylvestris sites in Estonia and two in Norway in order to analyse the relations between the abundance of D. septosporum and overall fungal richness, specific fungal species composition, time of season, needle age and position in the canopy. In both countries, the overall species richness of fungi was highest in autumn, showing a trend of increase with needle age. The overall species richness in the second-year needles in Estonia and third-year needles in Norway was similar, suggesting that a critical colonization threshold for needle shed in P. sylvestris is breached earlier in Estonia than in Norway. The fungal species richness in P. sylvestris needles was largely affected by Lophodermium conigenum. Especially in older needles, the relative abundance of L. conigenum was significantly higher in spring compared to summer or autumn. The timing of recruitment and colonization mechanisms of different foliage endophytes are shortly discussed.
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Sporothrix (Sordariales, Ascomycota) is a well-supported monophyletic lineage within the Ophiostomatales, species of which occur in a diverse range of habitats including on forest trees, in the soil, associated with bark beetles and mites as well as on the fruiting bodies of some Basidiomycota. Several species have also been reported as important human and animal pathogens. During surveys of insect- and wound-associated Ophiostomatales from hardwood trees in Poland, many isolates with affinity to Sporothrix were recovered. In the present study, six undescribed Sporothrix spp. collected during these surveys are characterized based on their morphological characteristics and multi-locus phylogenenetic inference. They are described as Sporothrix cavum, Sporothrix cracoviensis, S. cryptarchum, S. fraxini, S. resoviensis, and S. undulata. Two of the Sporothrix spp. reside in the S. gossypina-complex, while one forms part of the S. stenoceras-complex. One Sporothrix sp. is a member of lineage F, and two other species grouped outside any of the currently defined species complexes. All the newly described species were recovered from hardwood habitats in association with sub-cortical insects, wounds or woodpecker cavities. These species were morphologically similar, with predominantly asexual states having hyaline or lightly pigmented conidia, which produce holoblastically on denticulate conidiogenous cells. Five of the new taxa produce ascomata with necks terminating in long ostiolar hyphae and allantoid ascospores without sheaths. The results suggest that Sporothrix species are common members of the Ophiostomatales in hardwood ecosystems of Poland.
Forfattere
Volkmar Timmermann Andreas Myki Beachell May Bente Brurberg Isabella Børja Nicholas Clarke Inger Sundheim Fløistad Ari Hietala Gro Hylen Jane Uhd Jepsen Jørn-Frode Nordbakken Martin Pettersson Sverre Solberg Halvor Solheim Venche Talgø Ole Petter Laksforsmo Vindstad Bjørn Økland Wenche AasSammendrag
Skogens helsetilstand påvirkes i stor grad av klima og værforhold, enten direkte ved tørke, frost og vind, eller indirekte ved at klimaet påvirker omfanget av soppsykdommer og insektangrep. Klimaendringene og den forventede økningen i klimarelaterte skogskader gir store utfordringer for forvaltningen av framtidas skogressurser. Det samme gjør invaderende skadegjørere, både allerede etablerte arter og nye som kan komme til Norge i nær framtid. I denne rapporten presenteres resultater fra skogskadeovervåkingen i Norge i 2020 og trender over tid. I den landsrepresentative skogovervåkingen har kronetettheten hos gran og furu holdt seg stabil i 2020 sammenlignet med tidligere år. Det ble registrert lite misfarging hos bartrærne. Skadenivået hos både bartrær, bjørk og andre løvtrær var lavere enn i 2019. Abiotiske faktorer med snø, vind og tørke som de viktigste årsakene dominerte skadebildet hos alle treslag. Kjemiske analyser av luft og nedbør i den intensive skogovervåkingen viser at det fortsatt er høyest verdier av antropogene svovel- og nitrogenforbindelser på den sørligste overvåkingsflata i Birkenes grunnet langtransportert forurensing. Den høyeste konsentrasjonen av nitrogendioksid i luft ble målt på stasjonen i Hurdal i 2020, noe som skyldes utslipp fra veitrafikken i regionen. Det var lave nivåer av bakkenært ozon i Norge i 2020 og ingen overskridelser av UNECEs grenseverdi på 5000 ppb-timer for skog. Vegetasjonsanalysene fra Hurdal har påvist en endring i bunn-vegetasjonens artssammensetning grunnet økt lystilgang og mye barnålstrø. Både hogst utenfor overvåkingsflata og flere skrantende, råteangrepne og døde grantrær i flata har bidratt til økt lystilgang og til større strømengde på bakken. Mange grantrær på flata i Hurdal er sterkt preget av råte med lav kronetetthet og mye misfarging. Flere trær på flata har dødd de seinere årene som følge av råteskader, ofte i kombinasjon med andre faktorer som vindfelling og skader etter tørken i 2018 med påfølgende barkbilleangrep. Overvåking av bjørkemålere har vist at fjellbjørkeskogen både i Nord-Norge og fjellregionene i sørlige halvdel av landet har vært utsatt for betydelige utbrudd av bjørkemålere i løpet av perioden 2012–2018. Overvåkingsdata fra 2019 og 2020 tyder imidlertid på at målerbestandene nå er lave eller i sterk tilbakegang i det meste av landet. I Troms har målerbestandene allerede nådd et bunnpunkt, og bestandene er nedadgående også i fjellet i Sør-Norge. Vi forventer derfor at skogen i mesteparten av Norge vil bli mindre utsatt for angrep av bjørkemålere de neste par årene. De fleste fylkene hadde en økning i fangstverdiene i barkbilleovervåkingen i 2020-sesongen. Alle fangstverdiene var imidlertid under 10 000 biller per felle, mens de høyeste verdiene ved slutten av utbruddet på 1970-tallet var rundt 25 000 biller per felle. Fylkene rundt Oslofjorden hadde noen lokale tilfeller av tørke- og barkbilleskader. Det ble ikke funnet noen tydelig økning av fellefangstene i tiden for en annen generasjon, men modellberegninger viser at stor granbarkbille har nok døgngrader til å gjennomføre to generasjoner før overvintring. I august 2020 ble soppen Diplodia sapinea funnet på sterkt skadet vrifuru i Ås kommune. Tidligere har det blitt gjort noen få funn av soppen på andre bartrearter i det samme området. D. sapinea er vanlig i varmere strøk på flere kontinenter, spesielt på furuarter. De pågående klima-endringene har trolig bidratt til at soppen har kunnet spre og etablere seg mot nord, men vi kan heller ikke utelukke innførsel av soppen via plantemateriale til bruk i grøntanlegg eller skog. D. sapinea er trolig bare i etableringsfasen i Norge, og har til dags dato gjort liten skade på våre stedegne bartrær.....
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The scope of this study was to provide an update on fluoride (F) emission effects on vegetation around three aluminium smelters. We visited Årdal and Sunndal smelters in 2019-2020 and Mosjøen in 2020, assessed and documented the visual symptoms of F-damage on vegetation and related these to detected values of F in plant tissue. Three plant species showed qualities as useful indicators: Rowan, pine and St. John’s wort. Because male-fern accumulated extreme F-values and showed clear grazing damage, the monitoring of this species may be warranted because of the potential health hazard for the grazing animals. In Årdal and Sunndal, during 2019 and 2020, we detected the highest F-values in male-fern, ranging from 94 to 925 mg F/kg. In rowan, the highest F-concentration was detected in trees growing within the Årdal smelter (1161 mg F/kg) but on all other locations the F-concentrations in rowan ranged from 4 to 327 mg F/kg. In pine, the F-concentrations ranged from 6-351 mg F/kg for all needle ages, but older needles always accumulated more F than younger ones. In St. John’s wort the accumulated F-values ranged from 10-84 mg F/kg. At all smelters there was a gradient of decreasing F-concentration in vegetation with increasing distance from the smelter. F-emissions in Årdal (12 and 11 kg F/hour in 2019 and 2020, respectively) and in Sunndal during 2019 (12 kg F/hour) were only slightly higher than the recommended limits (10 kg F/hour) for damage on vegetation, while in Mosjøen the F-emissions were 7 kg F/hour in 2020. The presence of F-damage on vegetation was consistent with the reported emission-levels. On basis of this evaluation, reductions in emissions are still advisable in Årdal and Sunndal, while the situation is acceptable in Mosjøen.
Forfattere
Martin S. Mullett Rein Drenkhan Kalev Adamson Piotr Boroń Anna Lenart-Boroń Irene Barnes Michal Tomšovský Zuzana Jánošíková Katarína Adamčíková Emília Ondrušková Valentin Queloz Barbara Piskur Dmitry L. Musolin Kateryna Davydenko Margarita Georgieva Sophie Schmitz Audrius Kačergius Luisa Ghelardini Jelena Kranjec Orlović Michael Müller Funda Oskay Tine Hauptman Ágnes Halász Svetlana Markovskaja Halvor Solheim Martti Vuorinen Renate Heinzelmann Richard C. Hamelin Adam KonečnýSammendrag
Dothistroma septosporum, the primary causal agent of Dothistroma needle blight, is one of the most significant foliar pathogens of pine worldwide. Its wide host and environmental ranges have led to its global success as a pathogen and severe economic damage to pine forests in many regions. This comprehensive global population study elucidated the historical migration pathways of the pathogen to reveal the Eurasian origin of the fungus. When over 3800 isolates were examined, three major population clusters were revealed: North America, Western Europe, and Eastern Europe, with distinct subclusters in the highly diverse Eastern European cluster. Modeling of historical scenarios using approximate Bayesian computation revealed the North American cluster was derived from an ancestral population in Eurasia. The Northeastern European subcluster was shown to be ancestral to all other European clusters and subclusters. The Turkish subcluster diverged first, followed by the Central European subcluster, then the Western European cluster, which has subsequently spread to much of the Southern Hemisphere. All clusters and subclusters contained both mating-types of the fungus, indicating the potential for sexual reproduction, although asexual reproduction remained the primary mode of reproduction. The study strongly suggests the native range of D. septosporum to be in Eastern Europe (i.e., the Baltic and Western Russia) and Western Asia.
Forfattere
Hanno Sandvik Olga Hilmo Snorre Henriksen Reidar Elven Per Arvid Åsen Hanne Hegre Oddvar Pedersen Per Anker Pedersen Heidi Solstad Vigdis Vandvik Kristine Bakke Westergaard Frode Ødegaard Sandra Charlotte Helene Åström Hallvard Elven Anders Endrestøl Øivind Gammelmo Bjørn Arild Hatteland Halvor Solheim Björn Nordén Leif Sundheim Venche Talgø Tone Falkenhaug Bjørn Gulliksen Anders Jelmert Eivind Oug Jan Henry Sundet Elisabet Forsgren Anders Gravbrøt Finstad Trygve H. Hesthagen Kjell Harald Nedreaas Rupert Wienerroither Vivian Husa Stein Fredriksen Kjersti Sjøtun Henning Steen Haakon Hansen Inger Sofie Hamnes Egil Karlsbakk Christer Magnusson Bjørnar Ytrehus Hans Christian Pedersen Jon Swenson Per Ole Syvertsen Bård Gunnar Stokke Jan Ove Gjershaug Dag Dolmen Gaute Kjærstad Stein Ivar Johnsen Thomas Correll Jensen Kristian Hassel Lisbeth GederaasSammendrag
1. Due to globalisation, trade and transport, the spread of alien species is increasing dramatically. Some alien species become ecologically harmful by threatening native biota. This can lead to irreversible changes in local biodiversity and ecosystem functioning, and, ultimately, to biotic homogenisation. 2. We risk-assessed all alien plants, animals, fungi and algae, within certain delimitations, that are known to reproduce in Norway. Mainland Norway and the Arctic archipelago of Svalbard plus Jan Mayen were treated as separate assessment areas. Assessments followed the Generic Ecological Impact Assessment of Alien Species (GEIAA) protocol, which uses a fully quantitative set of criteria. 3. A total of 1519 species were risk-assessed, of which 1183 were species reproducing in mainland Norway. Among these, 9% were assessed to have a severe impact, 7% high impact, 7% potentially high impact, and 49% low impact, whereas 29% had no known impact. In Svalbard, 16 alien species were reproducing, one of which with a severe impact. 4. The impact assessments also covered 319 so-called door-knockers, i.e. species that are likely to establish in Norway within 50 years, and 12 regionally alien species. Of the door-knockers, 8% and 10% were assessed to have a severe and high impact, respectively. 5. The impact category of most species was driven by negative interactions with native species, transformation of threatened ecosystems, or genetic contamination. The proportion of alien species with high or severe impact varied significantly across the different pathways of introduction, taxonomic groups, time of introduction, and the environments colonised, but not across continents of origin. 6. Given the large number of alien species reproducing in Norway and the preponderance of species with low impact, it is neither realistic nor necessary to eradicate all of them. Our results can guide management authorities in two ways. First, the use of quantitative assessment criteria facilitates the prioritisation of management resources across species. Second, the background information collected for each species, such as introduction pathways, area of occupancy and ecosystems affected, helps designing appropriate management measures.
Forfattere
Hanno Sandvik Olga Hilmo Snorre Henriksen Reidar Elven Per Arvid Åsen Hanne Hegre Oddvar Pedersen Per Anker Pedersen Heidi Solstad Vigdis Vandvik Kristine Bakke Westergaard Frode Ødegaard Sandra Charlotte Helene Åström Hallvard Elven Anders Endrestøl Øivind Gammelmo Bjørn Arild Hatteland Halvor Solheim Björn Nordén Leif Sundheim Venche Talgø Tone Falkenhaug Bjørn Gulliksen Anders Jelmert Eivind Oug Jan Henry Sundet Elisabet Forsgren Anders Gravbrøt Finstad Trygve H. Hesthagen Kjell Harald Nedreaas Rupert Wienerroither Vivian Husa Stein Fredriksen Kjersti Sjøtun Henning Steen Haakon Hansen Inger Sofie Hamnes Egil Karlsbakk Christer Magnusson Bjørnar Ytrehus Hans Christian Pedersen Jon Swenson Per Ole Syvertsen Bård Gunnar Stokke Jan Ove Gjershaug Dag Dolmen Gaute Kjærstad Stein Ivar Johnsen Thomas Correll Jensen Kristian Hassel Lisbeth GederaasSammendrag
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Forfattere
Melissa Magerøy Erik Christiansen Bo Långström Anna-Karin Borg-Karlson Halvor Solheim Niklas Björklund Tao Zhao Axel Schmidt Carl Gunnar Fossdal Paal KrokeneSammendrag
Plants can form an immunological memory known as defense priming, whereby exposure to a priming stimulus enables quicker or stronger response to subsequent attack by pests and pathogens. Such priming of inducible defenses provides increased protection and reduces allocation costs of defense. Defense priming has been widely studied for short‐lived model plants such as Arabidopsis, but little is known about this phenomenon in long‐lived plants like spruce. We compared the effects of pretreatment with sublethal fungal inoculations or application of the phytohormone methyl jasmonate (MeJA) on the resistance of 48‐year‐old Norway spruce (Picea abies) trees to mass attack by a tree‐killing bark beetle beginning 35 days later. Bark beetles heavily infested and killed untreated trees but largely avoided fungus‐inoculated trees and MeJA‐treated trees. Quantification of defensive terpenes at the time of bark beetle attack showed fungal inoculation induced 91‐fold higher terpene concentrations compared with untreated trees, whereas application of MeJA did not significantly increase terpenes. These results indicate that resistance in fungus‐inoculated trees is a result of direct induction of defenses, whereas resistance in MeJA‐treated trees is due to defense priming. This work extends our knowledge of defense priming from model plants to an ecologically important tree species.
