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.
2004
Authors
Erlend Ystrøm Haartveit R.A. Kozak T.C. ManessAbstract
In this paper, we review the development of supply chain management (SCM) and identify a number of considerations for applying these techniques to the forest products industry. A review of the literature found that SCM initiatives were primarily customer focused, where a significant amount of market pull exists. However, the forest products industry is characterized by sales of commodity products with push marketing. Successful implementation of SCM in these types of supply chains were found to focus on efficiencies through: 1) increasing throughput and 2) reducing inventories. Potential for efficiency improvements are larger when a holistic perspective is applied, integrating processes across companies in the supply chain. Two supply chain mapping methods were identified from the literature as key techniques for use in the forest products industry, and these were applied to three case companies in the western Canadian province of British Columbia. In general, it was found to be especially challenging to apply these techniques (and SCM in general) to commodity-based supply chains because of uncertainty in raw material supply, the relatively long lead times in production, and production processes that generate a relatively high percentage of consequence products. However, the mapping processes yielded some promising results with respect to creating an overview of supply chain structures, time consumption, and inventories. One major benefit derived from applying these methods would be improved communications between actors, customers, and suppliers along the supply chain. The authors suggest that SCM mapping tools be modified to improve their performance in analyzing supply chains for the forest products industry.
Authors
Peder GjerdrumAbstract
EMC is traditionally analysed using small, clear wood specimens. However, some discrepancy was observed in full-size boards in a sawmill. In this experiment specimens of varying length from 10 to 120 mm clear wood and from 120 to 900 mm natural quality were tested. Commercial spruce boards were used. After kiln drying and proper conditionning, the samples were kept in a constant climate (40 °C, 65% RH) for half a year, until apparent equilibrium was reached. The EMC was observed by the dry weight method separately for adsorption and desorption. The EMC (average for ad- and desorption) was found to increase proportionally to the natural logarithm of the specimen length. Further, clear wood showed sifgnificantly higher EMC than natural quality. While for desorption the EMC was hardly influenced by length, desorption was highly length dependent. The difference in EMC (desorption) between a full-length board and a 10-mm clear specimen was estimated to 0.013 (fraction of dry wood). Accordingly, the hysteresis A:D ratio decreased from 0.96 for the shortest specimens to 0.88 for the longest. The results verify and extend earlier findings and are important for understanding and estimating the wood-moisture interaction of kiln dried timber, particulary for high drying quality specifications. However, the difficulty of deciding the EMC for large specimens should not be underestimated.
Abstract
Utvalgt Forelesning/Selected Talk: Survival and competitive successes of boreal forest trees depend on a balance between exploiting the full growing season and minimising frost injury through proper timing of hardening in autumn and dehardening in spring. Our research has shown that the female parents of Norway spruce adjust these timing events in their progeny according to the prevailing temperature conditions during sexual reproduction. Reproduction in a cold environment advances bud-set and cold acclimation in the autumn and dehardening and flushing in spring, whereas a warm reproductive environment delays these progeny traits by an unknown non-Mendelian mechanism. We have performed identical crosses in combination with timed temperature treatments during shorter and longer periods from female meiosis, pollen tube growth, syngamy and embryogenesis, tested the progenies for bud-set and frost hardiness, and concluded that the effect of temperature most likely is a response to accumulated heat during embryogenesis and seed maturation. Our first attempt to look for a molecular mechanism has revealed that transcription of PHYO, PHYP and PHYN and the class IV chitinase PaChi4 (using RealTime PCR) all show higher transcription levels in progenies born under cold conditions than their full-sibs born under warmer conditions. This result is consistent with preliminary findings that methylation of cytosine in total DNA is higher in progenies reproduce under warm conditions than their colder full-sib counterparts. If these observations are related to methylation, we may explain why progenies with a memory of a past time cold embryogenesis are more sensitive to short days than their full-sibs with a warmer embryonic history.
Abstract
We estimated time from death to fall (standing time) of Norway spruce (Picea abies (L.) Karst.) snags in a submountainous old-growth forest in south-central Norway, applying four calculation methods to 124 dendrochronologically cross-dated still-standing snags and 64 fallen logs. The calculation methods consistently estimated expected standing time of snags at 26–34 years, with a median of 16–21 years and 20% of snags standing for >48–58 years. The survival function from all methods took the approximate form of a negative exponential, with a 3%–4% annual fall rate for snags. In the distribution of time since death, a small peak in dead trees 20–30 years ago (late 1970s) coincides with a historic epidemic of bark beetles. The method using only time since death of still-standing snags appears to be the most feasible for estimating total standing time of snags in old-growth forests with constant tree mortality.
