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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.

2020

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Abstract

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Abstract

The dataset presented here was collected by the GenTree project (EU-Horizon 2020), which aims to improve the use of forest genetic resources across Europe by better understanding how trees adapt to their local environment. This dataset of individual tree-core characteristics including ring-width series and whole-core wood density was collected for seven ecologically and economically important European tree species: silver birch (Betula pendula), European beech (Fagus sylvatica), Norway spruce (Picea abies), European black poplar (Populus nigra), maritime pine (Pinus pinaster), Scots pine (Pinus sylvestris), and sessile oak (Quercus petraea). Tree-ring width measurements were obtained from 3600 trees in 142 populations and whole-core wood density was measured for 3098 trees in 125 populations. This dataset covers most of the geographical and climatic range occupied by the selected species. The potential use of it will be highly valuable for assessing ecological and evolutionary responses to environmental conditions as well as for model development and parameterization, to predict adaptability under climate change scenarios.

Abstract

In this study, we aim at developing ways to directly translate raw drone data into actionable insights, thus enabling us to make management decisions directly from drone data. Drone photogrammetric data and data analytics were used to model stand-level immediate tending need and cost in regeneration forests. Field reference data were used to train and validate a logistic model for the binary classification of immediate tending need and a multiple linear regression model to predict the cost to perform the tending operation. The performance of the models derived from drone data was compared to models utilizing the following alternative data sources: airborne laser scanning data (ALS), prior information from forest management plans (Prior) and the combination of drone +Prior and ALS +Prior. The use of drone data and prior information outperformed the remaining alternatives in terms of classification of tending needs, whereas drone data alone resulted in the most accurate cost models. Our results are encouraging for further use of drones in the operational management of regeneration forests and show that drone data and data analytics are useful for deriving actionable insights. Key words: UAV, DAP, forest inventory, photogrammetry, precommercial thinning, airborne laser scanning.

Abstract

Begrepet ‘naturskog’ blir brukt i skogbruks-, friluftslivs- og naturvernsammenheng for å beskrive skog som er lite påvirket av mennesker. Naturskog er definert som «skog framkommet ved naturlig foryngelse av stedegent genmateriale der menneskelig påvirkning har funnet sted i så liten utstrekning, for så lang tid tilbake, eller er utført på en slik måte, at skogens naturlige struktur, sammensetning, og økologiske prosesser ikke er endret i vesentlig grad». Naturskog blir brukt som motsats til ‘kulturskog’, der de økologiske prosessene i stor grad er påvirket av menneskelig aktivitet, i første rekke skogbruk. Historisk har vi satt et skille ved 1940-årene, fordi bestandsskogbruket på denne tiden fikk sitt gjennomslag som rådende driftsform med flatehogster og påfølgende planting og aktiv skogskjøtsel. I rapporten har vi gjennomgått Landsskogtakseringens data fra seks takstomdrev av permanente prøveflater (1986-2018) for å se på de endringene som har skjedd hogstklasser og bestandsalder. Deretter har estimert arealet med naturskog som har sitt opphav i de gamle avvirkningsregimene....

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Abstract

Rapporten presenterer resultater fra en undersøkelse av arealer registrert som MiS-livsmiljøet Rik bakkevegetasjon i tre områder på Østlandet. De overordnete målene var å undersøke om arealene tilfredstilte kravene til vegetasjonstyper som definerer livsmiljøet, og om de utvalgte arealene satt av som nøkkelbiotoper skilte seg ut fra arealer utenfor nøkkelbiotopene på samme bonitet og skogtype med hensyn på forekomster av arter innen karplanter og jordboende sopp. Prøveflater (50x50m) i tilfeldig utvalgte nøkkelbiotoper inneholdt Rik bakkevegetasjon i 92% av tilfellene, og hadde en høyere andel av kalklågurtskog og høystaudeskog enn referanseflatene. Det ble funnet et høyere antall karplanter i MiSflatene enn i referanseflatene, men ikke jordboende sopp. For sopp på rødlisten ble det funnet et stort antall rødlistearter, et noe høyere antall arter i MiS-flatene enn i referanseflatene, og at fem av seks flater med >10 rødlistete sopp var MiS-flater. Forskjeller i sammensetningen av arter på flatene var i hovedsak knyttet til geografisk beliggenhet og til vegetasjontyper. Flater i middelaldret kulturskog hadde færre karplanter, men minst like mange arter sopp (inkludert rødlistearter) som naturlig forynget skog. Resultatene viser at nøkkelbiotoper basert på MiS-registreringer fanger opp de vegetasjonstypene og arter som definerer livsmiljøet, men at bruk av skillearter innen karplanter for å lokalisere kalklågurtskog ikke alltid fungerer i tett skog med lite karplanter.

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Abstract

Red-listed species are often used as target species in selection of sites for conservation. However, limitations to their use have been pointed out, and here we address the problem of expected high spatio-temporal dynamics of red-listed species. We used species data (vascular plants, bryophytes, macrolichens and polypore fungi) from two inventories 17 years apart to estimate temporal turnover of red-listed and non-red-listed species in two forest areas (147 and 195 ha) and of plots (0.25 ha) within each area. Furthermore, we investigated how turnover of species afected the rank order of plots regarding richness of red-listed species, using two diferent national Red List issues (1998 and 2015). In both study areas, temporal turnover was substantial, despite minor changes in the overall number of species. At plot level, temporal turnover in red-listed species was higher than in non-red-listed species, but similar to non-red-listed species of the same frequency of occurrence. Adding the efect of changing identities of species red-listed according to the two Red List issues, further increased the estimated spatio-temporal dynamics. Recorded spatio-temporal turnover also resulted in substantial changes in the rank order of plots regarding richness of red-listed species. Using rare red-listed species for site selection may therefore be accompanied by a higher loss of conservation efectiveness over time than for more common species, and particularly at fner scales. Red-listed species · Site selection · Spatio-temporal dynamics · Temporal turnover

Abstract

A new stand-level growth and yield model, consisting of component equations for stand volume, basal area, survival, and dominant stand height, was developed from a dataset of long-term trials for managed thinned and unthinned even-aged Norway spruce (Picea abies (L.) Karst.) forests in Norway. The developed models predict considerably faster growth rates than the existing Norwegian models. Further, it was found that the existing Norwegian stand-level models do not match the data from the thinning trails. The significance of thinning response functions indicated that thinning increases basal area growth while reducing competition related mortality. No significant effects of thinning were found in the dominant stand height growth. Model examination by means of cross-validation indicated that the models were unbiased and performed well within the data range. An application of the developed stand-level model highlights the potential use for these models in comparing different management scenarios.

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Abstract

An understanding of the relationship between volume increment and stand density (basal area, stand density index, etc.) is of utmost importance for properly managing stand density to achieve specific management objectives. There are two main approaches to analyse growth–density relationships. The first relates volume increment to stand density through a basic relationship, which can vary with site productivity, age, and potentially incorporates treatment effects. The second is to relate the volume increment and density of thinned experimental plots relative to that of an unthinned experimental plot on the same site. Using a dataset of 229 thinned and unthinned experimental plots of Norway spruce, a growth model is developed describing the relationship between gross or net volume increment and basal area. The models indicate that gross volume increases with increasing basal area up to 50 m2 and thereafter becomes constant out to the maximum basal area. Alternatively, net volume increment was maximized at a basal area of 43 m2 and decreased with further increases in basal area. However, the models indicated a wide range where net volume increment was essentially constant, varying by less than 1 m3 ha−1 year−1. An analysis of different thinning scenarios indicated that the relative relationship between volume increment and stand density was dynamic and changed over the course of a rotation.