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During surveys of insect-associated mycobiomes in Norway, Poland, and Russia, isolates with affinity to Graphilbum (Ophiostomatales, Ascomycota) were recovered. In this study, eight known Graphilbum species as well as the newly collected isolates were compared based on morphology and DNA sequence data for four gene regions. The results revealed seven new species, described here as G. acuminatum, G. carpaticum, G. curvidentis, G. furuicola, G. gorcense, G. interstitiale, and G. sexdentatum. In addition to these species, G. crescericum and G. sparsum were commonly found in Norway. All new species were recovered from conifers in association with bark beetles, cerambycid beetles, and weevils and were morphologically similar, predominantly with pesotum-like asexual morphs. Where sexual morphs were present, these were small ascomata with short necks and rodshaped ascospores having hyaline sheaths. The results suggest that Graphilbum species are common members of the Ophiostomatales in conifer ecosystems.
Forfattere
Volkmar Timmermann Kjell Andreassen Andreas Myki Beachell Isabella Børja May Bente Brurberg Nicholas Clarke Rune Halvorsen Gro Hylen Jane Uhd Jepsen Juliana Perminow Sverre Solberg Halvor Solheim Venche Talgø Mari Mette Tollefsrud Ole Petter Laksforsmo Vindstad Bjørn Økland Tonje Ingeborg Økland Wenche AasSammendrag
Skogens helsetilstand påvirkes i stor grad av klima og værforhold, enten direkte ved tørke, frost og vind, eller indirekte ved at klimaet påvirker omfanget av soppsykdommer og insektangrep. Klimaendringene og den forventede økningen i klimarelaterte skogskader gir store utfordringer for forvaltningen av framtidas skogressurser. Det samme gjør invaderende skadegjørere, både allerede etablerte arter og nye som kan komme til Norge i nær framtid. I denne rapporten presenteres resultater fra skogskadeovervåkingen i Norge i 2019 og trender over tid.....
Forfattere
Ahto Agan Rein Drenkhan Kalev Adamson Leho Tedersoo Halvor Solheim Isabella Børja Iryna Matsiakh Volkmar Timmermann Nina Elisabeth Nagy Ari HietalaSammendrag
European ash (Fraxinus excelsior) is threatened by the invasive ascomycete Hymenoscyphus fraxineus originating from Asia. Ash leaf tissues serve as a route for shoot infection but also as a sporulation substrate for this pathogen. Knowledge of the leaf niche partitioning by indigenous fungi and H. fraxineus is needed to understand the fungal community receptiveness to the invasion. We subjected DNA extracted from unwashed and washed leaflets of healthy and diseased European ash to PacBio sequencing of the fungal ITS1-5.8S-ITS2 rDNA region. Leaflets from co-inhabiting rowan trees (Sorbus aucuparia) served as a reference. The overlap in leaflet mycobiomes between ash and rowan was remarkably high, but unlike in rowan, in ash leaflets the sequence read proportion, and the qPCR-based DNA amount estimates of H. fraxineus increased vigorously towards autumn, concomitant with a significant decline in overall fungal richness. The niche of ash and rowan leaves was dominated by epiphytic propagules (Vishniacozyma yeasts, the dimorphic fungus Aureobasidion pullulans and the dematiaceous hyphomycete Cladosporium ramotenellum and H. fraxineus), and endophytic thalli of biotrophs (Phyllactinia and Taphrina species), the indigenous necrotroph Venturia fraxini and H. fraxineus. Mycobiome comparison between healthy and symptomatic European ash leaflets revealed no significant differences in relative abundance of H. fraxineus, but A. pullulans was more prevalent in symptomatic trees. The impacts of host specificity, spatiotemporal niche partitioning, species carbon utilization profiles and life cycle traits are discussed to understand the ecological success of H. fraxineus in Europe. Further, the inherent limitations of different experimental approaches in the profiling of foliicolous fungi are addressed.
Forfattere
Beata Strzałka Robert Jankowiak Piotr Bilański Nikita Patel Georg Hausner Riikka Linnakoski Halvor SolheimSammendrag
Bark beetles belonging to the genus Dryocoetes (Coleoptera, Curculionidae, Scolytinae) are known vectors of fungi, such as the pathogenic species Grosmannia dryocoetidis involved in alpine fir (Abies lasiocarpa) mortality. Associations between hardwood-infesting Dryocoetes species and fungi in Europe have received very little research attention. Ectosymbiotic fungi residing in Ceratocystiopsis and Leptographium (Ophiostomatales, Sordariomycetes, Ascomycota) were commonly detected in previous surveys of the Dryocoetes alni-associated mycobiome in Poland. The aim of this study was to accurately identify these isolates and to provide descriptions of the new species. The identification was conducted based on morphology and DNA sequence data for six loci (ITS1-5.8S, ITS2-28S, ACT, CAL, TUB2, and TEF1-α). This revealed two new species, described here as Ceratocystiopsis synnemata sp. nov. and Leptographium alneum sp. nov. The host trees for the new species included Alnus incana and Populus tremula. Ceratocystiopsis synnemata can be distinguished from its closely related species, C. pallidobrunnea, based on conidia morphology and conidiophores that aggregate in loosely arranged synnemata. Leptographium alneum is closely related to Grosmannia crassivaginata and differs from this species in having a larger ascomatal neck, and the presence of larger club-shaped cells.
Forfattere
Hanno Sandvik Dag Dolmen Reidar Elven Tone Falkenhaug Elisabet Forsgren Haakon Hansen Kristian Hassel Vivian Husa Gaute Kjærstad Frode Ødegaard Hans Christian Pedersen Halvor Solheim Bård Gunnar Stokke Per Arvid Åsen Sandra Åström Tor Erik Brandrud Hallvard Elven Anders Endrestøl Anders Gravbrøt Finstad Stein Fredriksen Øivind Gammelmo Jan Ove Gjershaug Bjørn Gulliksen Inger Hamnes Bjørn Arild Hatteland Hanne Hegre Trygve Hesthagen Anders Jelmert Thomas C Jensen Stein Ivar Johnsen Egil Karlsbakk Christer Magnusson Kjell Nedreaas Björn Nordén Eivind Oug Oddvar Pedersen Per Anker Pedersen Kjersti Sjøtun Jon Kristian Skei Heidi Solstad Leif Sundheim Jon E Swenson Per Ole Syvertsen Venche Talgø Vigdis Vandvik Kristine B Westergaard Rupert Wienerroither Bjørnar Ytrehus Olga Hilmo Snorre Henriksen Lisbeth GederaasSammendrag
We present the results of an inventory and status assessment of alien species in Norway. The inventory covered all known multicellular neobiota, 2496 in total, 1039 of which were classified as naturalised. The latter constitute c. 3% of all species known to be stably reproducing in Norway. These figures are higher than expected from Norway’s latitude, which may be due a combination of climatic and historical factors, as well as sampling effort. Most of the naturalised neobiota were plants (71%),followed by animals (21%) and fungi (8%). The main habitat types colonised were open lowlands (79%), urban environments (52%) and woodlands (42%). The main areas of origin were Europe (67%), North America (15%) and Asia (13%). For most taxa, the rate of novel introductions seems to have been increasing during recent decades. Within Norway, the number of alien species recorded per county was negatively correlated with latitude and positively correlated with human population density. In the high-Arctic territories under Norwegian sovereignty, i.e. Svalbard and Jan Mayen, 104 alien species were recorded, of which 5 were naturalised.
Forfattere
R. Ioos P. Chrétien J. Perrault C. Jeandel C. Dutech P. Gonthier F. Sillo Ari Hietala Halvor Solheim J. HubertSammendrag
Four species of the destructive forest pathogen Heterobasidion annosum sensu lato (s.l.) are present in Europe: H. annosum sensu stricto (s.s.), H. abietinum and H. parviporum are native species, while H. irregulare is a non‐native invasive species currently reported only in Italy, yet recommended for regulation throughout Europe. In this study, real‐time PCR detection tests were developed for each of the four species, which can be used simultaneously or individually thanks to probes labelled with species‐specific fluorescent dyes. The different performance criteria of each assay were evaluated, and it was determined that they were theoretically capable of detecting amounts of DNA corresponding to 311, 29 and 29 cell nuclei in H. annosum s.s., H. irregulare and H. parviporum, respectively. The specificity of each assay was assessed with a wide set of strains. Real‐time PCR tests successfully detected Heterobasidion species from 36 fruiting bodies taken from the forest, as well as from artificially inoculated or naturally infected wood samples. The multiplex real‐time PCR assays developed in this study could have practical applications both in forest management and in phytosanitary monitoring.
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Hvert år importeres det store mengder av tømmer og treprodukter til Norge fra ulike land og verdensdeler. Uten tilstrekkelig årvåkenhet kan import av noen trevarer resultere i at det innføres fremmede arter av insekter, sopp, nematoder eller planter med svært uheldige virkninger i norske skoger. Import av tømmer og treprodukter kan dessuten i noen tilfeller medføre at Norge bidrar til handel med tømmer og treprodukter basert på tropiske treslag og hogst som på annen måte er ulovlig, og som kan bidra negativt for bærekraftig skogforvaltning og økonomi, fattigdomsreduksjon, beskyttelse av biomangfold og skogdekning for å redusere CO2-utslipp. Norge er del av tømmerforordningen som skal bidra til at import fra slik hogst ikke skal skje. I denne rapporten benytter vi tollstatistikk for å vurdere omfanget og variasjonen i import av tømmer og andre treprodukter som er relevant både for import av fremmede arter og for tømmerforordningen.
Forfattere
Volkmar Timmermann Kjell Andreassen May Bente Brurberg Isabella Børja Nicholas Clarke Daniel Flø Jane Uhd Jepsen Torstein Kvamme Jørn-Frode Nordbakken Per Holm Nygaard Martin Pettersson Sverre Solberg Halvor Solheim Venche Talgø Ole Petter Laksforsmo Vindstad Gro Wollebæk Bjørn Økland Wenche AasSammendrag
Skogens helsetilstand påvirkes i stor grad av klima og værforhold, enten direkte ved tørke, frost og vind, eller indirekte ved at klimaet påvirker omfanget av soppsykdommer og insektangrep. Klimaendringene og den forventede økningen i klimarelaterte skogskader gir store utfordringer for forvaltningen av framtidas skogressurser. Det samme gjør invaderende skadegjørere, både allerede etablerte arter og nye som kan komme til Norge i nær framtid. I denne rapporten presenteres resultater fra skogskadeovervåkingen i Norge i 2018 og trender over tid for følgende temaer: (i) Landsrepresentativ skogovervåking; (ii) Skogøkologiske analyser og målinger av luftkjemi på de intensive overvåkingsflatene; (iii) Overvåking av bjørkemålere i Troms og Finnmark; (iv) Granbarkbilleovervåking – utvikling av barkbillepopulasjonene i 2018; (v) Ny barkbille på vei – vil den like klimaet?; (vi) Phytophthora i importert jord på prydplanter og faren det utgjør for skog; (vii) Overvåking av askeskuddsyke; (viii) Skog- og utmarksbranner i 2018; (ix) Andre spesielle skogskader i 2018...….
Sammendrag
I Europa er det registrert økende omfang av skogskader de siste hundre år, og klimaendringer er identifisert som en viktig driver bak økningene i for eksempel vindskader, barkbilleangrep og skogbranner. Det er likevel store regionale forskjeller i Europa, med en tendens til økt vekst og produktivitet i nordlige og høyereliggende skogområder, og mer tørkestress og mortalitet i sør. Ikke are endringer i klima, men også endringer i skogskjøtsel og skogstruktur påvirker forekomsten av skader i skog...
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Det er ikke registrert sammendrag
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Forfattere
Leif Sundheim Christer Magnusson Arild Sletten Per Hans Micael Wendell Guro Brodal Åshild Ergon Halvor Solheim Anne Marte Tronsmo Trond RafossSammendrag
Det er ikke registrert sammendrag
Forfattere
Ari Hietala Isabella Børja Hugh B. Cross Nina Elisabeth Nagy Jørn Henrik Sønstebø Volkmar Timmermann Adam Vivian-Smith Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Sammendrag
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Forfattere
Ari Hietala Isabella Børja Hugh Cross Nina Elisabeth Nagy Halvor Solheim Volkmar Timmermann Adam Vivian-SmithSammendrag
European ash (Fraxinus excelsior), a keystone species with wide distribution and habitat range in Europe, is threatened at a continental scale by an invasive alien ascomycete, Hymenoscyphus fraxineus. In its native range of Asia, this fungus is a leaf endophyte with weak parasitic capacity and robust saprobic competence in local ash species that are closely related to European ash. In European ash, H. fraxineus has a similar functional role as in Asia, but the fungus also aggressively kills shoots, resulting in crown dieback and tree death. H. fraxineus is a typical invasive species, as its spread relies on high propagule pressure. While crown dieback of European ash is the most obvious symptom of ash dieback, the annual colonization of ash leaves is a crucial key dependency for the invasiveness of H. fraxineus, since its fruiting bodies are formed on overwintered leaf vein tissues in soil debris. Leaves of European ash host a wide range of indigenous epiphytes, endophytes, facultative parasites and biotrophic fungi, including Hymenoscyphus albidus, a relative of H. fraxineus that competes for the same sporulation niche as the invader. At face value, leaves of European ash are colonized by a large and diverse indigenous mycobiome. In order to understand why this invader became successful in Europe, we discuss and summarize the current knowledge of diversity, seasonal dynamics and traits of H. fraxineus and indigenous fungi associated with leaves of European ash.
