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  • 1.
    Hematimatin, Narges
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Slovak Univ Agr, Slovakia.
    Igaz, Dusan
    Slovak Univ Agr, Slovakia.
    Aydin, Elena
    Slovak Univ Agr, Slovakia.
    Horak, Jan
    Slovak Univ Agr, Slovakia.
    Biochar application regulating soil inorganic nitrogen and organic carbon content in cropland in the Central Europe: a seven-year field study2024Ingår i: Biochar, ISSN 2524-7972, E-ISSN 2524-7867, Vol. 6, nr 1, artikel-id 14Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biochar incorporation into soil has shown potential, in enhancing nitrogen fertilizer (N-fertilizer) efficacy and soil organic carbon content (SOC). This study addresses a critical gap in the literature by investigating the effects of biochar addition over a seven-year period (2014-2020) on inorganic N, SOC, and pH in Haplic Luvisol. The research involved a rain-fed field experiment, with a crop rotation comprising spring barley, maize, spring wheat, and pea. Biochar, applied at the rates of 0, 10, and 20 t ha-1 in 2014, was reapplied to specific plots in 2018. Biochar was also combined with N-fertilizer at three level (N0, N1, and N2). Results showed a significant interactive influence of biochar and N-fertilizer combination on NO3- and NH4+ contents. Intriguingly, the addition of 10 t biochar ha-1 consistently decreased soil inorganic N levels across most of the examined months. Increasing biochar application rates led to a significant rise in pH, establishing a clear, negative correlation between soil pH and inorganic N content. Biochar significantly increased SOC compared to the control, particularly after the reapplication in 2018. However, this effect showed a diminishing trend over time. The study suggests that incorporating biochar treatments may enhance N-fertilizer effectiveness. However, the long-term implications of biochar application with N-fertilizer on N mineralization are specific to individual soil and biochar combinations. Except the application of 20 t ha-1 biochar at N2 in 2019, biochar did not affect the crop yields. Studied soil properties, including those influenced by biochar had nuanced impact on different aspects of crop yield. Biochar obtained from mixed paper fiber sludge and the grain husks resulted in a significant increase of SOC over 7 years.Biochar aging resulted in a decrease in pH one year after its application in 2015 and 2019.The combination of N-fertilizer with biochar caused an improvement in soil inorganic N content in 2014 and reapplication in 2018.

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  • 2.
    Lankinen, Asa
    et al.
    Swedish University of Agricultural Sciences, Sweden.
    Witzell, Johanna
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Swedish University of Agricultural Sciences, Sweden.
    Aleklett, Kristin
    Swedish University of Agricultural Sciences, Sweden;Lund University, Sweden.
    Furenhed, Sara
    Swedish Board of Agriculture, Sweden.
    Green, Kristina Karlsson
    Swedish University of Agricultural Sciences, Sweden.
    Latz, Meike
    Swedish University of Agricultural Sciences, Sweden;Univ Copenhagen, Denmark.
    Liljeroth, Erland
    Swedish University of Agricultural Sciences, Sweden.
    Larsson, Rebecca
    Swedish University of Agricultural Sciences, Sweden.
    Löfkvist, Klara
    Advisory Unit of The Rural Economy and Agricultural Societies, Sweden.
    Meijer, Johan
    Swedish University of Agricultural Sciences, Sweden.
    Menkis, Audrius
    Swedish University of Agricultural Sciences, Sweden.
    Ninkovic, Velemir
    Swedish University of Agricultural Sciences, Sweden.
    Olson, Åke
    Swedish University of Agricultural Sciences, Sweden.
    Grenville-Briggs, Laura
    Swedish University of Agricultural Sciences, Sweden.
    Challenges and opportunities for increasing the use of low-risk plant protection products in sustainable production. A review2024Ingår i: Agronomy for Sustainable Development, ISSN 1774-0746, E-ISSN 1773-0155, Vol. 44, nr 2, artikel-id 21Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Plant production systems worldwide are struggling to meet the diverse and increasing needs of humankind while also facing challenges such as climate change and biodiversity loss. This, combined with the desirable transition from the use of conventional pesticides to more sustainable plant protection solutions, has led to an urgent, and increasing, need for low-risk plant protection products (PPPs) to be developed, applied, and integrated into management practices across all types of plant production systems. Despite a high demand from end users and consumers together with joint political goals at the EU level to replace conventional pesticides, the number of low-risk PPPs on the European market remains low, in comparison to synthetic agrochemicals. In this review, we summarize knowledge about the policy, technical, and administrative issues hampering the process of bringing new low-risk PPPs to the European market. We present an overview of the challenges in using the low-risk PPPs that are currently available within the EU agricultural, horticultural, and forestry sectors. We describe the variation in modes of action and the limitations associated with different application techniques and give concrete examples of problems and solutions from Swedish plant production sectors, in contrast to global perspectives as demonstrated by examples from African agriculture. Finally, we conclude that trans-sectoral, multi-actor approaches are required and provide suggestions on how to address the remaining knowledge gaps related to efficiency, application, and economics of low-risk PPP use in Integrated Pest Management (IPM) solutions for plant protection to improve future food security in Europe.

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  • 3.
    Bader, Thomas K.
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Oscarsson, Jan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Olsson, Anders
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Schweigler, Michael
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Dorn, Michael
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Competitive CLT - Improving the competitive advantage of CLT-based building systems through engineering design andreduced carbon footprint: Final report2024Rapport (Övrigt vetenskapligt)
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  • 4.
    Martinez-Garcia, Eduardo
    et al.
    Swedish University of Agricultural Sciences, Sweden;Nat Resources Inst Finland Luke, Finland.
    Nilsson, Mats B.
    Swedish University of Agricultural Sciences, Sweden.
    Laudon, Hjalmar
    Swedish University of Agricultural Sciences, Sweden.
    Lundmark, Tomas
    Swedish University of Agricultural Sciences, Sweden.
    Fransson, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Swedish University of Agricultural Sciences, Sweden.
    Wallerman, Jörgen
    Swedish University of Agricultural Sciences, Sweden.
    Peichl, Matthias
    Swedish University of Agricultural Sciences, Sweden.
    Drought response of the boreal forest carbon sink is driven by understorey-tree composition2024Ingår i: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 17, s. 197-204Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The boreal forest is an important global carbon sink, but its response to drought remains uncertain. Here, we compiled biometric- and chamber-based flux data from 50 boreal forest stands to assess the impact of the 2018 European summer drought on net ecosystem production (NEP) across a 68 km2 managed landscape in northern Sweden. Our results reveal a non-uniform reduction in NEP (on average by 80 +/- 16 g C m-2 yr-1 or 57 +/- 13%) across the landscape, which was greatest in young stands of 20-50 years (95 +/- 39 g C m-2 yr-1), but gradually decreased towards older stands (54 +/- 57 g C m-2 yr-1). This pattern was attributed to the higher sensitivity of forest-floor understorey to drought and its decreasing contribution to production relative to trees during stand development. This suggests that an age-dependent shift in understorey-tree composition with increasing stand age drives the drought response of the boreal forest NEP. Thus, our study advocates the need for partitioning ecosystem responses to improve empirical and modelling assessments of carbon cycle-climate feedbacks in boreal forests. It further implies that the forest age structure may strongly determine the carbon sink response to the projected increase in drought events across the managed boreal landscape. Carbon sink in young boreal forests is more vulnerable to drought than in mature forests due to the greater contribution and drought sensitivity of understorey relative to trees, according to carbon flux assessments of managed boreal forests in northern Sweden during the 2018 European summer drought.

