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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.

2000

Sammendrag

Relationships between crown density and growth of Norway spruce stands are presented, after removal of the effects of major natural influences. On 569 monitoring plots comprising 40 000 trees, crown density has been annually assessed during 1991 to 1996.Stand growth was determined from measurements of diameter and height in 1991 and in 1996. Various models explaining mean crown density and annual growth of the stands as a function of natural factors, like age and site index, were compared.The influence of the natural factors were then removed by recalculating crown density to residual values from one preferred model, and by recalculating growth to relative values given in percent of model predictions.Crown density and its residuals were positively correlated to growth. These relationships were weak in terms of their ability to explain variation (low R2). However, the various relationships consistently indicated that roughly 1% change in crown density corresponded to 1% change in growth. This relationship also included common spatial variation over Norway: a large part of southeast Norway had unexplained low crown density and unexplained low growth.Some other, smaller regional consistencies were found as well. The study supports the use of crown density assessments, and further it encourages the use of growth data in the search for major stress factors responsible for present forest condition.

Sammendrag

Preharvest cuticular fractures in sweet cherry fruits have been suggested to facilitate pathogen invasion, and a method to classify amount of cuticular fracturing into five categories (1 = no visible fractures, 5 = severe fracturing) has previously been proposed (18). Sweet cherry fruits of the four cultivars Early Burlat, Lapins, Van, and Vista were sorted into these five categories of cuticular fracturing and inoculated with conidial suspensions of either Botrytis cinerea or Monilinia laxa. After incubating the fruits at 20°C and 100% RH for 4 - 7 days, they were assessed for visible fungal growth. Due to quiescent infections of M. laxa, fruits treated with B. cinerea developed more brown rot than grey mold. However, a significant linear relation (p < 0.05) between the amount of cuticular fracturing and fungal infections was obtained in 5 of 7 trials with B. cinerea and in 2 of 4 trials with M. laxa, indicating that fungal infections in sweet cherry fruits may be facilitated by cuticular fractures. Independent of cultivar and year, a significant linear relation was found between the category of cuticular fracturing and percentage of infected fruits after inoculation with both B. cinerea and M. laxa, and in control fruits (p = 0.0001, p = 0.0183, and p = 0.0182, respectively). This is the first report quantifying an increase in fungal infection with increasing amount of cuticular fracturing. The mean difference in fruit rot (%) ± std.dev. between fruits in fracturing categories 1 and 5, expressed as the linear contrast of amount of fruit rot in category 5 minus amount of fruit rot in category 1, was 37.2 ± 7.4 (p = 0.0001), 35.4 ± 11.0 (p = 0.0022), 17.0 ± 6.7 (p = 0.0135), and 29.8 ± 4.7 (p = 0.0001), after treatments with B. cinerea, M. laxa, water control, and for all data pooled, respectively