Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2011
Abstract
Biodiversity is assumed to have high value for many people, but the necessary preservation also incurs a cost for the forest owner. Typically, studies of this cost are at the stand level, and hence, not very accurate as the cost may vary even within the stand. In this work, we use a 1m×1m grid, generated from LIDAR data, to estimate the cost for harvesting and forwarding. The method could be utilized to calculate compensation, and to select between key woodland habitats to minimise the cost. In three of four test cases, the main cost was reduced harvested volume, but in one case the key woodland habitat also made the harvesting operations more expensive.
Abstract
Aspen (Populus tremula L.) is associated with high biodiversity and provides high-quality forage for wild browsing herbivores in boreal and temperate ecosystems. The long-term persistence of aspen in many regions in Scandinavia has been questioned due to the historically high browsing levels. We here review the basic ecology, genetics and life histories of aspen in a browsing context. Browsers can suppress the regeneration of aspen and the relatively short lifespan of the trees result in frequent regeneration cycles and concurrent exposure to browsers. In the long term, browsing may reduce recruitment and delay maturation, increase mortality and ultimately cause a decline of aspen. Norwegian forest inventory data indicate a reduced recruitment rate of young aspen (diameter at breast height; 60–79 mm) during the last 25 years, but it is unclear whether this is all due to browsing. Regeneration may also be hampered by lack of disturbance. Recent genetic studies have shown that aspen may have substantial regeneration by seeds, which allows for effective migration. The main conclusion of this review is that although browsing may affect demography and local abundance of aspen, it is very unlikely to lead to the eradication of the species in Fennoscandia.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
Development of surface moulds and staining fungi on painted spruce panels with known origin and wood properties was investigated over a period of 4 years. Materials of Norway spruce (Picea abies) were sampled from two sites with high-productive forest on lowland in South-eastern Norway and two low-productive sites at higher altitudes and somewhat farther north. Claddings were processed from inner centreboards (mainly heartwood) and outer centerboards of both butt logs and second logs. A sub-sample of radially sawn claddings was compared with corresponding tangentially sawn claddings. Heartwood proportion, density, annual ring width, knot diameters and knot area were measured. All panels were coated with the same water-borne alkyd modified acrylic paint system. Most of the tangentially sawn claddings were coated on the side facing pith, but a sub-sample was coated on the opposite side for comparison. The specimens were exposed with 45˚ angle of inclination facing south in a field trial in Oslo from 2007 to 2011, and mould growth was evaluated visually according to EN 927-3. 7.7% of the specimens were rated as 2, 71.4% were rated as 3, 19.4% were rated as 4, and 1.5% were rated as 5. Outer boards were rated significantly higher than inner boards, while differences between origins were not significant. There was a tendency of decreased rating with increasing heartwood proportion, but the relationship was not significant. Nor was there any significant effect of annual ring with, density or knot properties. Neither the difference between radially and tangentially sawn claddings, nor the difference between specimens coated on the side facing pith was significant.
Abstract
Wood used in outside applications is susceptible to weathering and photo degradation, which often leads to surface discoloration, loss of brightness and surface deterioration. Research has shown that acetylated wood is more resistant against brown rot, white rot and soft rot, and more dimensionally stable than untreated wood. However, acetylated wood seems still to be disfigured by surface moulds and staining fungi. Samples of acetylated Southern Yellow pine at three different treatment levels; low, intermediate and high acetyl content were exposed at two test sites, Ås (Norway) and Bogesund (Sweden) against north and south from September 2010 until March/May 2011. Considerably more precipitation was recorded in Ås in the initial potential fungal growth phase than in Bogesund. As expected, untreated wood had higher mould ratings than acetylated wood. At Ås the tendency was that samples with low acetyl content had lower mould ratings than samples with higher acetyl content. This effect was not found in Bogesund. This may be due to considerably less precipitation in Bogesund compared to Ås. At Ås samples exposed against north tended to have higher mould ratings than panels exposed against south which could be due by less direct sun causing longer time of wetness and more ideal conditions for mould growth.
