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
B. Slyngstad Arne Grønlund H. WekreSammendrag
Det er ikke registrert sammendrag
Forfattere
Tore SkrøppaSammendrag
Det er ikke registrert sammendrag
Forfattere
Tore SkrøppaSammendrag
Det er ikke registrert sammendrag
Forfattere
Øystein Johnsen Ketil KohmannSammendrag
Toårige granplanter ble frysetestet til forskjellige tidspunkt under kjølelagring om vinteren. Plantene ble lagret på 0,5 °C og -2,5 °C for å se om dette kunne gi forskjeller i toleranse overfor frost. Tester ble utført både rett etter uttak fra lager og etter 10-12 dagers driving i oppvarmet veksthus (20°/15 °C; dag/natt). Temperaturen som ga 50 % skade på plantene (LT50) ble brukt som et mål på plantenes frosttoleranse. LT50 gir rett etter uttak fra lager informasjon om plantenes frosttoleranse under vinterherdig tilstand på lager. Differansen mellom LT50 før og etter driving i veksthus gir informasjon om plantenes reaksjon på varme og lys (utvintring). Forsøket viste at plantene taper noe av sin frosttoleranse på kjølelager. Tapet økte med lagringstiden, og var større ved lagring på 0,5 °C (13 °C tap i LT50 etter 148 døgn) enn ved lagring på -2,5 °C (9 °C tap). Differansen mellom LT50 før og etter driving var derimot 2 °C større for planter lagret ved -2,5 °C enn for planter lagret ved 0,5 °C, og denne forskjellen mellom lagringstemperaturene var uavhengig av lagringstiden. Likevel, etter 148 døgns lagertid og deretter 10 dagers driving i veksthus, var planter fra -2,5 °C totalt sett mer frosttolerante enn planter fra 0,5 °C. Dette kom av at herdighetstapet før varmebehandling etter 148 døgn på lager var 4 °C større ved 0,5° enn ved -2,5 °C.Resultatet tyder på at det er forskjellige biokjemiske og fysiologiske prosesser som på den ene siden forårsaker tap av frosttoleranse i mørke på lager, og på den andre siden tap av herdighet som følge av en aktiv respons overfor varme og lys under utvintring. Stikkprøver av kjølelagrede planter kan frysetestes på planteskolene for å få informasjon om frosttoleranse før utvintring. Har plantene en dårlig frosttoleranse bør man unngå et tidlig uttak fra lager og for tidlig planting på våren.
Forfattere
Tore SkrøppaSammendrag
Det er ikke registrert sammendrag
Forfattere
Karl ThunesSammendrag
Det er ikke registrert sammendrag
Forfattere
Jarle BerganSammendrag
The main objective of the investigation was to study survival, height growth and injuries to planting stock material originating from different latitudes in Helgeland, Nord- and Sr-Trndelag when planted in Troms. In the years 1975 to 1978 nine test-fields of Norway spruce were laid out at different localities in Middle-Troms at about 69N (Table 1). According to Kielland-Lund (1981), the vegetation types represented in the investigation are: 13. ass.: Eu-Piceetum abietis a) Subass.: myrtilletosum b) Subass.: dryopteridetosum 14. ass.: Melico nutantis - Piceetum abietis b) Subass.: typicum c) Subass.: aconitetosumThe frost risk is classified from 1 to 3, with 3 as the locality most exposed to severe night frost. The seed was collected in twentytwo districts at different latitudes from the most northern autochthon grown Norway spruce districts at about 6620N in Rana to 6301N in Sr-Trndelag (Table 2). The cones were gathered from ten trees in three stands within each district. In addition, three stands in the lowland at about 5937N in southern Norway is represented at two plots (T.127 and T.131). Plants originated from commercial seed lots collected at larger areas within Rana (No. 23), have been planted at some plots. From Table 2 it will also be seen that a commercial provenance from northern Sweden (No. 24) together with an other provenance from high altitudes in South-East Norway (No. 25) are represented in the plant material. They have been compared with the plants from the other districts at plot T.127. Due to limited quantities of seed, especially from the southern districts, the number of districts and stands differ between plots. 22 districts and 66 stands are investigated at T.127 together with the commercial seed provenances. According to previous reports, the northern districts are the most interesting by afforestation in Troms (Bergan 1978, 1991, 1992). The results from each plot have been dealt with and discussed separately in the report. Except for a few tables, the results from each plot are presented in Figs. 1 to 62. The plots have been scrutinized or inspected in all the years from planting to the last scrutiny in the autumn 1992 or 1993. For each plot the height development and decrease in survival percentage are shown in figures for a selection of representative districts. The mean heights are either calculated on all living plants (Htot) or as a mean of the highest plants (H20) corresponding to 889 trees per hectare. Variance and regression analysis have been executed on the data of heights and survival by the last scrutiny in 