  • 5.
    Persson, Magnus
    et al.
    Forestry Res Inst Sweden Skogforsk, Sweden.
    Bader, Martin K.-F.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Holmström, Emma
    Swedish University of Agricultural Sciences, Sweden.
    Exploring the interplay between within-stand variation and thinning practices in southern Sweden2024Ingår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 561, artikel-id 121888Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The state of within-stand variation (WSV) in boreal, coniferous production forests and how it is dealt with in thinning operations is a scarcely researched topic. In the autumn of 2018, we surveyed a series of Norway spruce (Picea abies (L.) Karst) or Scots pine (Pinus sylvestris L.) dominated production stands scheduled for first commercial thinning from below. Here, we evaluate the potential causes of WSV in basal area, how WSV was addressed in the thinning operations, and finally how the stands and subsequent thinning practice conformed with the basal area target specified in the thinning guidelines. WSV in the yield attributes was defined as the dispersion in a stand attribute within a stand and quantified using the Qn scale estimator (a robust measure of dispersion). First, WSV in basal area at the time of first thinning was evaluated as a function of WSV in stem number and WSV in site index. Next, yield attributes before and after thinning were compared using paired ttests, and the future development of WSV in basal area was evaluated using linear mixed-effects models. Finally, the thinning practice was evaluated before and after thinning by modelling the compliance with the basal area target as a function of stem number and dominant height, also using linear mixed-effects models. WSV in basal area appeared to be influenced by WSV in site index and WSV in stem number for Norway spruce, but not for Scots pine. Thinning reduced the WSV in basal area, standing volume, and stem number, while dominant height, quadratic mean diameter and basal area weighted mean height remained unaffected. At first thinning, compliance with the thinning guideline increased with increasing stem density and dominant height. However, moderate to high compliance with the basal area target in the thinning guidelines was only reached for plots with elevated dominant height (>15 m) in combination with high stem number (>2250 N ha-1). Thus, the recommended range in dominant height (12-14 m) for first thinning was generally exceeded, which may be attributed to the generally low stem number at the time of thinning. This study suggests that sub-optimal regeneration efforts and management of young forests can lead to WSV across a wide range of stand attributes, and likely also reductions in yield. Thinning decreased WSV in basal area, standing volume and stem number, however, the plots were heavily thinned to such a degree that it could potentially cause production losses.

  • 6.
    Bari, Ehsan
    et al.
    Technical and Vocational University, Iran.
    Ghorbanian Far, Mohammad
    Technical and Vocational University, Iran.
    Daniel, Geoffrey
    Swedish University of Agricultural Sciences, Sweden.
    Bozorgzadeh, Younes
    Gorgan University of Agriculture Sciences and Natural Resources, Iran.
    Ribera, Javier
    University of Valencia, Spain.
    Aghajani, Hamed
    ari Agricultural Science and Natural Resources University, Iran.
    Hosseinpourpia, Reza
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Fungal behavior and recent developments in biopulping technology2024Ingår i: World Journal of Microbiology & Biotechnology, ISSN 0959-3993, E-ISSN 1573-0972, Vol. 40, nr 7, artikel-id 207Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biological pretreatment of wood chips by fungi is a well-known approach prior to mechanical- or chemical pulp production. For this biological approach, a limited number of white-rot fungi with an ability to colonize and selectively degrade lignin are used to pretreat wood chips allowing the remaining cellulose to be processed for further applications. Biopulping is an environmentally friendly technology that can reduce the energy consumption of traditional pulping processes. Fungal pretreatment also reduces the pitch content in the wood chips and improves the pulp quality in terms of brightness, strength, and bleachability. The bleached biopulps are easier to refine compared to pulps produced by conventional methodology. In the last decades, biopulping has been scaled up with pilot trials towards industrial level, with optimization of several intermediate steps and improvement of economic feasibility. Nevertheless, fundamental knowledge on the biochemical mechanisms involved in biopulping is still lacking. Overall, biopulping technology has advanced rapidly during recent decades and pilot mill trials have been implemented. The use of fungi as pretreatment for pulp production is in line with modern circular economy strategies and can be implemented in existing production plants. In this review, we discuss some recent advances in biopulping technology, which can improve mechanical-, chemical-, and organosolv pulping processes along with their mechanisms.

  • 7.
    Doeweler, Fabian
    et al.
    Dragonfly Data Science, New Zealand.
    Fransson, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Bader, Martin K.-F.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Linking High-Resolution UAV-Based Remote Sensing Data to Long-Term Vegetation Sampling: A Novel Workflow to Study Slow Ecotone Dynamics2024Ingår i: Remote Sensing, E-ISSN 2072-4292, Vol. 16, nr 5, artikel-id 840Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Unravelling slow ecosystem migration patterns requires a fundamental understanding of the broad-scale climatic drivers, which are further modulated by fine-scale heterogeneities just outside established ecosystem boundaries. While modern Unoccupied Aerial Vehicle (UAV) remote sensing approaches enable us to monitor local scale ecotone dynamics in unprecedented detail, they are often underutilised as a temporal snapshot of the conditions on site. In this study in the Southern Alps of New Zealand, we demonstrate how the combination of multispectral and thermal data, as well as LiDAR data (2019), supplemented by three decades (1991-2021) of treeline transect data can add great value to field monitoring campaigns by putting seedling regeneration patterns at treeline into a spatially explicit context. Orthorectification and mosaicking of RGB and multispectral imagery produced spatially extensive maps of the subalpine area (similar to 4 ha) with low spatial offset (Craigieburn: 6.14 +/- 4.03 cm; Mt Faust: 5.11 +/- 2.88 cm, mean +/- standard error). The seven multispectral bands enabled a highly detailed delineation of six ground cover classes at treeline. Subalpine shrubs were detected with high accuracy (up to 90%), and a clear identification of the closed forest canopy (Fuscospora cliffortioides, >95%) was achieved. Two thermal imaging flights revealed the effect of existing vegetation classes on ground-level thermal conditions. UAV LiDAR data acquisition at the Craigieburn site allowed us to model vegetation height profiles for similar to 6000 previously classified objects and calculate annual fine-scale variation in the local solar radiation budget (20 cm resolution). At the heart of the proposed framework, an easy-to-use extrapolation procedure was used for the vegetation monitoring datasets with minimal georeferencing effort. The proposed method can satisfy the rapidly increasing demand for high spatiotemporal resolution mapping and shed further light on current treeline recruitment bottlenecks. This low-budget framework can readily be expanded to other ecotones, allowing us to gain further insights into slow ecotone dynamics in a drastically changing climate.

