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.
2009
Authors
Ari Hietala Nina Elisabeth Nagy Arne Steffenrem Harald Kvaalen Carl Gunnar Fossdal Halvor SolheimAbstract
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.
Authors
Øystein Johnsen Harald Kvaalen Igor A. Yakovlev O.G. Dæhlen Carl Gunnar Fossdal Tore SkrøppaAbstract
No abstract has been registered
2008
Abstract
No abstract has been registered
Abstract
Progenies from a natural stand of Picea abies planted on a forest site with heterogeneous growth conditions were characterized for genetic and environmental control of internodal and whorl branch formation and lammas growth. The progenies studied were 27 years old from seed and planted in a randomized complete block experiment. Internodes and whorls studied were located in the top section of the trees. Significant genetic variation (p<0.01) was found for a number of internodal and whorl branches. Block means for the length of internodes, a strong indicator for the site index in respective blocks, were correlated strongly with branch dimensions (r >= 0.90), intermediately with the frequency of lammas growth (r = 0.81) and number of branches in whorls (r = 0.68), and only weakly with the number of internodal branches per length unit of internode (r = 0.25). A strong environmental effect on branch dimensions was supported by the relative size of variance components. The results show that the environmental effect expressed by site index dominates the control of branch dimensions, while the number of branches is under stronger genetic control in P. abies.
Abstract
This paper reports the results from a study of modulus of elasticity (MOE) and modulus of rupture (MOR) of 42 small clear specimens prepared from 300 year old roundwood floor girders containing high levels of NaCl at Bryggen in Bergen, Norway. NaCl concentration was 6.5 % of the dry matter of the wood. MOE and MOR were 25 % lower than the values obtained from a reference material with equivalent annual ring width and density. The considerable reduction of MOE and MOR should be taken into consideration in conservation of load-bearing wooden structures that have been exposed to NaCl.
Authors
Tor MykingAbstract
An international EU/Interreg III Kolarctic project `Development and implementation of an environmental monitoring and assessment program in the joint Finnish, Norwegian and Russian border area`, was carried out during 2003–2006 as a joint undertaking between Norwegian, Finnish and Russian research institutes and environmental authorities. The aim of the terrestrial ecosystem sub-project of the Pasvik project was to develop and implement a monitoring and assessment programme for terrestrial ecosystems in the joint Finnish, Norwegian and Russian border area...
Abstract
Harmonization was achieved by carrying out joint sampling and assessment exercises at selected sites, inter-laboratory ring tests for the chemical analyses of deposition, plant and soil material, and by drawing up data compilation, data analysis and reporting guidelines and templates for the researchers working in the three countries.
Abstract
No abstract has been registered
Authors
Arne SteffenremAbstract
Wood based products come from a renewable resource playing an important part of the carbon cycle and are therefore regarded environmentally friendly compared to many other alternatives. We might therefore expect a more intensive use of the timber resource in the future. An increase in the supply and net value of timber products from a given area requires more intensive and cost efficient forest management. However, a faster growth rate in general and an increase in the juvenile wood proportion specifically, might come in conflict with the desirable wood quality. Tree breeding programs for Norway spruce (Picea abies L. Karst.) aim to follow up the general demands by providing forestry with plant materials that have superior growth and high wood quality. It is therefore important to establish a better knowledge of the potential of improving wood quality characters in this species through breeding. Characteristics important for structural strength and dimensional stability in conifers are wood density, spiral grain, microfibril angle (MfA) in the S2 layer in the secondary cell wall, branch characteristics and stem straightness. We have studied the genetic variation and correlation patterns for these traits and the direct end-use performance of clearwood samples in terms of stiffness (MOE) and strength (MOR) in four studies of Norway spruce (Paper I-IV). Wood quality traits of defect free wood were studied in Paper I and II. The materials used were 28 and 29 year old progeny trials planted in South East Norway on fertile soils. Significant genetic variation was found for wood density, MfA and spiral grain in both studies (p < 0.05). MOE and MOR, measured by static bending, were studied in one of the materials and the genetic variation was found to be highly significant (p < 0.01). There was also significant genetic variation (p < 0.05) in MOE estimated (MOEest) from wood density and the x-ray diffractometry pattern from the S2 layer obtained by SilviScan®-3. Genetic parameters were estimated in Paper II with large standard errors. The parameters must therefore be used with caution and preferably with support from other studies. We could confirm earlier studies of high genetic variation and low genotype by environment interactions (GxE) for wood density and spiral grain. Parameter estimates for MfA and MOEest, from one site, suggest that these are under moderate to strong genetic control in Norway spruce. Phenotypic correlations between growth traits (height and diameter growth) and wood quality traits were negative for wood density, positive for MfA and negative for MOEest. Genetic relationships showed the same trends for diameter growth, but not for height growth. The genetic and environmental variation in branch characteristics (Paper III and IV) were studied in three sets of progeny trials that were 22, 28 and 29 years old from planting. Stem straightness was studied in the 22-year old trial only. The branch diameter was highly influenced by site index and spacing. Number of branches formed and stem straightness seems to be under stronger genetic control. Individual tree heritabilities for growth traits, branch diameter and stem straightness were estimated in the 22-year old progeny trial planted at two sites. The trials were planted with different spacing, which allowed us to study genotype by spacing interactions. Heritability for growth traits and branch diameter across sites were moderate (0.14 - 0.19) compared to the higher values found for stem straightness (0.28). GxE, and thereby genotype by spacing interactions were not important for any of the traits. Heritability for number of branches, estimated from one of the sites, was 0.24. There was a strong and positive genetic correlation between growth traits and branch diameter. The presence of genetic variation for most wood quality traits suggests that these can be improved by tree breeding. However, genetic correlations with growth traits indicate that selection solely for growth might have adverse effects on wood quality. It is therefore important to balance the gain in growth and wood quality. Implementation of several adversely correlated traits in a breeding program reduces its efficiency. It is therefore essential that tree breeding, silvicultural practices and forest industrial needs interact when developing tree breeding programs to obtain an optimal strategy for selection and utilization of improved plant materials.