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.
2010
Abstract
No abstract has been registered
Abstract
Today the spruce bark beetle Ips typographus is always univoltine in Northern Europe including Norway and completes development from egg to adult between May and August. Further south in Europe, development is bivoltine with the completion of two generations in most years. A temperature-driven developmental model suggests that by 2070-2100 the voltinism of I. typographus will change dramatically in Norway. If summers become only 2.5°C warmer than today bivoltinism can be expected every single year in the major spruce growing areas in S-Norway. This is likely to have dramatic effects on forestry since two generations per year will give two, instead of one, attack periods each summer. In addition to increasing the number of attacked trees the effect of the attacks may also be more severe, as Norway spruce is more susceptible to beetle attacks later in the summer. However, climate change will probably also change the phenology of Norway spruce and thus its susceptibility to attack by I. typographus and its phytopathogenic fungal associates. We are currently modelling how tree resistance varies with temperature and tree phenology in order to provide more well-founded advice to forest managers on the interaction between bark beetles and tree in a future climate.
2009
Abstract
No abstract has been registered
Authors
Holger Lange Nicholas Clarke O. Janne Kjønaas Wenche Aas Kjell Andreassen Rasmus Astrup Susanne Eich-Greatorex Toril Eldhuset Kjersti Holt Hanssen Tonje Økland Ingvald Røsberg Trine A SognAbstract
No abstract has been registered
Abstract
In trees adapted to cold climates, conditions during autumn and winter may influence the subsequent timing of bud burst and hence tree survival during early spring frosts. We tested the effects of two temperatures during, dormancy induction Mid mild spells (MS) during chilling, on the timing of bud burst in three Picea abies (L.) Karst. provenances (58-66 degrees N). One-year-old seedlings were induced to become dormant at temperatures of 12 or 21 degrees C applied during 9 weeks of short days (12-h photoperiod). The seedlings were then moved to cold storage and given either continuous chilling at 0.7 degrees C (control), or chilling interrupted by one 14-day MS it either 8 or 12 degrees C. Interruptions with MS were staggered throughout the 175-day chilling period, resulting in 10 MS differing in date of onset. Subsets of seedlings were moved to forcing conditions (12-h photoperiod, 12 degrees C) throughout the chilling period, to assess dormancy status different timings of the MS treatment. Finally, after 175 days of chilling, timing of bud burst was assessed in a 24-h photoperiod at 12 degrees C (control and MS-treated seedlings). The MS treatment did not significantly affect days to bud burst when given early (after 7-35 chilling days). When MS was given after 49 chilling days or later, the seedlings burst bud earlier than the controls, and the difference increased with increasing length of the chilling period given before the MS. The 12 degrees C MS treatment was more effective than the 8 degrees C MS treatment, and the difference remained constant after the seedlings had received 66 or more chilling days before the MS treatment was applied. In all provenances, a constant temperature of 21 degrees C during dormancy induction resulted in more dormant seedlings (delayed bud burst) than a constant temperature of 12 degrees C, but this did not delay the response to the MS treatment.
Abstract
Wood is a traditional building material but in general it underlies restrictions in outdoor applications due to its respective durability against microbiological decay. To face this problem, different impregnation systems are applied to enhance the materials\" servicelife. Scots pine (Pinus sylvestris) is the most widely distributed pine in Eurasia and hence easily available. Despite of the previously defined good treatability of Scots pine sapwood, large differences in treatment performance are reported from industry. As process parameters are always adjusted to the material most difficult to treat, permeability variations in wood material are an economical problem. Therefore, it is important to understand the material in order to make a more reasonable material selection possible.....
Authors
Holger Lange Nicholas Clarke O. Janne Kjønaas Wenche Aas Kjell Andreassen Isabella Børja Harald Bratli Susanne Eich-Greatorex Toril Drabløs Eldhuset Kjersti Holt Hanssen Tonje Økland Ingvald Røsberg Trine Aulstad Sogn Tomasgaard Volkmar TimmermannAbstract
No abstract has been registered
Abstract
New environmental benign wood protection agents often come from natural resources, and are sometimes a waste product. Chitosan, a derivative from chitin which is among other sources a by-product from the shellfish industry, is tested as well as known wood protection agents and their synergetic effect with chitosan. The objective of the research presented in this paper, is to describe the leaching properties of the following compounds: Chitosan, chitosan/copper, chitosan/boron and chitosan/ScanImp (a commercial wood preservative). A leaching procedure was performed on treated Scots pine sapwood samples. The four solutions have also been tested with and without post treatment. A new effective fire preservative has been included in the test. Common wood preservatives have been tested as references. The combination with chitosan did improve the fixation of the wood protection agent ScanImp. Furthermore, the post treatment of the chitosan treated samples did significantly reduce the leaching of glucosamine and to some extend also the leaching of boron.
Abstract
The durability of wood in exterior use is limited by to climatic factors and wood deteriorating organisms. The natural durability of the Nordic wood species is generally regarded as low, and for e.g. decking and use in soil contact wood protection is needed. Within the last years, new non-biocidal treatments, like wood modification systems, have been developed to improve the biological resistance of wood. For information about the decay resistance of untreated and modified wood, natural outside exposure is necessary. European standard EN 252 is the main field test method for use class 4. In use class 3 the need of new or improved test setups has been put forward. Traditionally evaluation of field trials has mainly been based on visual evaluation and pick-test. However, to get in depth knowledge about: 1) different field trial methods and 2) fungal colonization of new wood protection systems, additional assessment methods can be used. Hence, comparative studies are needed.....
Abstract
No abstract has been registered