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.
2007
Sammendrag
The objective was to evaluate whether Lowry-impregnation of Scots pine with FA100-mix, instead of the FA40-mix, would lead to similar or slightly higher WPGs and to investigate any potential changes in penetration pattern. The results indicate that the penetration was better, also penetrating the outer zone of the heartwood. Furthermore, it was possible to reduce the WPG-levels for pine down to 50-70% (corresponding to PFA retentions of 260- 315 kg/m³) from 120% (approx. 550 kg/m³) with full-cell impregnation using FA100-mix. Using the Lowry process with FA100-mix would probably be a possible treating schedule for products aimed for use in ground contact. The reduced content of hygroscopic salts in the furfurylated wood product would also further reduce hygroscopisity compared with FA-40 mix. However, more trials are needed in order to optimize penetration while still keeping the final WPG low.
Sammendrag
Furfurylated wood (wood modified by furfuryl alcohol) has over the last years gained marked shares from both tropical wood and conventional preservative treated wood and this has, in turn, generated several research projects concerning process development. The impregnation of spruce is well known from literature to be a difficult task. Furthermore, the sapwood of Scandinavian grown Scots pine is also known to be difficult to fully impregnate from time to time. The primary objective of the study was to evaluate whether the Oscillating Pressure Method (OPM) could be used to impregnate green and dry Norway spruce wood (Picea abies) with a Furfuryl alcohol (FA) - mixture. The secondary objective of the study was to evaluate if OPM could improve the penetration of FA in Scots pine (Pinus sylvestris) as compared to conventional full cell (Bethell) treatment. Impregnation tests were carried out on boards and planks as well as 300 mm and 500 mm clear wood samples. Samples were removed for MC measurement and the initial weight of the test samples was determined. Four different impregnation schemes were tested. The results indicate that Norway spruce can be impregnated by the OPM method to produce a protective shell of treated wood around a core of untreated wood. The penetration in Spruce showed great variation between different boards and between different parts of the individual boards. This is in part expected, but can also be caused by uncontrolled pre drying of the test material which was stacked uncovered after sawing. For Scots pine, the OPM improved the penetration of both sapwood and, to some extent, the outer heartwood.
Forfattere
Svein Solberg Lars Eklundh Arnt Kristian Gjertsen Tomas Johansson Steve Joyce Holger Lange Erik Næsset Håkan Olsson Yong Pang Anne SolbergSammendrag
The REMFOR project evaluates remote sensing data and methods for monitoring forest health using variation in leaf area index (LAI) as a primary measure of defoliation. A large-scale pine sawfly outbreak in Norway serves as a test case. An LAI map of the study area was derived from airborne LIDAR measurements before and after the insect attack to serve as ground truth for satellite image analysis. The method predicts LAI from laser penetration rates through the canopy layer in accordance with the Beer- Lambert law calibrated with point measurements of LAI with LICOR LAI-2000. Comparing two cloud-free SPOT scenes from September 2004 and September 2005 shows obvious visual patterns of defoliation in pine forests from the 2005 outbreak. Preliminary analysis shows that the insect defoliation caused an increase in middle-infrared (SPOT band4) reflectance and a decrease in SPOT NDVI, and both these responses may be used as a reasonable predictor of LAI loss as derived from laser scanning. MODIS NDVI data were gathered for the area over the period 2000-2006, and the Timesat algorithm is used to smooth the seasonal variation. The insect attack is evident from the smoothed NDVI data both as a reduction in the summer mean value, and as an alteration of the seasonal profile during the larvae feeding period in June and July. REMFOR also encompasses a range of other remote sensing data types, including GLAS LIDAR, SAR and hyperspectral data from both airborne and satellite platforms (e.g. Hyspex and Hyperion). Landsat TM is used to generate a tree species map.
