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.
1988
Forfattere
Mette M. HandlerSammendrag
This report describes a square spacing experiment with Picea abies situated in the eastern part of Norway approximately 350 m above sea level. The following distances are represented: 1.2 m, 1.8 m, 2.4 m and 3.0 m. The experiment is a Latin square i.e. with 4 replications of each treatment. Each plot is 20 m x 20 m (Fig. 1). The experiment was measured in 1977 after heavy snow damage (Braastad 1979) and in 1984 at a top height of 14 m and total age 35 years (Table 1-3). The site index class (H40) is 20.6. The report deals with the measurement in 1984 and the increment period 1977-1984. The preliminary results show: The snow damage caused a heavy reduction in stem number in the 1.2 m spacing, moderate reduction in the 1.8 m spacing, while the two widest spacings were almost unaffected. In the last period the natural thinning has been negligible (Fig. 2). The top height does not seem to have been influenced by the spacing (Fig. 3). The basal area mean diameter and the diameter increment increase with increasing spacing (Fig. 4 and 6). The widest spacing has lost about 60 m3 per ha in standing volume in proportion to the other spacings and has a lower volume increment (Fig. 5 and 7). Diameter and diameter increment of the 800 largest trees per ha (according to diameter) increase with increasing spacing, but the differences are small (Fig. 4 and 6). Volume and volume increment of the 800 largest trees increase with increasing spacing (Fig. 5 and 7). The difference in standing volume between the widest and closest spacing is 24 m3 per ha. The experiment will be left unthinned in the future, and it is expected that the difference in volume production between the close and the widest spacing will not increase considerable. Time will show, whether the competition from the smaller trees in the close spacings will reduce the growth of the largest trees and thereby increase the tendency to increased growth of the largest trees with increasing spacing. The height to first live branch has increased by approximately 2 m since the measurement in 1977; from 1.9 m to 4.1 m in the closest spacing and from 0.5 m to 2.9 m in the widest spacing (Fig. 8). Branch diameter on bark was measured on the 15 largest trees on an inner plot of 15 m x 15 m. The horisontal diameter of the thickest branch in each whorl from 1.3 m to 5.0 m above ground was measured. The mean branch diameter of the thickest branches between 1.3 m and 5.0 m above ground increases with increasing spacing from 14.8 mm to 20.4 mm. Mean branch diameter of the thickest branch per tree increases from 19.1 mm for spacing 1.2 m to 24.3 mm for spacing 3.0 m (Fig. 9). On average for each spacing this branch diameter has increased maximum 1 mm, and for 95 % of the single trees less than 3 mm since the measurement in 1977. The diameter of the thickest branch is expected to have reached almost its final magnitude. The thickest branch is for 79 % of the trees situated 4.5 m or more above the ground. The planting distance should not exceed 2.4 m on this locality and with this provenance (Norwegian), if the maximum branch diameter is not to exceed 20 mm u.b. 5.0 m above ground.
Forfattere
Torbjørn OkstadSammendrag
Geometric properties, wood properties and quality were measured in a sample of pulpwood logs from Central Norway. The average middle diameters with bark of butt logs, middle logs and top logs were 17.2 cm, 16.6 cm and 10.6 cm respectively (Table 1). The frequency distribution of the diameters is given in Fig. 1. The average log length in this sample is 4.32 m (Table 2). The frequency distribution of the log length is illustrated in Fig. 2. Log taper was calculated to be 1.40 cm/m on the average (Table 3). Log taper increases with increasing diameter (Fig. 3). The ovality of the logs increases with increasing diameter (Fig. 4). The average basal area quotient is calculated to be 0.88 (Table 4). Double bark thicknesses of the butt logs, middle logs and top logs in this sample are 10.9 mm, 10.3 mm and 7.2 mm respectively (Table 5). Average bark volume percentages are 11.7%, 12.0% and 13.2% respectively. The corresponding figures measured according to special rules by the measurement society are 11.2%, 12.4% and 14.6% respectively (Table 6). The average log volume with bark of this sample is 75.3 dm3 (Table 7). The frequency distribution of the log volume is given in Fig. 7. The proportion of knotwood and compression wood of the total wood volume is on the average 2.0% and 5.8% respectively (Tables 8 and 9). The proportion of decayed wood is 3.3% (Table 10). The measurement society classified 86.6% of the total volume as first class quality, 6.6% as second class quality and 6.8% as cull (Table 11). The growth ring width in this sample was on the average 1.3 mm (Table 12). The basic density of the logs is given in Table 13 and was on the average 415.0 kg/m3. The relationship between basic density decreases with increasing growth ring width. The moisture content (per cent of green weight) at the time of delivery is highest in the winter and lowest in the late summer (Fig. 11).
