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
Tore SkrøppaSammendrag
Det er ikke registrert sammendrag
Forfattere
Bjørn Langerud Martin Sandvik Anders SjøvoldSammendrag
Norway spruce seedlings were grown with three, peat based growth media (Table 1) subjected to three irrigation regimes in three forest nurseries in the Eastern part of Norway. The irrigation regimes were defined by the volume of liquid in the growth growth substrate one hour after irrigation and re-irrigation started when 20, 40 or 60 % of this volume of liquid was lost. The irrigation frequency and intensity was determined by the weight of specific multipot containers (Fig. 1). The results differed from what we expected from literature and laboratory studies: The deviations were mainly attributed to variation within the `experimental treatments`. Great variation was observed in bulk density, ash concentration and phase distribution in the growth media (Table 1, Figs. 2 and 3), and within, although not always between, irrigation regimes (Figs. 4, 5, 6 and 7). The experiment was further disturbed by the influence of growth media on germination (Table 2). The dry weight of seedlings did not relate to irrigation and growth media in an unique manner (Fig. 8): The variation in important factors and the improper control of the irrigation regimes made a discussion with respect to `average` growing conditions impossible. The results initiated a discussion on research strategies in the `applied sciences`, and the conclusion was towards more distinct criteria for the `applied` and the `science`. The variation and the unreliable routines induced this question: Which of the individual seedlings were under which of the irrigation regimes in which growth substrate and under which climate at which time and at which of the nurseries?. In conclusion, the variations in growth media properties, germination and growing routines have to be delt with in a better way than at present before a satisfactory growing control is achieved.
Forfattere
Kåre Olav Venn Arne Olav StuanesSammendrag
Det er ikke registrert sammendrag
Forfattere
Oddvar SkreSammendrag
Frost damages may take place by rapid intracellular freezing or by extracellular ice formation and cell dehydration. The damages are measured visually or by electroconductivity measurements.The first hardeing stage is induced by short days and light, and is related to dormancy induction. The second stage is induced by low temperatures (-2-5 C). During this and the third stage, water binding forms of proteins and sugars are formed, and the membranes are re-structured in order to better withstand dehydration.Potassium prevents frost damages by increasing the resistance against dehydration while nitrogen and phosphorus in high concentrations are extending the growth period and exhaust carbohydrate reserves, making the plants more exposed to frost damages.
Forfattere
Sverre SkoklefaldSammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Jarle BerganSammendrag
In the spring 1955 an experimental plot with 6 provenances of Scots pine from Norway was laid out in a fjord district at 69°04\"N - 60 m a.s.l.: Prov. 1. Målselv - 69°N, 0-150 m a.s.l. Prov. 2. Grovfjord - 68°40\"N, 0-150 m a.s.l. Prov. 3. Skjomen - 68°15\"N, 0-150 m a.s.l. Prov. 4. Saltdal - 66°55\"N, 0-150 m a.s.l. Prov. 5. Halsa - 63°05\"N, 0-150 m a.s.l. Prov. 6. Rindal - 63°05\"N, 0-150 m a.s.l. The plot was laid out on a clear-cut in a birch forest. In the surrounding area, the pine occurs spontaneously only as scattered single trees. The plot (90 m x 90 m) was divided in 36 squares (15 m x 15 m), and each provenance repeated 6 times. The spacing of plants was 1,5 m x 1,5 m. Each provenance was represented by 600 plants. Prov. 3 has been transferred about 100 km (aerial line) from south to north, Prov. 4 about 240 km. Fig. 1 shows the reduction in the survival percentage in the years 1955 to 1985. At the total age of 34 years, a strong correlation has been found between the survival percentage and the northern latitude of the provenances. In Fig. 8 is shown that the total production is related to the number of plants per hectare. The number of plants per hectare is decreasing with decreasing latitude of the provenances (Table 6). Provenances transferred 100 km or more from south to the north are not to be recommended by plantations in the fjord districts in Troms. They probably give less total production, larger diameters of stems and branches (Table 5), and lower values in the relationship of H/D (Height in m/Diameter in cm) than the most northern provenance (Table 6). The main reason is the lower density of plants caused by lower survival percentages by the southern provenances. However, the trees of the two most southern provenances (Prov. 5 and 6) have also revealed considerably less height growth than the others (Table 3). Prov. 1 and 2 originate respectively from inland and fjord districts. The results from the actual experiment show that the provenance from the inland of Troms has to be preferred by planting of Scots pine in the actual fjord district. In 1956 another experiment was laid out in the same area. This experiment included also comparison between Prov. 1 and 2 (Bergan 1987). The results at the total age of 27 years confirm the conclusions about these two provenances in this report.
Forfattere
Richard HorntvedtSammendrag
Det er ikke registrert sammendrag
Forfattere
Richard HorntvedtSammendrag
Det er ikke registrert sammendrag