1992 or 1993. In addition, analysis have been done on injuries to the plants caused by heavy frost, small rodents or hares. Lammas shoot on the plants has been observed in a few years at some of the plots. The differences in heights, survival and injuries between districts or stands have been best expressed by regression analysis showing the relation between heights, survival or injuries and the latitude of the seed collection sites. The main conclusions of the results are: At most of the plots there is a correlation between mean heights of the plants and the latitude of the stands and districts where the plant seed is collected. The plant height decreases from northern to southern districts. However, at localities with low frost risk, such as T.140, the differences in heights are not significant. Even at these localities, the results do not indicate that southern districts and stands are to be preferred to more northerly. No stands in the various districts have turned out to be significant different from the others. Between the most northern districts Rana, Bardal and Korgen, the differences in heights is very small. The northern commercial provenance (Rana P1-4145) does not deviate significantly from the plants of selected districts and stands at the same latitude. This is the case for the plants of the northern Swedish provenance, too. As regards plant survival, there is only at a couple of plots (T.131 and T.144) that the survival percentage decreases successively from the north to the south. However, at all the plots, the survival of plants from northern districts is equal to other districts with high survival percentage. The most southern lowland provenance (Hurum) has shown low survival percentage at the two plots where it is represented. In years with a high percentage of plants injured by frost, the results at several plots show that the frost damages increase from the north to the south. In years with less frost injuries to the plants, there are no significant differences between plants of districts from different latitudes. The frost injuries usually occur in late summer or early winter/spring. At some of the plots a correlation has been shown between lammas shoot frequency on the plants and the latitude of the origin of the plants. The lammas shoot frequency increases with southerly latitudes. As regards damages by small rodents and hares, a relationship between damages and the latitude of the origin of the seed has only been found at a few plots in a single year. In these cases the damages by small rodents increase from the north to the south, while browsing of top shoots by hares decreases to the south (Fig. 56).Significant differences between provenances and injuries by hares have not been shown in earlier investigations in this part of the country (Bergan 1991, 1992), or at the other plots in this report. A probable cause may be explained by heavy snow depth conditions combined with differences in the plant heights of the various districts when the browsing by hares is most intensive in the winter, and only the highest plants reach above the snow cover. The results presented in this report correspond well to the results of earlier reports dealing with the use of spruce provenances in North-Norway (Bergan 1978, 1991, 1992).
Forfattere
Knut J. Huse Halvor Solheim Kåre VennSammendrag
Rapporten redegjør for resultatene fra en råteregistrering utført av skogeiere etter hogst vinteren 1992, og den omfatter i alt 4 914 bestand og 271 023 stubber. Råtevurderingen ble utført visuelt på stubber større enn 10 cm ved stubbeavskjær. Beregningene viste at 26,8% av grantrærne hadde synlig råte i stubbeavskjær. Skogreisingsområdene Vest-Agder, hele Vestlandet og Troms, hadde minst råte (5,7%-15,9%), mens de opprinnelige granskogfylkene hadde mest råte (25,5%-31,2%). Det ble ikke påvist trender avhengig av eiendomsstørrelse, balansekvantum eller hogstnivå, men de største eiendommene, og de med høyest hogstnivå eller balansekvantum, hadde lavest råtefrekvens. Det var tendens til stigende råtefrekvens med økende alder. Tynningsinngrep økte råtefrekvensen. Treslagsblanding reduserte råtefrekvensen, klarest var trenden for innblanding av furu. Plantet skog (Vestlandet) hadde mindre råte enn naturskog. Det ble ikke påvist forskjeller med stigende høyde over havet eller hogstklassesammensetning. Årsak til råten ble vurdert visuelt. Rotkjuke alene eller som kombinasjonsråte ble registrert i 71%, honningsopp alene eller som kombinasjonsråte i 28% og andre råtesopper i 11% av de råtne stubbene. Det betyr at tiltak for å begrense forekomst av rotkjuke vil ha størst effekt på råtesituasjonen. Råte har stor innvirkning på tømmerkvalitet. Etter de krav som gjaldt ved hogsten måtte 3,8% av rotstokkene vrakes eller bultes på grunn av råte. I tillegg hadde 5,9% og 17,0% av rotstokkene så mye råte at de måtte nedklassifiseres til henholdsvis sekunda og prima massevirke.
