Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2009
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
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.
Sammendrag
Genetic parameters were estimated for wood density and spiral grain in two long-term field trials with families of Picea abies (L.) Karst., and for microfibril angle (MfA) and model-predicted wood stiffness (MOEest) at one of the sites. The trials were located at 600-720 m altitude in Norway and the progenies, which were a sample of 13 half-sib families from plus-trees in a breeding population, were 33 years old from seed when measured. Significant genetic variation (p0.05) was found for all wood quality traits. The narrow-sense heritability was estimated to be 0.50 for density (across two sites), 0.38 for MfA, 0.29 for MOEest and 0.37 for spiral grain (across two sites). No significant genotype by environment interactions were found for density or spiral grain (p0.05). Genetic relationships between ring width and wood quality traits were negative for density and MOEest, and positive for MfA. Site index and competition had major effects on wood density and predicted MOEest but not on MfA and spiral grain.
Forfattere
Mari Mette Tollefsrud Jørn Henrik Sønstebø Christian Brochmann Øistein Johnsen Tore Skrøppa GG VendraminSammendrag
Det er ikke registrert sammendrag
2008
Forfattere
Harald Kvaalen Arne Steffenrem Øystein Johnsen Øyvind Meland Edvardsen Ragnar Johnskås Bernt-Håvard ØyenSammendrag
Bruk av foredla plantemateriale kan gi varig økt volumtilvekst og forbedret kvalitet. Men det siste er avhengig av tilstrekkelig utgangstetthet, større enn den som vanligvis brukes ved planting i dag.
Sammendrag
Huldrestry er en epifyttisk lavart som står på den norske rødlista som sterkt truet (EN). Arten synes å være i sterk tilbakegang i mange av de kjente lokalitetene i hele Norge. Det er mangelfull kunnskap om artens økologiske krav og toleranse for hogst. En av flere grunner til tilbakegangen antas å være at skogen i noen lokaliteter er blitt for tett. Mjøsen Skog har en betydelig andel av huldrestryforekomstene i landet i sitt område og har dermed et ansvar for å bidra til å ivareta lavarten. Mjøsen har derfor gjennom prosjektet tatt initiativ til å skaffe fram et bedre grunnlag for å forvalte arten. Prosjektet har gått over 3 år, 2005 – 2007. Huldrestryforekomstene i Lillehammer ble registrert under kartlegging av biologisk viktige områder (MiSregistreringer) i 2003. Huldrestry er her mest tallrik i hogstmoden granskog i produktive skoglier. Historisk utvikling Forskere ved Norsk institutt for skog og landskap har gjennomført undersøkelser av huldrestry og skoghistorie. I forsøksområdet, Saksumdalen og Korsåsen i Lillehammer, ble tidligere tiders plukkhogst erstattet av flatehogst og kulturskogbruk fra 1950tallet. Den eldre skogen i dag framstår som rester etter de gamle hogstene...
Forfattere
Tor MykingSammendrag
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...
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Arne SteffenremSammendrag
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.
Sammendrag
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.