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  • 8.
    Fjeld, Dag
    et al.
    Swedish University of Agricultural Sciences, Sweden;Norwegian Inst Bioecon Res, Norway.
    Persson, Magnus
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Skogforsk, Sweden.
    Fransson, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Bjerketvedt, Jan
    Norwegian Inst Bioecon Res, Norway.
    Brathen, Martin
    Skogkurs, Norway.
    Modelling forest road trafficability with satellite-based soil moisture variables2024Ingår i: International Journal of Forest Engineering, ISSN 1494-2119, E-ISSN 1913-2220, Vol. 35, nr 1, s. 93-104Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent decades have seen increased temperatures and precipitation in the Nordic countries with long-term projections for reduced frost duration and depth. The consequence of these trends has been a gradual shift of delivery volumes to the frost-free season, requiring more agile management to exploit suitable weather conditions. Bearing capacity and trafficability are dependent on soil moisture state and in this context two satellite missions offer potenially useful information on soil moisture levels; NASA's SMAP (Soil Moisture Active Passive) and ESA's Sentinel-1. The goal of this pilot study was to quantify the performance of such satellite-based soil moisture variables for modeling forest road bearing capacity (e-module) during the frost-free season. The study was based on post-transport registrations of 103 forest road segments on the coastal and interior side of the Scandinavian mountain range. The analysis focused on roads of three types of surface deposits. Weekly SMAP soil moisture values better explained the variation in road e-module than soil water index (SWI) derived from Sentinel-1. Soil Water Index (SWI), however, reflected the weather conditions typical for operations on the respective surface deposit types. Regression analysis using (i) SMAP-based soil dryness index and (ii) its interaction with surface deposit types, together with (iii) the ratio between a combined SMAP_SWI dryness index and segment-specific depth to water (DTW) explained over 70% of the variation in road e-module. The results indicate a future potential to monitor road trafficability over large supply areas on a weekly level, given further refinement of study methods and variables for improved prediction.

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  • 9.
    Blom, Åsa
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Svensson Meulmann, Sebastian
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Obehandlade träfasader: En handledning2024Rapport (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Denna skrift baseras på erfarenheter och observationer från flertalet olikaforskningsförsök vid Linnéuniversitetet samt följeforskning av ett parpågående och planerade byggprojekt med träfasader. Syftet har varit attöka och sprida kunskapen om obehandlade träfasader i allmänhet ochobehandlad gran i synnerhet. En obehandlad fasad kan vara en lämpligersättningsprodukt till andra typer av obehandlade fasader som i nulägetofta har ett avsevärt högre klimatavtryck, ofta beroende på långvägatransporter. Målet är att ökade kunskaper om obehandlat trä ska möjliggöraoch skapa en ökad användning av trä i utomhusapplikationer.Handledningen är tänkt att vara en hjälp för de som är intresserade av,projekterar för, eller bygger med obehandlade träfasader.Författarna vill rikta ett stort tack till kollegor och samarbetspartners,särskilt Derome, Granitor, JGA och Södra. Denna skrift tillkom medbidrag från CBBT: Centrum för Byggande och Boende i trä.

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  • 10.
    Ghavidel, Amir
    et al.
    University of Northern British Columbia, Canada.
    Hosseinpourpia, Reza
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Michigan Technological University, USA.
    Photodegradation stability of huminated European pine (Pinus sylvestris L.) microveneers2024Ingår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 78, nr 5, s. 283-292Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Humins are heterogeneous and polydisperse furanic macromolecules derived from sugar biorefinery. Improving wood properties by humination has become of interest recently. This study examined the photodegradation stability of European pine sapwood microveneers modified with humins at different concentrations of citric acid (CA) and succinic acid (SA) as reaction catalysts, e.g., 1.5 %, 3 %, and 4.5 % wt.%. The photostability of huminated wood was assessed after 48 h, 96 h, and 144 h of exposure to the accelerated weathering test by means of mass loss and finite-span tensile strength. The results were compared with unmodified and also unweathered samples. The FT-IR spectroscopy showed apparent changes in the chemical structure of wood by humination modifications. The weight percentage gains of the samples increased with increasing the concentration of the catalyst. While no differences were observed between the samples after two weeks of the water leaching. The strength losses of weathered microveneers were, however, mostly reduced by humin-based formulas containing catalysts, where the microveneers modified with 1.5 % and 3 % CA showed respectively 32 % and 41 % lower strength loss values than the unmodified samples after 144 h of weathering. Overall, the results showed a high potential for humins to protect wood against photodegradation.

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  • 11.
    Imrefi, Ildikó
    et al.
    Eötvös Loránd University, Hungary.
    Knapp, Dániel G.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Kovács, Gábor M.
    HUN-REN Centre for Agricultural Research, Hungary.
    Poaceascoma zborayi sp. nov. and Agrorhizomyces patris gen. et spec. nov.: Two novel dark septate endophytes colonizing wheat (Triticum aestivum) roots from a cropland in Hungary2024Ingår i: Mycological progress, ISSN 1617-416X, E-ISSN 1861-8952, Vol. 23, nr 1, artikel-id 35Artikel i tidskrift (Refereegranskat)
    Abstract [ja]

    In this study, we investigated two distinct new phylogenetic lineages of root-colonizing dark septate endophytic fungi colonizing wheat (Triticum aestivum) roots from a long-term agricultural experimental site in Hungary. According to four-locus (internal transcribed spacer, partial large and small subunit regions of nuclear ribosomal DNA, and partial translation elongation factor 1-alpha) phylogenetic analyses, the isolates belong to the Lentitheciaceae and Didymosphaeriaceae of the Pleosporales (Dothideomycetes). We studied the morphology and culture characteristics of the strains. We carried out in vitro resynthesis pot experiments with their original hosts and found no overall negative effect of the inoculation with different isolates of the new taxa. One of the lineages belonged to the genus Poaceascoma (Lentitheciaceae) and represented a novel species described here as Poaceascoma zborayi. We could describe conidia-like structures from this species. Isolates of the other lineage represented a monotypic novel genus in the Didymosphaeriaceae. Accordingly, the new genus, Agrorhizomyces, represented by the species A. patris, is introduced. Sterile, globose structures resembling immature sporocarps were detected. Sequence similarity searches indicated that P. zborayi might be widely distributed, while no sequence similar to A. patris was found outside the sampling area.

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  • 12.
    Ræbild, Anders
    et al.
    University of Copenhagen, Denmark.
    Anamthawat-Jónsson, Kesara
    University of Iceland, Iceland.
    Egertsdotter, Ulrika
    Swedish University of Agricultural Sciences, Sweden.
    Immanen, Juha
    Natural Resources Institute Finland (Luke), Finland;University of Helsinki, Finland.
    Jensen, Anna M.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Koutouleas, Athina
    University of Copenhagen, Denmark.
    Martens, Helle Jakobe
    University of Copenhagen, Denmark.
    Nieminen, Kaisa
    Natural Resources Institute Finland (Luke), Finland;University of Helsinki, Finland.
    Olofsson, Jill Katharina
    University of Copenhagen, Denmark.
    Röper, Anna-Catharina
    Danish Technological Institute, Denmark.
    Salojärvi, Jarkko
    University of Helsinki, Finland.
    Strömvik, Martina
    McGill University, Canada.
    Vatanparast, Mohammad
    Royal Botanic Gardens Kew, UK.
    Vivian-Smith, Adam
    Norwegian Institute of Bioeconomy Research (NIBIO), Norway.
    Polyploidy – A tool in adapting trees to future climate changes? A review of polyploidy in trees2024Ingår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Forest Ecology and Management, ISSN 0378-1127, Vol. 560, s. 121767-121767, artikel-id 121767Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Polyploidy, or genome doubling, has occurred repeatedly through plant evolution. While polyploid plants are used extensively in agriculture and horticulture, they have so far found limited use in forestry. Here we review the potentials of polyploid trees under climate change, and investigate if there is support for increased use. We find that polyploid trees like other plants have consistent increases in cell sizes compared to diploids, and that leaf-area based rates of photosynthesis tend to increase with increasing levels of ploidy. While no particular trend could be discerned in terms of biomass between trees of different ploidy levels, physiology is affected by polyploidization and several studies point towards a high potential for polyploid trees to adapt to drought stress. The ploidy level of most tree species is unknown, and analysis of geographical patterns in frequencies of polyploid trees are inconclusive. Artificial polyploid trees are often created by colchicine and in a few cases these have been successfully applied in forestry, but the effects of induced polyploidization in many economically important tree species remains untested. Polyploids would also be increasingly useful in tree breeding programs, to create synthetic hybrids or sterile triploids that could control unwanted spreading of germplasm in nature. In conclusion, this review suggests that polyploid trees may be superior under climate change in some cases, but that the potential of polyploids is not yet fully known and should be evaluated on a case-to-case basis for different tree species.