Forfattere
Liv G. HineSammendrag
Bakgrunnen for forsøksresultatene fra Vestlandet er følgende flater: Erdalsdalen, 7 vekstsesonger Hamra og Skiple, 5 vekstsesonger Frotveit, 11 vekstsesonger Valdersnes, 12 vekstsesonger. Den oppgitte alderen er tidsrommet mellom etablering av forsøket og den siste registreringen på feltet. Marktypen var røsslyngmark på Valdersnes og Frotveit. Forsøket på Hamra ble lagt på en hogstflate i ei bratt nordøstvendt li, der blåbær utgjør den vanligste arten i feltskiktet. På Skiple ligger feltet i et gammelt bjørkebestand i ei nordvestvendt li. I Erdalsdalen kan marktypen karakteriseres som oremark. Følgende plantetyper og plantemetoder ble brukt: Barrot - hakkeplanting Kopparfors (pluggplanter) - hullpipe med og uten flekking og Pottiputki. En sammenlikning mellom de to plantetypene barrotplanter og pluggplanter, viser at barrotplantene i de fleste tilfelle har hatt minst avgang. Bare ved sommerplanting, spesielt i juni, har resultatet vært dårligere enn for pluggplantene. Også når det gjelder høydetilvekst har barrotplantene generelt sett vært best. Dette hovedresultatet går igjen på alle forsøksflater der barrotplanter er med. Det kan således ikke påvises noen effekt av feltenes beliggenhet og markbonitet. Bare plantetidspunktet synes å påvirke forholdet mellom de to plantetypene. For pluggplantene ble det brukt tre plantemetoder. Hullpipe med flekking, det vil si fjerning av vegetasjonsdekket på planteplassen, har i de fleste tilfeller gitt gode resultater både med hensyn til tilslag og vekst. Plantemetoden hullpipe uten flekking har så og si uten unntak ført til størst avgang og minst vekst. Resultatene viser at en flekkstørrelse på 9 dm2 fører til signifikant større overleving sammenliknet med planting uten flekking. Flekking av plantestedet har hatt den samme gunstige virkningen på alle marktyper og ved alle plantetidspunkter. Resultatene viser således at hullpipe med flekking definitivt er den beste plantemetoden for pluggplantene. I denne undersøkelsen har bruk av barrotplanter gitt best resultat. Det beste alternativet til barrotplantene ser ut til å være pluggplanter plantet om våren på avflekkete planteplasser. Det er på grunnlag av disse forsøkene ikke mulig å gi anbefalinger om plantetype/-metoder på ulike boniteter.
Forfattere
Jarle Bergan Trygve EideSammendrag
During 1979-82 seven field tests were carried out at 69°N in Norway (Table 1). Four tests included seeding of Pinus sylvestris under plastic cones (K) and funnels (T) compared to seeding without cover (S) and plug planting (P) (see Fig. 1). Three field tests included seeding of Picea abies in funnels located in virgin vegetation in birch forests on the hillsides. Here the seeding in funnels was compared to plug planting. The plant percentage means the percentage of seeds forming plants up to the first autumn. The germination percentage of the seed used has been 92.5% to 95.0%. The number of pine seeds per spot was four seeds in cones and funnels, and 15 seeds in open sowings on scarified patches. Six spruce seeds were used in each funnel in the tests on the hillside. The survival percentage means the percentage of cones, funnels or patches with one or more living plants. The vegetation type of the areas of pine plots is Vaccinio-Pinetum boreale, and on spruce areas Eu-Piceetum abietis-subass. dryopteridetosum. The seeding in cones (Method K) has turned out to be a reliable method with high survival percentage and relatively good height development, especially the first years with seedlings inside the cones. The consumption of seed is very low in relation to open sowings (Method S). The plant percentage in cones has in average been about 80% compared to 53% in open sowings (Table 2). However, there is a risk of cones being removed by persons, birds, and strong wind. Method S has shown more varying results as regards plant percentage and survival percentage. However, by using 25 seeds per patch instead of 15 seeds, the possibility of increasing the survival percentage in years with unfavourable climatic conditions, would have been quite good. Bergan (1957 and 1981) found high positive correlation between the number of plants per patch and the survival percentage. Also plug planting is a highly acceptable regeneration method. On the other hand, sowing in funnels (Method T) has been less successful in all tests both regarding survival percentage and height development. The choice of regeneration method between the methods K, S and P at pine areas at these northern latitudes depends on the supply of seed, economic calculations, and administration conditions.
1987
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Tore SkrøppaSammendrag
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Forfattere
Mekjell MelandSammendrag
Det er ikke registrert sammendrag
Sammendrag
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Sammendrag
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Forfattere
Mekjell MelandSammendrag
Det er ikke registrert sammendrag