Abstract
Pathogen colonization and transcript levels of three host chitinases,putatively representing classes I, II, and IV, were monitored with real-time PCR after wounding and bark infection by Heterobasidion annosum in 32-year-old trees of Norway spruce (Picea abies) with low (clone 409) or high (clone 589) resistance to this pathogen. Three days after inoculation, comparable colonization levels were observed in both clones in the area immediately adjacent to inoculation. At 14 days after infection, pathogen colonization was restricted to the area immediately adjacent to the site of inoculation for clone 589 but had progressed further into the host tissue in clone 409. Transcript levels of the class II and IV chitinases increased after wounding or inoculation, but the transcript level of the class I chitinase declined after these treatments. Transcript levels of the class II and class IV chitinases were higher in areas immediately adjacent to the inoculation site in clone 589 than in similar sites in clone 409 3 days after inoculation. This difference was even more pronounced 2 to 6 mm away from the inoculation point, where no infection was yet established, and suggests that the clones differ in the rate of chitinase-related signal perception or transduction. At 14 days after inoculation, these transcript levels were higher in clone 409 than in clone 589, suggesting that the massive upregulation of class II and IV chitinases after the establishment of infection comes too late to reduce or prevent pathogen colonization.
Abstract
We have monitored the H. annosum colonization rate and expression of host chitinases in Norway spruce material with differing resistances. Transcript levels of three chitinases, representing classes I, II and IV, were monitored with real-time PCR. Ramets of two 32 -year-old clones differing in resistance were employed as host material and inoculation and wounding was performed. Quantification of fungal colonization: Multiplex real-time PCR detection of host and pathogen DNA was performed. Chitinase transcript levels were also monitored with real-time PCR. Three days after inoculation, comparable colonization levels were observed in both clones in the area immediately adjacent to inoculation. Fourteen days after infection, pathogen colonization was restricted to the area immediately adjacent to the site of inoculation for the strong clone (589), but had progressed further into the host tissue in the weak clone (409). Transcript levels of the class II and IV chitinases increased following wounding or inoculation, while the transcript level of the class I chitinase declined following these treatments. Transcript levels of the class II and class IV chitinases were higher in areas immediately adjacent to the inoculation site in 589 than in similar sites in 409 three days after inoculation, suggesting that the clones differ in the rate of chitinase-related signal perception. The spatiotemporal accumulation patterns obtained for the two clones used are consistent with their resistance classifications, these warranting further and more detailed studies on these chitinases.
Authors
Amy M. Brunner Igor A. Yakovlev Steven H. StraussAbstract
Background Real-time reverse transcription PCR (RT-PCR) has greatly improved the ease and sensitivity of quantitative gene expression studies. However, accurate measurement of gene expression with this method relies on the choice of a valid reference for data normalization. Studies rarely verify that gene expression levels for reference genes are adequately consistent among the samples used, nor compare alternative genes to assess which are most reliable for the experimental conditions analyzed. Results Using real-time RT-PCR to study the expression of 10 poplar (genus Populus) housekeeping genes, we demonstrate a simple method for determining the degree of stability of gene expression over a set of experimental conditions. Based on a traditional method for analyzing the stability of varieties in plant breeding, it defines measures of gene expression stability from analysis of variance (ANOVA) and linear regression. We found that the potential internal control genes differed widely in their expression stability over the different tissues, developmental stages and environmental conditions studied. ConclusionOur results support that quantitative comparisons of candidate reference genes are an important part of real-time RT-PCR studies that seek to precisely evaluate variation in gene expression. The method we demonstrated facilitates statistical and graphical evaluation of gene expression stability. Selection of the best reference gene for a given set of experimental conditions should enable detection of biologically significant changes in gene expression that are too small to be revealed by less precise methods, or when highly variable reference genes are unknowingly used in real-time RT-PCR experiments.
Authors
Tove M. Østensvik Kaj Bo VeierstedAbstract
No abstract has been registered
Abstract
Sampling the catchment outlet generally is assumed to be a convenient way to infer information about a variety of biogeochemical processes at the catchment scale as it provides a spatial and temporal integral of the predominating catchment output fluxes for a number of chemical compounds of interest.Moreover, the short-term dynamics and long-term trends of the hydrograph and of solute concentrations in the catchment runoff can provide information about the predominating processes at the catchment scale and can be used to refine conceptual and mathematical models.Additional measurements inside the catchment, e.g., of soil solution, groundwater, and stream water at different sites, are used to relate the findings to within-catchment processes and thus to further constrain hypotheses and models.
Authors
Birger VenneslandAbstract
No abstract has been registered