  • 13.
    Olsson, Anders
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Abdeljaber, Osama
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Predicting out-of-plane bending strength of cross laminated timber: Finite element simulation and experimental validation of homogeneous and inhomogeneous CLT2024Ingår i: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 308, artikel-id 118032Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The strength of cross laminated timber (CLT) depends on the stiffness and strength of the lamellas and on thestrength of the finger joints. A model for how stiffness and strength vary along and between lamellas is used incombination with a finite element model of CLT and Monte Carlo simulations to calculate out-of-plane bendingstrength of homogeneous and inhomogeneous CLT. Calculated and experimentally obtained results of characteristicbending strengths, coefficient of variation of bending strength and the proportion of finger joint failures,agree very well for both types of CLT. The characteristic out-of-plane bending strength and the mean bendingstiffness were 23% and 16% higher, respectively, for inhomogeneous CLT with outer layer lamellas graded in thestrength class C35, compared to homogeneous CLT with all lamellas graded in the class C24. Simulation resultsgive basis for simple equations by which bending strength of CLT can be determined as function of the layup, thestrength class of outer layer lamellas and characteristic strength of the finger joints. Furthermore, system effectsare investigated. For inhomogeneous CLT, with outer layer lamellas of high strength class, the system effects turnout to be quite different from those of ordinary, homogeneous CLT.

  • 14.
    Jones, Grace
    et al.
    TEAGASC, Ireland.
    Ulan, Maria
    RISE, Sweden.
    Liziniewicz, Mateusz
    Skogforsk, Sweden.
    Lindeberg, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Adamopoulos, Stergios
    Swedish University of Agricultural Sciences, Sweden.
    Relating estimates of wood properties of birch to stem form, age and species2024Ingår i: Journal of Forestry Research, ISSN 1007-662X, E-ISSN 1993-0607, Vol. 35, nr 1, artikel-id 14Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Birch has long suffered from a lack of active forest management, leading many researchers to use material without a detailed management history. Data collected from three birch (Betula pendula Roth, B. pubescens Ehrh.) sites in southern Sweden were analyzed using regression analysis to detect any trends or differences in wood properties that could be explained by stand history, tree age and stem form. All sites were genetics trials established in the same way. Estimates of acoustic velocity (AV) from non-destructive testing (NDT) and predicted AV had a higher correlation if data was pooled across sites and other stem form factors were considered. A subsample of stems had radial profiles of X-ray wood density and ring width by year created, and wood density was related to ring number from the pith and ring width. It seemed likely that wood density was negatively related to ring width for both birch species. Linear models had slight improvements if site and species were included, but only the youngest site with trees at age 15 had both birch species. This paper indicated that NDT values need to be considered separately, and any predictive models will likely be improved if they are specific to the site and birch species measured.

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  • 15.
    Kooch, Yahya
    et al.
    Tarbiat Modares University, Iran.
    Kartalaei, Zahra Mohmedi
    Tarbiat Modares University, Iran.
    Amiri, Mojtaba
    Semnan University, Iran.
    Zarafshar, Mehrdad
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Shabani, Saeid
    Golestan Agricultural and Natural Resources Research and Education Center, Iran.
    Mohammady, Majid
    Semnan University, Iran.
    Soil health reduction following the conversion of primary vegetation covers in a semi-arid environment2024Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 921, artikel-id 171113Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A degraded forest is the outcome of a degradation process that has adverse effects on ecosystem functions and services. This phenomenon results in alterations of soil physicochemical and biological properties, which serve as valuable indicators for assessing soil health that has been recognized as a crucial component of soil quality. For several decades, the conversion of forested areas into rangeland has been documented in specific regions of the world. There is a widespread lack of global understanding regarding the lasting consequences of land degradation on soil health indicators. The present study aims to investigate the impact of forest degradation on soil health indicators in a mountainous semi-arid region located in northern Iran. The study area was predominantly forested, but due to human activities over the past 30 years, it has been transformed into three distinct land uses: forest, forest-rangeland ecotones and rangeland. In each of these land covers, a total of 20 litter (O-horizon) and 20 soil (from two depths of 0–15 and 15–30 cm) samples were collected in the summer (August 2022) season. According to our results, the highest litter thickness, P and Mg were in forest ecosystem, the lowest in rangeland ecosystem. The findings indicated that following the conversion of forest to rangeland, there was a decrease in soil aggregate stability, porosity, soil organic matter, POC, PON, NH4+, NO3− and nutrient levels, while soil bulk density increased. The forest ecosystem showed notably higher C and N stocks (45 and 5.21 Mg ha−1) in comparison to the rangeland (38 and 3.32 Mg ha−1) ecosystem. In addition, P, K, Ca, and Mg exhibited elevated levels within the total root of the forest ecosystem (2.12, 1.23, 0.71, and 0.38 %, respectively), whereas the lower values (1.29, 1.01, 0.43, and 0.23 %, respectively) were found in the rangeland ecosystem. Following the shift of land cover from forest to rangeland, soil fauna, microflora populations, soil enzymes and microbial activities decreased (about 1–2 times higher in the forestland). This research emphasizes the urgent need to advance sustainable management practices to prevent further degradation and promote the implementation of restoration or rehabilitation techniques in degraded forests. Despite being conducted in a semi-arid region situated in northern Iran, the findings of this study have considerable value for the sustainable management of soil and land conservation in various other semi-arid regions around the world.

  • 16.
    Zarafshar, Mehrdad
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Univ Paris Saclay, France.
    Vincent, Gaelle
    Univ Paris Saclay, France.
    Korboulewsky, Nathalie
    Domaine Barres, France.
    Bazot, Stephane
    Univ Paris Saclay, France.
    The impact of stand composition and tree density on topsoil characteristics and soil microbial activities2024Ingår i: Catena (Cremlingen. Print), ISSN 0341-8162, E-ISSN 1872-6887, Vol. 234, artikel-id 107541Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The assessment of long-term effects of forest management practices, particularly species mixing and stand density, provides valuable information for the forestry sectors. This study evaluated and compared the effect of stand composition and density on organic horizon (i.e., OL, OF, OH) and organo-mineral horizon characteristics of nine stands in the Orleans State Forest (France), seven years after the first thinning treatments. To this end, three triplets of stands of pure Quercus petraea Matt., pure Pinus sylvestris L. and a mixture of both species were selected. Each stand consisted of two plots with different tree densities: low and normal. Physicochemical variables were measured on the organic humus horizon (OH), while microbial biomass carbon (MBC) and nitrogen (MBN), and soil microbial metabolic profile were evaluated on the organo-mineral horizon; the abundance of soil microbial populations (i.e., bacteria, fungi and archaea) in each plot was also assessed by qPCR. The OH thickness consistently increased under pure pine stands (25-35 mm), while other OH characteristics showed no variation based on stand composition and tree density. Low-density plots exhibited changes in microbial biomass, with a significant decrease in both MBC and MBN. Moreover, the highest MBC was recorded under pure pine stands (1241 mg C.kg(- 1 )DW soil), and the highest MBN under pure oak stands (24-39 mg N.kg(- 1 ) DW soil). The highest C assimilation rates were recorded in the mixed stands, especially under low tree density. Bacteria and archea were similarly abundant across stand compositions and tree densities, while fungi tended to be more abundant in the mixed coniferous-broadleaf stands. Our findings should be considered by the forestry sectors of European countries where these two species are distributed, and suggest that EU forestry strategies should promote biodiversity in the context of tree plantations.

