Endre søk
Begrens søket
1234567 1 - 50 of 531
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Abrahamsson, Håkan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Skogstillståndet på ön Blå Jungfrun2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The aim of the study was to investigate the forest in the national park on the Blue Maiden Island and compare with mainland forest data. The study was made in a quantitative way. The results from the field measurement were related to data from the Swedish National Forest Inventory.

    Oak, Scots pine and Lime were the most common tree species and constituted 47, 18 and 16 % of basal area, respectively, on the island.

    The mean heigt was 7 m and the volume of living trees was on average 72 m³/ha and dead wood 30 m³/ha. The average age at breast height was 137 years and the oldest tree was an oak with the age of 335 years at breast height. The amount of dead wood constituted 40 % of the total volume. Disturbances have had influence on the forest on the Island. To what extent cannot be determined without further investigations.

  • 2.
    Adamopoulos, Stergios
    Technological Educational Institute of Larissa, Greece.
    Νέες τεχνολογίες συγκοµιδής δασικών προϊόντων: [New technologies for harvesting forest products]2012Inngår i: "Harvesting, Supply and Trade of Woody Biomass". Centre for Renewable Energy Sources and Saving (CRES) and Department of Forestry and Management of Natural Environment, TEI of Larissa, 19 October 2012, Karditsa, Greece, 2012Konferansepaper (Annet vitenskapelig)
  • 3. Adolf, Carole
    et al.
    Wunderle, Stefan
    Colombaroli, Daniele
    Weber, Helga
    Gobet, Erika
    Heiri, Oliver
    van Leeuwen, Jacqueline F. N.
    Bigler, Christian
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Connor, Simon E.
    Galka, Mariusz
    La Mantia, Tommaso
    Makhortykh, Sergey
    Svitavska-Svobodova, Helena
    Vanniere, Boris
    Tinner, Willy
    The sedimentary and remote-sensing reflection of biomass burning in Europe2018Inngår i: Global Ecology and Biogeography, ISSN 1466-822X, E-ISSN 1466-8238, Vol. 27, nr 2, s. 199-212Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aim: We provide the first European-scale geospatial training set relating the charcoal signal in surface lake sediments to fire parameters (number, intensity and area) recorded by satellite moderate resolution imaging spectroradiometer (MODIS) sensors. Our calibration is intended for quantitative reconstructions of key fire-regime parameters by using sediment sequences of microscopic (MIC from pollen slides, particles 10-500 mu m) and macroscopic charcoal (MAC from sieves, particles > 100 mu m). Location: North-south and east-west transects across Europe, covering the mediterranean, temperate, alpine, boreal and steppe biomes. Time period: Lake sediments and MODIS active fire and burned area products were collected for the years 2012-2015. Methods: Cylinder sediment traps were installed in lakes to annually collect charcoal particles in sediments. We quantitatively assessed the relationships between MIC and MAC influx (particles/cm(2)/year) and the MODIS-derived products to identify source areas of charcoal and the extent to which lake-sediment charcoal is linked to fire parameters across the continent. Results: Source area of sedimentary charcoal was estimated to a 40-km radius around sites for both MIC and MAC particles. Fires occurred in grasslands and in forests, with grass morphotypes of MAC accurately reflecting the burned fuel-type. Despite the lack of local fires around the sites, MAC influx levels reached those reported for local fires. Both MIC and MAC showed strong and highly significant relationships with the MODIS-derived fire parameters, as well as with climatic variation along a latitudinal temperature gradient. Main conclusions: MIC and MAC are suited to quantitatively reconstructing fire number and fire intensity on a regional scale. However, burned area may only be estimated using MAC. Local fires may be identified by using several lines of evidence, e.g. analysis of large particles (> 600 mu m), magnetic susceptibility and sedimentological data. Our results offer new insights and applications to quantitatively reconstruct fires and to interpret available sedimentary charcoal records.

  • 4. Akselsson, Cecilia
    et al.
    Belyazid, Salim
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi.
    Critical biomass harvesting - Applying a new concept for Swedish forest soils2018Inngår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 409, s. 67-73Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The contribution of forest harvesting to base cation losses and soil acidification has increased in recent years in Sweden, as the demand for bioenergy has increased and the sulphur deposition has decreased. Thus, new policy tools are required to evaluate the progress of the recovery from acidification, and as a basis for forest management recommendations. In this study we introduce and test a concept, Critical biomass harvesting. The concept builds on the concept Critical loads, which has been used world-wide for several decades as a bridge between science and policies related to transboundary air pollution and acidification. The basis for the concept is an acidity mass balance, with sources and sinks of acidity. A critical limit defines the highest acceptable acidification status of the water leaving the root zone. Based on the critical limit, the highest allowed biomass harvesting can be calculated, keeping the other parameters constant. In this study the critical limit was set to ANC (Acid Neutralizing Capacity) = 0. Nitrogen was assumed to be affecting acidity only if it leaches from the root zone. The critical biomass harvesting was calculated for almost 12000 National Forest Inventory sites with spruce and pine forest, using the best available data on deposition, weathering and nitrogen leaching. The exceedance of critical biomass harvesting was calculated as the difference between the estimated harvest losses and the critical biomass harvesting. The results were presented as median values in merged catchments in a catchment database, with totally 2079 merged catchments in Sweden. According to the calculations, critical biomass harvesting was exceeded in the southern half of Sweden already at stem harvesting in spruce forests. Whole-tree harvesting expanded the exceedance area, and increased the exceedance levels in southern Sweden. The exceedance in pine forest was lower and affected smaller areas. It was concluded that the concept of critical biomass harvesting can be successfully applied on the same database that has been used for critical load calculations in Sweden, using basically the same approach as has been extensively applied, evaluated and discussed in a critical load context. The results from the calculations in Sweden indicate that whole-tree harvesting, without wood ash recycling, can be expected to further slow down recovery, especially in the most acidified parts of the country, in the southwest.

  • 5.
    Albaugh, Timothy J
    et al.
    North Carolina State University, USA.
    Bergh, Johan
    Swedish University of Agricultural Sciences.
    Lundmark, Tomas
    Swedish University of Agricultural Sciences.
    Nilsson, Urban
    Stape, José Luiz
    North Carolina State University, USA.
    Allen, H Lee
    North Carolina State University, USA.
    Linder, Sune
    Swedish University of Agricultural Sciences.
    Do biological expansion factors adequately estimate stand-scale aboveground component biomass for Norway spruce?2009Inngår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 258, nr 12, s. 2628-2637Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We developed site specific component (stem, branch, and foliage) biomass functions for two sites in Sweden (64° and 57° North latitude) where four treatments (control, irrigated, fertilized, irrigated plus fertilized) were applied in the existing Norway spruce stands (Picea abies L. Karst.) for 17 years. We tested for site effects in the component biomass equations and compared site specific biomass estimates to those generated using published functions ( Lehtonen et al., 2004 and Wirth et al., 2004). Site effects were significant for all components and indicated it would be unlikely to generate equations that well estimate biomass across the Norway spruce range as implicitly indicated in our efforts to generate species biomass expansion factors. We rejected our hypothesis that the published functions would well estimate component biomass for control plots. The published functions did not compare well with site specific component biomass estimates for the other treatments; both published functions well estimated stem mass up to stem mass of 25 Mg ha−1, beyond which stem mass was overestimated, and both functions over and under estimated foliage and branch mass. Nor did the published functions compare well with each other, with stem, foliage and branch mass estimate differences of 12, 55, −8% and 11, 77, and 59% for the southern and northern sites, respectively, when averaged over all treatments and years. Adding limiting resources through fertilization increased stem, foliage and branch mass 57, 11, 18% and 120, 37, and 69% at the southern and northern sites, respectively, which would increase carbon sequestration and available stemwood and bioenergy materials. We recommend that more effort is spent in process-based modeling to better predict mass at a given site and ultimately provide better estimates of carbon sequestration and bioenergy material production changes.

  • 6.
    Almstedt, Åsa
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för geografi och ekonomisk historia.
    Keskitalo, E. Carina H.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för geografi och ekonomisk historia.
    The role of market measures in forest governance: the example of forest certification in boreal forests2017Inngår i: CAB Reviews, ISSN 1749-8848, Vol. 12, nr 11, s. 1-11Artikkel i tidsskrift (Fagfellevurdert)
  • 7.
    Almstedt, Åsa
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för geografi och ekonomisk historia, Kulturgeografi.
    Reed, Maureen G.
    Introducing a framework for good and adaptive governance: an application to fire management planning in Canada's boreal forest2013Inngår i: Forestry Chronicle, ISSN 0015-7546, Vol. 89, nr 5, s. 664-674Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Planning for and managing disturbances in protected areas requires governance arrangements that are both adaptive to changing conditions and effective in dealing with multiple challenges. This paper presents a framework composed of principles and criteria of good and adaptive governance that pays attention to inclusiveness, responsibility, fairness, strategic vision, performance orientation, and adaptiveness. The framework was empirically tested on fire management planning in Prince Albert National Park, Saskatchewan, Canada, involving interactions between Parks Canada and Saskatchewan Environment. Our results suggest that while the principle of performance orientation was upheld, principles such as inclusiveness and adaptiveness were only partially supported. Additional testing beyond fire management planning can help determine the utility of the framework for other environmental management situations.

  • 8.
    Alvskog, Kristina
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Rotstock av tall: Hur blir den framtida virkeskvaliteten?2014Independent thesis Basic level (degree of Bachelor), 180 hpOppgave
    Abstract [sv]

    För tallen finns många alternativa slutanvändningsområden, och kraven på virket varierar. Några egenskaper som har stor betydelse är stamrakhet, grengrovlek, grenvinkel och om det finns sprötkvist eller ej. Kvalitetsförsämringen i Sydsveriges tallskogar kan vara ett allvarligt problem och härör bl.a. till ökad produktion och rationaliseringar inom skogsbruket. Lönsamhet har varit målet, men har det skett på bekostnad av kvalitet?

    För att närmare belysa frågan om förekomsten av tall av god kvalitet syftar denna studie till att bedöma rotstockar i konventionellt skötta och stamkvistade bestånd samt deras potential att växa in i värdefulla klasser eller sortiment.

