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.

1987

Sammendrag

During the 1980/81 logging year (August - July) the wood supply, wood consumption and wood stock are calculated for the different forest industry groups. The investigation is based upon interviews of 73 sawmills with a total wood consumption of 2.91 mill. m3, 17 pulpmills with total wood consumption (roundwood and chips) of 2.72 mill. m3, and 10 board mills with total wood consumption of 0.45 mill. m3 (All volume measurements are based upon volume without bark). Sawmills. The average volume of wood used per mill was 39800 m3. Of the domestic wood supply (38400 m3) 88.5% was whitewood, 11.2% baltic redwood and 0.3% wood from broadleaf species. During the logging year the monthly wood supply increased from 4.5% in August to 13.8% in March (Fig. 5). From March to July the supply decreased. July supply was 6.1% of the total annual delivery. Of the total supply of wood to the sawmill industry, 71% was delivery timber. Pulp Industry. The average mill supply of roundwood and chips was 132000 m3 and 80800 m3 respectively. Of the domestic roundwood supply (116685 m3) 88.8% was whitewood, 3.9% baltic redwood and 7.3% was broadleaf species. The roundwood supply during the logging year was relatively high in the summer and low in the winter (Fig. 5). Chips supply was lowest in July, but otherwise the monthly supply varied little. Seventy-five per cent of the total wood supply was delivery timber. Board Mill. The average supply of roundwood and chips was 26400 m3 and 48400 m3 respectively. Of the domestic roundwood (26300 m3) 20.3% was whitewood, 39.7% baltic redwood and 40.0% was broadleaf species (mainly birch). The supply of roundwood to the board industry during the logging year varied greatly from month to month with peaks in September, March and June (Fig. 5). The roundwood supply was lowest in December and July. The supply of chips was highest in March and lowest in December. Of the total wood supply to the board industry, about 98% was delivery timber. The average consumption of wood in a sawmill was 38600 m3. In the period of August to June consumption varied between 8 and 10% per month of the total yearly consumption (Fig. 6). The consumption was lowest in the month of July. In the pulp industry the consumption of roundwood and chips per mill was 142700 m3 and 86700 m3 respectively. The consumption varied a little (between 8 and 9% per month) in the period from August to June (Fig. 6). Only 7% was consumed in July. The average consumption in a board mill was 21100 m3 of roundwood and 45400 m3 chips. In the August - June period the consumption varied between 7 and 10% per month (Fig. 6). Consumption in the month of July was relatively low (2.7% ). The average stock capacity in the sawmill industry was 12400 m3 per mill. Stock decreased in the period from August through November (Fig. 7), and increased in the period December - March. A following reduction occured in April and May, followed by a new increase in June and July. In the sawmill industry 49% of the mills used water sprinkling for storing timber and 11% used `the water-storing method`. The stock capasity per mill in the pulp industry was 60000 m3 of roundwood and 60000 m3 chips. The stock increased in the period from August through November (Fig. 8). From December through April the stock decreased, followed by a new increase until July. In the pulp industry 59% of the mills used water sprinkling and 42% used water-storing as the storing method. The stock capasity per mill in the board industry was 14600 m3 of roundwood and 10600 m3 chips. The wood stock increased in the period from August through October (Fig. 9). The stock was reduced in the period from November through February, followed by a new increase from March to July. None of the mills in the board industry used water sprinkling or water storing methods.