  • 17.
    Svensson Meulmann, Sebastian
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Blom, Åsa
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Sjökvist, Tinh
    Södra Innovation, Sweden.
    Wood properties influencing surface cracking and moisture dynamics of untreated Norway spruce exposed outdoors2024Ingår i: BioResources, E-ISSN 1930-2126, Vol. 19, nr 2, s. 3362-3374Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Untreated wood has excellent environmental benefits due to the lack of treatments; however, its durability needs to be great enough to provide a sufficient service life to not override the environmental benefits. The aim of this study was to investigate some wood properties of untreated, unfinished Norway spruce and their influence on moisture dynamics and crack development under natural exposure. Three field-trials were carried out, all under natural exposure during various exposure times. The specimens differed in their exposure direction (north/south), composition (heartwood/ sapwood), density, and thickness. Moisture measurements were carried out either by use of sensors or weighing the specimens, while the crack formation was measured using digital calipers. Generally, high-density spruce exhibited more rapid moisture fluctuations than low-density; this agreed well with the increased crack development observed in the field-trials. More cracks were observed for specimens containing sapwood rather than heartwood. This was likely caused by an increase in moisture uptake, generating greater moisture gradients. The results also showed that the crack tendency was greater in specimens within the high-density group placed facing south, which is likely due to an increase in moisture variation, and perhaps also faster UV-deterioration. No clear correlation between crack tendency and thickness was found.

  • 18.
    Olsson, Anders
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Bader, Thomas K.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    A design model for out of plane bending of CLT with consideration of properties of lamellas and finger joints2023Ingår i: International Network on Timber Engineering Research: Meeting fifty-six Biel/Bienne, Switzerland August 2023 / [ed] Rainer Görlacher, Karlsruhe, Germany, 2023, s. 191-210, artikel-id 56-12-1Konferensbidrag (Refereegranskat)
  • 19.
    Neitzel, Nicolas
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Hosseinpourpia, Reza
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Michigan Technological University, USA.
    Adamopoulos, Stergios
    Swedish University of Agricultural Sciences, Sweden.
    A dialdehyde starch-based adhesive for medium-density fiberboards2023Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 18, nr 1, s. 2155-2171Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bio-based adhesives have gained considerable attention in the last years as more sustainable and healthier alternatives to the formaldehyde-based adhesives used today in wood-based panel manufacturing. In this study, dialdehyde starch (DAS) with various aldehyde contents was prepared by using sodium metaperiodate as an oxidizing agent. Characterizations were performed by employing Fourier-transform infrared spectroscopy, nuclear magnetic resonance, and thermal stability analysis. Different adhesive compositions were used for making medium-density fiberboard (MDF) panels. They were based on DAS (12 wt% based on fiber), emulsifiable diphenylmethane diisocyanate (eMDI, 2-4 wt% based on DAS), and microfibrillated cellulose (MFC, 0.5-1.0 wt% based on DAS). Fibers and the adhesive components were mixed with a combination of dry mixing and wet spraying. The physical and mechanical properties of MDF panels bonded with different DAS-based adhesives were compared with those of melamine urea-formaldehyde (MUF) adhesive and sole eMDI. The results showed that the MDF panels made with DAS-MFC-eMDI of 99.52% bio-based content showed comparable properties to standard panels with a commercial MUF adhesive. It was implied that DAS in the presence of small amount of eMDI can create strong bonds with wood fibers, while an additional positive effect on bonding was due to the contact surface enlargement of MFC.

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  • 20.
    Lerman, Peter
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Scheepers, Gerhard
    RISE, Sweden.
    Wiberg, Pär
    IKEA Sweden, Sweden.
    A laboratory setup for measuring the wood-surface temperature during drying by means of thermography2023Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 18, nr 2, s. 701-706Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The surface temperature of a drying wooden board is strongly related to the drying process. However, it is relatively difficult to determine the surface temperature accurately during drying. In this paper, an experimental setup for analyzing the wood surface during drying by thermal imaging as well as dry and wet-bulb temperature reference surfaces was tested. Spruce sapwood samples were dried in various climates and evaluated with respect to both mass loss and surface temperature. The experimental setup enabled both qualitative and quantitative analysis of the wood drying process. The results showed that thermal imaging enabled a detailed view of the drying progression. The distinct correlation between surface temperature and mass change showed that an accurate determination of a basic, often considered, and difficult-to-determine drying potential is possible.

  • 21.
    Neitzel, Nicolas
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Agro-industry feedstock and side stream materials for wood panel manufacturing2023Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Wood-based panels are indispensable in many areas, such as the construction industry and furniture production. The intensified demand for renewable materials, rising wood prices and increasing protection zones of forest areas make the wood panel industry consider alternative raw materials. The agricultural sector provides, at the same time, large amounts of sustainable and renewable lignocellulosic materials. By-products can arise along the entire agricultural production chain, i.e., during harvesting or further processing into food, but their potential has not yet been fully exploited. This thesis explored the potential of agro-industry feedstocks and side streams as raw materials for wood panel manufacturing. A literature review on the research of agricultural residues as a raw material in wood panels provided an overview of the investigated wood alternatives and their performance in final products. Most of the studies focused on the production of particleboard and its mechanical and physical properties. Often only up to 30% of wood could be replaced by alternative raw materials before the properties decreased remarkably.This thesis focused on an intensive material characterisation of barley husks (BH), oat husks (OH) and wheat bran (WB). Husks are the protective surrounding of their cereal grain and have an anatomical leaf structure. Wheat bran is a side stream of flour production and consists of the grain's outer layers. It was found that BH and OH have at 70% and 66% a slightly lower holocellulose content than wooden materials (poplar, spruce), while their hemicelluloses content exceeding that of cellulose. Additionally, WB had a very high lignin content of 43%. The chemical composition, especially the ash content (5% BH, 6% OH) and the high silicon occurrence on the husks’surfaces, reduced their wettability, as demonstrated by low contact angle measurements. Micromechanical tests showed that OH could resist a higher ultimate stress load than BH and WB, but the modulus of elasticity (MOE) was lower. The MOE was noticeably affected by the microfibril angle, which was three to four-times larger in the husks compared to wooden materials. Furthermore, the results of OH showed larger particle lengths and widths on average, approximately half as much extractive content and slightly higher thermal stability compared to BH. Therefore, OH was suggested as promising raw material and evaluated for particleboard manufacturing. In an experimental investigation, OH was explored as raw material in aspecial particleboard type, i.e., tubular particleboards. Although the boards showed higher insulation properties than wood particle-based ones, the mechanical properties were considerably affected by the reduced wettability, and the manufacturing method led to poor density distribution. In addition, the agricultural feedstock wheat starch, in combination with microfibrillated cellulose (MFC) and emulsifiable diphenylmethane diisocyanate (eMDI), was investigated as an adhesive system for fibreboard production. Wheat starch was modified to dialdehyde starch (DAS) and served as the backbone in an adhesive formulation of 99.5% bio-based content using 1% MFC and 4% eMDI based on DAS, which showed excellent mechanical and water resistance performance in fibreboards. Especially, internal bond and MOE values even exceeded those obtained in boards manufactured with commercial formaldehyde-based adhesive. The application process should be optimized in the future since the DAS was applied in powder form, and long press times were necessary because the adhesive system required a high-water content. The DAS-based adhesive was used to bond OH in particleboards, where as challenges in practical implementation were encountered. The severely shortened starch molecule reacted with the proteins of the OH, and from temperatures of 160°C, it led to accelerating degradation and reduced bonding capacity of the adhesive. Finally, this thesis provided a deeper knowledge of husked-based raw materials' properties in the context of panel manufacturing and showed that they are a possible but challenging alternative to wood. Further experimental investigations are necessary to improve the interfacial adhesion of OH and there spective adhesive system in order to produce panels with mechanical and physical properties that meet current requirements. The investigation of a DAS based adhesive opened a promising path for bio-based adhesives and the independence of formaldehyde systems. But subsequent studies must convert the used application method into a sprayable process for industrial integration