    Fältstudien är avgränsad till Bergslagen. I mätningarna har endast rotstock (upp till 3,4 m i längd) av träden bedömts, huruvida de har potential att hålla klass 1-kvalitet, sortiment stamblocks-kvalitet eller sortiment rotstock-kvalitet vid en brösthöjdsdiameter av 320 mm. Andelen rotstockar ≥ klass 1 uppskattades i de stamkvistade bestånden bli 72-94 %, då skötseln också syftat till en värdeökning.  Andelen rotstockar ≥ klass 1 i de konventionellt skötta bestånden uppskattades bli 46-56 %. Med stor sannolikhet kommer ingen av dem dock få växa in i de värdefullaste klasserna. Vanligaste nedklassningssorsakerna är för många kvistar och ibland även i kombination med krök i de konventionellt skötta bestånden samt långkrök i de stamkvistade bestånden.

    I rapportens teori avhandlas olika sortiment och kvalitetsklasser, och sedan undersöks kvalitetsdanande faktorer bl.a. ekologiska förutsättningar och olika skötselåtgärder. En hög röjningsstyrka kan t.ex. resultera i en grövre diameter på grenar. Likaså har sen röjning inverkan på den grövsta grenens diameter, då den minskar. Det finns alltså en potential att erhålla god virkeskvalitet av tall i våra skogar. Detta är möjligt genom aktiv skötsel, att hålla täta förband, genom att gallra ut lågkvalitativa stammar och stamkvistning. Raka tallar ur vilka kan man utvinna ett högt sågutbyte är och kommer att vara en värdefull resurs i framtiden.

  • 9.
    Andersson, Björn
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Utvärdering och utveckling av Fiskarhedens Trävaru AB:s traktdirektiv för slutavverkning2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Bruttoavverkningen har accelererat de senaste decennierna och i takt med detta har kraven inom skogsbruket ökat. Idag behöver en omfattande miljöhänsyn tas. Detta ställer även högre krav på entreprenörerna. För att entreprenörerna ska klara av att leva upp till kraven är det viktigt att beställaren av tjänsten överlämnar en arbetsinstruktion i samband med avropande av traktuppdrag. Denna arbetsinstruktion och arbetsorder skapas i form av ett traktdirektiv. Ett kvalitativt traktdirektiv betraktas vara viktigt för Fiskarhedens Trävaru AB och för deras entreprenörer. En fallstudie har genomförts för att utvärdera och beskriva företagets nuvarande traktdirektiv. Resultatet visar att dagens traktdirektiv stundtals är bristfälliga genom att de är dåligt ifyllda. Viktigt innehåll kommuniceras därmed ej som det behövs. Ett förslag på nytt, förbättrat traktdirektiv, där innehållet är tänkt att fyllas i bättre, har därför tagits fram. Med hjälp av detta traktdirektiv kan Fiskarheden upprätthålla ett hållbart skogsbruk.

  • 10. Andersson, Elias
    et al.
    Keskitalo, E. Carina H.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för geografi och ekonomisk historia.
    Adaptation to climate change?: Why business-as-usual remains the logical choice in Swedish forestry2018Inngår i: Global Environmental Change, ISSN 0959-3780, E-ISSN 1872-9495, Vol. 48, s. 76-85Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The two latest IPCC assessment reports have concluded that knowledge is not sufficient for inducing action on climate change. This study problematizes the issue of going beyond business-as-usual through a study of the forestry sector in Sweden, which is a large economic sector and could be expected to be an early adapter, given that newly planted forest may stand some 70-90 years into the future. Therefore resources, economic motivation in the longer term and environmental foundations for early adaptation action could be expected to exist. This study draws upon the Foucauldian conceptualization of governmentality to explain the particular institutional logics that nevertheless lead to business-as-usual arguments dominating discussion on adaptation in the case of Swedish forestry. The study emphasizes that adaptation must be seen as steered and limited by existing institutional, social system logics, rather than by externally defined "rational" motivations. Efforts on adaptation to climate change must thus be considered in relation to, and seek to change, existing institutionally based motivational and incentive structures, and must thus be conceived through social rather than environmental logics. In fact, social logics may even define the types of actions that may be regarded as adaptations.

  • 11.
    Andersson, Elias
    et al.
    Department of Forest Resource Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Keskitalo, E. Carina H.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för geografi och ekonomisk historia. Department of Forest Resource Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Lawrence, Anna
    Adaptation to climate change in forestry: a perspective on forest ownership and adaptation responses2017Inngår i: Forests, ISSN 1999-4907, E-ISSN 1999-4907, Vol. 8, nr 12, artikkel-id 493Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Adaptation to climate change has often been discussed from the perspectives of social vulnerability and community vulnerability, recognising that characteristics at local level will influence the particular adaptations undertaken. However, the extent to which national-level systemic factors influence and shape measures defined as adaptations has seldom been recognised. Focusing on adaptation to climate change in forestry, this study uses the example of two countries in the northern hemisphere with different forest ownership structures, forestry industry and traditions: Sweden, with strong private, non-industrial ownership, dominant forest industry and long forestry traditions; and Scotland, with forest ownership dominated by large estates and investment forestry based on plantations of exotic conifer species. The study shows how adaptation to climate change is structurally embedded and conditioned, which has resulted in specific challenges and constraints for different groups of forest owners within these two different contexts. This produces a specific set of political spaces and policy tools by rendering climate change in relation to forestry manageable, negotiable and practical/logical in specific ways. It is recommended that the focus of future work on climate-related issues and development of adaptation measures and policy should not be primarily on climate-related factors, but on institutional analysis of structural factors and logics in target sectors, in order to critically explore concepts of agency and power within these processes.

  • 12.
    Andersson, Haidi
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). 1965.
    Hur upplevs estetik i skogsbruket?: How is aesthetics in forestry perceived?2016Independent thesis Basic level (degree of Bachelor), 180 hpOppgave
  • 13.
    Andersson, Ida
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Distansskogsägares nöjdhet med Södras tjänsteutbud och kvalité på tjänster2015Independent thesis Basic level (degree of Bachelor), 180 hpOppgave
    Abstract [en]

    The development of technology and the mechanization in the Swedish forestry has during the last 60 years resulted in depopulation of the country side and due to that the amount of distance forest owners has increased. Therefore the forest companies need to make some adjustments in order to keep the distance forest owners as customers and to attract new ones. The purpose of this essay was to examine and analyze the distance forest owners satisfaction with Södras service offering and quality of service and further develop some proposals for action. A web-based survey was sent out to 634 distance forests owners in Stockholm, Sweden, all members of Södra. 269 respondents participated in the survey and of them, 27 did also participate in a follow-up telephone interview. The results show that the members generally was satisfied with the service offering and the quality of service. Suggestions for improvement regarding the service offering is all about implementing forest management courses in Stockholm and including providing financial and generational counseling, also on location in Stockholm. The quality of service can be improved if the inspector changes the way of working towards an even more customer adapted way and also improve the dialogue with the entrepreneurs. Further suggestions for improvement is to a greater extent welcome complaints and to give some compensation and/or apologize when it is motivated.

  • 14.
    Andersson, Jonas
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Föryngring med tallsådd- ett underskattat alternativ?2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    I de svenska skogarna är tallen (Pinus sylvestris L.) det näst vanligaste trädslaget och konkurrerar bäst på torrare och blötare marker. Av den anledningen är det viktigt vid föryngring att ståndortsanpassa. Det har dock blivit allt vanligare att privata skogsägare planterar gran (Picea abies L.) på typiska tallmarker på grund av det höga betestrycket. Detta kan vara förödande för tillväxten och kvaliteten. Ett sätt att klara betestrycket är att ha en högstamtäthet för att få många alternativa stammar kvar till älgsäker höjd. Där kan föryngringsmetoden vara avgörande. Mellan 2013–2016 planterades och självföryngrades 92,2 % av tallföryngringsarealen i Sverige, de resterande 7,8 % såddes. Att så tall på lämpliga marker resulterar ofta i en hög stamtäthet och det finns möjlighet att välja förädlat material. Detta ger en trängseleffekt vilket bidrar till hög virkeskvalitet, samtidigt som det kan ge en tillväxtökning upp till 25 % gentemot beståndsfrön om förädlat material används. Detta är en kombination som bara är möjlig att åstadkomma med sådd. Studiens syfte har varit att undersöka vilken inställning skogsägare har haft till tallsådd och varför så få använt metoden. Dessutom har det kartlagts vilka som använt metoden och varför. Detta har gjorts med en enkätundersökning som skickades ut till 240 skogsägare jämt fördelat över Sverige, varav 103 svarade. Det har även gjorts intervjuer med skogsbolag med eget skogsinnehav från nord- och mellansverige. Resultatet visade att 15 % av respondenterna från enkätundersökningen någon gång sått tall. Det var vanligare att de som ägde en skogsfastighet på 100 hektar eller mer någon gång hade sått tall i jämförelse med de som ägde 49 hektar eller mindre. Av de som sått svarade 92 % att de var nöjda med resultatet och 73 % kunde tänka sig att så igen. Det var ingen skogsägare från Götaland som sått tall. Av de som inte hade sått tall svarade 48 % att anledningen till de inte gjort de var för att de inte tänkt på det och 69 % svarade att de hade en varken positiv eller negativ inställning till metoden. Detta kan jämföras mot de som någon gång hade sått tall där 86 % svarade att de hade en positiv eller ganska positiv inställning. De skogsbolag som låtit sig intervjuas svarade samtliga att de har sått tall, dock i olika omfattning. Det bolag som sått mest var Sveaskog som svarade att de har sått 27 % av deras tallföryngringsareal. Detta kan jämföras med Holmen skog som sådde strax över 20 % och då är contortatall inkluderad. De främsta anledningarna till att de har sått var för att det bedömdes vara kostnadseffektivt och ger många stammar per hektar vilket har varit positivt i områden med högt betestryck. Alla intervjupersoner berättade att det är viktigt att välja rätt mark för ett positivt resultat. Resultatet från enkäten visade att de som svarat att de någonsin sått tall hade en positivare inställning till sådd, vilket tyder på positiva erfarenheter. Nära hälften av de som inte sått tall svarade att de hade varken en positiv eller negativ inställning. En möjlig orsak till det är att de inte hade någon erfarenhet av metoden och därför ingen åsikt. De som någon gång har sått var i regel större skogsägare. En möjlig orsak till det är att det är större sannolikhet att de har en lämplig mark tillgänglig och att de troligen föryngrar oftare än mindre skogsägare. En hög andel av de som inte sått svarade att de inte tänkt på det. Detta skulle kunna bero på ointresse eller okunskap. En stark orsak till detta är sannolikt på grund av tradition. Skulle de privata skogsägarna skaffa sig kunskap om detta och vilka marker som är lämpliga skulle det kunna finnas pengar att tjäna. Detta eftersom det är billigare, lättare, och skapar bättre kvalitet än de andra föryngringsmetoderna. Tallsådd går dessutom bra att kombinera med andra metoder och anpassa föryngringsåtgärden efter förutsättningarna. I områden där betesskador ställer till stora problem kan tallsådd vara ett outnyttjat verktyg i verktygslådan.

