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
Authors
Bernt-Håvard ØyenAbstract
Sitka spruce (Picea sitchensis (Bong.) Carr) is native to the Pacific North West of America and was introduced to Western Europe in the early 19th century. It is now an important commercial species along the extreme western seaboard of Europe – namely Ireland and Great Britain – and this is where most progress has been made in the area of selection and breeding. Sitka spruce has been the subject of more limited selection and breeding work in some other European countries where it is of secondary or minor significance - Denmark, France, Germany, and Norway. These programmes have now effectively come to a close due to perceived lack of importance. In Sweden Sitka spruce is being planted at an increasing rate and is seen as a species of great potential in the light of climate change. This monograph presents details and statistics relating to Sitka spruce breeding across Europe. It summarises the work carried out to date (plus trees, field testing, orchards), the gains achieved, knowledge of genetic relationships between selection traits, and acts as a conduit to further references for the interested reader.
Authors
Felix Herzog Katalin Balázs Peter Dennis Tetyana Dyman Wendy Fjellstad Jürgen Friedel Salah Garchi Philippe Jeanneret Rob Jongman Maximilian Kainz Gerardo Moreno Charles Nkwiine Maurizio Paoletti Philippe Pointereau Jean-Pierre Sarthou Siyka Stoyanova Davide ViaggiAbstract
Farmland biodiversity is an important component of Europe’s biodiversity. More than half the continent is occupied by agricultural lands. They host specific habitats and species, which - in addition to their conservation values they provide - perform vital ecological functions. Indicators are needed to enable the monitoring of biodiversity at the farm level for the purpose of assessing the impacts of farming practices and of agricultural policies. Our research aims at identifying farmland biodiversity indicators which are scientifically sound, operational and relevant for stakeholders. We screened the literature for farmland biodiversity indicators and, in an iterative process with stakeholders, we identified 28 candidate indicators for genetic, species and habitat diversity. Those selected biodiversity indicators, as well as 14 management indicators that are known to relate to biodiversity, were assessed in 12 case study regions across Europe. Each case study region represents a typical production system (i.e. specialist field crops, horticulture and permanent crops; specialist grazing with cattle and other livestock types; mixed crop and livestock farming). In each region, 8-20 farms were randomly selected, mostly within the two groups of organic and non-organic farms, to obtain a gradient of farming intensity. Indicators were measured applying standardized sampling procedures and farm interviews. Sampling effort was recorded in order to assess the cost of indicator measurement. For each case study region, biodiversity indicators are presently being evaluated in conjunction with management indicators. Surrogate indicators will be proposed when possible and indicators will be prioritized taking into account their validity, practicality, cost and priority for stakeholders. Based on preliminary results, the presentation will focus on the specific challenges of farm level monitoring, addressing issues of sampling design within the farms and up-scaling from plot to farm to region. Part of this research was funded by the EU FP7 contract KBBE-2B-227161. For more information consult www.biobio-indicator.org
Abstract
Understanding the driving forces affecting species occurrences is a prerequisite for determining the indicator suitability of crenic plants. We analysed 18 environmental variables in a two-step approach, evaluating their ability to explain the species composition of 222 springs on five siliceous mountain ranges, in central Germany and north-west Czech Republic (49.9°–50.8°N, 10.6°–12.8°E). First, we identified the significant environmental variables in three subsets of spatial, hydrophysical and hydrochemical variables using a forward-selection procedure. We then performed a partial canonical correspondence analysis (pCCA) to estimate the influence of each subset alone, as well as in combinations. We also used a multiple response permutation procedure (MRPP) to compare the five regions with respect to the dissimilarity of their vegetation composition and environmental variables. Hydrochemical factors played a fundamental role in determining the plant community of the investigated springs. Spatial factors, in particular altitude, were correlated with the hydrochemical factors, but were less important. Hydrophysical factors played only a marginal role. More precisely, species occurrence was mainly driven by a gradient of nutrient availability, which in turn reflected the acidity status. This gradient was primarily represented by high Al, Cd, and Mn concentrations in acidic crenic waters, high Ca and Mg concentrations were encountered in circumneutral springs. By comparing the five regions we could show that there are spatial patterns in the vegetation of springs, which provide valuable ecological information on the water quality. We therefore suggest that biomonitoring approaches to vegetation are suitable for revealing the acidity status of springs and their forested catchments.
Authors
Peder GjerdrumAbstract
Scaling accuracy is of utmost importance to obtain optimal yield in log breakdown. In this paper we have combined sawmill experience, a review of available publications and supplementary observations to analyse the accuracy of roundwood scaling for Norway spruce and Scots pine. The influence of ovality, bark thickness variation and bark damage were analysed for scaling in one-directional and two- directional shadow scanners, and for three-dimensional (3D) reflected beam scanners. The overall accuracy for diameter under bark can be calculated by adding the variances for each independent term. For unbarked logs, shadow scanners with two perpendicular directions are most accurate. Results show that 3D scanners are most accurate, provided used for barked logs. For a case study, transferring from scaling unbarked logs in a two-dimensional shadow scanner to a full 3D scan of barked logs reduced annual roundwood consumption by 2.0%.
Authors
Helmer BelboAbstract
The theoretical potential for increased efficiency in early thinning by using accumulating harvester heads was investigated through simulation. Thinning was performed in corridors perpendicular to the strip road in 75 artificially generated stands with varying average tree size and density. The work pattern and work time in the crane work for five sizes of heads, with grapple diameters in the range of 10 to 50 cm, was estimated by the simulation model. The efficiency increased rapidly when the grapple diameter increased from two to four times the average diameter in the harvested stand, reducing the work time per tree by 15 to 50 percent compared to the single tree handling harvester head. Further increases in grapple dimension also increased the efficiency, but not at the same rate. In real work, the efficiency increase by an accumulating harvester head will probably be slightly lower due to less optimal harvesting conditions, operator skills and other non-productive work tasks that are not affected by work method.
