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.
1993
Forfattere
Jarle BerganSammendrag
The main objection of the investigation was to study survival, height growth and injuries to plant material originating from different localities in the central pine forests of Troms and Finnmark (Fig. 1). The distance between the most northern and southern central pine forests in Troms and Finnmark is about 110 to 120 kilometres. On the other hand, the corresponding distance west to east is 400 to 450 kilometres.Previous investigations and experiences have shown that provenances from the inner parts of Troms have achieved good results as regards survival and height development when planted or sown in fjord districts and inner parts of Finnmark (Bergan 1988, 1989a). However, comparative studies of plants originating from all the main districts of pine forests have not been made before the present investigation.In the years 1974 to 1985, 21 test fields of Scots pine were laid out at different localities in the central districts of pine forests in Troms and Finnmark (Table 1). The seed was collected in Febr. - April 1973 from ten selected trees in different stands situated in eight of the most important districts of pine forests in this northern part of the country (Table 2, Fig. 1). The germination percentage of the seed was 90 to 97 per cent, except for the localities Bollo (80 %) and Slepelvli (75 %).The plots are divided into three groups. Group 1 includes plots where all or nearly all the localities of seed collection are represented (named \"main plots\"). Group 2 includes a section of the localities. The plots in Group 2 are situated at lower altitudes, while most of the plots in Group 3 are laid out at high altitudes. All plots have been frequently examined and heights measured until the autumn in 1991 or 1992.The Tables present the relative heights and survival percentages in the last year of inspection (Heikamelen, Nordreisa=100). The results of the main plots (Group 1) are shown in the Tables 3 to 5. As an average of the eight main plots, Table 6 shows the relative mean heights of all living trees (Htot) and a section of the highest trees (H20=889 trees per ha) together with the relative survival percentages.Analyses of variance and rangetests (Student-Newman-Keul = SNK) show that plants of seed from the smaller and most isolated districts of pine forests - Trany, Skibotn and Kvenangen - have less height growth and/or lower survival than plants from the larger districts: Mlselv, Nordreisa, Karasjok and Pasvik. The difference seems to increase at the frosty sites. The results of the plots in Groups 2 and 3 confirm the results of the main plots.Slepelvli in Mlselv has relatively small heights and low survival percentage, too. The locality of Slepelvli is relatively isolated from the rest of the pine forests in Mlselv. One outstanding feature of the climate at Skibotn and Slepelvli is the snow conditions, which are characterized by very little snow in the winter.One of the most frequent causes of a large decrease in plant survival of some of the seed collections at the plots has been attack from fungal diseases as Phacidium infestans and Gremmeniella abietina on the plants. Decrease in plant survival, especially in the first 5-6 years after cultivation, has been caused by physiological response due to extremely bad climatic conditions in some years. Injuries by frost, elk and hare have to a certain degree influenced the height development at some of the plots.The main conclusion of the investigation is as follows: By shortage of local seed in future cultivations in the central districts of pine forests in Troms and Finnmark, equally good survival and height growth will be achieved by using seed from the central pine forests at Mlselv, Nordreisa, Karasjok or Pasvik.
Forfattere
Bjørn TveiteSammendrag
Det er ikke registrert sammendrag
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Bernt-Håvard ØyenSammendrag
Rapporten beskriver forurensningseffekter i skogvegetasjonen i Mosjøen og omegn, relatert til fluoridutslipp fra et aluminiumverk. Resultatene er sammenholdt med kjemiske analyser av fluorid i plantedeler. Kritisk belastningsgrense er overskredet i et større område rundt aluminiumverket, hvor det er påvist sviskader på arter i skogvegetasjonen. Nærområdene til verket er de mest forurensningsbelastede, og konsentrasjonene av fluorid i blad og nåler avtar med økende avstand fra aluminiumverket. Sviskader forårsaket av fluorid er funnet på liljekonvall opp til 10 km fra aluminiumverket i hovedvindretningen. Utbredelse av sviskader, konsentrasjoner av fluorid i analyserte plantedeler og sammensetning av lav på granstammer viser at forurensninger av fluorid har forårsaket moderate vegetasjonsskader. Analyser viser godt samsvar mellom fluoridopptak i planter og visuell vurdering av skadeomfanget.
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Forfattere
C. Carter Øystein AustaråSammendrag
Det er ikke registrert sammendrag
Forfattere
Seif S. Madoffe Øystein AustaråSammendrag
Det er ikke registrert sammendrag
Forfattere
Tore Frogner Arne Olav Stuanes Richard Frederic WrightSammendrag
Det er ikke registrert sammendrag
Sammendrag
Norwegian forests receive various amounts of air pollutants. Several of them are harmful to trees. The forest health situation is therefore monitored by regular surveys, in accordance with internationally recommended methods. Investigations so far have shown that the deposition of air pollutants is largest in southeastern Norway and in a limited area close to the Russian border, in northeastern Norway.Sulphur and nitrogen compounds are among the main pollutants that may lead to adverse effects. However, their airborne concentrations are not high enough to cause direct injury to trees in Norway, except for northeastern parts being affected by emissions from Russian industries. Indirect injury, by leaching of nutrients from trees and soils, and disturbances of the nutrient balance in various ways, is more likely. Ozone concentrations may reach harmful levels, and may affect vegetation directly, especially in the southern part of Norway.Monitoring is performed in order to reveal whether forest damage occurs from such causes, and if so, where, and whether the amount of damage will change with time. So far the results show that there is no extensive dieback of forests in Norway; the annual death rate of trees is low and appears normal.Based on the international criteria applied, the vitality of the forest appears to be low. Part of the reason for that may be the location of Norwegian forests towards the north, towards mountains, and towards the ocean, where forest growth is limited naturally.However, results indicate that forest conditions in the southern part of the country are affected by air pollution. Most cases of crown discolouration are found in that region, and the number of discoloured (yellow) trees has increased noticeably during the last few years. In the same region crown density has been low, and has been further reduced lately. According to a conservative estimate the average crown density is being reduced by 0.4% (units) annually.Crown density has been shown to be related to tree increment. However, the negative effect of reduced tree vitality is believed to be over-shadowed by the positive effect on growth of nitrogen deposition.Air pollutants are causing various effects in forest ecosystems. It appears that regions in southern Norway receiving large amounts of air pollutants have a high number of acidified lakes containing high concentrations of sulphate and nitrate. In this region the soil is shown to be low in base saturation and leachable phosphate, and high in nitrogen, sulphur and zinc.Those monitored plots showing the highest concentrations of Al and the lowest Ca:Al ratio in their soil water are also located here. The forest in this region receives a more acidic precipitation than elsewhere in Norway, which may contribute to increased leaching from needles. Higher nitrogen deposition is taking place here, causing a heavy cover of epiphytic algae on needles.It is noteworthy that this region contains more low vitality forests (of low crown density and yellowish discolouration) than other regions, and that the negative changes in vitality have been more pronounced than in other regions.More clearly we see that forests in southern, southeastern, and northeastern parts of Norway, next to Russia, are negatively affected. The causal factors may be several, and they may interact in complex processes. The symptoms are not specific, but their regional occurrence seems to indicate a causal relationship with deposition of air pollutants. This indication is now more pronounced than found earlier.
Forfattere
Jan-Ole SkageSammendrag
Det er ikke registrert sammendrag