  • 15.
    Andersson, Matilda
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Naturkultur för bättre kvalitet i rotstocken i tallungskog?: Utvärdering av röjningsförsök i Kråkerödjan2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Scots pine (Pinus sylvestris L.) form a large part of Swedish forestry and has many alternative end-use areas with different requirements for quality. The ability to influence the quality is high in the initial planting and juvenile forest phase, as studies have shown relationships between good quality and dense planting, where competition between trees has a good impact on timber quality. Competition can also be achieved by shading from above, through seed trees or multi-layered forest. Interest in continuous cover forestry grows, and investigating differences in future timber quality between layered and clear cutting treatments can therefore be valuable. Such a method is “Naturkultur”, which aims to optimize the net present value at every point in the forest. The purpose of this study is to highlight the question of whether layered forests methods similar to “Naturkultur” can be used for higher timber quality in pine forests in a cleaning trial in southern Östergötland, Sweden. The goal is to find out if any difference in timber quality exists in the future butt log between the different cleaning treatments, layered (Uneven) and conventional (Even). The survey was limited to studying only the Kråkerödjan pre-commercial thinning trial, located on the property Kråkerödjan between Småland and Östergötland. Parameters for quality estimation were delimited to knot quantity and knot thickness. In order to answer the purpose, a field survey was conducted with quantitative assumptions where data about stem quantity, tree species distribution, height, diameter, height of the living crown, number of knots and diameter for the thickest knot from the base of the trunk up to 2 m on the trunk were collected. The result showed that the number of stems per ha was significantly higher in Uneven than in Even while the volume was next to the same. The average diameter was about 4 cm in Uneven and about 10 cm in Even. The tree species distribution was the same for trees with a diameter > 5 cm a breast height (bh) in both parcels,> 95% pine. For trees <5 cm bh, the distribution in Uneven was 14 % pine, 10 % spruce and 76 % deciduous, in Even there were almost exclusively deciduous trees. When examining pine > 5 cm at bh, there was a significant difference in the knot quantity with fewer knots/m in Uneven than in Even. The thickest knot was smaller in Uneven than in Even, but the difference was only significant when the data without dominants was examined. The thickest knot was slightly smaller relative to the diameter of the trunk in bh in Uneven but the difference was not significant. The average diameter in pine > 5 cm at bh was slightly less in Uneven, 10.7 cm, than in Even, 10.8 cm. The survey gives an indication that the layered forest according to the method of “Naturkultur” in the parcel Uneven, where dominants shades smaller trees, may be used for a better timber quality in pine in the investigated premises. However, the results are not sufficiently clear, if this is due to the fact that the quality difference is small or if it is because quality differences have not yet occurred V cannot be read in the survey. Estimating timber quality early in the rotation period is difficult as a lot can happen until final felling. However, the survey has been valuable as more data is needed in the area in question. Follow-up of the survey is needed to further explore the relationships between stock treatments and quality development.

  • 16.
    Androsiuk, P.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. University of Warmia & Mazury, Poland.
    Shimono, A.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Westin, J.
    Lindgren, D.
    Fries, A.
    Wang, X. -R
    Genetic status of Norway spruce (Picea abies) breeding populations for northern Sweden2013Inngår i: Silvae Genetica, ISSN 0037-5349, Vol. 62, nr 3, s. 127-136Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Efficient use of any breeding resources requires a good understanding of the genetic value of the founder breeding materials for predicting the gain and diversity in future generations. This study evaluates the distribution of genetic variation and level of relatedness among and within nine breeding populations of Norway spruce for Northern Sweden using nuclear microsatellite markers. A sample set of 456 individuals selected from 140 stands were genotyped with, 15 SSR loci. Over all loci each individual was identified with unique multilocus genotype. High genetic diversity (average H-e=0.820) and low population differentiation (F-ST = 0.0087) characterized this material. Although low in F-ST, the two northernmost populations were clustered as a distinct group diverged from the central populations. The population differentiation pattern corresponds well with the post glacial migration history of Norway spruce and the current gene flow and human activity in the region. The average inbreeding coefficient was 0.084 after removal loci with high frequency of null alleles. The estimated relatedness of the trees gathered in the breeding populations was very low (average kinship coefficient 0.0077) and not structured. The high genetic variation and low and not structured relatedness between individuals found in the breeding populations confirm that the Norway spruce breeding stock for northern Sweden represent valuable genetic resources for both long-term breeding and conservation programs.

  • 17.
    Angelstam, Per
    et al.
    Swedish University of Agricultural Sciences.
    Elbakidze, Marine
    Swedish University of Agricultural Sciences,.
    Tikhomirov, Valery
    Belarusian State University, Minsk, Belarus.
    15. Forests and Forestry in three Eastern European Countries2012Inngår i: Rural Development and Land Use / [ed] Lars Rydén and Ingrid Karlsson, Uppsala: Baltic University Press , 2012, 1, s. 176-185Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 18.
    Angelstam, Per
    et al.
    Sveriges Lantbruksuniversitet.
    Jonsson, Bengt Gunnar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Törnblom, Johan
    Sveriges Lantbruksuniversitet.
    Andersson, K
    Sveriges Lantbruksuniversitet.
    Axelsson, Robert
    Sveriges Lantbruksuniversitet.
    Roberge, Jean-Michel
    Sveriges Lantbruksuniversitet.
    Landskapsansats för bevarande av skoglig biologisk mångfald: en uppföljning av 1997 års regionala bristanalys, och om behovet av samverkan mellan aktörer2010Rapport (Annet vitenskapelig)
  • 19.
    Angelstam, Per
    et al.
    Sveriges Lantbruksuniversitet.
    Roberge, Jean-Michel
    Sveriges Lantbruksuniversitet.
    Jonsson, Bengt-Gunnar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Törnblom, Johan
    Sveriges Lantbruksuniversitet.
    Hur mycket är nog för att bevara arterna?2010Inngår i: Fakta Skog, ISSN 1400-7789, nr 12, s. 1-4Artikkel, forskningsoversikt (Annet vitenskapelig)
  • 20. Anugwom, Ikenna
    et al.
    Maki-Arvela, Paivi
    Virtanen, Pasi
    Willfor, Stefan
    Damlin, Pia
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Treating birch wood with a switchable 1,8-diazabicyclo-[5.4.0]-undec-7-ene-glycerol carbonate ionic liquid2012Inngår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 66, nr 7, s. 809-815Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The suitability of a new switchable ionic liquid (SIL) has been investigated as a solvent for fractionation of lignocellulosic materials. SIL was prepared from inexpensive chemicals, e. g., glycerol, CO2, and 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU). Fresh Nordic birch wood (B. pendula) was treated with the SIL for a time period of 1-5 days at 100 degrees C and under atmospheric pressure. Upon SIL treatment, at best, 57 % of the hemicelluloses were dissolved and 50 % of lignins were dissolved from the native birch. The slightly fibrillated SIL treated chips contained about 55 % cellulose. Up to 76 % of the recovered species removed from the spent SIL liquor was originating from hemicelluloses, mainly from xylan. The spent SILs were reused for fresh wood dissolution in four consecutive cycles and each time the wood dissolution efficiency was similar. SILs could offer affordable (easy-to-synthesize) solvent systems for partial elimination of hemicelluloses and lignin from wood. SILs can also be prepared in-situ and on-site.

  • 21.
    Athanassiadis, Dimitris
    et al.
    Dept. of Forest Resource Management, Swedish University of Agricultural Sciences.
    Bergström, Dan
    Hellström, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindroos, Ola
    Dept. of Forest Resource Management, Swedish University of Agricultural Sciences.
    Nordfjell, Tomas
    Dept. of Forest Resource Management, Swedish University of Agricultural Sciences.
    Ringdahl, Ola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Path tracking for autonomous forwarders in forest terrain2010Inngår i: Precision Forestry Symposium: developments in Precision Forestry since 2006 / [ed] Ackerman P A, Ham H, & Lu C, 2010, s. 42-43Konferansepaper (Fagfellevurdert)
  • 22. Ausin, Israel
    et al.
    Feng, Suhua
    Yu, Chaowei
    Liu, Wanlu
    Kuo, Hsuan Yu
    Jacobsen, Elise L.
    Zhai, Jixian
    Gallego-Bartolome, Javier
    Wang, Lin
    Egertsdotter, Ulrika
    Street, Nathaniel R.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik.
    Jacobsen, Steven E.
    Wang, Haifeng
    DNA methylome of the 20-gigabase Norway spruce genome2016Inngår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 113, nr 50, s. E8106-E8113Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    DNA methylation plays important roles in many biological processes, such as silencing of transposable elements, imprinting, and regulating gene expression. Many studies of DNA methylation have shown its essential roles in angiosperms (flowering plants). However, few studies have examined the roles and patterns of DNA methylation in gymnosperms. Here, we present genome-wide high coverage single-base resolution methylation maps of Norway spruce (Picea abies) from both needles and somatic embryogenesis culture cells via whole genome bisulfite sequencing. On average, DNA methylation levels of CG and CHG of Norway spruce were higher than most other plants studied. CHH methylation was found at a relatively low level; however, at least one copy of most of the RNA-directed DNA methylation pathway genes was found in Norway spruce, and CHH methylation was correlated with levels of siRNAs. In comparison with needles, somatic embryogenesis culture cells that are used for clonally propagating spruce trees showed lower levels of CG and CHG methylation but higher level of CHH methylation, suggesting that like in other species, these culture cells show abnormal methylation patterns.