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  • 22.
    Abdeljaber, Osama
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Habite, Tadios
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Olsson, Anders
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Automatic estimation of annual ring profiles in Norway spruce timber boards using optical scanning and deep learning2023Ingår i: Computers & structures, ISSN 0045-7949, E-ISSN 1879-2243, Vol. 275, artikel-id 106912Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In softwood species, annual ring width correlates with various timber characteristics, including the density and modulus of elasticity along with bending and tensile strengths. Knowledge of annual ring profiles may contribute to more accurate machine strength grading of sawn timber. This paper proposes a fast and accurate method for automatic estimation of ring profiles along timber boards on the basis of optical scanning. The method utilizes two 1D convolutional neural networks to determine the pith location and detect the surface annual rings at multiple cross-sections along the scanned board. The automatically extracted rings and pith information can then be used to estimate the annual ring profile at each cross-section. The proposed method was validated on a large number of board cross-sections for which the pith locations and radial ring width profiles had been determined manually. The paper also investigates the potential of using the automatically estimated average ring width as an indicating property in machine strength grading of sawn timber. The results indicated that combining the automatically estimated ring width with other prediction variables can improve the accuracy of bending and tensile strength predictions, especially when the grading is based only on information extracted from optical and laser scanning data.(C) 2022 The Author(s). Published by Elsevier Ltd.

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  • 23.
    Neitzel, Nicolas
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Eder, Michaela
    Max Planck Institute of Colloids and Interfaces, Germany.
    Hosseinpourpia, Reza
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Michigan Technological University, USA.
    Walther, Thomas
    IKEA Industry AB, Sweden.
    Adamopoulos, Stergios
    Swedish University of Agricultural Sciences, Sweden.
    Chemical composition, particle geometry, and micro-mechanical strength of barley husks, oat husks, and wheat bran as alternative raw materials for particleboards2023Ingår i: Materials Today Communications, ISSN 2352-4928, Vol. 36, artikel-id 106602Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Particleboards are used worldwide in various industry segments, like construction and furniture production. Nevertheless, increase in wood prices and logistical challenges urge the particleboard industry to find alternative raw materials. By-products and residues from the agricultural and food industries could offer possibilities for material sourcing at a local level. This study aimed to investigate the chemical composition, particle geometry, anatomical structure, and microtensile characteristics of such material, specifically barley husks (BH), oat husks (OH), and wheat bran (WB). Barley and oat husks were found to have comparable hemicelluloses and lignin contents to industrial wood chips but contained more ash. Wheat bran was rich in extractives and showed high buffering capacity. Light microscopy and microcomputed tomography revealed details of leaf structure for BH and OH as well as the multi-layer structure of WB. The ultimate microtensile strength of BH, various OH samples, and WB were respectively 2.77 GPa, 0.84-2.42 GPa, and 1.45 GPa. The results indicated that the studied materials could have potential uses as furnish materials in non-load bearing particleboards, where thermal or acoustic insulation properties are desirable.