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Ophiostoma spp. (Ophiostomatales, Ascomycota) are well-known fungi associated with bark and ambrosia beetles (Curculionidae: Scolytinae, Platypodinae). Fungi in the Ophiostomatales include serious tree pathogens as well as agents of timber blue-stain. Although these fungi have been extensively studied in the northern hemisphere, very little is known regarding their occurrence on hardwoods in Europe. The aims of the present study were to identify and characterize new Ophiostoma spp. associated with bark and ambrosia beetles infesting hardwoods in Norway and Poland, and to resolve phylogenetic relationships of Ophiostoma spp. related to the Norwegian and Polish isolates, using multigene phylogenetic analyses. Results obtained from five gene regions (ITS, LSU, b-tubulin, calmodulin, translation elongation factor 1-a) revealed four new Ophiostoma spp. These include Ophiostoma hylesinum sp. nov., O. signatum sp. nov., and O. villosum sp. nov. that phylogenetically are positioned within the Ophiostoma ulmi complex. The other new species, Ophiostoma pseudokarelicum sp. nov. reside along with Ophiostoma karelicum in a discrete, well-supported phylogenetic group in Ophiostoma s. stricto. The results of this study clearly show that the diversity and ecology of Ophiostoma spp. on hardwoods in Europe is poorly understood and that further studies are required to enrich our knowledge about these fungi.
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Kapping og beskjæring av tretopper langs kraftlinjer med sag fra helikopter reduserer risikoen for trefall på kraftlinja og kan være et kostnadseffektivt tiltak med få ulemper for skogeier. Topping eller kvisting med helikopter gir mindre sjanse for vindfall, toppbrekk og snøbøy, dels ved at trærne får mindre vindfang og mindre snølast, og dels ved at vektarmen som kraften virker på blir kortere.
Forfattere
Isabella Børja Kjell Andreassen Jan Čermák Lise Dalsgaard Arthur Gessler Douglas Lawrence Godbold Rainer Hentschel Zachary E. Kayler Paal Krokene Nadezhda Nadezhdina Sabine Rosner Halvor Solheim Jan Svetlik Mari Mette Tollefsrud Ole Einar TveitoSammendrag
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Forfattere
Louise Eriksson Johanna Boberg Thomas L. Cech Tamara Corcobado Marie-Laure Desprez-Loustau Ari Hietala Marilia Horta Jung Thomas Jung Hatice Tugba Dogmus Lehtijarvi Funda Oskay Slavtcho Slavov Halvor Solheim Jan Stenlid Jonas OlivaSammendrag
Political action can reduce introductions of diseases caused by invasive forest pathogens (IPs) and public support is important for effective prevention. The public’s awareness of IP problems and the acceptability of policies aiming to combat these pathogens were surveyed in nine European countries (N = 3469). Although awareness of specific diseases (e.g., ash dieback) varied, problem awareness and policy acceptability were similar across countries. The public was positive towards policies for informational measures and stricter standards for plant production, but less positive towards restricting public access to protected areas. Multilevel models, including individual and country level variables, revealed that media exposure was positively associated with awareness of IP problems, and strengthened the link between problem awareness and policy acceptability. Results suggest that learning about IPs through the media and recognizing the associated problems increase policy acceptability. Overall, the study elaborates on the anthropogenic dimension of diseases caused by IPs.
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Skogen blir en viktig ressurs i vår fremtidige fornybare bioøkonomi. Forskning og ny kunnskap om hvordan vi reduserer skader forårsaket av rotråte er da viktig.
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Dieback of European ash, caused by the ascomycete Hymenoscyphus fraxineus originating from Asia, has rapidly spread across Europe, and is threatening this keystone tree at a continental scale. High propagule pressure is characteristic to invasive species. Consistently, the enormous production of windborne ascospores by H. fraxineus in an ash forest with epidemic level of disease obviously facilitates its invasiveness and long distance spread. To understand the rate of build-up of propagule pressure by this pathogen following its local introduction, during 2011–2017 we monitored its sporulation at a newly infested ash stand in south-western Norway characterized with mild winters and cool summers. We also monitored the propagule pressure by Hymenoscyphus albidus, a non-pathogenic native species that competes for the same sporulation niche with H. fraxineus. During the monitoring period, crown condition of ash trees had impaired, and 20% of the dominant trees were severely damaged in 2017. H. fraxineus showed an exponential increase in spore production between 2012 and 2015, followed by drastic decline in 2016 and 2017. During 2011–2013, the two Hymenoscyphus species showed similar sporulation level, but thereafter spores of H. albidus were no longer detected. The data suggest that following local introduction, the population of H. fraxineus reaches rapidly an exponential growth stage if the local weather conditions are favorable for ascomata maturation across years. In the North Atlantic climate, summer temperatures critically influence the pathogen infection pressure, warm summers allowing the population to grow according to its biotic potential, whereas cold summers can cause a drastic decline in propagule pressure.
Forfattere
Volkmar Timmermann Kjell Andreassen May Bente Brurberg Nicholas Clarke Maria Herrero Jane Uhd Jepsen Halvor Solheim Gunn Strømeng Venche Talgø Ole Petter Laksforsmo Vindstad Gro Wollebæk Bjørn Økland Wenche AasSammendrag
Skogens helsetilstand påvirkes i stor grad av klima og værforhold, enten direkte ved tørke, frost og vind, eller indirekte ved at klimaet påvirker omfanget av soppsykdommer og insektangrep. Klimaendringene og den forventede økningen i klimarelaterte skogskader gir store utfordringer for forvaltningen av framtidas skogressurser. Det samme gjør invaderende skadegjørere, både allerede etablerte arter og nye som kan komme til Norge i nær framtid. Denne rapporten presenterer resultater fra skogskadeovervåkingen i Norge i 2017 og trender over tid for følgende temaer...
Forfattere
Mark McMullan Maryam Rafiqi Gemy Kaithakottil Bernardo J. Clavijo Lorelei Bilham Elizabeth Orton Lawrence Percival-Alwyn Ben J. Ward Anne Edwards Diane G.O. Saunders Gonzalo Garcia Accinelli Jonathan Wright Walter Verweij Georgios Koutsovoulos Kentaro Yoshida Tsuyoshi Hosoya Louisa Williamson Philip Jennings Renaud Ioos Claude Husson Ari Hietala Adam Vivian-Smith Halvor Solheim Dan MaClean Christine Fosker Neil Hall James K.M. Brown David Swarbreck Mark Blaxter J. Allan Downie Matthew D. ClarkSammendrag
Accelerating international trade and climate change make pathogen spread an increasing concern. Hymenoscyphus fraxineus, the causal agent of ash dieback, is a fungal pathogen that has been moving across continents and hosts from Asian to European ash. Most European common ash trees (Fraxinus excelsior) are highly susceptible to H.fraxineus, although a minority (~5%) have partial resistance to dieback. Here, we assemble and annotate a H.fraxineus draft genome, which approaches chromosome scale. Pathogen genetic diversity across Europe and in Japan, reveals a strong bottleneck in Europe, though a signal of adaptive diversity remains in key host interaction genes. We find that the European population was founded by two divergent haploid individuals. Divergence between these haplotypes represents the ancestral polymorphism within a large source population. Subsequent introduction from this source would greatly increase adaptive potential of the pathogen. Thus, further introgression of H.fraxineus into Europe represents a potential threat and Europe-wide biological security measures are needed to manage this disease.
Forfattere
Robert Jankowiak Agnieszka Ostafińska Truls Aas Halvor Solheim Piotr Bilański Riikka Linnakoski Georg HausnerSammendrag
Species of Leptographium are characterized by mononematous or synnematous conidiophores and are commonly associated with different arthropods. Some of them also produce a sexual state characterised by globose ascomata with elongated necks. Compared to investigations on coniferous trees, the occurrence of Leptographium species on hardwood trees has been poorly studied in Europe. During a survey of ophiostomatoid fungi on various hardwood tree species in Norway and Poland, three unusual species, which fit in the broader morphological description of Leptographium spp., were found in association with Trypodendron domesticum, Trypodendron signatum and Dryocoetes alni, and from wounds on a variety of hardwoods. Phylogenetic analyses of sequence data for six different loci (ITS1–5.8 S–ITS2, ITS2-LSU, ACT, b-tubulin, CAL, and TEF-1a) showed that these Leptographium species are phylogenetically closely related to the species of the Grosmannia olivacea complex. The first species forms a well-supported lineage that includes Ophiostoma brevicolle, while the two other new taxa resided in a separate lineage; possibly affiliated with Grosmannia francke-grosmanniae. All the new species produce perithecia with necks terminating in ostiolar hyphae and orange-section shaped ascospores with cucullate, gelatinous sheaths. These species also produce dark olivaceous mononematous asexual states in culture. In addition, two of the newly described species have a second type of conidiophore with a short and non-pigmented stipe. The new Leptographium species can be easily distinguished from each other by their appearance and growth in culture. Based on novel morphological characters and distinct DNA sequences, these fungi were recognised as new taxa for which the names Leptographium tardum sp. nov., Leptographium vulnerum sp. nov., and Leptographium flavum sp. nov. are provided.
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Forfattere
Isabella Børja Volkmar Timmermann Ari Hietala Mari Mette Tollefsrud Nina Elisabeth Nagy Adam Vivian-Smith Hugh Cross Jørn Henrik Sønstebø Tor Myking Halvor SolheimSammendrag
In Norway the common ash (Fraxinus excelsior L.) has its northernmost distribution in Europe. It grows along the coastal range as small fragmented populations. The first occurrence of ash dieback caused by Hymenoscyphus fraxineus in Norway was reported in 2008. At that time, the disease had already spread through large areas of southern and south-eastern parts of Norway. Since then the disease continued spreading with a speed of about 50- 60 km per year along the western coastal range. To monitor the disease development over time, we established eight permanent monitoring plots in south-eastern and western Norway in 2009 and 2012, respectively. In all plots tree mortality was high, especially among the youngest trees in south-eastern Norway. The extent of crown damage has continually increased in all diameter classes for both regions. In 2009, 76.8 % of all trees on the five monitoring plots in south-eastern Norway were considered to be healthy or slightly damaged, and only 8.9 % to be severely damaged. In 2015, 51.7 % were dead, 13.5 % severely damaged and only 25.7 % remained healthy or slightly damaged. To assess the infection pressure and spore dispersal patterns of the pathogen, we used a Burkard volumetric spore sampler placed in an infested ash stand in southern Norway. We examined the airborne ascospores of H. fraxineus and H. albidus captured on the sampling tape microscopically and with real-time PCR assays specific to these fungi. We detected very few ascospores of H. albidus, whereas ascospores of H. fraxineus dominated throughout entire sampling periods of 2009, 2010 and 2011. Spore discharge occurred mainly between the hours of 5 and 8 a.m., though the distinctive sporulation had yearly variation between 5-7 a.m. We observed the same diurnal pattern throughout the entire sampling period, with a seasonal peak in spore liberation between mid-July and midAugust, after which the number of ascospores decreased substantially. Similar diurnal patterns were observed throughout the sampling period except that after mid-August the number of trapped ascospores substantially decreased. To compare the genetic pattern of common ash in the northern and central ranges of Europe we analyzed the Norwegian samples together with available samples from central Europe by using chloroplast and nuclear microsatellite markers. We found that the northern range of common ash was colonized via a single migration route that originated in eastern or south-eastern Europe with little influence originating from other southern or western European refugia. In the northern range margins, genetic diversity decreased and population differentiation increased, coherent with a post-glacial colonization history characterized by founder events and population fluctuations. Based on our findings we discuss the future management and conservational implications.
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Askeskuddsjuke forårsakes av en liten sopp, Hymenoscyphus fraxineus, på norsk kalt askeskuddbeger. Sjukdommen har i løpet av kort tid spredd seg over store deler av Europas askeskoger. Soppen er en fremmed art som trolig stammer fra Asia hvor den er assosiert med asketrær som er nær beslektet med europeisk ask. Det er særlig unge trær som er utsatt, men også eldre trær kan drepes over tid. Mye er uklart angående hvordan soppen infiserer, men sporene spres med vind til bladene på asketrær. Dersom soppen klarer å vokse forbi bladfestet før bladfall vil den i løpet av vinteren angripe greinene. Typiske symptomer er sår i barken og døde skudd.
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Sammendrag
Dieback of European ash (Fraxinus excelsior L.), a disease caused by the ascomycete Hymenoscyphus fraxineus (previously referred to as H. pseudoalbidus or Chalara fraxinea), was first observed in Poland in the early 1990ies, and is currently present almost throughout the entire distribution area of European ash. The characteristic symptoms of the disease include dead shoots with necrotic lesions in the bark and discoloration of xylem and pith but the seasonal dynamics of pathogen spread in shoot tissues remain poorly understood. To investigate whether the internal spread of the fungus involves season-specific patterns, saplings with necrotic bark lesions in 1-2 -year-old stem regions were collected during 2014-2015 at time intervals in spring, summer, autumn and winter at several localities in western Ukraine and at two localities in south-eastern Norway. Tissuespecific presence of H. fraxineus was determined by a highly sensitive quantitative real-time PCR assay that is specific to DNA of H. fraxineus. The relatively high proportion of bark samples positive for H. fraxineus in the saplings collected during spring provides support to a model that H. fraxineus can be a primary causative agent of bark lesions and that other fungi may eventually replace it in old infection areas.
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Ask er et av våre vanligste edellauvtrær og et viktig levested for mange arter. Ask er mye brukt som prydtre og har vært vanlig både som tuntre og i alleer. Gamle styvede asketrær representerer mange steder viktige kulturminner. Treslaget representerer derfor både en viktig natur- og kulturarv. Dessverre er ask hardt rammet av askeskuddsjuken, nesten overalt hvor asken vokser ser vi utbrudd. Dødeligheten er høg, og ask er oppført som sårbar på Norsk rødliste for arter. Denne veilederen gir deg informasjon om i) hvordan du kan kjenne igjen askeskuddsjuken, ii) viktigheten av å bevare friske trær, iii) hvordan du kan minske spredningen av askeskuddsjuken og iv) viktigheten av å bevare ask som art i edellauvskogen.