  • 23.
    Backéus, Ingvar
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Växtbiologiska institutionen.
    Stenbeck, Gösta
    Konsekvenser av skogs- och myrdikning. Påverkan på flora och vegetation1981Annet (Annet (populærvitenskap, debatt, mm))
  • 24.
    Bahr, Adam
    et al.
    Lund University, Sweden.
    Ellström, Magnus
    Lund University, Sweden.
    Bergh, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Wallander, Håkan
    Lund University, Sweden.
    Nitrogen leaching and ectomycorrhizal nitrogen retention capacity in a Norway spruce forest fertilized with nitrogen and phosphorus2015Inngår i: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 390, nr 1-2, s. 323-335Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aims

    To estimate the production of external ectomycorrhizal mycelia (EMM) in Norway spruce forests with varying nitrogen (N) and phosphorus (P) levels, and to relate this to the N retention capacity of ectomycorrhizal fungi (EMF) and N leaching.

    Methods

    Seasonal changes in EMF production (in ingrowth mesh bags) and soil water N (in suction lysimeters) were analyzed after fertilization with N or N combined with P. The EMF N retention capacity was estimated by the addition of isotopically labeled N to the mesh bags.

    Results

    No relationship was found between the seasonal variation in EMF growth and N leakage from the soil. However, in the mesh bags, the total assimilation of 15N by EMF was almost halved by N fertilization, while twice as much 15N leached through.

    Conclusions

    We found a high specific N assimilation capacity per unit weight of EMF mycelia. This was unaffected by N fertilization, but the total assimilation of N by EMF was drastically reduced due to reduced production of EMM. However, N-retaining processes other than N assimilation by EMF must be taken into account to explain the losses of N after fertilization.

  • 25.
    Bandau, Franziska
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Importance of tannins for responses of aspen to anthropogenic nitrogen enrichment2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Boreal forests are often strongly nitrogen (N) limited. However, human activities are leading to increased N inputs into these ecosystems, through atmospheric N deposition and forest fertilization. N input into boreal forests can promote net primary productivity, increase herbivore and pathogen damage, and shift plant species composition and community structure. Genetic diversity has been suggested as a key mechanism to promote a plant species’ stability within communities in response to environmental change. Within any plant population, specific traits (e.g. growth and defense traits) can vary substantially among individuals, and a greater variation in traits may increase chances for the persistence of at least some individuals of a population, when environmental conditions change. One aspect of plant chemistry that can greatly vary among different genotypes (GTs) are condensed tannin (CTs). These secondary metabolites have been suggested to affect plant performance in many ways, e.g. through influencing plant growth, the interactions of plants with herbivores and pathogens, and through affecting litter decomposition, and hence the return of nutrients to plants. To investigate how genotypic variation in foliar CT production may mediate the effects that anthropogenic N enrichment can have on plant performance and litter decomposition, I performed a series of experiments. For these experiments, aspen (Populus tremula) GTs with contrasting abilities to produce foliar CTs (i.e. low- vs. high-tannin producers) were grown under 3 N conditions, representing ambient N (+0 kg ha-1), upper level atmospheric N deposition (+15 kg ha-1), and forest fertilization rates (+150 kg ha-1). This general experimental set-up was once established in a field-like environment, from which natural enemies were excluded, and once in a field, in which enemies were present. In my first two studies, I investigated tissue chemistry and plant performance in both environments. I observed that foliar CT levels decreased in response to N in the enemy‑free environment (study I), but increased with added N when enemies were present (study II). These opposing responses to N may be explained by differences in soil N availability in the two environments, or by induction of CTs after enemy attack. Enemy damage generally increased in response to N, and was higher in low-tannin than in high-tannin plants across all N levels. Plant growth of high‑tannin plants was restricted under ambient and low N conditions, probably due to a trade-off between growth and defense. This growth constraint for high‑tannin plants was weakened, when high amounts of N were added (study I and II), and when enemy levels were sufficiently high, so that benefits gained through defense could outweigh the costs of defense production (study II). Despite those general responses of low- and high‑tannin producers to added N, I also observed a number of individual responses of GTs to N addition, which in some case were not connected to the intrinsic ability of the GTs to produce foliar CTs. In study III, gene expression levels in young leaves and phenolic pools of the plants that were grown in the enemy‑free environment were studied. This study revealed that gene control over the regulation of the phenylpropanoid pathway (PPP) was distributed across the entire pathway. Moreover, PPP gene expression was higher in high-tannin GTs than in low‑tannin GTs, particularly under ambient N. At the low N level, gene expressions declined for both low- and high-tannin producers, whereas at the high N level expression at the beginning and the end of the PPP was upregulated and difference between tannin groups disappeared. Furthermore, this study showed that phenolic pools were frequently uncorrelated, and that phenolic pools were only to some extent related to tannin production and gene expression. In study IV, I investigated the decomposability of litter from the field plants. I found that N enrichment generally decreased mass loss, but there was substantial genetic variation in decomposition rates, and GTs were differentially responsive to added N. Study IV further showed that CTs only had a weak effect on decomposition, and other traits, such as specific leaf area and the lignin:N ratio, could better explain genotypic difference in mass loss. Furthermore, N addition caused a shift in which traits most strongly influenced decomposition rates. Collectively, the result of these studies highlight the importance of genetic diversity to promote the stability of species in environments that experience anthropogenic change.

  • 26.
    Bautista, Rocí­o
    et al.
    University of Malaga.
    Villalobos, David, P.
    University of Malaga.
    Diaz-Moreno, Sara M
    University of Malaga.
    Cantón, Francisco, R.
    University of Malaga.
    Cánovas, Francisco, M.
    University of Malaga.
    Gonzalo Claros, M.
    University of Malaga.
    Toward a Pinus pinaster bacterial artificial chromosome library2007Inngår i: Annals of Forest Science, ISSN 1286-4560, E-ISSN 1297-966X, Vol. 64, nr 8, s. 855-864Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Conifers are of great economic and ecological importance, but little is known concerning their genomic organization. This study is an attempt to obtain high-quality high-molecular-weight DNA from Pinus pinaster cotyledons and the construction of a pine BAC library. The preparation incorporates modifications like low centrifugation speeds, increase of EDTA concentration for plug maintenance, use of DNase inhibitors to reduce DNA degradation, use of polyvinylpyrrolidone and ascorbate to avoid secondary metabolites, and a brief electrophoresis of the plugs prior to their use. A total of 72 192 clones with an average insert size of 107 kb, which represents an equivalent of 11X pine haploid genomes, were obtained. The proportions of clones lacking inserts or containing chloroplast DNA are both approximately 1.6%. The library was screened with cDNA probes for seven genes, and two clones containing Fd-GOGAT sequences were found, one of them seemingly functional. Ongoing projects aimed at constructing a pinebacterial artificial chromosome library may benefit from the methods described here.

  • 27.
    Beland Lindahl, Karin
    et al.
    Luleå tekniska universitet.
    Sténs, Anna
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Sandström, Camilla
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statsvetenskapliga institutionen.
    Johansson, Johanna
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statsvetenskapliga institutionen.
    Lidskog, Rolf
    Örebro universitet.
    Ranius, Thomas
    Sveriges lantbruksuniversitet, SLU, Uppsala, Sweden.
    Roberge, Jean-Michel
    Sveriges lantbruksuniversitet, SLU, Umeå, Sweden.
    The Swedish forestry model: more of everything?2017Inngår i: Forest Policy and Economics, ISSN 1389-9341, E-ISSN 1872-7050, Vol. 77, s. 44-55Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    "The Swedish forestry model" refers to the forest regime that evolved following the 1993 revision of the Swedish Forestry Act. It is key to Swedish forest politics and used to capture the essence of a sustainable way of managing forests. However, the ideas, institutions and practices comprising the model have not been comprehensively analyzed previously. Addressing this knowledge gap, we use frame analysis and a Pathways approach to investigate the underlying governance model, focusing on the way policy problems are addressed, goals, implementation procedures, outcomes and the resulting pathways to sustainability. We suggest that the institutionally embedded response to pressing sustainability challenges and increasing demands is expansion, inclusion and integration: more of everything. The more-of-everything pathway is influenced by ideas of ecological modernization and the optimistic view that existing resources can be increased. Our findings suggest that in effect it prioritizes the economic dimension of sustainability. While broadening out policy formulation it closes down the range of alternative outputs, a shortcoming that hampers its capacity to respond to current sustainability challenges. Consequently, there is a need for a broad public debate regarding not only the role of forests in future society, but also the operationalization of sustainable development.

  • 28.
    Benjaminsson, Erik
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Åslund, Victor
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Höstplantering av tall - Ett komplement till vårplantering?2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detta examensarbete utfördes under våren 2017 på uppdrag av Södra skogsägarna, för att undersöka om höstplantering av tall ger ett bra föryngringsresultat och kan ses som ett likvärdigt alternativ till att plantera på våren. Traditionellt sett utförs den största delen av planteringar på våren men för att få en jämnare arbetsfördelning över året är det intressant att undersöka om höstplantering av tall fungerar.

    Undersökningen är utförd som en survey studie där trakter som planterades på hösten 2014 och trakter som planterades på våren 2015 låg till grund för datainsamlingen. Totalt gjordes det uppföljning på 38 trakter där hälften är vårplanterade och hälften är höstplanterade. Trakterna är sedan jämförda parvis med avseende på planttyp, ståndortsindex, viltbehandling, markfuktighet och blockighet. På varje trakt lades det ut 20 provytor med radien 2,82 vilket ger en provyta på 25 m2. I varje provyta mättes för varje planta; rothalsdiameter, toppskottslängd, totallängd, eventuella skador och eventuella avgång och avgångsorsak

    Höstplantering av tall hade en högre avgång än vårplanteringarna och snytbaggen var den skadegörare som orsakade störst avgång, följt av vilt och torka. Plantan växte något bättre på de trakter som var vårplanterade, men det var bara toppskottstillväxten som var signifikant längre vid vårplantering. Snytbaggeangreppen var lika omfattande vid både vår- och höstplantering medan viltbetningen var dubbelt så stor på de höstplanterade trakterna. 