Sammendrag

As in Western Norway, the deciduous trees play a more important role in North Norway than in the rest of the country. Except for some inconsiderable occurrences in the eastern part of Finnmark, Norway spruce does not exist originally north of the Polar circle. However, an afforestation is going on, which usually means conversion of birch forest to spruce plantations (80-90% Picea abies). In the period 1955 to 1963, 11 experimental plots were laid out at different vegetation types and under various climatic conditions (Tables 1 and 2). The vegetation types have been classified and coded according to Kielland-Lund (1981): 8: Vaccinio-Pinetum boreale. 13: Eu-Piceetum abietis a) Subass: myrtilletosum b) Subass: dryopteridetosum c) Subass: athyrietosum 14: Melico nutantis-Picceetum abietis b) Subass: typicum c) Subass: aconitetosum. The main objective of the investigations was to study survival, growth and damages to plants established under a shelterwood of birch (Betula pubescens) compared to planting at clear cut. Fig. 2 illustrates the principles of the experimental plans. The provenance P1 (Rana) is used as standard provenance of Picea abies at all plots. Picea abies has been regarded as the most important tree species in the experiments, since this species dominates the plantations in the afforestation. On sites rich of grass and herbs (up to one meter in height), shelterwood is necessary to achieve a satisfying result. Use of shelter trees is also necessary at areas exposed to early and late frosts and in steep terrain with a deep snow cover (> 1 m). Differences in ground vegetation together with damages by frost and small rodents (esp. Microtus agrestis L. and Euotomys rutilus) are the main reasons for higher survival percentage under shelterwood compared to clear cut. Besides shelterwood, the choice of provenance is very important. Well adapted northern provenances have turned out to be less attacked of voles than southern unfitted provenances. On good sites the height development of spruce plants is better under shelterwood the first years after planting. About 150 shelter trees per hectare seems to be sufficient when the shelter trees represent the biggest trees in mature stands of birch at these northern latitudes (See plots T.32, T.37 and T.55 in Table 2). In steep terrain with a deep snow cover in winter, a higher number of shelter trees is necessary (Plot N.4). When cutting the shelter trees, the mean height of the spruce plants can vary from one to three meters, depending on soil site, local climate, terrain, snow conditions and density of shelterwood. At steep terrain with deep snow cover, it can be necessary to keep the shelter trees even longer. At dry soil sites and localities where the risk of frost damages is small, the shelter trees can be cut before the plant height is one meter.

Sammendrag

Rådensiteten (lassets råvekt med bark i forhold til tømmermålingens volum med bark) er, for et materiale på 153 lass av granmassevirke, i gjennomsnitt beregnet til 841 kg/m3 for virke målt i vinterhalvåret, og 769 kg/m3 for virke målt i første del av sommerhalvåret. Korrigert for underkubering ved tømmermålingen er de tilsvarende rådensiteter henholdsvis 823 kg/m3 og 754 kg/m3. Råvolumvekten (lassets råvekt med bark i forhold til tømmermålingens volum under bark) er i gjennomsnitt beregnet til 959 kg/m3 for virke målt i vinterperioden. Det tilsvarende tall for sommerperioden var 875 kg/m3. Korrigerte tall for råvolumvekten er henholdsvis 937 kg/m3 og 858 kg/m3. Tørr-råvolumvekten (tørrvekt med bark i forhold til tømmermålingens volum med bark) er, for virke målt i vinterperioden, beregnet til 414 kg/m3. For sommerperioden er den tilsvarende tørr-råvolumvekt 407 kg/m3. Korrigerte tall for tørr-råvolumvekten i vinterperioden og sommerperioden er henholdsvis 404 kg/m3 og 399 kg/m3.

1986

Sammendrag

The method presented was based on a very simple approach of the forces operating in the pores of porous media. The standardized time (tv) needed to infiltrate a given volume of a liquid into a porous medium in a defined state was throught to be an integrated measure of pore geometry and continuity. The state of the pore system was defined by external suction (S) and medium porosity characterized by the parameters k1 and k2 in the equation tv=k1k2 S-0.5. The method theory was not rejected by experiments with glass beads and selected peat based growth media. The method ranked the media with respect to the probability for satisfactory gas exchange in the order of peat, peat and 26% perlite, peat and 34% perlite, and peat and 44% mineral wool. This ranking was achieved 95 days after the media were filled in containers and exposed to a daily watering procedure. Before this time, the ranking of the media was slightly different, if at all possible. Five days after the containers were filled, only peat and 44% mineral wood was significantly different from the other media. Judged by the standardized time method, the probability for satisfactory gas exchange decreased significantly during the 95 days experiment. This aggravation was supported by measurements of the volume fraction of pores filled with gas. The changes with time were least marked in the medium containing mineral wool.