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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.

2012

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Sammendrag

Models for predicting diameter increment in multi-storey spruce stands following mountain forest selective cutting (MFS) were developed. They were based on increment cores, tree ring analyses and stump registrations. The presented models rely upon time series data from 1600 trees in thirty-one Norway spruce stands in south-eastern and central parts of Norway. The selective cuttings were heavy; on average two thirds of the standing volume were cut. The increment following the interventions was highly variable, resulting in large random variability in the models with R2 varying between 0.18–0.31 for individual tree diameter growth and 0.40–0.50 for mean tree stand diameter growth. Dummy variables referring to three first 5-year periods after cutting were found to increase the precision and significantly reduce the random error. Selected models were validated using a test material from central Norway and also compared with the mostly applied Norwegian diameter increment models. Despite a large random variation in all models, the model performances appeared logical and the general fit to the data was acceptable. Based on tests, two diameter increment models are recommended for future yield prognoses in MFS. The models should also be of interest for wider use in other parts of the Nordic and Baltic boreal zone.

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Sammendrag

Spiders and beetles were pitfall-trapped in the foreland of the receding Hardangerjøkulen glacier in central south Norway. At each of six sampling sites, ages 3 to 205 years, twenty traps covered the local variation in moisture and plant communities. Thirty-three spider species and forty beetle species were collected. The species composition was correlated to time since glaciation and vegetation cover. A characteristic pioneer community of spiders and mainly predatory beetles had several open-ground species, and some species or genera were common to forelands in Svalbard or the Alps. While the number of spider species increased relatively constant with age, the number of beetle species seemed to level off after about 80 years. Half of the beetle species were Staphylinidae, and contrary to Carabidae, most of these were rather late colonizers. Most herbivore beetles colonized after more than 40 years, but the moss-eating Byrrhidae species Simplocaria metallica and also certain Chironomidae larvae developed in pioneer moss colonies after 4 years. The large Collembola Bourletiella hortensis, a potential prey, fed on in-blown moss fragments after 3 years. In the present foreland, chlorophyll-based food chains may start very early. Two pioneer Amara species (Carabidae) could probably feed partly on seeds, either in-blown or produced by scattered pioneer grasses.