  • 29. Berg, B.
    et al.
    Kjonaas, O. J.
    Johansson, M. -B
    Erhagen, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Åkerblom, S.
    Late stage pine litter decomposition: Relationship to litter N, Mn, and acid unhydrolyzable residue (AUR) concentrations and climatic factors2015Inngår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 358, s. 41-47Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this paper is to evaluate relationships between decomposition rates of Scots pine (Pinus sylvestris) and lodgepole pine (Pinus contorta var. contorta) needle litter in the late stage of decomposition (>30% accumulated mass loss), and the progressively changing concentrations of manganese (Mn), nitrogen (N), and acid unhydrolyzable residue (AUR), as well as mean annual temperature (MAT) and mean annual precipitation (MAP). Using available long-term decomposition studies on pine needle litter in a climate gradient in Sweden, we calculated annual mass loss and related to concentrations of Mn, N, and AUR at the start of each one-year period as well as to MAT and MAP. We investigated these relationships for (i) all data on annual mass loss combined and (ii) annual mass loss for five different decomposition categories as defined by accumulated mass loss. We found highly significant, negative, and dominant relationships between annual mass loss and N (R-2 = 0.39) and AUR (R-2 = 0.39), a slight but significant positive relationship to Mn (R-2 = 0.08) and a significant negative relationship to MAT (R-2 = 0.06). The relationships were dynamic, and changed with accumulated mass loss. The rate-dampening effect of N decreased to be a rate-enhancing effect at c. 60-80% accumulated mass loss. A similar trend was found for AUR, becoming rate-enhancing at 70-80% accumulated mass loss. For Scots pine needle litter the effect of MAT on mass loss decreased with increasing accumulated mass loss and changed to a rate-dampening effect at c. 50-70% accumulated mass loss. Mn showed a stimulating effect on mass loss rate in all categories whereas MAP showed no effect in this mainly boreal climatic gradient. The current approach indicates a method for detailed studies of rate-regulating factors for litter decomposition.

  • 30.
    Berg, Björn
    et al.
    Dipartimento biologia strutturale e funzionale, Complesso universitario di Monte S. Angelo, Napoli, Italy; Department of forest ecology, University of Helsinki, Helsinki, Finland.
    Davey, M. P.
    Department of plant sciences, University of Cambridge, Cambridge, United Kingdom.
    De Marco, A.
    Dipartimento biologia strutturale e funzionale, Complesso universitario di Monte S. Angelo, Napoli, Italy.
    Emmett, B
    Centre for ecology and hydrology, Bangor.
    Faituri, M.
    Department of soils and water, Omar AlMukhtar university, Elbeida, Libyan Arab Jamahiriya.
    Hobbie, S. E.
    Department of ecology, evolution and behavior, University of Minnesota, St. Paul, USA.
    Johansson, Maj-Britt
    Högskolan i Gävle.
    Liu, C.
    Department of landscape science and engineering, College of agriculture and biology, Shanghai, ChinaShanghai Jiao Tong university,.
    McClaugherty, C.
    Department of biology, Mount Union college, Alliance, USA.
    Norell, L.
    Unit of applied statistics and mathematics, SLU, Uppsala, Sweden.
    Rutigliano, F. A.
    Dipartimento di scienze ambientali, Seconda Università degli studi di Napoli, Caserta, Italy.
    Vesterdal, L.
    Forest & landscape Denmark, University of Copenhagen, Hørsholm, Denmark.
    Virzo De Santo, A.
    Dipartimento biologia strutturale e funzionale, Complesso universitario de Monte S. Angelo, Napoli, Italy.
    Factors influencing limit values for pine needle litter decomposition: A synthesis for boreal and temperate pine forest systems2010Inngår i: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 100, nr 1, s. 57-73Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We synthesized available data for decomposition of pine (Pinus) needle litter in pine forests to determine the litter chemical characteristics and climate factors that explained variation in the limit value, i. e. the level of accumulated mass loss at which the decomposition process either continues at a very low rate or possibly stops. Our data base included 56 separate studies on decomposition of pine needle litter, spanning Scots pine, lodgepole pine, Aleppo pine, stone pine and white pine, mainly incubated at the site of collection. Studies had 5 to 19 samplings, on average 10, and the decomposition was followed to a mass loss ranging from 47 to 83%, on average 67%. The periods from 3.0 to 5.4 years, on average 3.9 years, were of sufficient duration to allow estimates of limit values of decomposition. We used a linear mixed model with regression effects to relate limit values to potential explanatory variables, namely the sites' long-term mean annual temperature (MAT) and mean annual precipitation (MAP) and to substrate-chemistry factors. Regarding the latter, we explored two models; one that included initial concentrations of water solubles, lignin, N, P, K, Ca, Mg, and Mn and one that included only lignin, N, Ca, and Mn to focus on those nutrients known to influence lignin degradation. Using backward elimination significant explanatory variables were determined. For litter decomposed in its site of origin we found the limit value to depend mainly on the initial concentration of Mn, with higher Mn concentrations resulting in higher accumulated mass loss. Thus, litter with higher Mn reached a higher limit value and left a smaller stable fraction. This is likely due to the fact that Mn is an essential component of ligninolytic enzymes important for degrading litter in the later stages of decomposition. Manganese has received little attention in decomposition studies to date. Given its significance in this synthesis, the role of Mn in influencing variation in the late stages of decomposition among ecosystems and among litters of other genera besides Pinus deserves further attention.

  • 31.
    Berg, Björn
    et al.
    Department of Forest Sciences, University of Helsinki, Helsinki, Finland .
    Erhagen, Björn
    Department of Ecology and Environmental Sciences, University of Umeå, Umeå, Sweden .
    Johansson, Maj-Britt
    Högskolan i Gävle.
    Nilsson, Mats
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå.
    Stendahl, Johan
    Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala.
    Trum, Florence
    Earth and Life Institute, Universite' catolique de Louvain, Louvain-la-Neuve, Belgium .
    Vesterdal, Lars
    Department of Geosciences and Natural Resource Management, University of Copenhagen, Fredriksberg C, Denmark .
    Manganese in the litter fall-forest floor continuum of boreal and temperate pine and spruce forest ecosystems: a review2015Inngår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 358, s. 248-260, artikkel-id 15021Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    We have reviewed the literature on the role of manganese (Mn) in the litter fall-to-humus subsystem. Available data gives a focus on North European coniferous forests. Manganese concentrations in pine (Pinus spp.) foliar litter are highly variable both spatially and temporally within the same litter species and for the genus Pinus we found a range from 0.03 to 3.7mgg-1. Concentrations were related negatively to site mean annual temperature (MAT) and annual actual evapotranspiration (AET) for pine species litter but not for that of Norway spruce (Picea abies) as a single species. Combined data for several species showed a highly significant relationship to MAT.Manganese peroxidase is an Mn-dependent enzyme, found in white-rot fungi, essential for the degradation of lignin and ligninlike compounds. The decomposition rates of lignified litter tissue (late phase) is positively related to the litter’s Mn concentration. Further, the Mn concentration is positively related to the limit value for decomposition - the higher the Mn concentration the smaller the stable litter fraction. Manganese release from decomposing litter appears at least in part to be species related. Thus was release from pine needle litter significantly faster (p<. 0.001) than that from the Mn-richer litter of Norway spruce. Over Northern Europe concentrations of total Mn in mor humus as well as extractable Mn in the mineral soil increase with decreasing MAT and over a climatic gradient the Mn concentrations in Norway spruce mor increase more with decreasing MAT than in a gradient with Scots pine. Higher Mn concentrations in humus appear to decrease its stability and result in a higher release of carbon dioxide (CO<inf>2</inf>) and dissolved organic carbon (DOC). We conclude that this may explain (i) the lower amount of carbon (C) in mor layers under Norway spruce as compared to Scots pine as well as the higher amount of C in mineral soil under spruce. The increase in nitrogen (N) concentration in humus, following N fertilization resulted in a decrease in that of Mn. We have found four cases - empirical - with negative interaction between Mn and N; (i) in pine foliar litter fall concentrations of Mn decrease with site MAT whereas those of N increase, (ii) in decomposing late-stage litter with N retarding and Mn stimulating decomposition, (iii) for the stable phase, limit values are related negatively to N and positively to Mn, and (iv) Mn concentrations in humus decrease with MAT whereas those of N increase.

  • 32. Berg, Björn
    et al.
    Erhagen, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Johansson, Maj-Britt
    Nilsson, Mats
    Stendahl, Johan
    Trum, Florence
    Vesterdal, Lars
    Manganese in the litter fall-forest floor continuum of boreal and temperate pine and spruce forest ecosystems: A review2015Inngår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 358, s. 248-260Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    We have reviewed the literature on the role of manganese (Mn) in the litter fall-to-humus subsystem. Available data gives a focus on North European coniferous forests. Manganese concentrations in pine (Pinus spp.) foliar litter are highly variable both spatially and temporally within the same litter species and for the genus Pinus we found a range from 0.03 to 3.7 mg g(-1). Concentrations were related negatively to site mean annual temperature (MAT) and annual actual evapotranspiration (AET) for pine species litter but not for that of Norway spruce (Picea abies) as a single species. Combined data for several species showed a highly significant relationship to MAT. Manganese peroxidase is an Mn-dependent enzyme, found in white-rot fungi, essential for the degradation of lignin and ligninlike compounds. The decomposition rates of lignified litter tissue (late phase) is positively related to the litter's Mn concentration. Further, the Mn concentration is positively related to the limit value for decomposition - the higher the Mn concentration the smaller the stable litter fraction. Manganese release from decomposing litter appears at least in part to be species related. Thus was release from pine needle litter significantly faster (p < 0.001) than that from the Mn-richer litter of Norway spruce. Over Northern Europe concentrations of total Mn in mor humus as well as extractable Mn in the mineral soil increase with decreasing MAT and over a climatic gradient the Mn concentrations in Norway spruce mor increase more with decreasing MAT than in a gradient with Scots pine. Higher Mn concentrations in humus appear to decrease its stability and result in a higher release of carbon dioxide (CO2) and dissolved organic carbon (DOC). We conclude that this may explain (i) the lower amount of carbon (C) in mor layers under Norway spruce as compared to Scots pine as well as the higher amount of C in mineral soil under spruce. The increase in nitrogen (N) concentration in humus, following N fertilization resulted in a decrease in that of Mn. We have found four cases - empirical - with negative interaction between Mn and N; (i) in pine foliar litter fall concentrations of Mn decrease with site MAT whereas those of N increase, (ii) in decomposing late-stage litter with N retarding and Mn stimulating decomposition, (iii) for the stable phase, limit values are related negatively to N and positively to Mn, and (iv) Mn concentrations in humus decrease with MAT whereas those of N increase. (C) 2015 Elsevier B.V. All rights reserved.

