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
Forfattere
Kjell Andreassen Volkmar Timmermann Nicholas Clarke Erik Framstad Per Arild Aarrestad Vegar Bakkestuen Tonje Økland Jørn-Frode Nordbakken Ingvald Røsberg Inga E. Bruteig Marianne Evju John Atle Kålås Torgeir NygårdSammendrag
The report presents results for 2011 from three national monitoring programmes on long-range transboundary air pollution.
Forfattere
Nicholas ClarkeSammendrag
This report aims to summarise briefly the findings in the scientific literature concerning the effect of both stem-only and whole-tree harvesting on soil carbon stocks. Although the findings reported by previous authors vary, it is possible to draw some general conclusions about the effect of harvesting on soil carbon, and on whether whole-tree harvesting has a greater effect than stem-only harvesting. In general it appears that the organic C content in the soil’s organic layer is reduced after stem-only harvesting, sometimes by as much as 50%. This reduction has been explained in several ways. After a period of maybe 20 years, the carbon content of the organic layer starts to increase again. In the mineral soil a reduction is not always apparent and the C content can even increase, probably because of the incorporation of residues into the soil. Some studies have shown that this increase is short-lived, while others have found a longer-term increase. Unsurprisingly, thinning appears to affect the soil carbon content much less than clear-cutting; the effect tends to be proportional to the thinning intensity. The soil carbon content appears to be higher after selection cutting than after clear-cutting. Studies comparing effects of whole-tree harvest with those of stem-only harvest have tended to show smaller carbon contents in the mineral soil after whole-tree harvest than after stem-only harvest, although once again results vary greatly. There are many factors affecting soil C content and thus accounting for the observed differences, including temperature, moisture content, and harvesting type. Variation in the results obtained may depend on site-specific factors such as site nutrient status, especially with regard to the most common limiting nutrient nitrogen, which will affect growth in the next rotation. Making sure there are enough nutrients available, if necessary by compensatory fertilisation, will improve carbon sequestration in both trees and soil.
Sammendrag
This report has been prepared in the frame of Work Package 3 (Policy) of the Interreg IVB project Bioenergy Promotion. The main rationale of this work package is to support the development of coherent national and (sub)regional policies promoting the sustainable production and consumption of bioenergy. The purpose of the country policy assessment report is to describe the main promotional policies and support schemes for bioenergy and to assess to what extent national policy frameworks contribute to Sustainable Development and integrate related sustainability principles and criteria. At present and in the foreseeable future, the main source of raw materials for bioenergy in Norway is likely to be the forests. However, waste from agriculture, households and industry is another promising source. Investment support needs to be continued, at least at present levels. The main bottlenecks for increased use of bioenergy in Norway are economic, so economic support is necessary. Further development of the standard for sustainable forestry is required, in order to take into account aspects that are not yet covered (see above under Point 3.5). However, there is currently disagreement between the parties to the Living Forests standard, so revision is not likely to take place soon. Current research is being carried out, for example in CenBio and the project “Ecological consequences of increased biomass removal from forests in Norway” on the effects of whole-tree harvesting compared to stem-only harvesting on soil nutrients, carbon stocks, ground vegetation and regeneration). In addition, work is being carried out to study the applicability under Norwegian conditions of the guidelines of other countries such as Sweden, Finland, the UK and Ireland and to prepare preliminary guidelines for Norwegian forestry. There is disagreement on the likely short-term effects of biomass harvesting for bioenergy on carbon sequestration in forest ecosystems (see above under 5.2) and this needs to be further studied. In their present form, the binding EU sustainability criteria for biofuels/bioliquids should not be extended to solid/gaseous biomass used for electricity and heating/cooling. Some changes are necessary to take account of specific conditions e.g. in forestry. For example, it is stated in Point 4 of Article 17 of the Renewable Energy Directive that biofuels and bioliquids shall not be obtained from land that was continuously forested in January 2008 and is no longer continuously forested. It is unclear how this would affect clear-cuts. Also, in Point C7 of Annex V, the 20-year period for calculating carbon stock changes is completely unrealistic for forestry (although this refers to land-use change and it could be argued that felling is not land-use change if the land is used for forest afterwards; this should be clarified). These aspects of the Renewable Energy Directive are already problematic if forest biomass is to be used for biofuels or bioliquids.