Abstract
Two new species of Schistidium Bruch & Schimp., S. riparium H.H.Blom, Shevock, D.G.Long & Ochyra, and S. mucronatum H.H.Blom, Shevock, D.G.Long & Ochyra, are described and illustrated. They occur in rheophytic habitats in China, S. riparium in the southern Hengduan Mountains in Yunnan Province (Lancang Jiang and Nu Jiang catchments) and S. mucronatum from further north, on the Qinghai‐Tibet Plateau of Sichuan and Qinghai Provinces (Jinsha Jiang and Huang He catchments). The affinities of the new species are discussed and on the basis of their concave and broadly canaliculate leaves with plane and erect margins, S. riparium is tentatively placed in Schistidium Bruch & Schimp. subgen. Canalicularia Ochyra, whereas S. mucronatum on account of its keeled, ovate-lanceolate leaves and the strongly curved and twisted peristome teeth resembles very much species of sect. Apocarpiformia (Kindb.) Ochyra within subgen. Apocarpa Vilh.
Authors
Johannes BreidenbachAbstract
Digital aerial images over Vestfold county were acquired by TerraTec in summer 2007 with a Vexcel UltraCamX sensor. The flying height above-ground was approximately 2800-3000 m which resulted in images of approximately 1880x2880 m size. The images were acquired in north-south oriented flight strips with a 20% side and 60% within-strip overlap. Panchromatic image data were acquired in 20 cm ground sampling distance (GSD). Near infrared, red, green and blue image bands were acquired in 60 cm GSD but were pansharpened to a 20 cm pixel size by the data vendor. The original radiometric resolution of the images (12 bit) was resampled to 8 bit for archival storage. The plane location and orientation during image acquisition were logged using a GPS and an inertial navigation system (INS). To increase the accuracy of the external orientation, an aerial triangulation was performed based on 34 ground control points using the software Match-AT.
Authors
Johannes BreidenbachAbstract
The aim in the analysis of sample surveys is frequently to derive estimates of sub-population characteristics. This task is denoted small area estimation (SAE). Often, the sample available for the sub-population is, however, too small to allow a reliable estimate. Frequently, auxiliary variables exist that are correlated with the variable of interest. Several estimators can make use of auxiliary information which may reduce the variance of the estimate.
Abstract
Scots pine (Pinus sylvestris L.) is an important softwood species in Northern Europe and is frequently used as material for various wood protection systems. In Europe, EN 113 is the standard basidiomycete laboratory durability test method, using mass loss as evaluation criteria. In this paper quantitative real-time PCR (qPCR) and thermogravimetric analysis (TGA) was used to characterize colonization by basidiomycetes in Scots pine sapwood, but also to learn more about the EN 113 test. Two different wood sample sizes were tested. For Gloeophyllum trabeum the largest sample size gave the highest mass loss, while for the smallest samples Trametes versicolor gave the highest mass loss. As expected, fungal DNA content and mass loss in Scots pine sapwood samples decayed by G. trabeum became higher with increasing incubation time of 16 weeks. More unexpectedly, the T. versicolor DNA content in Scots pine sapwood samples was highest at the start of the incubation period and declined during the incubation period, while mass loss increased during the 28 week incubation period. The fungal colonization in the side and middle of EN 113 samples was tested. Highest DNA contents of G. trabeum were measured in the sides during 16 weeks of incubation. The T. versicolor DNA content was higher or similar in the side compared to the middle of the samples until week 20. For weeks 20 and 22 the DNA content was higher in the middle than in the sides, while for the remaining incubation period (weeks 24, 26 and 28) it was quite similar. TGA was shown to be a useful and fast method for chemical characterization of brown rot decayed wood, but cannot be used for white rot decayed wood. For T. versicolor moisture and fungal DNA explained most of the variation in mass loss, while for G. trabeum moisture explained most of the variation in mass loss.