  • 24.
    Franic, Iva
    et al.
    CABI, Switzerland;Univ Bern, Switzerland;Swiss Fed Inst Forest, Switzerland.
    Allan, Eric
    Univ Bern, Switzerland.
    Prospero, Simone
    Swiss Fed Inst Forest, Switzerland.
    Adamson, Kalev
    Estonian Univ Life Sci, Estonia.
    Attorre, Fabio
    Sapienza Univ Rome, Italy.
    Auger-Rozenberg, Marie-Anne
    URZF, France.
    Augustin, Sylvie
    URZF, France.
    Avtzis, Dimitrios
    Hellen Agr Org Demeter, Greece.
    Baert, Wim
    Meise Bot Garden, Belgium.
    Barta, Marek
    Slovak Acad Sci, Slovakia.
    Bauters, Kenneth
    Meise Bot Garden, Belgium.
    Bellahirech, Amani
    Natl Res Inst Rural Engn Water & Forests INRGREF, Tunisia.
    Boron, Piotr
    Agr Univ Krakow, Poland.
    Braganca, Helena
    Inst Nacl Invest Agr & Vet IP INIAV IP, Portugal;ITQB NOVA, Portugal.
    Brestovanska, Tereza
    Silva Tarouca Res Inst Landscape & Ornamental Gard, Czech Republic.
    Brurberg, May Bente
    Norwegian Inst Bioecon Res, Norway;Norwegian Univ Life Sci, Norway.
    Burgess, Treena
    Murdoch Univ, Australia.
    Burokiene, Daiva
    Nat Res Ctr, Inst Bot, Lithuania.
    Cleary, Michelle
    Swedish University of Agricultural Sciences, Sweden.
    Corley, Juan
    Inst Invest Forestales & Agr Bariloche INTA CONICE, Argentina.
    Coyle, David R.
    Clemson Univ, USA.
    Csoka, Gyoergy
    Clemson Univ, USA.
    Cerny, Karel
    Silva Tarouca Res Inst Landscape & Ornamental Gard, Czech Republic.
    Davydenko, Kateryna
    Ukrainian Res Inst Forestry & Forest Meliorat, Ukraine.
    de Groot, Maarten
    Slovenian Forestry Inst, Slovenia.
    Diez, Julio Javier
    Univ Valladolid, Spain.
    Dogmus Lehtijaervi, H. Tugba
    Isparta Univ Appl Sci, Turkiye.
    Drenkhan, Rein
    Estonian Univ Life Sci, Estonia.
    Edwards, Jacqueline
    La Trobe Univ, Australia;Agribio Ctr, Australia.
    Elsafy, Mohammed
    Swedish University of Agricultural Sciences, Sweden.
    Eoetvoes, Csaba Bela
    Clemson Univ, USA.
    Falko, Roman
    Ukrainian Res Inst Mt Forestry, Ukraine.
    Fan, Jianting
    Zhejiang A&F Univ, China.
    Feddern, Nina
    Swiss Fed Inst Forest, Switzerland.
    Fuerjes-Miko, Agnes
    Clemson Univ, USA.
    Gossner, Martin M.
    Swiss Fed Inst Forest, Switzerland;Swiss Fed Inst Technol, Switzerland.
    Grad, Bartlomiej
    Agr Univ Krakow, Poland.
    Hartmann, Martin
    Swiss Fed Inst Technol, Switzerland.
    Havrdova, Ludmila
    Silva Tarouca Res Inst Landscape & Ornamental Gard, Czech Republic.
    Horakova, Miriam Kadasi
    Slovak Acad Sci, Slovakia.
    Hrabetova, Marketa
    Silva Tarouca Res Inst Landscape & Ornamental Gard, Czech Republic.
    Justesen, Mathias Just
    Univ Copenhagen, Denmark.
    Kacprzyk, Magdalena
    Agr Univ Krakow, Poland.
    Kenis, Marc
    CABI, Switzerland.
    Kirichenko, Natalia
    Russian Acad Sci, Russia;Siberian Fed Univ, Russia.
    Kovac, Marta
    Croatian Forest Res Inst, Croatia.
    Kramarets, Volodymyr
    Ukrainian Natl Forestry Univ, Ukraine.
    Lackovic, Nikola
    Jastrebarsko, Croatia.
    Lantschner, Maria Victoria
    Inst Invest Forestales & Agr Bariloche INTA CONICE, Argentina.
    Lazarevic, Jelena
    Univ Montenegro, Montenegro.
    Leskiv, Marianna
    Ukrainian Natl Forestry Univ, Ukraine.
    Li, Hongmei
    CABI, China.
    Madsen, Corrie Lynne
    Univ Copenhagen, Denmark.
    Malumphy, Chris
    Natl Agrifood Innovat Campus, UK.
    Matosevic, Dinka
    Croatian Forest Res Inst, Croatia.
    Matsiakh, Iryna
    Ukrainian Natl Forestry Univ, Ukraine.
    May, Tom W.
    Royal Bot Gardens Victoria, Australia.
    Meffert, Johan
    Natl Plant Protect Org, Netherlands.
    Migliorini, Duccio
    Natl Res Council CNR, Italy.
    Nikolov, Christo
    Natl Forest Ctr, Slovakia.
    O'Hanlon, Richard
    Dept Agr Food & Marine, Ireland.
    Oskay, Funda
    Cankiri Karatekin Univ, Turkiye.
    Paap, Trudy
    Univ Pretoria, Forestry & Agr Biotechnol Inst FABI, South Africa.
    Parpan, Taras
    Ukrainian Res Inst Mt Forestry, Ukraine.
    Piskur, Barbara
    Slovenian Forestry Inst, Slovenia.
    Ravn, Hans Peter
    Univ Copenhagen, Denmark.
    Richard, John
    Tanzania Forestry Res Inst TAFORI, Tanzania.
    Ronse, Anne
    Meise Bot Garden, Belgium.
    Roques, Alain
    URZF, France.
    Ruffner, Beat
    Swiss Fed Inst Forest, Snow & Landscape Res WSL, Switzerland.
    Santini, Alberto
    Natl Res Council CNR, Italy.
    Sivickis, Karolis
    Nat Res Ctr, Lithuania.
    Soliani, Carolina
    Inst Invest Forestales & Agr Bariloche INTA CONICE, Argentina.
    Talgo, Venche
    Norwegian Inst Bioecon Res, Norway.
    Tomoshevich, Maria
    Russian Acad Sci, Russia.
    Uimari, Anne
    Nat Resources Inst Finland, Finland.
    Ulyshen, Michael
    USDA Forest Serv, USA.
    Vettraino, Anna Maria
    Univ Tuscia, Italy.
    Villari, Caterina
    Univ Georgia, USA.
    Wang, Yongjun
    Zhejiang A & F University, China.
    Witzell, Johanna
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Zlatkovic, Milica
    Univ Novi Sad, Serbia.
    Eschen, Rene
    CABI, Switzerland.
    Climate, host and geography shape insect and fungal communities of trees2023Ingår i: Scientific Reports, E-ISSN 2045-2322, Vol. 13, nr 1, artikel-id 11570Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Non-native pests, climate change, and their interactions are likely to alter relationships between trees and tree-associated organisms with consequences for forest health. To understand and predict such changes, factors structuring tree-associated communities need to be determined. Here, we analysed the data consisting of records of insects and fungi collected from dormant twigs from 155 tree species at 51 botanical gardens or arboreta in 32 countries. Generalized dissimilarity models revealed similar relative importance of studied climatic, host-related and geographic factors on differences in tree-associated communities. Mean annual temperature, phylogenetic distance between hosts and geographic distance between locations were the major drivers of dissimilarities. The increasing importance of high temperatures on differences in studied communities indicate that climate change could affect tree-associated organisms directly and indirectly through host range shifts. Insect and fungal communities were more similar between closely related vs. distant hosts suggesting that host range shifts may facilitate the emergence of new pests. Moreover, dissimilarities among tree-associated communities increased with geographic distance indicating that human-mediated transport may serve as a pathway of the introductions of new pests. The results of this study highlight the need to limit the establishment of tree pests and increase the resilience of forest ecosystems to changes in climate.

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  • 25.
    Macaya-Sanz, David
    et al.
    Instituto de Ciencias Forestales (ICIFOR-INIA), Spain.
    Witzell, Johanna
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Collada, Carmen
    Universidad Politécnica de Madrid, Spain.
    Gil, Luis
    Universidad Politécnica de Madrid, Spain.
    Martin, JuanA A.
    Universidad Politécnica de Madrid, Spain.
    Core endophytic mycobiome in Ulmus minor and its relation to Dutch elm disease resistance2023Ingår i: Frontiers in Plant Science, E-ISSN 1664-462X, Vol. 14, artikel-id 1125942Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The core microbiota of plants exerts key effects on plant performance and resilience to stress. The aim of this study was to identify the core endophytic mycobiome in U. minor stems and disentangle associations between its composition and the resistance to Dutch elm disease (DED). We also defined its spatial variation within the tree and among distant tree populations. Stem samples were taken i) from different heights of the crown of a 168-year-old elm tree, ii) from adult elm trees growing in a common garden and representing a gradient of resistance to DED, and iii) from trees growing in two distant natural populations, one of them with varying degrees of vitality. Endophyte composition was profiled by high throughput sequencing of the first internal transcribed spacer region (ITS1) of the ribosomal DNA. Three families of yeasts (Buckleyzymaceae, Trichomeriaceae and Bulleraceae) were associated to DED-resistant hosts. A small proportion (10%) of endophytic OTUs was almost ubiquitous throughout the crown while tree colonization by most fungal taxa followed stochastic patterns. A clear distinction in endophyte composition was found between geographical locations. By combining all surveys, we found evidence of a U. minor core mycobiome, pervasive within the tree and ubiquitous across locations, genotypes and health status.

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  • 26.
    Ghavidel, Amir
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Jorbandian, Amin
    University of Tehran, Iran.
    Bak, Miklós
    University of Sopron, Hungary.
    Gelbrich, Jana
    Leibniz-IWT, Germany.
    Morrell, Jeffrey J.
    University of the Sunshine Coast, Australia.
    Sandu, Ion
    Academy of Romanian Scientists (AOSR), Romania;Romanian Inventors Forum, Romania.
    Hosseinpourpia, Reza
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Linnéuniversitetet, Kunskapsmiljöer Linné, Avancerade material. Linnéuniversitetet, Kunskapsmiljöer Linné, Grön hållbar utveckling. Michigan Technological University , USA.
    Degradation assessment of archaeological oak (Quercus spp.) buried under oxygen-limited condition2023Ingår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 77, nr 3, s. 198-207Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The biological deterioration of archaeological wood under oxygen-limited conditions varies due to the limited activities of microorganisms. It is essential to expand the knowledge of the degradation types and the status of archaeological monuments for selecting the proper consolidates. The physical, chemical, and anatomical properties of approximately 600–650 year old archaeological oak collected from an archaeological site in Iasi-Romania were analysed to assess the quality and to identify the degradation types. The results were compared with similar tests on recently-cut oak. X-ray photoelectron spectroscopy (XPS) revealed the presence of more lignin-related peaks in the archaeological oak, which likely reflected the degradation of the wood carbohydrates as evidenced by the decreased oxygen-to-carbon ratio Cox/Cnon-ox. The differences in cellulose crystallinity were not significant suggesting that any cellulose degradation occurred in the amorphous regions. This was also reflected in the dynamic water vapor sorption analysis where the differences in sorption isotherms and hysteresis of archaeological and recently-cut oaks were marginal. Microscopic analysis of the oak cells illustrated bacterial degradation patterns, while the field emission scanning electron microscopy (FESEM) showed the presence of erosion bacteria in the archaeological oak collected from the site with low oxygen conditions.