Forfattere
Isabella Børja Kjell Andreassen Jan Čermák Lise Dalsgaard Arthur Gessler Douglas L. Godbold Rainer Hentschel Zachary E. Kayler Paal Krokene Nadezhda Nadezhdina Sabine Rosner Svein Solberg Halvor Solheim Jan Svetlik Mari Mette Tollefsrud Ole Einar TveitoSammendrag
Det er ikke registrert sammendrag
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Forfattere
Ned B. Klopfenstein Jane E. Stewart Yuko Ota John W. Hanna Bryce A. Richardson Amy L. Ross-Davis Rubén D. Elías-Román Kari Korhonen Nenad Djuro Keča Eugenia Iturritxa, Dionicio Alvarado-Rosales Halvor Solheim Nicholas J. Brazee Piotr Łakomy Michelle R. Cleary Eri Hasegawa Taisei Kikuchi Fortunato Garza-Ocañas Panaghiotis Tsopelas Daniel Rigling Simone Prospero, Tetyana Tsykun Jean A. Bérubé Franck O.P. Stefani Saeideh Jafarpour Vladimír Antonín Michal Tomšovský Geral I. McDonald Stephen Woodward Mee-Sook KimSammendrag
Armillaria possesses several intriguing characteristics that have inspired wide interest in understanding phylogenetic relationships within and among species of this genus. Nuclear ribosomal DNA sequence– based analyses of Armillaria provide only limited information for phylogenetic studies among widely divergent taxa. More recent studies have shown that translation elongation factor 1-α (tef1) sequences are highly informative for phylogenetic analysis of Armillaria species within diverse global regions. This study used Neighbor-net and coalescence-based Bayesian analyses to examine phylogenetic relationships of newly determined and existing tef1 sequences derived from diverse Armillaria species from across the Northern Hemisphere, with Southern Hemisphere Armillaria species included for reference. Based on the Bayesian analysis of tef1 sequences, Armillaria species from the Northern Hemisphere are generally contained within the following four superclades, which are named according to the specific epithet of the most frequently cited species within the superclade: (i) Socialis/Tabescens (exannulate) superclade including Eurasian A. ectypa, North American A. socialis (A. tabescens), and Eurasian A. socialis (A. tabescens) clades; (ii) Mellea superclade including undescribed annulate North American Armillaria sp. (Mexico) and four separate clades of A. mellea (Europe and Iran, eastern Asia, and two groups from North America); (iii) Gallica superclade including Armillaria Nag E (Japan), multiple clades of A. gallica (Asia and Europe), A. calvescens (eastern North America), A. cepistipes (North America), A. altimontana (western USA), A. nabsnona (North America and Japan), and at least two A. gallica clades (North America); and (iv) Solidipes/Ostoyae superclade including two A. solidipes/ostoyae clades (North America), A. gemina (eastern USA), A. solidipes/ostoyae (Eurasia), A. cepistipes (Europe and Japan), A. sinapina (North America and Japan), and A. borealis (Eurasia) clade 2. Of note is that A. borealis (Eurasia) clade 1 appears basal to the Solidipes/Ostoyae and Gallica superclades. The Neighbor-net analysis showed similar phylogenetic relationships. This study further demonstrates the utility of tef1 for global phylogenetic studies of Armillaria species and provides critical insights into multiple taxonomic issues that warrant further study.
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The goal of this study was to assess the long-term effects of partial harvesting and supplementary soil scarification on the frequency of root and butt rot in managed uneven-sized Norway spruce stands. Frequency of rot and the population structure of the rot fungi were assessed on 1353 stumps after clear-cutting 21 years after a selection harvesting experiment. The initial experiment was comprised of three harvest strength (low, intermediate and high) of single-tree selection, removing approximately 25, 45 and 65% of the stand basal area. Uncut control plots were established at the same time. Supplementary soil scarification was applied in subplots within the single-tree selection plots, using a medium-sized excavator. After clear-cutting the stumps were analyzed with respect to rot caused by Heterobasidion parviporum, Armillaria spp., Stereum sanguinolentum as well as other rot fungi. Rot caused by Armillaria spp. was most common (8.6% of the stumps), while infection by H. parviporum (2.9%) or S. sanguinolentum (3.0%) was less frequent. The group “other rot” (5.4%) comprised 21 identified taxa, each occurring in 1–15 stumps. Significantly lower rot frequencies were found for the uncut control (16.3%) and intermediate harvest strength (15.7%), compared with low harvest strength (23.6%). A rot frequency of 21.0% was found in the high harvest strength. In two of three harvest strengths, the rot frequency was higher than for the uncut control. As the observed rot frequencies did not increase consistently with increasing harvest strength, the results do not completely support the initial expectations of increased rot after single-tree selection compared with the uncut control. However, since the probability of rot in individual stumps on plots treated with single-tree selection was significantly affected by the distance to the nearest strip road (H. parviporum) as well as dependent on the size of and distance to the nearest stump of trees cut during the experimental harvest (H. parviporum, S. sanguinolentum and total rot), it is evident that the single-tree selection harvesting was partially responsible for some of the observed rot. One of the selection criteria in the initial harvest was a sanitary removal of trees of poor vitality. Varying degrees of sanitation felling may therefore have offset the effects of new infections in wounds or spread of rot fungi through adjacent stumps. Supplementary soil scarification in small gaps of the residual stand had no significant effect on the frequency of rot, suggesting that such treatment may be used to facilitate regeneration in uneven-sized spruce stands on similar sites.
Forfattere
Kalev Adamson Martin S. Mullett Halvor Solheim Irene Barnes Michael M. Müller Jarkko Hantula Martti Vuorinen Audrius Kačergius Svetlana Markovskaja Dmitry L. Musolin Kateryna Davydenko Nenad Keča Karli Ligi Rasa D. Priedite Hanna Millberg Rein DrenkhanSammendrag
Dothistroma septosporum, a notorious pine needle pathogen with an unknown historical geographic origin and poorly known distribution pathways, is nowadays found almost in all areas inhabited by pines (Pinus spp.). The main aim of this study was to determine the relationship between North European and East Asian populations. In total, 238 Eurasian D. septosporum isolates from 11 countries, including 211 isolates from northern Europe, 16 isolates from Russian Far East and 11 isolates from Bhutan were analysed using 11 species-specific microsatellite and mating type markers. The most diverse populations were found in northern Europe, including the Baltic countries, Finland and European Russia. Notably, D. septosporum has not caused heavy damage to P. sylvestris in northern Europe, which may suggest a long co-existence of the host and the pathogen. No indication was obtained that the Russian Far East or Bhutan could be the indigenous area of D. septosporum, as the genetic diversity of the fungus there was low and evidence suggests gene flow from northern Europe to Russian Far East. On the western coast of Norway, a unique genetic pattern was observed, which differed from haplotypes dominating other Fennoscandian populations. As an agent of dothistroma needle blight, only D. septosporum was documented in northern Europe and Asia, while D. pini was found in Ukraine and Serbia.
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Halvor SolheimSammendrag
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Halvor SolheimSammendrag
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Kalev Adamson Rein Drenkhan Martin Mullett Halvor Solheim Irene Barnes Michael Müller Jarkko HantulaSammendrag
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Ash dieback, caused by the ascomycete Hymenoscyphus fraxineus, has been spreading throughout Europe since the early 1990s, threatening European ash at a continental scale. Little is known about the development of the disease in individual forest trees and in different age classes. In this study we monitored ash dieback on trees of different diameter classes in five permanent plots in ash stands in south-eastern Norway from 2009 to 2016, and from 2012 to 2016 in three plots in western Norway with a shorter disease history. Our results showed that more than 80% of the youngest and more than 40% of the intermediate future crop trees in the plots in south-eastern Norway were dead by 2016, while the disease development in large, dominant trees was slower. Although less damage has been observed in the plots in western Norway, the trend for the juvenile trees is the same as in south-eastern Norway with rapidly increasing damage and mortality. Most dead trees in south-eastern Norway were found at sites with high soil moisture and showed symptoms of root-rot caused by Armillaria species. Infected trees, both young and old ones, are weakened by the disease and appear to be more susceptible to other, secondary pathogens, especially under unfavourable site conditions.
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Leif Sundheim Daniel Flø Micael Wendell Guro Brodal Åshild Ergon Christer Magnusson Arild Sletten Halvor Solheim Anne Marte Tronsmo Bjørn Økland Trond RafossSammendrag
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Gunnhild Søgaard Rasmus Astrup Micky Allen Kjell Andreassen Even Bergseng Inger Sundheim Fløistad Aksel Granhus Kjersti Holt Hanssen Ari Hietala Harald Kvaalen Svein Solberg Halvor Solheim Arne Steffenrem Jogeir N. Stokland Bjørn ØklandSammendrag
Fokus i denne rapporten er på skogbehandlingen, og på maksimering av verdiproduksjon. En forutsetning for dette er høy sagtømmerproduksjon, samtidig som det er viktig å vurdere arealets totale tømmerverdi. Følgende forutsetninger ligger til grunn for rapporten: Bevaring av biologisk mangfold og ivaretakelse av andre flerbrukshensyn Det legges til grunn at all skogbehandling utføres i henhold til dagens lovverk og frivillige sertifiseringsordninger, og at dette ivaretar hensyn til biologisk mangfold og andre flerbrukshensyn. Vi går derfor ikke inn på betydningen ulik skogbehandling vil ha for biologisk mangfold eller andre flerbrukshensyn, eller tilpasninger av skogbehandlingen for dette. Bærekraftig skogbruk i klimasammenheng Miljødirektoratet mfl. (2016) drøfter vern eller bruk av skog som klimatiltak. I rapporten konkluderes det med at det ikke er grunnlag for å vektlegge vern av norsk skog som klimatiltak. En forutsetning er at det drives et bærekraftig skogbruk i klimasammenheng. Dette ble definert som følger: «Bærekraftig skogbruk i klimasammenheng innebærer at skogens produktivitet og evne til å lagre karbon ikke forringes, og at karbonbeholdninger ikke reduseres permanent.» (Miljødirektoratet mfl. 2016). Vi forutsetter gjennom rapporten at skogbehandling drives bærekraftig i tråd med denne definisjonen, uten at vi går nærmere inn på betydningen og eventuelle nødvendige tilpasninger. Skogbehandling for å motvirke klimaendringer Skogbehandling som motvirker klimaendringer, for eksempel ved å øke karbonopptaket, vil i mange tilfeller være i samsvar med skogbehandling for maksimal verdiproduksjon, men ikke alltid. Vi har i denne rapporten kun fokusert på verdiproduksjon, og betydning av skogbehandling på ulike karbonbeholdninger er ikke vurdert. Driftstekniske forhold («hvordan ta ut tømmeret») Driftskostnader vil være av stor betydning for skogeiers økonomiske resultat, og både de endringer vi allerede ser og forventede klimaendringer er forventet å gi større driftstekniske utfordringer. I denne rapporten ser vi imidlertid utelukkende på den betydning skogbehandlingen vil ha for antatt verdiproduksjon.
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Den årlige skogovervåkingen viser at granas kronetilstand har bedret seg betraktelig på Vestlandet og i Midt-Norge etter de omfattende frosttørkeskadene der i 2013 og 2014. Furu hadde generelt lite skader. Det var mer skader på bjørk i 2016 enn i 2015, og både måler- og bjørkerustangrep økte i frekvens, men også abiotiske faktorer hadde stor betydning for bjørkas helsetilstand. Skadeomfanget var størst i Nord-Norge, der særlig gjentatte målerangrep over mange år utgjør et problem for bjørkeskogen. Askeskuddsjuke har i løpet av drøyt 10 år spredt seg gradvis gjennom mesteparten av askas utbredelsesområde i Norge. Overvåkingen viser at skadeutviklingen skjer fort, og særlig de yngste trærne har høy mortalitet. I Nord-Trøndelag og Oppland ble det registrert en økning i fangstverdiene av granbarkbiller i 2017, mens de øvrige fylkene opplevde en liten til moderat nedgang, mye på grunn av en kjølig og nedbørrik sommer.
Forfattere
Volkmar Timmermann Kjell Andreassen Nicholas Clarke Daniel Flø Christer Magnusson Jørn-Frode Nordbakken Ingvald Røsberg Halvor Solheim Karl Thunes Gro Wollebæk Bjørn Økland Wenche AasSammendrag
Skogens helsetilstand påvirkes i stor grad av klima og værforhold, enten direkte ved tørke, frost og vind, eller indirekte ved at klimaet påvirker omfanget av soppsykdommer og insektangrep. Klimaendringene og den forventede økningen i klimarelaterte skogskader gir store utfordringer for forvaltningen av framtidas skogressurser. Det samme gjør invaderende skadegjørere, både allerede etablerte arter og nye som kan komme til Norge som følge av økt handel og import. Eksempler på begge er omtalt i denne rapporten som presenterer resultater fra skogskadeovervåkingen i Norge i 2016........
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Ash dieback, caused by the ascomycete Hymenoscyphus fraxineus, was first observed in the eastern and southernmost Norway in 2008. Based on the age of stem bark lesions, it was concluded that the fungus had arrived to the region no later than 2006. Since 2008 the annual spread of the disease northwards along the west coast of Norway has been monitored. The registration was done each year during early summer around a disease frontier recorded in the previous year. The occurrence of necrotic bark lesions in the previous-year shoots and dieback of these shoots, and isolation of H. fraxineus from the discoloured wood associated with necrotic bark lesions were used as signs of ash dieback. These records indicate an annual spread of ash dieback in the range between 25 km and 78 km, and a mean annual spread of 51 km. The cause of the spread is discussed.
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Askeskuddsjuke har spredd seg med rekordfart i Europa og i Norge. Ask (Fraxinus excelsior) er meget sensitiv for denne nye sjukdommen. De aller fleste områder i Europa med dette treslaget er nå infisert med sekksporesoppen askeskuddbeger (Hymenoscyphus fraxineus) som forårsaker sjukdommen. I Norge ble askeskuddsjuke første gang registrert i 2008 og allerede da ble den funnet over store deler av Østlandet og Sørlandet. Deretter har askeskuddsjuke spredd seg nordover på Vestlandet i gjennomsnitt 51 km per år. I 2016 ble det nordligste funnet registrert i Aure kommune nær grensa til Trøndelag.
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Forfattere
Robert Jankowiak Beata Strzałka Piotr Bilański Riikka Linnakoski Truls Aas Halvor Solheim Małgorzata Groszek Z. Wilhelm de BeerSammendrag
Species of Leptographium are generally characterized by mononematous conidiophores and are commonly associated with bark beetles and weevils. These species are responsible for sapstain and in some cases serious diseases on a range of primarily coniferous trees. In comparison with coniferous trees, the occurrence of Leptographium species on hardwood trees has been poorly studied in Europe. During a survey of ophiostomatoid fungi on various tree species in Norway and Poland, three unusual species, which fit the broader morphological description of Leptographium spp., were found in association with Scolytus ratzeburgi, Dryocoetes alni and Trypodendron domesticum on a variety of hardwoods, and from wounds on Tilia cordata. Phylogenetic analyses of sequence data for three gene regions (ITS2-LSU, β-tubulin, and TEF1-α) showed that these Leptographium species are phylogenetically closely related to each other and form a well-supported lineage that included Grosmannia grandifoliae and Leptographium pruni. The first species could be distinguished from the other Leptographium species based on conidiophores arising from spiral hyphae, chlamydospore-like structures and a hyalorhinocladiella-like synanamorph in culture. The second species differs from the previous one by having distinctly shorter conidiophores and smaller conidia. This species also produces a well-developed sporothrix-like synanamorph with denticulate conidiogenous cells. Based on these unusual morphological characteristics and distinct DNA sequences, these fungi were recognised as new taxa for which the names Leptographium trypodendri sp. nov. and L. betulae sp. nov. are provided. The third group of isolates belonged to Grosmannia grandifoliae, representing the first report of this species outside of the USA. The newly defined G. grandifoliae complex is the first species complex in Leptographium s.l. consisting of only hardwood-infecting species.