  • 33.
    Berg, Björn
    et al.
    Department of Forest Ecology, University of Helsinki, Helsinki, Finland.
    Johansson, Maj-Britt
    Högskolan i Gävle.
    Liu, Chunjiang
    School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China; Shanghai Urban Forest Research Station, State Forestry Administration, Shanghai, China.
    Faituri, Mikaeel
    Department of Soils and Water, Omar AlMukhtar University, Elbeida, Libya.
    Sanborn, Paul
    Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, Canada.
    Vesterdal, Lars
    Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg, Denmark.
    Ni, Xiangyin
    Long-term Research Station of Alpine Forest Ecosystems, Key Laboratory of Ecological Forestry Engineering, Institute of Ecology and Forestry, Sichuan Agricultural University, Chengdu, China.
    Hansen, Karin
    IVL Swedish Environmental Research Institute, Stockholm, Sweden.
    Ukonmaanaho, Liisa
    Natural Resources Institute Finland, Helsinki, Finland.
    Calcium in decomposing foliar litter – A synthesis for boreal and temperate coniferous forests2017Inngår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 403, s. 137-144Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have synthesized available data for calcium (Ca) dynamics in decomposing foliar litter of mainly pine (Pinus), spruce (Picea), and birch (Betula) species to determine patterns of Ca concentration with climate in newly shed litter and its dynamics in decomposing litter as well as a possible role for Ca as regards limit values. Initial Ca concentration was negatively related to mean annual precipitation (MAP) with different relationships among genera. A limited data set showed a positive relationship across species (p &lt; 0.05) to extractable Ca in soil. In paired stands, litter of both Norway spruce (Picea abies) and lodgepole pine (Pinus contorta) had higher Ca concentrations than Scots pine (Pinus silvestris), Norway spruce litter even twice as high. Relationships between initial concentrations of Ca and those of other nutrients appeared to be dominated by the positive ones to potassium (K) and magnesium (Mg) and specifically for deciduous litter there was a negative relationship to nitrogen (N). In decomposing litter, Ca concentration followed a negative quadratic (Ca = a + t − t2) function and had a maximum, which was variable. The Ca maximum concentration during decomposition was positively related to initial Ca concentration both within and among species. Separate linear relationships based on species were combined into one, in common for all investigated species and genera (R2 = 0.914, n = 63, p &lt; 0.001). Limit values for decomposition were positively related to maximum Ca concentration at p &lt; 0.05 with separate functions for pine and spruce litter. Calcium net release started directly after the incubation and was linear to accumulated mass loss of litter, giving a slope coefficient for each study. The net release rates were linear to initial Ca concentration both within and across species/genera. All studies combined gave a negative linear relationship (R2 = 0.894, n = 67, p &lt; 0.001).

  • 34.
    Berg, Björn
    et al.
    Department of Forest Sciences, University of Helsinki, Helsinki, Finland.
    Kjønaas, O. J.
    Norwegian Institute of Bioeconomy Research, Ås, Norway.
    Johansson, Maj-Britt
    Högskolan i Gävle.
    Erhagen, B.
    Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden.
    Åkerblom, S.
    Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden .
    Late stage pine litter decomposition: Relationship to litter N, Mn, and acid unhydrolyzable residue (AUR) concentrations and climatic factors2015Inngår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 358, s. 41-47Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this paper is to evaluate relationships between decomposition rates of Scots pine (Pinus sylvestris) and lodgepole pine (Pinus contorta var. contorta) needle litter in the late stage of decomposition (>30% accumulated mass loss), and the progressively changing concentrations of manganese (Mn), nitrogen (N), and acid unhydrolyzable residue (AUR), as well as mean annual temperature (MAT) and mean annual precipitation (MAP). Using available long-term decomposition studies on pine needle litter in a climate gradient in Sweden, we calculated annual mass loss and related to concentrations of Mn, N, and AUR at the start of each one-year period as well as to MAT and MAP. We investigated these relationships for (i) all data on annual mass loss combined and (ii) annual mass loss for five different decomposition categories as defined by accumulated mass loss. We found highly significant, negative, and dominant relationships between annual mass loss and N (R2=0.39) and AUR (R2=0.39), a slight but significant positive relationship to Mn (R2=0.08) and a significant negative relationship to MAT (R2=0.06). The relationships were dynamic, and changed with accumulated mass loss. The rate-dampening effect of N decreased to be a rate-enhancing effect at c. 60-80% accumulated mass loss. A similar trend was found for AUR, becoming rate-enhancing at 70-80% accumulated mass loss. For Scots pine needle litter the effect of MAT on mass loss decreased with increasing accumulated mass loss and changed to a rate-dampening effect at c. 50-70% accumulated mass loss. Mn showed a stimulating effect on mass loss rate in all categories whereas MAP showed no effect in this mainly boreal climatic gradient. The current approach indicates a method for detailed studies of rate-regulating factors for litter decomposition. 

  • 35.
    Berg, Linus
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Skogsägares och jägares syn på älgbetesskador i Jönköpings län2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Tall (Pinus sylvestris) är ett viktigt vinterfoder för älgen (Alces alces), som är ett uppskattat jaktvilt i Sverige. Tall är också ett av de två absolut viktigaste trädslagen för Sveriges timmer- och massavedsproduktion. När betestrycket på tallungskog blir för högt, tenderar skogsägarna att föryngra tallbestånd med gran (Picea abies), vilket är mindre begärligt för älgen att beta än tall. Konsekvenserna blir en felaktig ståndortsanpassning och att fodertillgången minskar för älgen. Biologisk mångfald påverkas också negativt, då betestrycket på andra trädslag såsom rönn, asp, sälg och ek blir högt.

    Med världens högsta älgstam sett till skogsmarksareal, skapas stor debatt i Sverige kring älgstammens förvaltning och lämpliga storlek, mellan skogsägare som vill ha ett lönsamt skogsbruk och älgjägare som vill ha en stor älgstam för jakt. En älgstam i balans med fodernivån är bra för både viltet, mångfalden, miljön, samhället, skogsbruket och viltförvaltningen.

    Syftet med studien var att jämföra skogsägares och jägares syn på betesskador och hur de värderar konsekvenserna av dessa. Målet med studien var att kunna tillhandahålla ett underlag, som kan vara till nytta för älgförvaltningsorgan.

    Metoden som valdes var en enkätundersökning där kvantitativa data samlades in. Enkäten bestod av totalt 12 frågor, där fråga 7 bestod av flera delfrågor. Studiens urval gjordes som kluster- och bekvämlighetsurval, där totalt 304 enkäter samlades in och svaren från 258 enkäter användes, från skogsägare och jägare som var aktiva i Jönköpings län. Enkäten besvarades av tre olika fördefinierade grupper vilka definierades som jägare som inte äger någon egen skog, skogsägare som jagar och skogsägare som inte jagar. Gruppernas enkätsvar jämfördes med statistiska analyser.

    Resultatet visade att skogsägares och jägares syn på förekomsten av betesskador skilde sig signifikant. Jägare som inte äger någon egen skog bedömde betesskadeförekomsten som lägst, medan skogsägare som inte jagar bedömde förekomsten som högst. Skogsägare som jagar låg mellan de andra två grupperna. Resultatet visade också att det fanns ett signifikant samband mellan synen på betesskadors omfattning och hur stor vinterstam av älg per 1000 ha man tyckte var lämplig, där respondenterna önskade en lägre älgstam ju högre de bedömde förekomsten av betesskador.

    Studien visar att älgförvaltningsrepresentanters bakgrund som skogsägare eller jägare påverkar synen på älgstammens lämpliga storlek, eftersom de bedömer förekomsten av betesskadors omfattning olika, liksom betesskadornas konsekvenser. Älgförvaltningsgruppers fördelning av representanter bör därför spegla olika gruppers intressen för att sträva efter acceptans.

  • 36.
    Bergh, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Skogsbruk2015Inngår i: Klimatsäkrat Skåne / [ed] Hall, M, Lund, E & Rummukainen, M, Lund, Sweden: Centrum för miljö- och klimatforskning, Lunds Universitet , 2015, s. 111-120Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 37.
    Bergh, Johan
    et al.
    Swedish University of Agricultural Sciences, Sweden.
    Blennow, Kristina
    Swedish University of Agricultural Sciences, Sweden.
    Andersson, Mikael
    Swedish University of Agricultural Sciences, Sweden.
    Olofsson, Erika
    Swedish University of Agricultural Sciences, Sweden.
    Nilsson, Urban
    Swedish University of Agricultural Sciences, Sweden.
    Sallnäs, Ola
    Swedish University of Agricultural Sciences, Sweden.
    Karlsson, Matts
    Swedish University of Agricultural Sciences, Sweden.
    Effekter av ett förändrat klimat på skogen och implikationer för skogsbruket: Bilaga B 19, Arbetsrapport 342007Inngår i: Sverige inför klimatförändringarna: hot och möjligheter, Fritzes, 2007, s. 1-71Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
    Abstract [sv]

    Att klimatet kan komma att förändras påverkar svenskt skogsbruk. Skogen har i sig en direkt inverkan på klimatet samtidigt som skogsbruket kan behöva anpassas till de nya förhållandena. Ett osäkert klimat sätter brukandet av skogen i ett nytt läge som vi inte har någon tidigare erfarenhet av. Scenarier för framtida klimatutveckling är behäftade med stor osäkerhet och de förväntade effekterna på skogen blir således ännu mer osäkra. Trots detta kan man ändå förutsäga några sannolika huvuddrag i effekterna på den svenska skogen vid ett framtida ändrat klimat. En ökad potential för biomassaproduktion kan förväntas, liksom ökade möjligheter att använda nya arter i skogsbruket. Samtidigt ökar sannolikt risken för vissa typer av skador.