Abstract
Forest regrowth in rural districts of Norway is currently leading to extensive landscape changes. We aim to quantify and understand the future impact of outfield forest regrowth following land-use abandonment on red-listed vascular plant species which are supposedly threatened by regrowth in Norway, i.e. species classified to habitats within the semi-natural landscape. Vascular plant species were defined by the Norwegian Red List and presence data was downloaded from the Norwegian GBIF-node, Artskart. A newly developed spatially explicit model of deforested semi-natural heaths and meadows in Norway was used to evaluate the vulnerability of red-listed plants to future forest regrowth. The results show that some red-listed species may be greatly affected, since they have most of their known populations within the modelled areas of future forest regrowth. The study also revealed that there are many methodological challenges in using museum databases for hypothesis testing. However, the use of such databases was clearly hypothesis generating, giving us many ideas for future studies.
– Changes in landscape and vegetation heterogeneity of rural Norway
Lars Østbye Hemsing, Anders Bryn
Abstract
Extensive landscape and vegetation changes are apparent within rural districts of Norway, especially as forest regrowth on abandoned agricultural land. Forest regrowth changes the landscape and vegetation heterogeneity, thus affecting management issues related to, for example, biodiversity and landscape aesthetics. By comparing up-to-date actual vegetation maps (AVMs), interpreted previous vegetation maps (IPVs), and potential natural vegetation maps (PNVs), we assess and quantify structural changes on a landscape level which are important for biological diversity and also the tourism industry. Our findings indicate that landscapes in rural districts of Norway have changed and that changes will continue in the future. The landscapediversity did not decrease from the 1970s until 2009. Further forest regrowth however, will lead to reduced landscape heterogeneity, while landscape connectivity will increase.
Abstract
Wood exhibits a highly anisotropic mechanical behavior due to its heterogeneous microscopic structure and composition. Its microstructure is organized in a strictly hierarchical manner from a length scale of some nanometers, where the elementary constituents cellulose, hemicelluloses, lignin, and extractives are found, up to a length scale of some millimeters, where growth rings composed of earlywood and latewood are observed. To resolve the microscale origin of the mechanical response of the macro-homogeneous but micro-heterogeneous material wood, micromechanical modeling techniques were applied. They allow for prediction of clear wood stiffness (Hofstetter et al. 2005,2007, Bader et al. 2010a,b) from microstructural characteristics. Fungal decay causes changes in the wood microstructure, expressed by decomposition or degradation of its components (Côté 1965, Schwarze 2007). Consequently, macroscopic mechanical properties are decreasing (see e.g. Wilcox 1978). Thus, in the same manner as for clear wood, consideration of alterations of wood in a micromechanical model allows predicting changes in the macroscopic mechanical properties. This contribution covers results from an extensive experimental program, where changes in chemophysical properties and corresponding changes in the mechanical behavior were investigated. For this purpose, pine (Pinus sylvestris) sapwood samples were measured in the reference condition, as well as degraded by brown rot (G. loeophyllum trabeum) or white rot (Trametes. versicolor). Stiffness properties of the unaffected and the degraded material were not only measured in uniaxial tension tests in the longitudinal direction, but also in the three principal material directions by means of ultrasonic testing. The experiments revealed transversal stiffness properties to be much more sensitive to degradation than longitudinal stiffness properties. This is due to the degradation of the polymer matrix between the cellulose fibers, which has a strong effect on the transversal stiffness. On the contrary, longitudinal stiffness is mainly governed by cellulose, which is more stable with respect to degradation by fungi. Consequently, transversal stiffness properties or ratios of normal stiffness tensor components may constitute suitable durability indicators. Subsequently, simple micromechanical models, as well as a multiscale micromechanical model for wood stiffness, were applied for verification of hypotheses on degradation mechanisms and model validation.
Abstract
In 2005 an extensive test program including field tests was set up in order to obtain more data on the durability and long term performance of modified wood and semi-durable wood species. One of the main challenges for modified wood is to predict accurate service life time in UC3 (Use use class 3, above ground) and UC4 (use class 4, in soil or fresh water contact). So far, data from in-service conditions are rare, while several studies have evaluated the durability in lab or field test exposure. However, there is still a lack of studies comparing replicate modified wood products in both field and lab exposure. This study evaluates the efficacy of modified wood in AWPA E10, three different types of soil in lab (ENV 807), three test fields in-ground (EN 252) and two close to ground (horizontal double layer test) set-ups at two test sites. The test material includes furfurylated, acetylated and thermally modified wood in addition to reference treated and control samples. In laboratory, both furfurylated, acetylated and thermally modified pine (212ºC) performed well. The modified wood samples performed at the same level, or better, than the reference CC and CCA preservatives in retentions for UC4 applications. In the horizontal double layer test, five years is still too short time to be able to draw firm conclusions. However, in the most accelerated HDL set-up, all controls have failed or are moderately to severely decayed whereas most preservative treated, furfurylated and acetylated wood are sound or only slightly decayed. After 5 years of testing CCA-preserved wood performs better in-ground in field tests than in lab tests, whereas modified wood generally performs slightly poorer. Just like in the lab tests, however, acetylated wood performs equal to CCA-preserved wood in UC4. Furfurylated wood performs equal to or better than UC3 level preservative treated wood. Thermally modified wood actually performs much poorer than all preservative treated wood references. Finally, natural durability classification of the same treatment in different lab and field tests was surprisingly similar.
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.