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Forfattere
Leif Sundheim Åshild Ergon Christer Magnusson Jan Netland Egil Prestløkken Arild Sletten May Sæthre Elin Thingnæs Lid Tron Øystein Gifstad Micael Wendell Guro Brodal Halvor Solheim Anne Marte Tronsmo Bjørn Økland Trond RafossSammendrag
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Forfattere
Ari Hietala Hugh Cross Halvor Solheim Volkmar Timmermann Nina Elisabeth Nagy Isabella Børja Adam Vivian-Smith Jørn Henrik SønstebøSammendrag
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Forfattere
Hugh Cross Jørn Henrik Sønstebø Nina Elisabeth Nagy Volkmar Timmermann Halvor Solheim Isabella Børja Håvard Kauserud Tor Carlsen Barbara Rzepka Katarzyna Wasak Adam Vivian-Smith Ari HietalaSammendrag
High biodiversity is regarded as a barrier against biological invasions. We hypothesized that the invasion success of the pathogenic ascomycete Hymenoscyphus fraxineus threatening common ash in Europe relates to differences in dispersal and colonization success between the invader and the diverse native competitors. Ash leaf mycobiome was monitored by high-throughput sequencing of the fungal internal transcribed spacer region (ITS) and quantitative PCR profiling of H. fraxineus DNA. Initiation of ascospore production by H. fraxineus after overwintering was followed by pathogen accumulation in asymptomatic leaves. The induction of necrotic leaf lesions coincided with escalation of H. fraxineus DNA levels and changes in proportion of biotrophs, followed by an increase of ubiquitous endophytes with pathogenic potential. H. fraxineus uses high propagule pressure to establish in leaves as quiescent thalli that switch to pathogenic mode once these thalli reach a certain threshold – the massive feedback from the saprophytic phase enables this fungus to challenge host defenses and the resident competitors in mid-season when their density in host tissues is still low. Despite the general correspondence between the ITS-1 and ITS-2 datasets, marker biases were observed, which suggests that multiple barcodes provide better overall representation of mycobiomes.
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The root rot pathogens in Norway spruce (Picea abies) Heterobasidion ssp. cause substantial loss in carbon sequestered in forest and economic revenue for forest owners. To facilitate strategic breeding planning for increased resistance against this pathogen in particular, the blue stain fungus Endoconidiophora polonica, growth and wood quality traits (wood density and spiral grain), we estimated additive genetic parameters, correlations and the potential response from selection. Parameters were estimated from a progeny trial series established at two sites (25 years from planting) and their parents in a seed orchard (43 years from grafting). A standard half-sib analysis based on progenies and a parent–offspring regression was used for estimation of heritabilities. Resistance against the pathogens was measured as lesion length under bark after inoculations in phloem. Heritability values varied with site and estimation procedure from 0.06 to 0.33, whereas the phenotypic variance (as CV P ) is high and fairly stable around 40–50 %. Heritability values for wood density and spiral grain in the same material varied from 0.32 to 0.63. The highest heritability values were generally obtained from parent–offspring regression. There is no evidence of resistance traits being genetically correlated with growth or wood quality traits. Wood density is negatively correlated with stem diameter. Implications for breeding are discussed.
Forfattere
Rein Drenkhan V Tomesova-Haataja S Fraser RE Bradshaw P Vahalik MS Mullett J Martin-Garcia LS Bulman MJ Wingfield T Kirisits TL Cech S Schmitz R Baden K Tubby A Brown M Georgieva A Woods R Ahumada L Jankovsky IM Thomsen K Adamson B Marcais M Vuorinen P Tsopelas A Koltay A Halasz N La Porta N Anselmi R Kiesnere S Markovskaja A Kacergius I Papazova-Anakieva M Risteski K Sotirovski J Lazarevic Halvor Solheim P Boron H Braganca D Chira DL Musolin AV Selikhovkin TS Bulgakov N Keca D Karadzic V Galovic P Pap M Markovic L. Poljakovic Pajnik V Vasic E Ondruskova B Piskur D Sadikovic JJ Diez A Solla H Millberg J Stenlid A Angst V Queloz A Lehtijärvi HT Dogmus-Lehtijärvi F Oskay K Davydenko V Meshkova D Craig S Woodward Irene BarnesSammendrag
Dothistroma needle blight (DNB) is one of the most important diseases of pine. Although its notoriety stems from Southern Hemisphere epidemics in Pinus radiata plantations, the disease has increased in prevalence and severity in areas of the Northern Hemisphere, including Europe, during the last two decades. This increase has largely been attributed to expanded planting of susceptible hosts, anthropogenic dispersal of the causative pathogens and changes in climate conducive to disease development. The last comprehensive review of DNB was published in 2004, with updates on geographic distribution and host species in 2009. Importantly, the recognition that two species, Dothistroma septosporum and D. pini, cause DNB emerged only relatively recently in 2004. These two species are morphologically very similar, and DNA-based techniques are needed to distinguish between them. Consequently, many records of host species affected or geographic location of DNB prior to 2004 are inconclusive or even misleading. The objectives of this review were (i) to provide a new database in which detailed records of DNB from 62 countries are collated; (ii) to chart the current global distribution of D. septosporum and D. pini; (iii) to list all known host species and to consider their susceptibility globally; (iv) to collate the published results of provenance trials; and (v) to consider the effects of site factors on disease incidence and severity. The review shows that DNB occurs in 76 countries, with D. septosporum confirmed to occur in 44 and D. pini in 13. There are now 109 documented Pinaceae host taxa for Dothistroma species, spanning six genera (Abies, Cedrus, Larix, Picea, Pinus and Pseudotsuga), with Pinus being the dominant host genus, accounting for 95 host taxa. The relative susceptibilities of these hosts to Dothistroma species are reported, providing a resource to inform species choice in forest planting. Country records show that most DNB outbreaks in Europe occur on Pinus nigra and its subspecies. It is anticipated that the collaborative work described in this review will both underpin a broader global research strategy to manage DNB in the future and provide a model for the study of other forest pathogens.
Forfattere
R. Drenkhan Halvor Solheim A. Bogacheva T. Riit K. Adamson T. Drenkhan T. Maaten Ari HietalaSammendrag
Dieback of European ash was first observed in Europe in the early 1990s. The disease is caused by the invasive ascomycete Hymenoscyphus fraxineus, proposed to originate from Far East Asia, where it has been considered a harmless saprotroph. This study investigates the occurrence of H. fraxineus in tissues of local ash species in the Russian Far East, and assesses its population-specific genetic variation by ITS sequencing. Shoot dieback symptoms, characteristic of H. fraxineus infection on European ash, were common, but not abundant, on Fraxinus mandshurica and Fraxinus rhynchophylla trees in Far East Russia. High levels of pathogen DNA were associated with necrotic leaf tissues of these ash species, indicating that the local H. fraxineus population is pathogenic to their leaves. However, the low levels of H. fraxineus DNA detected in shoots with symptoms, the failure to isolate this fungus from such tissues, and the presence of other fungi with pathogenic potential in shoots with symptoms indicate that local H. fraxineus strains may not be responsible (or their role is negligible) for the observed ash shoot dieback symptoms in the region. Conspicuous differences in ITS rDNA sequences detected between H. fraxineus isolates from Russian Far East and European populations suggest that the current ash dieback epidemic in Europe might not directly originate from the Russian Far East. Revision of the herbarium material shows that the earliest specimen of H. fraxineus was collected in 1962 from the Russian Far East and the oldest H. fraxineus specimen of China was collected in 2004.
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Halvor SolheimSammendrag
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Foredrag – Monitoring of ash dieback on permanent plots in Norway
Volkmar Timmermann, Halvor Solheim
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Råte påfører norske skogeiere og skogbruket årlige tap estimert til rundt 100 mill. NOK (Solheim og Stamnes, upubl.). Basert på den siste nasjonale råteundersøkelsen i granskog (Huse m.fl. 1994), var det mest råte i granas naturlige utbredelsesområde (Aust-Agder, Østlandet og Midt-Norge opp til Saltfjellet), hvor i gjennomsnitt nesten hvert fjerde tre var råteinfisert ved slutthogst. I enkelte granbestand kan råtefrekvensen ved slutthogst komme opp mot 60- 70 %. I skogreisingsstrøk (Vest-Agder, Vestlandet og Nord-Norge nord for Saltfjellet) var bare opptil hvert tiende hogstmodent grantre råteinfisert. I 2014 ble det utført en liten spørreundersøkelse for å kartlegge hvor bevisste de forskjellige aktørene i skogbruket er på råteproblemet, om de mener problemet har endret seg de senere årene og i hvilken grad det brukes forebyggende kontrolltiltak mot råte.
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Halvor SolheimSammendrag
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Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Volkmar Timmermann Kjell Andreassen Nicholas Clarke Daniel Flø Jørn-Frode Nordbakken Ingvald Røsberg Halvor Solheim Gro Wollebæk Bjørn Økland Wenche AasSammendrag
Skogens helsetilstand påvirkes i stor grad av klima og værforhold, enten direkte ved tørke, frost og vind, eller indirekte ved at klimaet påvirker omfanget av soppsykdommer og insektangrep. Klimaendringene og den forventede økningen i klimarelaterte skogskader gir store utfordringer for forvaltningen av framtidas skogressurser. Det samme gjør invaderende skadegjørere, både allerede etablerte arter og nye som kan komme til Norge i framtida. Eksempler på begge er omtalt i foreliggende rapport. I denne rapporten presenteres resultater fra skogskadeovervåkingen i Norge i 2015: (i) Overvåking av skogens helsetilstand på de landsrepresentative flatene. (ii) Skogøkologiske analyser og målinger av luftkjemi på de intensive overvåkingsflatene. (iii) Barkbilleovervåking og analyse av klimaeffekter. (iv) Import skadegjørere og analyse av invasjonspotensialet til fremmede billearter. (v) Overvåking av askeskuddsyke. (vi) Andre skaderegistreringer fra Skogskader.no og befaringer i 2015. Skogovervåkingen på de landsrepresentative flater viser at gran- og furuskogens generelle helsetilstand var god i 2015, selv om det ble registrert uvanlig mange skader på gran og kronetettheten hos furu hadde sunket i forhold til året før. Siden 2007 har kronetettheten likevel økt hos begge treslagene mens trenden har vært motsatt i ICP Forests’ nettverk. Det var lite misfarging på gran og furu og få skader på furu i 2015, mens bjørk, som tidligere, hadde flest skader av alle undersøkte treslag. Det ble ellers registrert få spesielle skader på skog i 2015. Konsentrasjon og atmosfærisk avsetning av både svovel og nitrogen var generelt veldig lave i 2015. Konsentrasjonen av uorganiske nitrogenforbindelser i jordvann og nivået av bakkenært ozon var også lave i Norge i 2015. Ozonnivåene er i stor grad styrt av værforholdene og vil derfor kunne oppvise store årlige variasjoner. Kjemiske analyser på de intensive skogovervåkings-flatene i Norge har dokumentert en betydelig reduksjon over tid i nivåer av svovelkomponenter både i luft, nedbør og jordvann som følge av store utslippsreduksjoner i Europa. Overvåkingsflata på Sørlandet, som er mest utsatt for langtransporterte forurensinger, hadde som i tidligere år de høyeste nitrogen- og svovelverdier i barnålene i 2015. Verdiene hadde økt i forhold til 2013 og var på det høyeste nivået siden hhv. 1995 og 1999, til tross for at både tilførselen og deposisjonen av disse elementene har avtatt sterkt siden 1990. På de to andre flatene var nitrogenverdiene vesentlig lavere, og i Osen var det dessuten for lite nitrogen i forhold til de andre næringsstoffene. Nitrogenmangel er imidlertid normalt i boreale barskoger. Vegetasjonsanalyser på den intensive skogovervåkingsflata i Hurdal viser at dekningen av etasjehusmose og to vmoser har økt siden 1999, mens flere andr mosearter har gått tilbake. Økt vekst av store bladmoser som etasjehusmose er også dokumentert av andre norske studier og har blitt forklart som et resultat av at mange milde og nedbørrike høster har gjort vekstsesongen lengre. Resultatene fra granbarkbilleovervåkingen i 2015 viste en moderat økning av populasjonene for landet sett under ett. Analyser av tidsserier for klimaeffekter og utviklingen i granbarkbillebestanden indikerer en trend mot økende barkbillemengder i Trøndelag og Nordland, som har mye hogstmoden gran. Denne økningen er mest markert i tørre og varme år. Tidligere modellberegninger har predikert at den forventete temperaturøkningen kan føre til at granbarkbillen får to generasjoner per sommer i stedet for én så langt nord som Trøndelag, noe som kan gi en markert økning i antall angrep på stående trær...
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Forfattere
Riikka Linnakoski Robert Jankowiak Caterina Villari Thomas Kirisits Halvor Solheim Z. Wilhelm de Beer Michael J. WingfieldSammendrag
Two species of blue-stain fungi with similar morphologies, Ophiostoma brunneo-ciliatum and Ophiostoma clavatum, are associates of bark beetles infesting Pinus spp. in Europe. This has raised questions whether they represent distinct taxa. Absence of herbarium specimens and contaminated or mistakenly identified cultures of O. brunneo-ciliatum and O. clavatum have accentuated the uncertainty regarding their correct identification. The aim of this study was to reconsider the identity of European isolates reported as O. brunneo-ciliatum and O. clavatum by applying DNA-based identification methods, and to provide appropriate type specimens for them. Phylogenetic analyses of the ITS, βT, TEF-1α and CAL gene sequences revealed that the investigated isolates represent a complex of seven cryptic species. The study confirmed that ITS data is insufficient to delineate species in some Ophiostoma species clusters. Lectotypes and epitypes were designated for O. clavatum and O. brunneo-ciliatum, and three new species, Ophiostoma brunneolum, Ophiostoma macroclavatum and Ophiostoma pseudocatenulatum, are described in the newly defined O. clavatum-complex. The other two species included in the complex are Ophiostoma ainoae and Ophiostoma tapionis. The results suggest co-evolution of these fungi in association with specific bark beetles. The results also confirm the identity of the fungus associated with the pine bark beetle Ips acuminatus as O. clavatum, while O. brunneo-ciliatum appears to be mainly associated with another pine bark beetle, Ips sexdentatus.