Forfattere
Isabelle Schülli-Maurer Daniela Sauer Karl Stahr Ragnhild Sperstad Rolf SørensenSammendrag
We investigated the development of Albeluvisols and Podzols with time in southern Norway. The Vestfold region at the western shore of the Oslofjord was chosen because it is characterized by continuous glacio-isostatic uplift for the last 12,000 years. Due to the permanent elevation process, no distinct marine terraces have been built, and the age of the sediments continuously increases with distance from the modern coastline. Albeluvisol development was assessed in a soil chronosequence on loamy marine sediments with ages ranging from approximately 1,800 to 10,200 years. The most obvious change during soil development was that after 4,500 - 5,000 years light tongues intruded from the E horizon into the B horizon, and became more pronounced with time. The combined thickness of the A and E-horizons was constant at 40 ± 3 cm in 9 of the 12 profiles and did not change with age. The organic matter content of the A-horizons, the fine silt to coarse silt ratio of the Btg horizons and the Feo/Fed ratio all decreased with soil age, whereas the thickness of the organic surface horizon and B horizon, as well as the Fed/Fet ratio all increased. Podzol development was investigated in a chronosequence on sandy beach sediments, the ages of the soils ranging from 2,400 to 8,500 years. All soil properties investigated - the organic matter content of the B horizons, clay content, Feo, Alo, Sio, Feo/Fed and Fed/Fet - tend to increase with advancing podzolization, and are strongly correlated with soil age. Topsoil pH values decrease with age. The characteristic Bh and Bs horizons had developed after approximately 4,000 years.
Forfattere
Daniela Sauer Isabelle Schülli-Maurer Ragnhild Sperstad Rolf Sørensen Karl StahrSammendrag
The coastal areas of Scandinavia provide suitable conditions for studying soil development with time, due to glacio-isostatic uplift. Our study area is located along both sides of the Oslofjord (Vestfold and stfold). The climate in this area is rather mild although it is located between 59 and 59 40 latitude. The mean annual temperature ranges from 5.4 to 6. 0 C. Precipitation is 9751094 mm year1 in Vestfold and 751829 mm year1 in stfold. Due to the steadiness of the uplift, no separate terraces were formed in the study area, but soils continuously get older from the coast inland. We established two soil chronosequences comprising six pedons each, one in Vestfold (1650 9000 years) and one in stfold (300011050 years). The ages were estimated by use of several sea level curves established for various locations in the area, based on calibrated radiocarbon datings. The parent material is loamy marine sediment. The geological basement below the sediment consists of basic magmatite (monzonite, latite) in Vestfold and predominantly acid magmatite (granite) in stfold. Higher precipitation in Vestfold leads to earlier beginning of clay illuviation. Clay coatings are perceptible in Vestfold already in the 1650 years old soil. In stfold they become visible for the first time in the 3500 years old soil. The E horizon becomes lighter with age, but its thickness stays constantly around 40 cm in both areas. The development of the characteristic albeluvic tonguing starts after 4000 to 5000 years. The tongues initially develop mainly along intersections of cracks. Due to ongoing leaching they increase in length and width, progressively consuming the prisms in between the cracks in the upper part of the Bt horizon. Base saturation in the upper 25 cm exhibits a decrease with time which can be best described by an exponential model, while pH (water) stays constantly at pH 4.4 0.4 in all soils covering a range of 1650 to 11050 years in age. These findings indicate that the soil pH is buffered by protonation of surface charges occupied by exchangeable base cations over a time span of more than 9000 years. The Fed/Fet ratio shows an increase with time which can be described by both, a linear or potential model, reflecting progressive iron release from mineral weathering. The Feo/Fed ratio shows a linear decrease indicating increasing degree of iron oxide crystallization.
