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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

Sammendrag

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.

Sammendrag

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.