Forfattere
Tore SkrøppaSammendrag
Det er ikke registrert sammendrag
Forfattere
Knut Solbraa Jon Olav BrunvatneSammendrag
The project started in 1976/77 with a series of experiments in five burned areas. These were:Fyresdal, 80\" E and 591\" N, 610 m.a.s.l. on shallow moraine soilHeddal, 95\" E and 594\" N, 380 m.a.s.l. on shallow moraine soilElverum, 114\" E and 605\" N, 225 - 265 m.a.s.l., sites on shallow moraine soil and sandy, sedimental soil respectivelyDeset,\"113\" E and 612\" N, 300 m.a.s.l. on sandy, sedimental soilkrestrmmen, 112\" E and 614\" N, 300 m.a.s.l. in a rocky, former river bed. The site at Deset burned in 1959, krestrmmen in 1980 and the others in 1976. The experiments covered more than 30 000 plants, mainly of Scots pine (P. sylvestris), but also a few lodgepole pine (P. contorta). Direct seeding after scarification was tried as well, but in a small scale only. Mainly the last years results are fully reported here, because the others are published earlier.The following conclusions are drawn from the complete project.1. High soil temperatures in addition to fresh cut stumps and dead trees permitted the accumulation of pathogens after the fire. These cover Hylobius abietis and other insects feeding on bark or needles of the young conifer plants. Their attacks culminated the year after the fire, and were neglectible from the third year. Treating the plants with pyretroides before planting significantly reduced bark damages. Treatment against needle eaters should be repeated annually, but is not permitted in Norway.2. The fungus Rhizina undulata killed a great share of the transplants near fresh cut stumps in Elverum. These plants died within a few weeks after planting. Also this attack continued during the first two years only. The picture of attacks in Elverum was confirmed after a prescribed burning, close to the wild-fire area, in 1984. A suspension of systemic fungicides gave the plants a good protection against Rhizina undulata. The fungus was also found in high densities at krestrmmen and with a few specimen in Fyresdal and Heddal. It seems however, to be no relations between the presence of the fungus and mortality of plants these places.3. Direct seeding after ground scarification showed good results in areas not exposed to erosion. These small pine seedlings were not attacked to the same extent as older plants. Potential seedtrees should therefore be left in order to initiate natural regeneration.4. The combination of low temperatures during the growth season and the attack of the fungus Gremmeniella abietina was the main reason for total mortality of the Scots pine plants at Deset.5. If chemical protection against insects and fungi is unwanted, planting on sandy soil should be done in the spring the third year after the fire. Treatment with insecticides and fungicides may allow earlier planting.6. On sandy soil, the annual height increment culminated after 9 years, and decreased rapidly from about 35 to 10 centimeters. Planting later than three years after fire reduced growth compared to earlier planting. Application of nitrogen fertilizers initiated continued high growth rate. On sandy soil, fertilization with approximately 130 kg nitrogen should start 8 to 10 years after the fire. The nitrogen status of plants may be checked by needle analysis. A concentration of up to 1,6 - 1,8 % N is probably suitable at a tree age of 10 years. A mulch layer of 5 cm of crude sewage sludge gave the best growth of all treatments. On moraine, growth reductions were considerable less than on sandy soil.7. Application of nitrogen fertilizers increased damage both by Gremmeniella abietina and moose. Heavy fertilization may also increase the risk of climatic damages and reduces the final lumber quality. Therefore, fertilization should be limited to stands on deep soil layers, favourable climatic conditions and areas that are not exposed to heavy winter browsing by moose.