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Forfattere
Halvor SolheimSammendrag
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Sammendrag
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Sammendrag
Globally, billions of tons of carbon sequestered in trees are annually recycled back to the atmosphere through wood decomposition by microbes. In Norway, every fifth Norway spruce shows at final harvest infection by pathogenic white-rot fungi in the genera Heterobasidion and Armillaria. As these fungi can mineralize all components of wood, we predicted that they have a significant carbon footprint. Gas samples taken from infected stems were analyzed for CO2 and CH4 concentrations, and wood samples from different parts of the decay columns were incubated under hypoxic (4% O2) and anoxic laboratory conditions. In spring and summer the stem concentrations of CO2 were generally two times higher in trees with heartwood decay than in healthy trees. For most of the healthy trees and trees with heartwood decay, mean stem concentrations of CH4 were comparable to ambient air, and only some Armillaria infected trees showed moderately elevated CH4. Consistently, low CH4 production potentials were recorded in the laboratory experiment. Up-scaling of CO2 efflux due to wood decay in living trees suggests that the balance between carbon sequestration and emission may be substantially influenced in stands with high frequency of advanced root and stem heartwood decay.
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Forfattere
Halvor SolheimSammendrag
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Forfattere
Ari Hietala Isabella Børja Hugh Cross Volkmar Timmermann Nina Elisabeth Nagy Halvor Solheim Jørn Henrik Sønstebø adam vivian smithSammendrag
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Forfattere
Ari Hietala Isabella Børja Hugh Cross Nina Elisabeth Nagy Halvor Solheim Jørn Henrik Sønstebø Volkmar Timmermann Adam Vivian-SmithSammendrag
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Ari Hietala Hugh Cross Isabella Børja Nina Elisabeth Nagy Volkmar Timmermann Halvor Solheim Jørn Henrik Sønstebø Adam Vivian-SmithSammendrag
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Ten saplings of European ash (Fraxinus excelsior L.) naturally infected by the invasive ash dieback pathogen Hymenoscyphus fraxineus were collected in Ukraine and Norway and examined for bark necrosis and extension of discoloration in sapwood and pith in a stem region. Tissue-specific colonization profiles were determined by spatial analyses of symptomatic and visually healthy stem tissues using a H. fraxineus-specific qPCR assay and light microscopy. Our data suggest that hyphal growth in the starch-rich perimedullary pith is of particular importance for both axial and radial spread of H. fraxineus, but that most of its biomass accumulates in sapwood parenchyma. The study confirms the results from earlier work and presents new information that refines the current stem invasion model.
Forfattere
Jonas Oliva S. Rommel Carl Gunnar Fossdal Ari Hietala M. Nemesio-Gorriz Halvor Solheim Malin ElfstrandSammendrag
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Halvor SolheimSammendrag
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Halvor Solheim Isabella Børja Hugh Cross Ari Hietala Tor Myking Nina Elisabeth Nagy Jørn Henrik Sønstebø Volkmar Timmermann Mari Mette TollefsrudSammendrag
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Halvor SolheimSammendrag
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Leif Sundheim Trond Hofsvang Christer Magnusson Gunnar Sundstøl Eriksen Lars Olav Brandsæter Guro Brodal Siv Fagertun Remberg Anne Kjersti Uhlen Åshild Kristine Andreassen Augustine Arukwe Aksel Bernhoft Knut Egil Bøe Margaretha Haugen Gro Ingunn Hemre Åshild Krogdahl Torsten Källqvist Jørgen Fredrik Lassen Bjørn Næss Trond Rafoss Janneche Utne Skåre Arild Sletten Halvor Solheim Inger-Lise Steffensen Ole Torrissen Anne Marte Tronsmo Bjørn Økland Jan AlexanderSammendrag
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Sammendrag
Fortellingen om høstens farger kan få selv realfagsinker til å se skjønnheten i de kjemiske og biologiske prosessene. Hør bare: Grønt klorofyll, gule karotenoider og røde antocyaniner er alle fargestoffer som hjelper plantene å fange sollyset.
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Foredrag – Experiences of ash dieback in Norway
Ari Hietala, Volkmar Timmermann, Isabella Børja, ...
Sammendrag
Ari M. Hietala, Volkmar Timmermann, Isabella Børja & Halvor Solheim Norwegian Forest and Landscape Institute. PO Box 115, 1431 Ås, Norway: ari.hietala@skogoglandskap.no Owing to the Gulf Stream, the northernmost European populations of several tree species are found in Norway. Common ash (Fraxinus excelsior), the only native ash species in Norway, is present in the lowlands in the southeastern part with continental climate and in southern and southwestern coastal regions with North Atlantic climate up to Central Norway. The current standing volume of ash in Norway is ca 3 mill m3 (broadleaved trees in total 220 mill m3). The first documentation of Ash Dieback (ADB) is from 2008 from a nursery in the southeastern part of the country. A survey later that year showed that dieback symptoms were present over a distance of nearly 400 km in the southeastern region. In addition to nurseries and forests, ADB symptoms were observed on roadside, alley, garden and park trees. Based on the presence of old ADB-like stem lesions detected in 2008, the pathogen must have arrived to Norway no later than 2006. In 2008, the Norwegian Food Safety Authority laid down regulations with the aim of preventing further spread of ADB. These regulations divide the country into quarantine, observation and infection-free zones, and prohibit the export of ash seedlings, seed and wood from the quarantine zone. Despite of these regulations, the disease spread rapidly along the western coast in the period between 2009 and 2013, and currently only the ash stands in Central Norway are free of the disease. The rapid spread of the disease in Norway is obviously due to airborne dispersal of pathogen ascospores. In our experimental stand in SE Norway the number of pathogen fruit bodies can be as high as 10,000 per m2 in the peak season, mid-July to mid-August. During the early morning hours the amount of pathogen ascospores at a diseased stand can exceed 100,000 ascospores per m3 air. The first symptoms of the disease, necrotic lesions on leaf blade and petiole, appear typically during the first two weeks of August in SE Norway. To observe long-term impacts of ADB, eight monitoring plots have been established in continental and North Atlantic climate zones. In SE Norway with the oldest disease history, above 60 % of the trees with a breast height diameter (BHD) below 12.5 cm have so far died or suffer from severe defoliation, 1/3 of the larger trees being affected to a similar degree. The proportions of healthy (no signs of defoliation) small and larger trees are 20% and 37%, respectively. In SW Norway with more recent disease history a similar trend is observed but the proportion of dead trees is still small. As a consequence of ADB, the Norwegian nurseries no longer grow ash seedlings. There are currently no practical control options for the disease in forestland. Several European countries have reported that even at heavily diseased ash stands there are often some ash trees that show little symptoms. This may be due to genetic variation between trees in disease resistance, a hypothesis that is currently being investigated in several European projects. Thus implementation of forest management practices that eliminate ash could have a negative effect as survival of the tree ultimately depends on selection of trees with increased disease resistance. Bibliography for Ari M. Hietala Ari M. Hietala is a Senior Forest Pathologist at the Norwegian Forest and Landscape Institute, which is a primarily government funded organisation providing scientific research and services to government, non-governmental and commercial organisations. He has worked with a range of fungal root and shoot diseases occurring on broadleaved trees and conifers indigenous to the Nordic countries. Ari and the rest of the group participate currently in several European consortia engaged in ash dieback research.
Forfattere
Daniel Flø Halvor Solheim Christer Magnusson Trond Rafoss Leif Sundheim Juliana Irina Spies PerminowSammendrag
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Forfattere
Halvor SolheimSammendrag
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Svein Solberg Knut Bjørkelo Arnt Kristian Gjertsen Johannes May Marek Pierzchala Volkmar Timmermann Halvor SolheimSammendrag
Satellittdata har et potensial til å bidra til å dekke viktige kartleggings- og overvåkingsoppgaver i skog, særlig for deteksjon av skogskader og hogst. Formålet med prosjektet er å utvikle og demonstrere metoder for en operativ overvåkingstjeneste for stormskader og hogst. I tillegg skal det undersøkes om det er mulig å detektere og overvåke askeskuddsyke, som vil være særlig vanskelig. En test av mulighetene for dette er gjort på utvalgte tilfeller av hogst og stormskader i Norge, i tillegg til et område skadd av askeskuddsyken. Resultatene viste at • Stormskader i skog kan bare til en viss grad detekteres tilfredsstillende og innen rimelig tid (2 uker) med Landsat eller Sentinel-2. Det vil fungere i de tilfellene der o skadene er sterke, dvs tilnærmet alle trær er blåst ned, og o skadeområdet dekker et areal av en viss størrelse (minimum 10 daa), o skadene skjer utenfor mørketida om vinteren, og o det ikke er vedvarende skydekke. • Snauhogst kan detekteres tilfredsstillende med Landsat eller Sentinel-2. For dette formålet trenger man ikke en rask deteksjon, og det er uproblematisk å vente til sky- og lysforhold er tilfredsstillende. • Stormskader og hogst kan detekteres tilfredsstillende med Tandem-X, dersom man har en høydemodell fra før stormen. • Askeskuddsyke kan ikke detekteres med satellitt, fordi skadene i begynnelsen ofte er svake, de utvikler seg langsomt og de varierer mye fra tre til tre. • Automatisk prosessering av satellittbilder, og direkte overføring av resultatene over Internett for visning i Skog og landskaps Kilden krever noe systemutvikling, men er ikke problematisk dersom det er basert på åpne verktøy (Open source).
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Forfattere
Volkmar Timmermann Kjell Andreassen Nicholas Clarke Jørn-Frode Nordbakken Ingvald Røsberg Halvor Solheim Wenche AasSammendrag
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Forfattere
Leif Sundheim Daniel Flø Trond Rafoss Guro Brodal Åshild Ergon Christer Magnusson Arild Sletten Halvor Solheim May Sæthre Anne Marte Tronsmo Bjørn ØklandSammendrag
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Nina Elisabeth Nagy Katarzyna Sikora Paal Krokene Ari Hietala Halvor Solheim Carl Gunnar FossdalSammendrag
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Almesyke går på flere almearter og har nesten utradert alm fra store deler av Europa og Nord- Amerika. Til tross for at vanlig alm (Ulmus glabra) er særdeles mottakelig for almesyke, har den en begrenset utbredelse og betydning i Norge. Almesykesopp spres primært ved hjelp av almesplintborere i slekta Scolytus. I Norge har vi bare en art av almesplintborere og den er ikke så effektiv til å spre sykdommen. Klimaendringer vil trolig føre til at almesplintborere som er mer effektive til å overføre sykdommen, etablerer seg i Norge, noe som vil øke skadeomfanget betraktelig.
Sammendrag
Bjørkerust er vanlig i hele landet hvor vi har bjørk. Hvert år kan en finne angrepne bjørketrær, men enkelte år er soppangrepene store og omfattende. En fuktig forsommer i kombinasjon med en fuktig og varm ettersommer er avgjørende for store angrep. De siste 20 årene har det i varierende grad blitt observert store angrep. Om dette skyldes tilfeldige variasjoner eller klimaendringer er usikkert.
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Det er ikke registrert sammendrag
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Forfattere
Halvor SolheimSammendrag
Einertørke, forårsaket av Stigmina juniperina, ble første gang registrert i Norge i 2012. Det ble gjort funn av soppen mange steder i Sør-Norge. Om den er ny i Norge i dette århundre, eller om den har en oppblomstring grunnet klimaendringer er vanskelig å si nå, men soppen har hatt en oppblomstring både i Finland og Sverige.
Forfattere
Halvor SolheimSammendrag
I vårt langstrakte land langt mot nord er frost en viktig faktor og årsak til mye skogskader. Nå i vår er blåbærlyng brun mange steder på Østlandet, men også grana har fått frostskader. I tillegg er det en del angrep av granrustsoppen, og i granbestand kan frostskader og granrust opptre i samme bestand.
Forfattere
Halvor SolheimSammendrag
Furuas knopp- og grentørkesopp er en av furuskogens verste skadegjørere, og forårsaker år om annet store tap. Det største angrepet skjedde i 2001 hvor enorme områder i Sør-Norge og Sør-Sverige ble berørt. Milde høster og ustabile vintre kan føre til flere slike angrep.
Forfattere
Halvor SolheimSammendrag
Furuskytte har lenge vært kjent som en skadegjører i planteskoler. Lenger sør i Europa har furuskytte vært regnet som en av de viktigste skadegjørerne i furuforyngelser. De senere årene er det også registrert mye skade på furuforyngelse i de sørlige deler av Norge med et toppår i 2001. Mildvær med mye fuktighet på ettersommeren og høsten gir soppen gode betingelser for infeksjoner.
Forfattere
Igor A. Yakovlev Ari Hietala Pierre-Emmanuel Courty Taina Lundell Halvor Solheim Carl Gunnar FossdalSammendrag
The pathogenic white-rot basidiomycete Heterobasidion irregulare is able to remove lignin and hemicellulose prior to cellulose during the colonization of root and stem xylem of conifer and broadleaf trees. We identified and followed the regulation of expression of genes belonging to families encoding ligninolytic enzymes. In comparison with typical white-rot fungi, the H. irregulare genome has exclusively the short-manganese peroxidase type encoding genes (6 short-MnPs) and thereby a slight contraction in the pool of class II heme-containing peroxidases, but an expansion of the MCO laccases with 17 gene models. Furthermore, the genome shows a versatile set of other oxidoreductase genes putatively involved in lignin oxidation and conversion, including 5 glyoxal oxidases, 19 quinone-oxidoreductases and 12 aryl-alcohol oxidases. Their genetic multiplicity and gene-specific regulation patterns on cultures based on defined lignin, cellulose or Norway spruce lignocellulose substrates suggest divergent specificities and physiological roles for these enzymes. While the short-MnP encoding genes showed similar transcript levels upon fungal growth on heartwood and reaction zone (RZ), a xylem defense tissue rich in phenolic compounds unique to trees, a subset of laccases showed higher gene expression in the RZ cultures. In contrast, other oxidoreductases depending on initial MnP activity showed generally lower transcript levels on RZ than on heartwood. These data suggest that the rate of fungal oxidative conversion of xylem lignin differs between spruce RZ and heartwood. It is conceivable that in RZ part of the oxidoreductase activities of laccases are related to the detoxification of phenolic compounds involved in host-defense. Expression of the several short-MnP enzymes indicated an important role for these enzymes in effective delignification of wood by H. irregulare.
