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.
1994
Forfattere
Finn Roar Bruun Jon FrankSammendrag
Det er ikke registrert sammendrag
Forfattere
Alf BakkeSammendrag
Det er ikke registrert sammendrag
Forfattere
Jon FrankSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Hans Fredrik Hoen Knut VeistenSammendrag
The city of Oslo is surrounded by large forest areas, the socalled Oslomarka, which are intensively used for recreational purposes. During the autumn of 1992 and 1993 surveys were done among the users of Oslomarka to collect information about the reasons for visiting a particular area, the main purpose of the visit to the forest, the attitude on how the forest is influenced by the management practices, and the willingness to pay for increased restrictions on the management practices. A main hypothesis to be tested was if there were any differences in responses among users of private forests, which were judged more intensively managed for timber production, and users of municipal forests which have been managed with explicit multiple-use objectives during the last twenty years. Minor differences in responses among users of private forests and users of municipal forests were found. Only the attitude toward a statement saying that passability is not much affected by twigs and branches from forest operations could support a hypothesis that the users of private forests are more discontent (see Table 4). A smaller share of respondents in private forest agreed to this statement compared with the respondents in municipal forests, and a larger share disagreed. In both subsamples relatively more respondents agreed with positive statements about landscape attributes caused by forest management and disagreed with negative statements. Yet, 60% of the respondents gave at least one answer to the 7 or 9 statements indicating a negative view toward one aspect of the current management practices. The majority of the users gave reasons for visiting the forest which are not unique for forest areas, like calm and relaxation, be together with friends/family and exercise (see Table 2). Easiest access was the reason most of the users gave for visiting the specific area (see Table 3). This reason varied significantly with answers indicating a welfare reduction if the area where the interview took place was assumed to be reallocated from forestry and closed for recreational purposes (see Table 5). Yet, it was not given a clear definition of the size of the area connected to this question. Mean willingness to pay (WTP) for more cautious management practices in the Oslomarka, through an environmental tax on wood-products, was estimated to NOK 286 per household per year in 1992 (open-ended question) and NOK 235 in 1993 (conditional mean of a dichotomous choice). The only sosioeconomic variables varying significantly with WTP in both surveys were age (-), and expressing a negative view about the landscape in the area on at least 3 of 7/9 statements (). The regression analysis performed on the WTP-data indicated a stronger theoretical validity for responses in the 1992-sample than the 1993-sample, since WTP in 1992 varied significantly and positively with gross household income.
Forfattere
N. Vagstad Hans Olav EggestadSammendrag
Det er ikke registrert sammendrag
Forfattere
Hans Olav EggestadSammendrag
Det er ikke registrert sammendrag
Forfattere
Bernt-Håvard ØyenSammendrag
Rapporten beskriver lavvegetasjonen på stammer og greiner av gran i Mosjøenområdet, Nordland fylke, relatert til lokal luftforurensning. Epifyttiske lav er benyttet som biologiske indikatorer. Deler av undersøkelsesområdet er kjent utsatt for forurensning hvor fluorid er den viktigste komponent. Det er funnet effekter av luftforurensning på den epifyttiske lavfloraen i skogområdene som ligger mindre enn 4-5 km fra byen og aluminiumsverket i hovedvindretningen. I by- og verksnære områder er det funnet redusert artsantall i forhold til skogområdene lengre sør i dalføret. Samtidig som nærområdene er mest forurensningsbelastet, er naturlige skogøkologiske forhold, bl.a. trealder, avgjørende for artsdiversitet og dekning. Sammenlignet med en tidligere undersøkelse er det registrert rekolonisering av lav i områder som har vært forurensningsbelastet. Dette kan knyttes til en nedgang i fluoridforurensningen i de senere år. Effekter av andre kilder enn fluoridforurensning på lavfloraen er diskutert.
Forfattere
Harald KvaalenSammendrag
Ethylene production from an embryogenic culture of Norway spruce (Picea abies L.) was generally low, ca 2.5 nl g(-1) h(-1), whereas 1-aminocycloprapane-1-carboxylic acid (ACC) concentration was high, fluctuating between 50 and 500 nmol g(-1) during the 11-day incubation period. Hypoxia (2.5 and 5 kPa O-2) rapidly inhibited ethylene production without subsequent accumulation of ACC. Exogenous ACC (1, 10 and 100 mu M) did not increase ethylene production, but the highest concentrations inhibited tissue growth. Ethylene (7 mu l l(-1)) did not inhibit growth either when supplied as ethephon in the medium or in a continuous flow system. Benzyladenine (BA) had little effect on ethylene production, although it was necessary for sustaining the ACC level. Omission of 2,4-dichloro-phenoxyacetic acid (2,4-D) from the medium caused ethylene production to increase from about 2.5 to 7 nl g(-1) h(-1) within the 11-day incubation period. Although 2,4-D did not specifically alter the endogenous level of ACC, the lowest ACC level, 33 nmol g(-1), was observed in tissue treated with 2,4-D (22.5 mu M) and no BA for 11 days. Data from this treatment were used to estimate the kinetic constants for ACC oxidase, the apparent K-m was 50 mu M and V-max 2.7 nl g(-1) h(-1). Growth of the tissue was strongly inhibited by 2,4-D in the absence of BA, but weakly in the presence of BA (4.4 mu M). The results suggest that ethylene or ACC may be involved in the induction of embryogenic tissue and in the early stages of embryo maturation.
Forfattere
Richard HorntvedtSammendrag
Det er ikke registrert sammendrag