Forfattere
Erlend Ystrøm Haartveit Leif Kjøstelsen Bård Strand JacobsenSammendrag
The project Woodflow is a 3-year project aiming at quantifying logistics costs for wood products in a supply chain from manufacturer to consumer. Woodflow is financed by the Research Council of Norway, Innovation Norway and Optimera AS. The work is carried out in Optimera’s distribution network in Norway. In this paper we present and discuss two methods for estimating time consumption, one for material handling and one for activities in the information flow. For material handling a method based on time studies has been modified and adapted to the situation in a distribution centre. For activities in the information flow performance measures of sales personnel are combined with information about registered orders to develop estimates for time consumption for entering orders and order lines. These will also be used to estimate time consumption for other tasks in the information flow. The estimates for time consumption will later be combined with the time costs of the performing actors to calculate logistics costs for material handling and for activities in the information flow.
Forfattere
Arnt Kristian GjertsenSammendrag
A multi-source forest inventory (MSFI) method has been developed for use in the Norwegian National Forest Inventory (NFI). The method is based on a k-nearest neighbour rule and uses field plots from the NFI, land cover maps, and satellite image data from Landsat Thematic Mapper. The inventory method is used to produce maps of selected forest variables and to estimate the selected forest variables for large areas such as municipalities. In this study, focus has been on the qualitative variables ‘dominating species group\" and ‘development class\" because these variables are of central interest to forest managers. A mid-summer Landsat 5 TM scene was used as image data, and all NFI plots inside the scene were used as a reference dataset. The relationship between the spectral bands and the forest variables was analysed, and it was found that the levels of association were low. A leave-one-out method based on the reference dataset was used to estimate the pixel-level accuracies. They were found to be relatively low with 63% agreement for species groups. An independent control survey was available for a municipality and estimates from the MSFI were compared to it. The levels of error were quite high. It was concluded that the large area estimates were biased by the reference dataset.
Forfattere
Ketil Kohmann Øystein JohnsenSammendrag
The object of this study was to obtain Norway spruce seedlings with buds set, ready for summer planting from the 1st of July. With an early long night treatment we prevented flushing of the newly formed terminal buds, ceased height growth, but slightly reduced hardiness in buds and needles. Nevertheless, a sufficient hardiness level in the autumn was acquired at a Norwegian nursery at 59°46’ N, with plants of the local provenance given a long night treatment (14 hours) for 13 days from the 25th of June. The similar treatment at a nursery at 64°30’N did not give the same result; all treatments led to a second flush with resumed growth of the local provenance. A trial with seed lots from several provenances was therefore performed at this nursery, and a significant correlation between the critical night length of the seed lot, and their ability to produce non-flushing buds, was found; the longer the critical night length of the seed lot, the less non-flushing buds. Responses at the northern nursery are probably due to the non existing dark period after termination of the treatment, and a too short treatment period to attain bud dormancy. An early and successful long-night treatment will, in addition, produce shorter seedlings with a larger root collar diameter.
Forfattere
Carl Gunnar FossdalSammendrag
In collaboration with the NARC platform at Ås, we have taken the Norway spruce phytochrome and PaChi4 promoters and introduced them into Arabidopsis using GFP and YFP expression vectors in order to study their effect on expression under long and short day treatment. Said in other words we use of GFP and YFP as reporters and Arabidopsis as a host for the Norway spruce promoters in order to study their possible regulation by day-length in this model plant system. In completely separate experiments in collaboration with the NARC platform at Ås, we have introduced the Norway spruce glycohydrolase PaChi4 into Arabidopsis to examine what effect this might have on the response to wounding and to pathogens. The PaChi4 enzyme is produced at very high levels in tissues with high level of host cell death (PCD) following fungal infections and it might be a marker for or directly involved in PCD. We have obtained transgenic plants and the first examination for any day-length dependent expression of the GFP and YFP reporters in the transgenic Arabidopsis lines is currently being pursued while the examination of the PAChi4 enzyme overexpressing lines are yet to be initiated.
Sammendrag
Ecological studies are often confronted with short and fragmented or unevenly sampled time series. Examples are, e.g., time series of biogeochemical fluxes measured on a variety of scales. Characterizing the observed time series patterns, particularly the correlation structure is crucial for an integrated ecosystem assessment or possibly for improved processes understanding.