Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2005
Sammendrag
Various needle discolorations, often due to lack of uptake of certain nutrients are frequently observed in nordmann fir (Abies nordmanniana) in Norwegian Christmas tree plantations. Most common are the yellow to necrotic needle tips on older needles caused by magnesium (Mg) deficiency (confirmed by chemical analysis of foliage). Even though chemical analysis of soil samples show that Mg is present in sufficient amount, various soil factors may cause Mg-deficiency; too high or too low pH, excess potassium (K) or too wet or too dry conditions. Antagonism, causing imbalance in nutrient uptake, can lead to negative effects. High pH may give Ca2+/Mg2+ antagonism, too low pH NH4+/Mg2+ antagonism, and abundant K K+/Mg2+ antagonism. During wet conditions K+ and other monovalent cations may leave the colloids to regain equilibrium between liquid and solid material. Then Mg2+ may easily bind to the free spaces on the colloids, and thereby becomes unavailable for the plants. If the soil is very dry there may not be enough liquid for the nutrients to be dissolved, and thus uptake inhibited. Nordmann fir is mainly grown in the southwestern coastal region of Norway since the climate there is fairly mild and suitable for this plant species. The yearly rainfall is high in that region, so a main cause for Mg deficiency on nordmann fir is probably related to wet soil conditions. Uptake of Mg after foliage application has proved to be ineffective due to the wax layer on the fir needles. However application on young needles and shoots has been reported by the Norwegian extension service to be successful. K deficiency also results in discoloration of older needles, but symptoms can easily be distinguished from Mg deficiency. Both deficiencies results in yellowing of the needles, but different from K deficiency, the base remains green on needles suffering from Mg deficiency. Both Mg and K are very mobile nutrients in plants, and they are therefore easily translocated from older to younger needles. Samples with yellow discoloration of the youngest needles have been observed to be low in iron (Fe) and manganese (Mn), especially when the trees have grown in soil with high pH. Both nutrients are nearly immobile in plants after they have been transported to the cells, and they are therefore not available for the young shoots. Nitrogen (N) deficiency is seen as a uniform, pale green discolouration of both young and old needles.
Sammendrag
Næringsmangel kan føra til redusert vekst og dårlegare vinterherding, prydverdi og motstandskraft mot ulike skadegjerarar. Ofte er ikkje grunngjødsling nok til å få fram fine tre. Då må ein inn med supplerande gjødsling med ulike næringsstoff. På grunn av vokslag på eldre nåler, vert effektivt opptak av bladgjødsel hindra. Generelt bør difor alle former for bladgjødsling gjennomførast om våren i strekkingsperioden til dei nye skota. I denne perioden er skota mjuke og svært utsette for skade, så ein må vera varsam. I denne artikkelen vert det gitt ei tilråding om grunngjødsling og sett fokusert på symptom på ulike mangelsjukdomar og dei tiltaka som vert tilrådde av Pyntegrøntringen.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
In 2004, damages resembling those caused by Phytophthora spp. were observed on three different fir species in Norway. Isolations were carried out from all the host plants on the Phytophthora selective medium PARP (with and without hymexazol added). In a nordmann fir (Abies nordmanniana) Christmas tree field at the southwestern coast of Norway, approximately 70 % of the plants died within a few months after planting. The massive infestation in a field previously used for grass production over decades, left no doubt that the disease had followed the imported transplants. Symptoms included poorly developed roots and discoloration under the bark from the stem basis downwards. The foliage had different stages of drought symptoms; pale green, yellow or brown. Isolations were carried out from the area between healthy and diseased tissue, both from roots and stem base, and a Phytophthora sp. was isolated. The culture produced nonpapillate sporangia with internal proliferation. The sexual stage was observed in water, but not on agar. The oogonia were large. The oospores were aplerotic and the anteridia predominantly amphigynous. ITS rDNA sequences of the isolate were obtained and found to be most similar to P. inundata. Samples were examined from diseased 15-year-old noble fir (A. procera) grown in a bough plantation at the southwestern coast of Norway. Approximately 25 % of the trees were dead or dying. The foliage had turned chlorotic to brown. On one tree a typical stem canker extending approximately 1.5 meters above ground on one side of the tree resulted in dead basal branches (flagging). Isolations were carried out from both roots and the cankered stem. Based on morphological characters (nonpapillate sporangia, internal proliferation, characteristic hyphal swellings, heterothallic culture) and ITS rDNA sequencing, the isolate was identified as P. cambivora. In a Christmas trees planting in southeastern Norway, several seven-year-old trees of subalpine fir (A. lasiocarpa) were dying. The tree loss was estimated to 25 %. Typical Phytophthora canker was found at the base of several trees. Isolations resulted in a culture that readily produced oogonia. The average diameter of the oogonia was 48 "m. The oospores were aplerotic with an average diamerter of 40 "m. The antheridia were paragynous, but a few amphigynous antheridia were also observed. The culture produced nonpapillate sporangia with internal proliferation ITS rDNA sequences matched P. megasperma. A pathogenesis test to fulfil Koch"s postulate was carried out on all three species of fir, each of them inoculated with the respective isolate. After seven weeks, root growth was poor on all the inoculated plants, and canker symptoms had developed in the lower part of the stem. Reisolated culture from noble fir was ITS rDNA sequenced and found identical to the original culture used for inoculation. Results from the ITS rDNA sequencing of the other two reisolated cultures are not yet available.