Forfattere
Halvor SolheimSammendrag
Granrustsoppen angriper unge nåler. Sterke og gjentagende angrep kan gi tilveksttap. Størst skade gjør imidlertid soppen i juletreplantasjer. Fuktige forhold i infeksjonsfasen er viktig. I de siste 20 årene har det i varierende grad vært observert sterke angrep. Om det er klimaendringer eller bare tilfeldige variasjoner som er årsaken er usikkert.
Sammendrag
Vi har flere arter av honningsopp i Norge, og to av dem, skog- og hagehonningsopp, er svært aktive ute i skogen. Begge artene forårsaker innråte i trær, men kan også opptre mer aggressivt og drepe svekkede trær nokså raskt. Honningsopp er involvert i grantørke som i de senere årene har utviklet seg til det verre, trolig i takt med klimaendringer.
Forfattere
Halvor SolheimSammendrag
l år har eineren blitt utsatt for vinterskader over store deler av landet. Mer bekymringsfullt er den økende einertørken som har pågått noen få år nå. Årsaken er en sopp, Passalora juniperina, som ble registrert for første gang i Norge i 2012. Fram til nå er denne soppen funnet mange steder i Sør-Norge. Om den er ny i Norge, eller om den nå har en oppblomstring på grunn av klimaendringer er vanskelig å si.
Forfattere
Leif Sundheim Christer Magnusson Trond Rafoss Halvor Solheim Bjørn Økland Trond Hofsvang Arild Sletten Anne Marte Tronsmo Daniel FløSammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
Mange sopper har sporer som kan spres over lange avstander og dermed være blant organismene som raskt kan etablere seg på nye steder om klimaet tillater det. Det er derfor mange sopparter blant klimavinnerne. De kan plasseres i forskjellige kategorier alt etter deres levested i dag og hvilken skade de gjør. Adoptert fra en serie om klimavinnere blant insekter i Norsk Skogbruk i 2009 med bidrag hovedsakelig fra seniorforskerne Paal Krokene og Bjørn Økland, kan den samme inndelingen også brukes på de patogene soppene.
Redaktører
Halvor SolheimSammendrag
”Klimavinnerne” var tittelen på en artikkelserie i Norsk Skogbruk i 2012 der det ble gitt eksempler på sopper som ville kunne dra nytte av et varmere og våtere klima i Norge. Artiklene fokuserte på arter som opptrer som skadegjørere i skog. Problemene som disse soppene kan gi for det profesjonelle skogbruket, for hageeiere og den alminnelige turgåer, ble belyst. Forfatterne er alle forskere ved Norsk institutt for skog og landskap og har i en årrekke arbeidet med disse problemstillingene. De er Norges ledende innenfor dette fagfeltet. Seniorforsker Halvor Solheim tok initiativet til serien, og er seriens faglige redaktør. Vi er takknemlige for at Norsk Skogbruk trykket disse artiklene, og vi er også glad for at redaksjonen tillot oss å lage dette opptrykket som vi håper at mange vil ha nytte av.
Sammendrag
Ospeflekk er en forholdsvis ukjent skadegjører som i forrige århundre bare var rapportert noen få ganger i Norge. De siste 10 årene har det imidlertid skjedd en eksplosjonsartet oppblomstring, noe som kan skyldes endringer i klima. Og soppen ser ut til å spre seg til nye områder.
Forfattere
Halvor SolheimSammendrag
Common juniper (Juniperus communis) hosts not many pests or pathogens, but recently increasing needle blight has been observed in Norway. During a survey the needle blight was recorded in many parts of southern Norway but not above 550 m a.s.l., and it has been found both in forests, pastures and gardens. Trees are affected differently; some trees seem to be unaffected, while other trees may be killed. The cause of the disease is a fungus in the family Mycosphaerellaceae hitherto not reported from Norway. In forest pathology literature it has been named Stigmina juniperina, but also Asperisporium juniperinum. However, based on results of molecular sequence analyses it is proposed here that a more appropriate name should be Passalora juniperina (Georgescu & Badea) H. Solheim comb. Nov.
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Sammendrag
Phytophthora-arter, er aggressive, sopp-lignende skadegjørere, som fremmes av fuktig og mildt klima. I Norge er flere arter oppdaget på trær i parker eller skogholt nær hager. Varslede klimaendringer, med økt temperatur og nedbør, kan skape gode vekstforhold slik at flere arter kan etablere seg også i skogområder.
Forfattere
Aksel Bernhoft Gunnar Sundstøl Eriksen Leif Sundheim Marc Berntssen Anne Lise Brantsæter Guro Brodal Christiane Kruse Fæste Ingerd Skow Hofgaard Trond Rafoss Tore Sivertsen Anne Marte Tronsmo Heidi Amlund Augustine Arukwe Marit Aursand Margaretha Haugen Gro Ingunn Hemre Trond Hofsvang Helle Katrine Knutsen Åshild Krogdahl Jørgen Fredrik Lassen Christer Magnusson Audun Helge Nerland Live Lingaas Nesse Bjørn Næss Einar Ringø Anders Ruus Janneche Utne Skåre Halvor Solheim Arild Sletten Inger-Lise Steffensen Line Charlotte Sverdrup Birger Svihus Ole Torrissen Bente Elisabeth Torstensen Cathrine Thomsen Robin Ørnsrud Bjørn Økland Olav Østerås Jan AlexanderSammendrag
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Vi har to arter av rotkjuke i Norge, gran- og fururotkjuke. Som navnet sier så har de hvert sitt treslag som hovedvert, men begge kan gå på andre treslag, også løvtrær. Soppens spesielle biologi gjør at en kan forvente økende råteproblemer grunnet klimaendringer. Mer stormaktivitet gir mer rotrykking og lettere tilgang for rotkjuke, mens mildere klima med lengre vekstsesong gjør at perioden med sikker hogst blir kortere.
Forfattere
Halvor SolheimSammendrag
I 2009 ble rødbandsoppen registrert for første gang i Norge. De første årene var angrepene forholdsvis beskjedene, men våren 2012 ble det registrert sterke angrep i enkelte bestand. Rødbandsjuke har de siste 20 årene i stadig større omfang gjort skade på mange forskjellige furuarter og blir derfor regnet som en av de store klimavinnerne.
Sammendrag
Kronetilstanden hos gran, furu og bjørk som inngår i den landsrepresentative skogovervåkingen har vært stabil i 2012, og det ble observert færre biotiske og abiotiske skader enn året før. Avsetningen av svoveldioksid og sulfat har blitt redusert siden 1980 på fastlands-Norge. Derimot er det ingen tydelig trend i avsetning av uorganisk nitrogen gjennom nedbøren de siste årene. Askeskuddsyke er stadig på frammarsj i Norge, og har i 2012 spredd seg videre nordover i Sogn og Fjordane. 2012 var et gunstig år også for mange andre soppsykdommer, som einertørke, rødbandsyke på furu og toppskader på gran....
Sammendrag
A survey to identify ophiostomatoid fungi that infect wounds on native Norwegian and Swedish broadleaved trees was undertaken during summer 2004. A fungus resembling a species of Sporendocladia was commonly isolated from the exposed cambium and inner bark of wounds. Morphological examination and comparisons of DNA sequence data for the ITS and 5.8S regions of the rRNA gene region led to its identification as Sporendocladia bactrospora. Pathogenicity trials on young Populus tremula and Betula pubescens trees showed that S. bactrospora is capable of causing lesions on these trees. There have been few previous reports of S. bactrospora, and in most cases, these have been as saprophytes on wood. In contrast, results of this study show that it is a common inhabitant of freshly made wounds on native broadleaved trees in Scandinavia, and it appears to contribute to staining of wood.
Sammendrag
Shoot dieback disease of European ash caused by the ascomycete Hymenoscyphus pseudoalbidus threatens ash on a continental scale. A spore sampler placed in a diseased ash forest in Southern Norway, coupled with microscopy and DNA-based fungal species-specific real-time PCR assays, was employed to profile diurnal and within-season variation in infection pressure by ascospores of H. pseudoalbidus and the potentially co-existing non-pathogenic Hymenoscyphusalbidus. Hymenoscyphus pseudoalbidus was found to be predominant in the stand. Massive simultaneous liberation, by active discharge of pathogen ascospores in the morning, peaked in mid-Jul. to mid-Aug. Accumulation of pathogen DNA on leaflets of current-year leaves reached a high level plateau phase before appearance of autumn coloration, suggesting that pathogen establishment in leaves is terminated before the onset of leaf senescence.
Forfattere
Arild Sletten Trond Rafoss Trond Hofsvang Christer Magnusson Halvor Solheim Anne Marte Tronsmo Bjørn Økland Leif SundheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
Almesjuke, som kan forårsakes av to forskjellige sopparter, har vært kjent i Norge fra 1963. Fra 1981, da den aggressive arten O. novo-ulmi kom til Norge, har sjukdommen utviklet seg raskt. Den er nå etablert rundt Oslofjorden fra Fredrikstad til Skien. Almesjuke har de senere årene spredd seg lite og i skogsområder dør forholdvis få trær slik at gjenvekst og tilvekst kompenserer for tapet.
Sammendrag
Winter damage caused by frost is frequently observed on common ash (Fraxinus excelsior) in Norway. In spring 2007, extensive winter damage most likely camouflaged ash dieback caused by Chalara fraxinea. In 2008, ash dieback caused by C. fraxinea had spread to large areas in the southern part of Norway. The disease was widespread in forests and nurseries, but also on roadside trees, and in gardens and parks. In 2009, the disease had spread to new areas; about 30 km into Rogaland county in southwestern Norway and also further into some valleys in southeastern Norway.
Forfattere
Halvor SolheimSammendrag
Askeskuddbeger, Hymenoscyphus pseudoalbidus, ble registret i Norge første gang i 2008. Soppen har spredd seg med rekordfart og er nå etablert i store deler av Sør-Norge hvor det fins ask. De nordligste funnene er gjort i tre kommuner nord for Sognefjorden. Soppen infiserer blad og kommer inn i grener og stamme før bladfall. Soppen dreper små trær raskt, større trær over lenger tid. Ask er nå rødlistet grunnet denne soppen.
Sammendrag
Askeskuddbeger, årsak til askeskuddsjuke, er i rask spredning. Store deler av Europas askeskoger er nå infisert og i år kom den til England. I Norge har soppen, som er av asiatisk opprinnelse, snart erobret hele Vestlandet. På Østlandet og Sørlandet er mange unge trær drept. Mange store trær har lite kronemasse, men foreløpig er få av disse drept.
Sammendrag
Askeskuddsjuke utvikler seg stadig til det verre og nå er store deler av Vestlandet også angrepet. Foreløpig har det gått verst utover de små trærne og mange er drept. De store trærne klarer seg bedre, men noen av dem har lite kronemasse igjen.
Forfattere
Alberto Santini Luisa Ghelardini Ciro De Pace Marie-Laure Desprez-Loustau Paolo Capretti Anne Chandelier Thomas Cech Danut Chira Stephanos Diamandis Talis Gaitnieks Jarkko Hantula Ottmar Holdenrieder Libor Jankovský Thomas Jung Dusan Jurc Thomas Kirisits Andrej Kunca Vaidotas Lygis Monika Malecka Benoit Marcais Sophie Schmitz Jörg Schumacher Halvor Solheim Alejandro Solla Ilona Szabò Panaghiotis Tsopelas Andrea Vannini Anna Maria Vettraino Joan Webber Stephen Woodward Jan StenlidSammendrag
A large database of invasive forest pathogens (IFPs) was developed to investigate the patterns and determinants of invasion in Europe. Detailed taxonomic and biological information on the invasive species was combined with country-specific data on land use, climate, and the time since invasion to identify the determinants of invasiveness, and to differentiate the class of environments which share territorial and climate features associated with a susceptibility to invasion. IFPs increased exponentially in the last four decades. Until 1919, IFPs already present moved across Europe. Then, new IFPs were introduced mainly from North America, and recently from Asia. Hybrid pathogens also appeared. Countries with a wider range of environments, higher human impact or international trade hosted more IFPs. Rainfall influenced the diffusion rates. Environmental conditions of the new and original ranges and systematic and ecological attributes affected invasiveness. Further spread of established IFPs is expected in countries that have experienced commercial isolation in the recent past. Densely populated countries with high environmental diversity may be the weakest links in attempts to prevent new arrivals. Tight coordination of actions against new arrivals is needed. Eradication seems impossible, and prevention seems the only reliable measure, although this will be difficult in the face of global mobility.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
The relative frequency of Therrya fuckelii and T. pini fruiting on dead branches of Scots pine was investigated in southern Norway by examining lightning-damaged and wind-fallen trees, randomly collected branches and Nordic herbarium collections of these ascomycetes representing the order Rhytismatales. Ascus, ascospore, and subhymenium characteristics were used as criteria for species identification, while a sequence analysis of ITS rDNA gene cluster was performed to compare the relatedness of the species to each other and to corresponding fungal sequences available at the NCBI GenBank Sequence Database. In a few cases, the two Therrya species co-occurred on the same branch, but in general, whether field or herbarium material, T. fuckelii was clearly more common than T. pini.Within the Nordic countries, both species occurred throughout the natural distribution area of Scots pine. The ITS rDNA sequence of T. pini strains was 91% similar to T. fuckelii strains, the differences locating both within the internal transcribed spacers ITS1 and ITS2 and the 5.8 S rDNA gene. More variation in the ITS1-5.8S-ITS2 sequence was observed among T. pini than T. fuckelii samples; genetic implications of this finding are discussed. Upon sequence analysis, we discovered that a T. pini sequence has been deposited in the NCBI GenBank under a false identity. We emphasize the importance of co-examining strains that originate from mature fruit bodies with fully developed morphologic features as reference samples.
Forfattere
Nadeem Yaqoob Igor A. Yakovlev Paal Krokene Harald Kvaalen Halvor Solheim Carl Gunnar FossdalSammendrag
We compared gene expression in Norway spruce secondary phloem (bark) and developing xylem (sapwood) in response to the necrotrophic pathogen Heterobasidion parviporum, wounding and methyl jasmonate (MeJ). The pathogen induced systemic and local up-regulation of PaPX3, PaPX2 and PaChi4 in both bark and sapwood that returned to constitutive levels as the plants recovered from the infection, whereas the local responses to MeJ were similar in both tissues but was longer lasting for PaPX3 and PaChi4. Genes involved in lignin biosynthesis (PaPAL1, PaPAL2, PaC4H3/5 and PaHCT1) were up-regulated locally in the bark in response to pathogen and wounding whereas MeJ induced a similar but stronger local response. The ethylene biosynthesis related transcripts PaACO and PaACS did not increase in response to MeJ treatment or the pathogen, however it increased both locally and systemically as a response to wounding in the sapwood. These results demonstrate that the local and systemic host responses to pathogen infection and wounding largely correspond and reveal striking similarities between the local response to a necrotroph, wounding and MeJ treatment in both bark and living wood.