    Att väga eventuella fördelar i form av ökad produktion och ökade möjligheter i trädslagsval mot ökade risker för skador är viktigt för att ge samhället ett helhetsperspektiv och för att en större grupp ska ha möjlighet att ta till sig frågan. Det är också viktigt att i största möjliga mån kvantifiera eller ge ramarna i ekonomiska termer för hur det förändrade klimatet kan tänkas påverka skogsbruket. Vidare kan det vara styrande för prioritering av fortsatta forskningsarbeten och riskbedömning och för att prioritera åtgärder. Därför har vi försökt utifrån befintlig kunskap idag, konstruera en Tabell över den ekonomiska betydelsen och forskningsbarheten för olika risk/ämnesområden (se Tabell 17 sidan 39). De kanske största effekterna av ett förändrat klimat på ekonomin inom skogsbruket skulle vara om vi lyckas utnyttja den ökade produktionspotentialen. Det förutsätter att vi kan bemästra de negativa effekterna i första hand av en ökad risk för vindfällning, skadeangrepp från insekter och svampar. Mot bakgrund av skogsbrukets stora betydelse som naturresurs och industriell bas, så finner vi att det är viktigt att vi står rustade inför en framtid med såväl ökade hot som nya möjligheter.

    I denna skrift försöker vi beskriva och analysera tänkbara effekter av ett förändrat klimat på skogen och bedömt deras implikationer för produktionsskogsbruket. Andra aspekter än produktionsaspekter på skogsbruket har inte behandlats. Analysen sker i fyra steg. Vi inleder med att, så långt nuvarande kunskapsläge tillåter, kvantifiera effekterna på den skogliga primärproduktionen – tillväxten i skogen. I ett andra steg omsätts dessa effekter till effekter på produktionsekonomin i ett bestånd. Därefter analyseras tänkbara effekter på risken för stormfällning i skogen. I ett sista steg breddas diskussionen till en något mera spekulativ bild av tänkbara effekter på skogsbrukets ekonomi.

  • 38.
    Bergh, Johan
    et al.
    Swedish University of Agricultural Sciences (SLU).
    Johansson, U
    Nilsson, U
    Sallnäs, O
    Är anpassning av skogsskötseln nödvändigt i dagsläget för att minska skogsskador i ett förändrat klimat? Del 1 – analyser på bestådsnivå2012Rapport (Fagfellevurdert)
  • 39.
    Bergh, Johan
    et al.
    Swedish University of Agricultural Sciences (SLU).
    Johansson, Ulf
    Jönsson, Anna Maria
    Lund University.
    Lagergren, Fredrik
    Lund University.
    Lundström, Anders
    Nilsson, Urban
    Sallnäs, Ola
    Är anpassning av skogsskötseln nödvändigt i dagsläget för att minska skogsskador i ett förändrat klimat?: Del 2 –analyser på regional nivå2012Rapport (Annet vitenskapelig)
  • 40.
    Bergh, Johan
    et al.
    Swedish University of Agricultural Sciences.
    Nilsson, Urban
    Swedish University of Agricultural Sciences.
    Allen, H Lee
    North Carolina State University, USA.
    Johansson, Ulf
    Swedish University of Agricultural Sciences.
    Fahlvik, Nils
    Swedish University of Agricultural Sciences.
    Long-term responses of Scots pine and Norway spruce stands in Sweden to repeated fertilization and thinning2014Inngår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 320, s. 118-128Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recent investigations have shown that annual wood production in Sweden can be increased by 30 million m3 per year in a long-term perspective (>50 years) by using new forest management methods such as new tree species or seedling materials. However, to meet the increased demands during the next 20 years, Sweden will have to rely on silvicultural methods available today. Growth in boreal and cold temperate forest is with only few exceptions limited by nutrients availability, primarily nitrogen, and one way to satisfy the increased demands in a short-term perspective is nitrogen fertilization. A set of thinning and fertilization experiments were started in the 1960’s in Scots pine and Norway spruce stands over the whole of Sweden representing different soil, moisture and vegetation types. We used data from these experiments to examine the long-term effects of repeated fertilization in thinned stands on growth, stand development, and yield. The 34 Scots pine sites and 13 Norway spruce sites included in our analyses had at least four treatment plots (no thinning, repeated light thinnings, repeated light thinnings with repeated N fertilization, and repeated light thinnings with repeated N + P fertilization). In northern Sweden, 100 kg N ha−1 and 150 kg N ha−1 were applied at each fertilization event for Scots pine and Norway spruce stands, respectively. In southern Sweden, 150 kg ha−1 N was applied in Scots pine stands and 200 kg ha−1 N in Norway spruce stands. Phosphorus was applied at the rate of 100 kg ha−1. Several sites also included non-thinned fertilized plots. Pine stands but not spruce stands were responsive (up to 25% more growth depending of the attribute assessed) to repeated fertilization. Surprisingly, the non-thinned pine stands showed strong continuing response to fertilization throughout the 30+ year observation period resulting in higher cumulative volume response than the thinned stands. In thinned stands incremental volume response to fertilization continued but slowly diminished with time indicating that fertilization and thinning effects were less than additive. However, thinning and fertilization effects were additive for diameter growth. Fertilization accelerated stand development with significant shifts in diameter distributions to larger and potentially more valuable trees. Conclusively, repeated nitrogen fertilization is a silvicultural practice that will result in significant and sustained increases in Scots pine production.

  • 41.
    Bergh, Johan
    et al.
    Swedish University of Agricultural Sciences (SLU).
    Nilsson, Urban
    Kjartansson, Bjarki
    Karlsson, Matts
    Impact of climate change on the productivity of Silver birch, Norway spruce and Scots pine stands in Sweden with economic implications for timber production2010Inngår i: Ecological Bulletins, ISSN 0346-6868, Vol. 53, nr 16, s. 185-195Artikkel i tidsskrift (Fagfellevurdert)
  • 42.
    Berglind, Lennart
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Skogsägares uppfattning om tillväxtdata i skogsbruksplaner2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    SAMMANFATTNING

    Skogens tillväxt är naturligtvis en central och grundläggande aspekt i skogsbruk

    och själva grunden för ett lönsamt skogsägande. Frågan är i vilken utsträckning

    skogsägare använder sig av data om tillväxt i skogsbruksplaner, och om de

    upplever att dessa uppgifter är väsentliga och användbara. Eller kan det finnas

    alternativa sätt att presentera tillväxt och kanske även annan typ av information i

    skogsbruksplanerna som bedöms som minst lika värdefull?

    Denna studie försökte främst ta reda på vilken tilltro skogsägarna fäster vid data

    om tillväxt i skogsbruksplaner. Svaren pekade mot att skogsägarna hyste en

    relativt stor tilltro till tillväxt angivet som ett numeriskt värde (3,47 av 5 poäng)

    och även till dess substantiella informationsvärde, men att även annan

    beståndsinformation som exempelvis åtgärdsförslag bedömdes som minst lika

    viktig.

    Felkällorna vid bestämning av ståndortsindex och bonitet kan vara ganska

    betydande, och det mest osäkra är vid översättning från ståndortsindex till

    bonitet. Detta kan sedan bidra till att ge en felaktig bild av värden på tillväxt,

    liksom det faktum att kvaliteten på, och användbarheten av inventeringsdata

    tydligt försämras över tid.

    Det är tydligt att det är svårt att sätta en sann siffra på kommande skoglig

    tillväxt. Kanske är det mest tillförlitligt att ange tillväxt som ett relativt värde i

    procent av aktuell stående volym, och som uppskattas för exempelvis fem år

    framåt? Att ange tillväxten i m3sk/ha och år kan ses som mera oprecist och

    momentant. Visarprocent kan vara en användbar indikator i skogsbruksplaner på

    den tillväxt som finns i bestånden, och som avser att genom rangordning jämföra

    olika bestånds räntabilitet. Ett annat sätt att beskriva beståndens utveckling mot

    timmerträd kan vara att skapa ett värde för formtalsutvecklingen, och att

    skogsägaren därmed på sikt kan jämföra dessa värden med tidigare mätningar.

    Det kan vara intressant för en skogsägare med en nyupprättad plan att få muntlig

    information om begreppen bonitet, tillväxt, visarprocent och formtal, och hur de

    konkret kan kopplas till den egna skogsmarken på både bestånds- och

    fastighetsnivå vid inventeringstillfället. Det bör vara ett bra läge vid den

    tidpunkten att erbjuda dessa upplysningar, troligen som en debiterad

    tilläggstjänst i samband med planläggningen.

    En tydlig insikt av studien är att det är just den säkerställda kvaliteten på

    beståndsdata, liksom hur färska inventeringsdata är, som är de enskilt viktigaste

    faktorerna för att få högkvalitativ information om inte minst skoglig tillväxt i

    skogsbruksplaner

  • 43.
    Berglund, Marie
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Röjningsformen och stamantalets effekt på höjd- och diametertillväxt i toppröjda och konventionellt röjda tallbestånd.2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Topping is a precommercial thinning (PCT) method where secondary stems are cut higher above the ground compared to conventional PCT. The secondary stems continue to live for a period and are supposed to compete with the main stems and promote their quality.

    The objective of the study was to compare the effect of PCT on height and diameter growth between topping and conventional PCT. The study also analysed the relationship between height and diameter growth and the number of stems after PCT.

    Nine topped stands and six conventional precommercially thinned stands were visited between February 28th and March 5. One sample plot per hectare was laid out in the investigated stands. In every sample plot the number of stems was counted and five main stems were measured for height, height growth since PCT, diameter and diameter growth since PCT.

    The results showed significantly higher effect on height growth after topping as compared to conventional PCT but no significant difference in the effect of diameter growth between topping and conventional PCT. After PCT the H/D quote (height/diameter quote) was higher (less taper) in topped stands and lower (larger taper) in conventional PCT.