Sammendrag
Svampen Phytophthora har i mange år været problematisk i den norske produktion af cypres (Chamaecyparis lawsoniana). Til gengæld har pyntegrøntproduktionen med forskellige granarter indtil videre været forskånet for angreb af denne alvorlige skadevolder.
Forfattere
Dan AamlidSammendrag
Det er ikke registrert sammendrag
Forfattere
P. Neville Richard Fischer A.L. Axelsson Dan Aamlid Marco Marchetti T.B. Larsson Annemarie Bastrup-BirkSammendrag
The joint network of tree crown condition monitoring under the EU and ICP Forests operates at two levels, a systematic extensive approach (Level I) based on a 16 km x 16 km trans-national grid of sample plots (>6000 plots) and an intensive approach (Level II) on more than 800 plots across continental Europe. Three ongoing projects embrace the different levels of monitoring, the above mentioned Level I and Level II systems, and the National Forest Inventories (NFIs). All of the three projects are based on a stand structure approach that assumes an increased potential for species diversity with increasing complexity of stand structure. An intensive test-phase of forest biodiversity assessment at more than 100 Level II plots, known as ForestBIOTA is underway during 2005. This project aims to test standardized methods of forest biodiversity assessment in the field and examine the relationship between stand structure, forest deadwood, ground vegetation and epiphytic lichens. A forest classification of the plots is also included. A separate approach, known as BioSoil (due to its combination with a detailed chemical inventory of the soils) is a demonstration project which aims to record indicators of forest biodiversity at the extensive Level I plots. Practical measures of stand structure, including records of tree species, lists of vascular plant species, and simple measures of forest deadwood are included for field assessment during 2006. A pan-European forest type classification elaborating on the EUNIS system and including the Natura 2000 habitat types is proposed. These initiatives are linked to a third project, COMON, operating at the level of the National Forest Inventories aiming to test the same core variables at national levels.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Gjennomsnittlig kronetetthet for landet økte for gran og furu, mens den gikk svakt tilbake for bjørk sammenliknet med året før. Det ble imidlertid observert avtagende kronetetthet for gran på Østlandet. Utviklingen av kronefarge for gran fulgte stort sett det samme regionale mønsteret som ble observert for kronetetthet, med økende misfarging på Østlandet. I resten av landet var det ingen klare tendenser for gran. Totalt for landet økte andelen gule misfargede bjørketrær, mens andelen gul furu var på samme nivå som året før . Det er de eldste trærne som har mest misfarging. Avdøingen var i gjennomsnitt omtrent som i tidligere år. For gran var det en liten økning på Østlandet i antall nye døde trær. Skogens helsetilstand, registrert ved kronetetthet, misfarging og avdøing, påvirkes i stor grad av klimatiske forhold, enten direkte som ved tørke, frost og vind, eller indirekte ved at det påvirker omfanget av soppsykdommer og insektangrep. Det ble registrert få sopp- og insektangrep i løpet av registreringsperioden. I skogovervåkingen med permanente felt vil også økt alder bidra til negative trender over tid. Langtransporterte luftforurensninger kan komme i tillegg til eller virke sammen med klimatiske forhold. I 2004 ble det ikke registrert noe unormalt skadeomfang i skogen.
Sammendrag
Intensive monitoring plots of the ICP Forests gathered an amount of data about the ground vegetation in forest ecosystems throughout Europe. Each Country, applying different field techniques, conform to common rules of procedure, under the suggestions of a dedicated Expert Panel which implemented a Unified Coded Flora and comparability targets. Data series are foreseen to contribute to: definition of the forest ecosystem state and changes evaluation; assessment of the specific plant diversity at the ecosystems level. The contribution to scientific knowledge and to Global and Pan-European biodiversity initiatives and networks (ICP-IM, MCPFE, CBD, Forest BIOTA, ALTER-net, etc.) are also underlined. In spite of site-related data, first results (more than 670 plots, with large differences in plant diversity) depict the linkages with temperature, precipitation, dominant tree species and actual soil acidity. Nitrogen deposition seems to have some significant influence, which claims to further studies. Plant data series from ICP Forest’s plot, can be used for on-site confirmation of models including biodiversity k-factors and environment relations.