Sammendrag
Ceratocystis polonica and Heterobasidion parviporum are important fungal pathogens in Norway spruce (Picea abies). Tree susceptibility to these pathogens with respect to phenology was studied using artificial fungal inoculations at six stages of bud development, and assessed by measuring phloem necroses in the stems of 2- and 8-year-old trees. Tree capacity for resistance was assessed by measuring phloem nonstructural carbohydrates at each stage. Phloem necroses were significantly larger in trees with fungal versus control inoculations and increased significantly over time. Changes in nonstructural carbohydrates occurred in the trees; a significant decline in starch and a slight but significant increase in total sugars occurred over time. These results suggest that susceptibility to fungal pathogens and carbohydrate levels in the stems of the trees were related to fine-scale changes in bud development. A trade-off may occur between allocation of starch (the major fraction of the stem carbohydrate pool) to bud development/shoot growth versus defence of the stem. Previous tests of plant defence hypotheses have focused on herbivory on plants growing under different environmental conditions, but the role of phenology and the effect of pathogens are also important to consider in understanding plant resource allocation patterns.
Forfattere
Halvor SolheimSammendrag
Eikemjøldogg ble første gang registrert i Norge i 1911 og spredte seg meget raskt. Den er nå vidt utbredt i eikeskoger og parker fra svenskegrensa til Møre og Romsdal. Den infiserer eikeblad som ved sterke angrep kan bli helt kvitkalket.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Bjørn Økland Isabella Børja Halvor Solheim Volkmar Timmermann Ari M. Hietala Paal Krokene Daniel FløSammendrag
Arter av sopp og insekter som introduseres til nye områder kan forårsake omfattende tredød og store endringer i skogøkosystemer. Introduksjoner i andre deler av verden viser tydelig hvilket skadepotensial slike arter har. Skog og landskap søker å være i forkant med forskning som kan møte utfordringen fra nye arter i norske skoger.
Forfattere
Tao Zhao Paal Krokene Niklas Björklund Nadir Erbilgin Erik Christiansen Bo Långström Halvor Solheim Anna-Karin Borg-KarlsonSammendrag
Det er ikke registrert sammendrag
Sammendrag
Import av tømmer og andre treprodukter kan bringe fremmede arter av insekter, sopp og planter som kan gi store skadeeffekter om de etableres i Norge. I verden kan det vises til flere eksempler på at import av nye arter med slike varer har ført til betydelig effekter på skogøkosystem og biomangfold og store kostnader for skogbruk og forvaltning. Det finnes knapt noe eksempel på at forsøk på å utrydde innførte insekter og sopp etter etablering har vært vellykket, selv når ressursinnsatsen har vært svært stor. Mange arter er vanskelig å oppdage før de allerede er godt etablert og under god spredning, og for noen arter med alvorlige effekter på skogøkosystemer har det ikke lykkes å finne gode metoder for rask påvisning til tross for omfattende innsats både i forskning og overvåking. Overvåking av tømmer og andre tre-produkter ved importsteder synes ikke å være et tilstrekkelig effektivt virkemiddel for å stoppe og utrydde fremmede arter. Dette skyldes at prøvene oftest blir for små i forhold til importvolumene og at eventuell påvisning skjer for sent til å kunne hindre etablering og videre spredning. Denne rapporten analyserer importstatistikk for siste 20 år fra ulike regioner og drøfter hvilke trender som gjør seg gjeldende for volumer av tømmer og treprodukter som potensielt kan føre med aktuelle arter av insekter, sopp og planter som en vil unngå å importere til Norge. [...]
Forfattere
Carl Gunnar Fossdal Nina Elisabeth Nagy Ari Hietala Harald Kvaalen Rune Slimestad Steve Woodward Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Åke Olson Andrea Aerts Fred Asiegbu Lassaad Belbahri Ourdia Bouzid Anders Broberg Björn Canback Pedro M. Coutinho Dan Cullen Kerstin Dalman Giuliana Deflorio Linda T.A. van Diepen Christophe Dunand Sébastien Duplessis Mikael Durling Paolo Gonthier Jane Grimwood Carl Gunnar Fossdal David Hansson Bernard Henrissat Ari Hietala Kajsa Himmelstrand Dirk Hoffmeister Nils Högberg Timothy Y. James Magnus Karlsson Annegret Kohler Ursula Kües Yong-Hwan Lee Yao-Cheng Lin Mårten Lind Erika Lindquist Vincent Lombard Susan Lucas Karl Lundén Emmanuelle Morin Claude Murat Jongsun Park Tommaso Raffaello Pierre Rouzé Asaf Salamov Jeremy Schmutz Halvor Solheim Jerry Ståhlberg Heriberto Vélëz Ronald P. de Vries Ad Wiebenga Steve Woodward Igor A. Yakovlev Matteo Garbelotto Francis Martin Igor V. Grigoriev Jan StenlidSammendrag
• Parasitism and saprotrophic wood decay are two fungal strategies fundamental for succession and nutrient cycling in forest ecosystems. An opportunity to assess the trade-off between these strategies is provided by the forest pathogen and wood decayer Heterobasidion annosum sensu lato. • We report the annotated genome sequence and transcript profiling, as well as the quantitative trait loci mapping, of one member of the species complex: H. irregulare. Quantitative trait loci critical for pathogenicity, and rich in transposable elements, orphan and secreted genes, were identified. • A wide range of cellulose-degrading enzymes are expressed during wood decay. By contrast, pathogenic interaction between H. irregulare and pine engages fewer carbohydrate-active enzymes, but involves an increase in pectinolytic enzymes, transcription modules for oxidative stress and secondary metabolite production. • Our results show a trade-off in terms of constrained carbohydrate decomposition and membrane transport capacity during interaction with living hosts. Our findings establish that saprotrophic wood decay and necrotrophic parasitism involve two distinct, yet overlapping, processes.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
Furuas knopp- og grentørkesopp er en av furuskogens verste skadegjørere, og forårsaker år om annet store tap. Det største angrepet skjedde i 2001, da enorme områder i Sør-Norge og Sør-Sverige ble berørt. Milde høster og ustabile vintre kan føre til flere slike angrep.
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Sammendrag
Vi har flere arter av honningsopp i Norge, og to av dem, skog- og hagehonningsopp, er svært aktive ute i skogen. Begge artene forårsaker innråte i trær, men kan også opptre mer aggressivt og drepe svekkede trær nokså raskt. Honningsopp er involvert i grantørke som i de senere årene har utviklet seg til det verre, trolig i takt med klimaendringer.
Sammendrag
Ospeflekk er en forholdsvis ukjent skadegjører som i forrige århundre bare var rapportert noen få ganger i Norge. De siste 10 årene har det imidlertid skjedd enn eksplosjonsartet oppblomstring, noe som kan skyldes endringer i klima. Og soppen ser ut til å spre seg til nye områder.
Sammendrag
Phytophthora-arter er aggressive, sopplignende skadegjørere som fremmes av fuktig og mildt klima. I Norge er flere arter oppdaget på trær i paker eller skogholt nær hager. Varslede klimaendringer med økt temperatur og nedbør kan skape gode vekstforhold slik at flere arter kan etablere seg også i skogområder.
Sammendrag
Vi har to arter av rotkjuke i Norge, gran- og fururotkjuke. Som navnet sier har de hvert sitt treslag som hovedvert, men begge kan gå på andre treslag, også løvtrær. Soppens spesielle biologi gjør at en kan forvente økede råteproblemer grunnet klimaendringer. Økt stormaktivitet gir mer rotrykking og lettere tilgang for rotkjuke, mens mildere klima med lengre vekstsesong gjør at perioden med sikker hogst blir kortere.
Forfattere
Halvor SolheimSammendrag
I 2009 ble rødbandsoppen registrert for første gang i Norge. De første par årene var angrepene forholdsvis beskjedne, men våren 2012 er det registrert sterke angrep i enkelte bestand. Rødbandsjuke har de siste 20 årene i stadig større omfang gjort skade på mange forskjellige furuarter og blir derfor regnet som en av de store klimavinnerne.
Forfattere
Halvor SolheimSammendrag
Noen har vært her i årevis, andre har nettopp ankommet, mens atter andre venter på tur.
Forfattere
Carl Gunnar Fossdal Nadeem Yaqoob Paal Krokene Harald Kvaalen Halvor Solheim Igor A. YakovlevSammendrag
Background: NB-LRR resistance proteins are involved in recognizing pathogens and other exogenous stressors in plants. Resistance proteins are the first step in induced defence responses and a better understanding of their regulation is important to understand the mechanisms of plant defence. Much of the post-transcriptional regulation in plants is controlled by microRNAs (miRNA). We examined the expression of five Norway spruce miRNA that may regulate NB-LRR related transcripts in secondary phloem (bark) of resistant Norway spruce after wounding and inoculation with the necrotrophic blue stain fungus Ceratocystis polonica. Results: The plants of this clone recovered from both the pathogen inoculations and wounding alone. We found local and systemic induction of the resistance marker genes PaChi4, PaPAL and PaPX3 indicative of an effective induced host defence response. There were minor local and systemic changes in the expression of five miRNAs and 21 NB-LRRs between healthy and treated plants. Only five putative NB-LRRs (PaLRR1, PaLRR3, PaLRR14, PaLRR15 and PaLRR16) showed significant increases greater than two-fold as a local response to C. polonica. Of all NB-LRRs only PaLRR3, the most highly differentially regulated NB-LRR, showed a significant increase also due to wounding. The five miRNAs showed indications of an initial local and systemic down-regulation at day 1, followed by a later increase up to and beyond the constitutive levels at day 6. However, the initial down-regulation was significant only for miR3693 and miR3705. Conclusions: Overall, local and systemic expression changes were evident only for the established resistance marker genes and PaLRR3. The minor expression changes observed both for the followed miRNAs and their predicted NB-LRR targets suggest that the expression of most NB-LRR genes are maintained close to their constitutive levels in stressed and healthy Norway spruce plants.
Forfattere
Halvor SolheimSammendrag
Toppskader på gran i ungskog kan gi store økonomiske tap da det kan bli gankvist eller dobbelttopper i den mest verdifulle delen av stammen. Nå har to uvanlige sopper slått til, og i de mest berørte bestandene kan opp mot to tredjedeler av trærne ha fått skader.
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
Orerust er vidt utbredt i Sør-Norge og et stykke nord i Nordland. Etter introduksjon til Europa har den spredd seg meget raskt. Den infiserer oreblad og ved sterke angrep kan det bli tidlig bladfall. Gråor blir lettere angrepet enn svartor.
Sammendrag
I 2011 var det en nedgang i helsetilstanden hos bartrær, og hos gran ble det observert en del toppskranting og avdøing i hogstklasse 3 og 4. Vi registrerte få insekt- og soppskader på gran der 1 % av trærne var angrepet, mens 1,2 % av furutrærne hadde slike biotiske skader. Antall abiotiske skader (stort sett snø- og vindrelaterte) hos bartrærne var omtrent på samme nivå som tidligere i overvåkingsperioden (1,7 og 1,2 % for hhv. gran og furu). Av treslagene gran, furu og bjørk er det fortsatt bjørk som er mest utsatt for skader: 10,6 % av bjørketrærne var angrepet og skadet av insekter, hovedsakelig av fjellbjørkemåleren, mens 14,2 % av bjørketrærne var angrepet av bjørkerustsopp eller andre sopper og 3,5 % hadde skader med abiotiske årsaker....
Forfattere
Arild Sletten Trond Hofsvang Christer Magnusson Trond Rafoss Halvor Solheim Anne Marte Tronsmo Bjørn Økland Leif SundheimSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
The ascomycete fungus Hymenoscyphus pseudoalbidus (anamorph Chalara fraxinea) is responsible for ash dieback currently expanding over large parts of Europe. Our objective was to investigate the genetic structure of H. pseudoalbidus and to examine its relationship to the species H. albidus, known as a saprotroph. The study comprised 181 isolates of H. pseudoalbidus collected within the diseased area, 17 H. albidus isolates from six apothecia, collected outside the diseased area in Norway, and nine apothecia of H. pseudoalbidus collected in Sweden. By analysis of microsatellite markers developed for this study, combined with AP-PCR using the M13 primer, we demonstrated sexual heterothally in H. pseudoalbidus, detected high gene flow and low geographic structure of the H. pseudoalbidus population and found indications of a founder effect. Also, substantial genetic differences were detected between the two species of fungi; only four of seven microsatellite markers developed for H. pseudoalbidus were amplified for H. albidus, and no alleles were shared among the species. Furthermore, AP-PCR banding patterns were distinctly different for the two species. We conclude that even though the two fungi have a similar habitat and are morphologically virtually identical, they do not share a recent common ancestor.
Forfattere
Leif Sundheim Daniel Flø Trond Hofsvang Christer Magnusson Trond Rafoss Arild Sletten Halvor Solheim Anne Marte Tronsmo Bjørn ØklandSammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
Mycosphaerella pini med det anamorfe stadiet Dothistroma septosporum er nå kjent fra to kommuner i Troms, Bardu og Målselv, og mange steder i sør-øst Norge. Soppen infiserer furunåler under fuktige forhold og forårsaker en sjukdom kalt rødbandsjuke.
Sammendrag
Aspen trees are exposed to a range of attackers and employ varied strategies to reduce their impact. The diversity of responses may have importance for resistance properties at the stand level, and justifies the search for varied defensive strategies in natural populations. We used transcriptomic tools to evaluate diverse responses at the gene activity level in Populus tremula in response to wounding, and to inoculation with two pathogenic fungi (Melampsora magnusiana vs Ceratocystis sp.) that differ in life style (biotroph vs necrotroph) and host tissue requirement (live leaf vs dead wood tissues). Two aspen genotypes from the SwAsp collection with differences in growth and phenolic composition were used to study differences in resistance properties. High defence gene induction, high growth and elevated defence properties toward the biotroph appeared to support each other in this study exemplified in the more resistant SwAsp clone, whereas the more susceptible SwAsp clone was much less responsive to infections, and displayed more symptoms when infected with M. magnusiana. Interestingly, in the more resistant clone wounding gave greater systemic activity of selected candidate genes than when combined with the necrotroph, suggesting that this pathogen has some ability to suppress the induction or translocation of the systemic defence signal in this particular clone.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
I 2009 ble rødbandsjuke første gang registrert i norge, i Bardu og Målselv kommuner i Troms. I 2010-12 er sjukdommen observert i tre områder på Østlandet. Fram til 2012 var angrepne beskjedne, men i år var det kraftige angrep i enkelte bestand, noe som vakte stor oppmerksomhet på en internasjonal konferanse om denne sjukdommen.