Sammendrag
A crucial process of the terrestrial carbon cycle is photosynthetic uptake through plants. This may be quantified by calculating the fraction of absorbed photosynthetic active radiation (fapar), based on multispectral reflectance properties of the earth surface. The fapar index is available with global coverage from satellite sensors.Here, we combine two satellite missions, SeaWifs on board OrbView2 and MERIS on board Envisat, to produce time series with 10 days resolution for a period of 14 years (19982011) at a spatial resolution of 0.5 latitude x 0.5 longitude. These more than 50000 individual time series represent a huge range of dynamical behavior with respect to variability, periodicities and correlation structure.To characterize differences as a function of spatial location or distance, we employ Recurrence Quantification Analysis (RQA) and Recurrence Network Analysis (RNA). Two strategies are followed. On one hand, RQA and network variables are calculated for individual time series using identical recurrence parameters, and compared to see whether differences between them resemble different climate regimes, biomes, plant functional types or landuse classes. On the other hand, a multivariate extension of RNA will be exploited to see whether networks within networks occur, i.e. whether RNA provides sufficient contrasts to discern different clusters of pixels on the globe.Taken together, the recurrence analysis might lead to a new classification of the terrestrial biosphere which in turn can be compared to existing partitioning based on climate and/or vegetation properties. A number of technical issues will be addressed as well, such as the impact of the finite length of the series (504 values each), the necessity to gapfill parts of the data, the stability of network variables against changes in the recurrence parameters, or the computational challenges involved in the multinetwork analysis of many series. http://dames.pik-potsdam.de/Abstracts.pdf
Forfattere
Arne BardalenSammendrag
Intensiteten i den norske skog- og klimadebatten er tidvis høy, men er den dermed også relevant? Det kan synes som man anser veivalg i norsk skogforvaltning og bruken av biomasse fra norske skoger som avgjørende for å redde kloden fra irreversible klimaendringer....
Forfattere
Anne B. NilsenSammendrag
Den XXII Congress of the International Society for Photogrammetry and Remote Sensing (ISPRS) ble arrangert i Melbourne, Australia, 25. august-1. september i år. Drøye 1900 deltagere fra 74 land hadde funnet veien til Melbourne. Norge stilte sterkt med 8 deltagere og 3 foredrag.
Forfattere
Lone Ross Gobakken Olav Albert HøibøSammendrag
The aesthetic service life of outdoor exposed wooden surfaces are often decided by growth of moulds and blue stain fungi, but also other visual changes caused by weathering such as colour changes, abrasion or wear, blistering, flaking, and even cracks in the wood or coating will contribute. When developing models that describe changes in the wood material and aim to predict the service life, it is essential to understand the impact of different climatic factors, the effect of variation in the wooden product itself and in the quality of craftsmanship and building design. The objective of this presentation is to gather knowledge about which factors influence surface mould growth on wood substrates in an outdoor environment. The analysis and the model development are based on data from evaluation of mould growth coverage on outdoors exposed wood panels consisting of different combinations of wood substrates and surface finishes from a number of field studies performed over the last years [1, 2, 3, 4, 5, 6 and 7].
Forfattere
Peder GjerdrumSammendrag
Sawmillers want to have predictable and homogeneous timber outcome from their industry. This paper analyses and discusses how well timber quality of boards from the same log, and in particular pairs of sister boards, correspond to each other, i.e. the limit for quality homogeneity.Observations from three different sawn timber outcome experiments were analysed. Varying quality traits were observed: appearance and machine strength grading, knot size and number, and board value.The results showed that 80% and 53% respectively, for two different samples, of the boards had different quality grade from their sister boards, and less homogeneity when more boards are sawn from the same log. The correlation between observations made in sister boards were modestly 0.42 for biggest green knot diameter, and almost absent for dry knots and other traits. Board value and machine strength are better correlated, 0.76 and 0.69, respectively.Relative pairwise difference for these parameters was found to follow the exponential distribution with mean 0.169 and 0.068, respectively. The results clearly indicate that there is no easy way achieving a consistent and pre-requested quality, at the same time avoiding an inherent portion of diverted quality boards.
Forfattere
Lars Sandved DalenSammendrag
Myr dekker ca. 550 millioner hektar av jordas overflate og har stor betydning både som karbonlager og for utslipp eller opptak av klimagasser som karbondioksid, metan og lystgass. Forvaltning av norsk myrskog og fuktskog er viktig for å sikre høg og vedvarende karbonbinding i skog.
Forfattere
Camilla BaumannSammendrag
De siste fem årene har Genressurssenteret ettersøkt og etterlyst i overkant av 50 navngitte sorter vi gjerne skulle ha inn i samlingene våre. I leteaksjonen har vi funnet 12 av de savnede sortene. Samtidig må vi erkjenne at de øvrige sannsynligvis er borte for alltid.