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.
2020
Forfattere
Lars T. HavstadSammendrag
Det er ikke registrert sammendrag
Forfattere
Annette Folkedal SchjøllSammendrag
Det er ikke registrert sammendrag
Forfattere
Lars T. HavstadSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Redaktører
Oddmund HjukseSammendrag
Det er ikke registrert sammendrag
Forfattere
Tomasz Leszek WoznickiSammendrag
Det er ikke registrert sammendrag
Sammendrag
Forest inventories provide predictions of stand means on a routine basis from models with auxiliary variables from remote sensing as predictors and response variables from field data. Many forest inventory sampling designs do not afford a direct estimation of the among-stand variance. As consequence, the confidence interval for a model-based prediction of a stand mean is typically too narrow. We propose a new method to compute (from empirical regression residuals) an among-stand variance under sample designs that stratify sample selections by an auxiliary variable, but otherwise do not allow a direct estimation of this variance. We test the method in simulated sampling from a complex artificial population with an age class structure. Two sampling designs are used (one-per-stratum, and quasi systematic), neither recognize stands. Among-stand estimates of variance obtained with the proposed method underestimated the actual variance by 30-50%, yet 95% confidence intervals for a stand mean achieved a coverage that was either slightly better or at par with the coverage achieved with empirical linear best unbiased estimates obtained under less efficient two-stage designs.
Forfattere
Mekjell MelandSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Iben M. Thomsen Håvard Kauserud Paal Krokene Mogens Nicolaisen Per Hans Micael Wendell Beatrix Alsanius Christer Magnusson Johan A. Stenberg Sandra A .I. Wright Trond RafossSammendrag
Key words: VKM, risk assessment, Norwegian Scientific Committee for Food and Environment, Norwegian Environment Agency, mycorrhiza. Mycorrhiza is a beneficial association between plant roots and fungi. This mutualistic symbiosis is essential for plant growth in most natural terrestrial ecosystems and in agriculture. Commercial mycorrhizal products containing fungi and bacteria may promote plant growth, especially on sites without a natural microbial community. Due to the risk of unintended negative effects, introduction of new species or genetically different isolates of native species should always be considered carefully. This report assesses the risk of establishment and spread of six fungal species and six bacterial species included in different commercial mycorrhizal products, as well as the species’ potential impact on Norwegian biodiversity. Most of the evaluated fungi and bacteria are probably present in Norway, even though presence at present data only exist for two of the six fungal species. Establishment of the assessed fungi on the plants and sites where they are applied is considered moderately likely, with medium uncertainty, while establishment of the bacterial species is considered to range from very unlikely to very likely depending on the bacterial group, with low uncertainty. The probability of spread to the wider environment ranges from unlikely (four fungal species), to moderately likely (two fungal species), to very likely (five of the six bacterial species). However, for all species it is considered unlikely that establishment and spread would have negative effects on other native species, habitats and ecosystems in Norway.