  • 44.
    Berglund, Torkel
    et al.
    KTH.
    Lindström, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Aghelpasand, Hooman
    KTH.
    Stattin, Eva
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Ohlsson, Anna B.
    KTH.
    Protection of spruce seedlings against pine weevil attacks by treatment of seeds or seedlings with nicotinamide, nicotinic acid and jasmonic acid2016Inngår i: Forestry (London), ISSN 0015-752X, E-ISSN 1464-3626, Vol. 89, nr 2, s. 127-135Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sustainable methods are required to protect newly planted tree seedlings from insect herbivore attack. To this end, here Norway spruce (Picea abies (L.) Karst.) seeds were treated with 2.5 mM nicotinamide (NIC), 2.5 mM nicotinic acid (NIA), 3 mM jasmonic acid (JA) or 0.2 mM 5-azacytidine (5-Aza), and 6-month-old seedlings grown from these seeds were planted at a reforestation area in central Sweden. Attack by pine weevils (Hylobius abietis) was reduced by 50 per cent by NIC treatment, 62.5 per cent by JA treatment and 25 per cent by 5-Aza treatment, when compared with seedlings grown from untreated seeds. Watering 18-month-old spruce seedlings with 2 mM NIC or 2 mM NIA did reduce attack during the first season in the field by 40 and 53 per cent, respectively, compared with untreated plants. Girdling was also reduced by the different treatments. Analysis of conifer seedlings treated with 5-Aza points at a possible involvement of epigenetic mechanisms in this defensive capacity. This is supported by a reduced level of DNA methylation in the needles of young spruce seedlings grown in a greenhouse from NIC-treated seeds. Seed treatment for seedling defense potentiation is simple, inexpensive and also a new approach for forestry with many potential applications.

  • 45.
    Berhe, Leakemariam
    et al.
    Umeå universitet, Samhällsvetenskaplig fakultet, Statistik.
    Arnoldsson, Göran
    Umeå universitet, Samhällsvetenskaplig fakultet, Statistik.
    Tree taper models for Cupressus lusitanica plantations in Ethiopia2008Inngår i: Southern Forests: a Journal of Forest Science, Vol. 70, nr 3, s. 193-203Artikkel i tidsskrift (Fagfellevurdert)
  • 46.
    Berlin, Mats
    et al.
    Uppsala Science Park.
    Sonesson, Johan
    Uppsala Science Park.
    Bergh, Johan
    Swedish University of Agricultural Sciences (SLU).
    Jansson, Gunnar
    Uppsala Science Park.
    The effect of fertilization on genetic parameters in Picea abies clones in central Sweden and consequences for breeding and deployment2012Inngår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 270, s. 239-247Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study was to analyze the effect of repeated fertilizer application on the genetic parameters of Norway spruce. Genetic and environmental variances of growth and phenological traits were estimated to find differences between fertilized and control treatments in broad sense heritability and accuracy of estimated genotypic value. Furthermore, genotype × environment interactions (GxE) between the two treatments were investigated. Two Norway spruce clonal field trials in central Sweden were subjected to both treatments and were measured at various points in time up to a field age of 15 years, to monitor the effects of fertilization. For growth traits, trees in the fertilized treatment exhibited lower environmental variance than those in the non-fertilized treatment; consequently, fertilization yielded higher heritability and greater accuracy of estimated genotypic value. Furthermore, the GxE increased as the effects of fertilization became more pronounced; the genetic correlation between treatments dropped to around 0.5 in the last measured growth period. For phenological traits, no GxE but a slight increase in heritability of prolepsis on the leader shoot was found. The results from this study show that, for the conditions encountered in central Sweden, Norway spruce clones should be tested and selected under the conditions in which they are to be deployed. If repeated fertilizer application is to be adopted under operational conditions, substantial losses in genetic gain for growth can be expected when using current selected clones due to the induced GxE. While the fertilized treatment yielded a higher heritability and accuracy of estimated genotypic value for growth traits than did the control, the Swedish Norway spruce breeding program will not benefit from fertilizing genetic field trials because the increased accuracy of estimated genotypic value is nullified by the GxE.

  • 47.
    Bernhardsson, Erica
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap.
    Andersson, Anna-Carin
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap.
    GROT uttag i Värmlands Län: Extraction of Harvest residues in the County of Värmland2006Independent thesis Advanced level (degree of Magister), 20 poäng / 30 hpOppgave
    Abstract [sv]

    På uppdrag av skogsstyrelsen skall beräkning av framtida potential för uttag av skogsbränsle (GROT) vid slutavverkning av skog göras. Skogsbränsle utgörs till stor del av GROT som är avverkningsrester i form av GRenar Och Toppar. Flera faktorer påverkar hur mycket skogsbränsle det blir vid uttag efter avverkning. Stora snabbväxande träd har en större gren- och barrmassa. I detta arbete har lämplig mark, beståndens ålder och sammansättning selekterats ut med hjälp av GIS för att erhålla största möjliga volym GROT. De områden i naturen som inte kommer ifråga är de som klassats som naturreservat och biotoper. När de lämpliga Grot-områdena selekterats ut, räknas, med hjälp av kNN-Sverige, volymer ut för total mängd skog och volymer för de enskilda trädslagen gran, tall och björk. Beräkningar görs på de arealer som är lämpliga för GROT-uttag, de volymer som hade varit möjliga att få ut på de avverkade områdena 2001-2005 samt de områden som har anmält GROT-uttag. Resultaten visar att det finns ca 104 000 ha lämplig skog för GROT-uttag i Värmland. Ur denna kan man utvinna 36 ton torrsubstans (TS)/ha gran, tall 7 ton TS/ha och björk 2,4 ton TS/ha. De områden som har avverkats under 2001-2005 har en areal på 35 000 ha. Av dessa skulle det varit möjligt att få ut 39 ton TS/ha gran, 7 ton TS/ha tall och björk 2,1 ton TS/ha. Vid en del avverkningar har också anmälts GROT-uttag till Skogsstyrelsen. Denna areal uppgick till 5 000 ha och beräknad torrsubstans gran 31 ton TS/ha, tall 8 ton TS/ha och björk 2,3 ton TS/ha. För att påvisa lönsamheten med avseende på avstånd från väg har MF-kurvor tagits fram. Inom en kilometer har man i princip täckt in hela den totala volymen GROT som kan tas ut, men redan efter 500 meter har man uppnått ca 75 %.

  • 48.
    Bjurhager, Ingela
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Ljungdahl, Jonas
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Wallstrom, Lennart
    Gamstedt, E. Kristofer
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Berglund, Lars A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer.
    Towards improved understanding of PEG-impregnated waterlogged archaeological wood: A model study on recent oak2010Inngår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 64, nr 2, s. 243-250Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To prevent deformation and cracking of waterlogged archaeological wood, polyethylene glycol (PEG) as a bulk impregnation agent is commonly applied. PEG maintains the wood in a swollen state during drying. However, swelling of wood can reduce its mechanical properties. In this study, the cellular structure of oak and cell wall swelling was characterized by scanning electron microscopy (SEM) of transverse cross-sections, and the microfibril angle of oak fibers was determined by wide angle X-ray scattering (WAXS). Samples of recent European oak (Quercus robur L) impregnated with PEG (molecular weight of 600) were tested in axial tension and radial compression. Mechanical tests showed that axial tensile modulus and strength were only slightly affected by PEG, whereas radial compressive modulus and yield strength were reduced by up to 50%. This behavior can be explained by the microstructure and deformation mechanisms of the material. Microfibril angles in tensile test samples were close to zero. This implies tensile loading of cellulose microfibrils within the fiber cell walls without almost any shear in the adjacent amorphous matrix. These results are important because they can help separate the impact of PEG on mechanical properties from that of chemical degradation in archaeological artifacts, which display only small to moderate biological degradation.

  • 49.
    Bjärstig, Therese
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statsvetenskapliga institutionen.
    Sténs, Anna
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Social values of forests and production of new goods and services: the views of Swedish family forest owners2018Inngår i: Small-scale Forestry, ISSN 1873-7617, E-ISSN 1873-7854, Vol. 17, nr 1, s. 125-146Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Forests are considered crucial assets for sustainable rural development, and contemporary forestry is an industry where production, environmental and social goals can – and should – be handled simultaneously. Swedish family forest owners (FFOs) are expected to both manage and conserve their forests for the benefit of the whole country, but there are contradictions between development and conservation and between traditional and alternative forms of utilization, representing dilemmas in rural areas. Tensions between urban and rural areas, between demands on what to produce and protect, are often linked to the FFOs’ views on opportunities for forest management. The aim of this study is to identify and analyse the extent to which FFOs perceive that social values have the ability to generate “new” goods and services as a supplement or alternative to traditional forestry, and to suggest how the forests might be managed to render high social values. Fifty-seven interviews were conducted with FFOs (both resident and non-resident). The results indicate that regardless of where they reside, FFOs have a multifunctional view of their forests and forest management, that the social values attached to forests can play an important role in the development of local recreation- and forest-based tourism activities, and in this respect they can enhance sustainable rural development. It is, however, not obvious who might start and develop these businesses, since there seems to be a lack of interest among the FFOs themselves.

  • 50.
    Björkemar, Kristian
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Agroforestry in Sierra Leone –examining economic potential with carbon sequestration2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis aimed to examine the possibilities and benefits of implementing

    agroforestry projects in Sierra Leone by comparing different agroforestry

    systems used in a Tanzanian project that consider carbon sequestration.

    Farmers involved in this type of projects get income from sold carbon

    credits as well as from other products that an agroforestry system could

    provide.

    Sierra Leone is one of the most vulnerable countries to climate change, with

    most of the population living in rural conditions. It was investigated what

    the potential economic and environmental impact different agroforestry

    systems considering carbon storage could have in Sierra Leone. The study

    was based on empirical material from a case community Makari. The

    conclusions were that Sierra Leone could benefit greatly from agroforestry

    projects, especially at community level where it could provide additional

    sources of food and income. From a greater perspective it could give

    environmental benefits as well as securing wood commodities like fuelwood

    for the future. Starting up a project would however be a high risk investment

    with a troublesome implementation process and complications on a daily

    basis.

1234567 1 - 50 of 531
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf