Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2017
Authors
Tore SkrøppaAbstract
No abstract has been registered
Abstract
Natural and rural land provides resources for the majority of ecosystem services we need. Typical provisioning services from these resources are timber logging, collection of berries, mushrooms and hunting. Typical regulating services are carbon storage, regulation of flooding and temperature, and typical cultural services are education, science and nature based tourism. The use of one ecosystem service always affects the other services. How can we evaluate how the various use of services affect each other? In our research group, we work innovatively with multi-criteria analyses to find ways of trading-off contradicting interests in ecosystem services. The red tread is to consider «all» sides of multiuse and thereby reduce conflicts between stakeholders. To achieve this, it is necessary to combine conventional valuation methods (market-oriented recourse-economy) and new socioecological approaches.
Abstract
The goal of this study was to assess the long-term effects of partial harvesting and supplementary soil scarification on the frequency of root and butt rot in managed uneven-sized Norway spruce stands. Frequency of rot and the population structure of the rot fungi were assessed on 1353 stumps after clear-cutting 21 years after a selection harvesting experiment. The initial experiment was comprised of three harvest strength (low, intermediate and high) of single-tree selection, removing approximately 25, 45 and 65% of the stand basal area. Uncut control plots were established at the same time. Supplementary soil scarification was applied in subplots within the single-tree selection plots, using a medium-sized excavator. After clear-cutting the stumps were analyzed with respect to rot caused by Heterobasidion parviporum, Armillaria spp., Stereum sanguinolentum as well as other rot fungi. Rot caused by Armillaria spp. was most common (8.6% of the stumps), while infection by H. parviporum (2.9%) or S. sanguinolentum (3.0%) was less frequent. The group “other rot” (5.4%) comprised 21 identified taxa, each occurring in 1–15 stumps. Significantly lower rot frequencies were found for the uncut control (16.3%) and intermediate harvest strength (15.7%), compared with low harvest strength (23.6%). A rot frequency of 21.0% was found in the high harvest strength. In two of three harvest strengths, the rot frequency was higher than for the uncut control. As the observed rot frequencies did not increase consistently with increasing harvest strength, the results do not completely support the initial expectations of increased rot after single-tree selection compared with the uncut control. However, since the probability of rot in individual stumps on plots treated with single-tree selection was significantly affected by the distance to the nearest strip road (H. parviporum) as well as dependent on the size of and distance to the nearest stump of trees cut during the experimental harvest (H. parviporum, S. sanguinolentum and total rot), it is evident that the single-tree selection harvesting was partially responsible for some of the observed rot. One of the selection criteria in the initial harvest was a sanitary removal of trees of poor vitality. Varying degrees of sanitation felling may therefore have offset the effects of new infections in wounds or spread of rot fungi through adjacent stumps. Supplementary soil scarification in small gaps of the residual stand had no significant effect on the frequency of rot, suggesting that such treatment may be used to facilitate regeneration in uneven-sized spruce stands on similar sites.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
For å verifisere beregningsmetoder og modeller for endringer av karbonlagre i skogsjord brukt i UNFCCC rapporteringen er det behov for data fra jordprøver med gjentak over tid og der prøvetakingsmetoder er konsistente. I Norge finnes ikke denne typen data på nasjonalt / landsdekkende nivå. For å møte behovet for verifisering av beregningsmetodikken brukt i UNFCCC rapporteringen innenfor rammene av eksisterende data med metodisk konsistens over tid, er det i denne undersøkelsen gjennomført ny prøvetaking av jord og vegetasjon i to etablerte forsøksfelt i skog i sør-øst Norge der vi fra før av både har data fra tidligere jordprøveanalyser og tilvekstdata for trær i skogsbestand. De to forsøksfeltene ligger på Nordmoen i Akershus (etablert 1973 og tilplantet 1974) og i Skiptvet i Østfold (etablert 1976 i eksisterende foryngelse med supplerplanting i 1977). Med nye jordprøver, biomassemålinger og vegetasjonsanalyser i 2011 gir dette to tidsserier på hhv. 38 og 34 år med hensyn på endringer i jordkarbon og inngangsverdier i beregningsmodellene. Den eksperimentelle behandlingen i Skiptvet omfatter ulik grad av treslagsblanding av bjørk og gran på de enkelte forsøksrutene, mens på Nordmoen sammenliknes rene bestand av hhv. bjørk, gran og furu. De klimatiske forhold er tilnærmet like, mens jordsmonntypen er ulik med næringsfattig sandjord på Nordmoen og næringsrik leirjord i Skiptvet. Resultatene fra forsøkene er begrenset til å representere klimatiske og vegetasjonsmessige forhold på Østlandet (og forhold tilsvarende de to lokalitetene), og forsøksfeltene er dermed ikke representative eksempelvis for kystnære og kontinentale strøk.
Authors
Isabella Børja Kjell Andreassen Jan Čermák Lise Dalsgaard Arthur Gessler Douglas L. Godbold Rainer Hentschel Zachary E. Kayler Paal Krokene Nadezhda Nadezhdina Sabine Rosner Svein Solberg Halvor Solheim Jan Svetlik Mari Mette Tollefsrud Ole Einar TveitoAbstract
No abstract has been registered
Authors
Nicholas Clarke Silje Skår O. Janne Kjønaas Kjersti Holt Hanssen Tonje Økland Jørn-Frode Nordbakken Toril Drabløs Eldhuset Holger LangeAbstract
Short-term (three to four years) effects of forest harvesting on soil solution chemistry were investigated at two Norway spruce sites in southern Norway, differing in precipitation amount and topography. Experimental plots were either harvested conventionally (stem-only harvesting, SOH) or whole trees, including crowns, twigs and branches were removed (whole-tree harvesting, WTH), leaving residue piles on the ground for some months before removal. The WTH treatment had two sub-treatments: WTH-pile where there had been piles and WTH-removal, from where residues had been removed to make piles. Increased soil solution concentrations of NO3–N, total N, Ca, Mg and K at 30 cm depth, shown by peaks in concentrations in the years after harvesting, were found at the drier, less steep site in eastern Norway after SOH and WTH-pile, but less so after WTH-removal. At the wetter, steeper site in western Norway, peaks were often observed also at WTH-removal plots, which might reflect within-site differences in water pathways due largely to site topography.
Authors
Isabella Børja Volkmar Timmermann Ari Hietala Mari Mette Tollefsrud Nina Elisabeth Nagy Adam Vivian-Smith Hugh Cross Jørn Henrik Sønstebø Tor Myking Halvor SolheimAbstract
In Norway the common ash (Fraxinus excelsior L.) has its northernmost distribution in Europe. It grows along the coastal range as small fragmented populations. The first occurrence of ash dieback caused by Hymenoscyphus fraxineus in Norway was reported in 2008. At that time, the disease had already spread through large areas of southern and south-eastern parts of Norway. Since then the disease continued spreading with a speed of about 50- 60 km per year along the western coastal range. To monitor the disease development over time, we established eight permanent monitoring plots in south-eastern and western Norway in 2009 and 2012, respectively. In all plots tree mortality was high, especially among the youngest trees in south-eastern Norway. The extent of crown damage has continually increased in all diameter classes for both regions. In 2009, 76.8 % of all trees on the five monitoring plots in south-eastern Norway were considered to be healthy or slightly damaged, and only 8.9 % to be severely damaged. In 2015, 51.7 % were dead, 13.5 % severely damaged and only 25.7 % remained healthy or slightly damaged. To assess the infection pressure and spore dispersal patterns of the pathogen, we used a Burkard volumetric spore sampler placed in an infested ash stand in southern Norway. We examined the airborne ascospores of H. fraxineus and H. albidus captured on the sampling tape microscopically and with real-time PCR assays specific to these fungi. We detected very few ascospores of H. albidus, whereas ascospores of H. fraxineus dominated throughout entire sampling periods of 2009, 2010 and 2011. Spore discharge occurred mainly between the hours of 5 and 8 a.m., though the distinctive sporulation had yearly variation between 5-7 a.m. We observed the same diurnal pattern throughout the entire sampling period, with a seasonal peak in spore liberation between mid-July and midAugust, after which the number of ascospores decreased substantially. Similar diurnal patterns were observed throughout the sampling period except that after mid-August the number of trapped ascospores substantially decreased. To compare the genetic pattern of common ash in the northern and central ranges of Europe we analyzed the Norwegian samples together with available samples from central Europe by using chloroplast and nuclear microsatellite markers. We found that the northern range of common ash was colonized via a single migration route that originated in eastern or south-eastern Europe with little influence originating from other southern or western European refugia. In the northern range margins, genetic diversity decreased and population differentiation increased, coherent with a post-glacial colonization history characterized by founder events and population fluctuations. Based on our findings we discuss the future management and conservational implications.
Authors
Igor A. Yakovlev Thomas Solvin Harald Kvaalen Arne Steffenrem Marcos Viejo Carl Gunnar FossdalAbstract
No abstract has been registered