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  • 27.
    Lerman, Peter
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Scheepers, Gerhard
    RISE, Sweden.
    Determination of a mass-transfer coefficient for wood drying by means of thermography2023Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 18, nr 6, s. 2104-2111Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present work, it was demonstrated that mass transfer and mass transfer coefficients related to the wood drying process can be satisfactorily quantified using thermography. The method was based on continuous measurements of the wood's surface temperature, which were converted to a vapor pressure at the wood surface. The results showed that the values of the experimentally obtained transfer coefficients were in the same order of magnitude as values obtained with classical empirical correlations that apply in boundary layer theory. The measurements also showed that an average value of the mass transfer coefficient obtained during drying satisfactorily describes the complete process. The measurement set-up makes it possible to determine a surface potential accurately and continuously, which is useful in the assessment of wood drying processes.

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  • 28.
    Ulander, Lars M.H.
    et al.
    Chalmers University of Technology, Sweden.
    Monteith, Albert R.
    Chalmers University of Technology, Sweden.
    Fransson, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Development and Initial Evaluation of the Tower-based Borealscat-2 P- and L-Band Tomographic SAR2023Ingår i: IGARSS 2023 - 2023 IEEE International Geoscience and Remote Sensing Symposium: Pasadena, CA, USA, 2023, IEEE, 2023, s. 2192-2194Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper describes the development and initial evaluation of the BorealScat-2 radar. It is installed on a 50 m tall tower at a boreal forest site in northern Sweden and acquires tomographic and multi-polarization measurements at P- and L-band every 5 min. It is of the same design as its predecessor BorealScat except that the antenna frame can be moved along a 4 m horizontal track. A moveable antenna position is motivated by the need to acquire independent samples to reduce backscatter fluctuations. It also enables focused 3D imaging by combing tomographic and SAR processing when the backscatter fluctuations are temporally stable. We show results from data acquired in 2022, which demonstrates 3D imaging of a forest as well as the response from a trihedral.

  • 29.
    Svensson, Carl
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Bader, Martin K.-F.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Forsmark, Benjamin
    Swedish University of Agricultural Sciences, Sweden.
    Nilsson, Urban
    Swedish University of Agricultural Sciences, Sweden.
    Lundmark, Tomas
    Swedish University of Agricultural Sciences, Sweden.
    Nordin, Annika
    Swedish University of Agricultural Sciences, Sweden.
    Bergh, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Early and repeated nutrient additions support far greater stemwood production in Norway spruce than traditional late-rotation fertilisation2023Ingår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 549, artikel-id 121425Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Silvicultural techniques aimed at promoting forest biomass production can help meet the growing demand for renewable materials and mitigate climate change. One-time nitrogen (N) addition late in the rotation is a well-established method to stimulate growth in coniferous forests in northern Europe, but the potential gains from earlier and repeated fertiliser application remain uncertain. Here, we tested the impact of repeated fertilisation in juvenile Norway spruce stands across 9 sites covering a wide range of growing conditions over a 700 km stretch from central to southern Sweden. We tested the fertilisation effects using two separate studies: i) an interval trial with a fertilisation frequency of one (F1), two (F2), or three years (F3) performed at plot-level across five sites (2002–2014), and ii) a practice-oriented trial with a two-year fertilisation interval (F2) applied at stand-level and replicated at four sites (2003–2013). The composition of the nutrient mix in each plot was optimised based on foliar nutrient analyses. In the interval trial, all three fertilisation schedules strongly increased periodic annual increment (PAI) (F1: 105 %, F2: 93 %, F3: 79 %) relative to the unfertilised control, resulting in more than a doubling of stem volume yield in the F1 and F2 treatments (120 % and 110 %, respectively) and a significantly smaller but still sizeable yield stimulation of 82 % in the F3 treatment. Nitrogen use efficiency (NUE, stemwood volume increase per unit mass of N added) was similar among fertilisation intervals (on average 130 m3 ha−1 1000 kg N−1), indicating that the extra N provided through yearly fertilisation (F1) is redundant given the similar stemwood yields in the F2 treatment. In the practice-oriented trial, the sole F2 treatment increased PAI by 95 % over the control, translating into a yield stimulation of 114 % and an almost identical NUE to that of the interval trial. NUE greatly exceeded the figures typically observed with traditional late-rotation fertilisation and correlated inversely with baseline site productivity (using site index as a proxy) in the F1 and F2 treatments (the latter pooled across the two trials). Our results clearly indicate that nutrient limitation restricts growth and carbon (C) capture in young Norway spruce plantations in northern Europe to less than half of their potential, highlighting repeated fertilisation at nutrient-poor sites as an effective management tool to support a growing bioeconomy and enhance C sequestration.

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  • 30.
    Kuqo, Aldi
    et al.
    University of Göttingen, Germany.
    Mayer, Aaron Kilian
    University of Göttingen, Germany.
    Amiandamhen, Stephen O.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Adamopoulos, Stergios
    Swedish University of Agricultural Sciences, Sweden.
    Mai, Carsten
    University of Göttingen, Germany.
    Enhancement of physico-mechanical properties of geopolymer particleboards through the use of seagrass fibers2023Ingår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 374, artikel-id 130889Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two types of geopolymer-bonded boards were produced using initial wetting of lignocellulosic aggregates followed by dry mixing and hot-pressing. Boards were prepared by incorporating large fractions of lignocellulosic material (up to 50 wt%). Geopolymer particleboards (GP) were produced using wood particles whereas geopolymer sandwich boards (GSB) were produced from wood particles and seagrass fibers, with the latter allocated in the outer layers. Inclusion of seagrass fibers was found to enhance bending strength and toughness of GSB by up to 20 and 40 % respectively. The bending strength tended to increase with the addition of lignocellulosic aggregates, reaching up to 8.9 N mm−2. Fire resistance of GSB was slightly higher compared to GP. Further investigations such as FT-IR, XRD analysis and visual examination by digital microscopy showed an adequate degree of geopolymerization and mixing of the precursor and alkaline activator, indicating the high effectiveness of the mixing technique.

  • 31.
    Mellqvist, Daniel
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Buck, Dietrich
    Luleå tekniska universitet, Sweden.
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Experimental study of the effect of velocity on cutting forces for bevelled handsaw teeth2023Ingår i: Proceedings of the 25th International Wood Machining Seminar / [ed] Gary S. Schajer, 2023, artikel-id 2Konferensbidrag (Refereegranskat)
    Abstract [en]

    Handsaws are well-established tools for wood processing. Handsaw tooth geometries have customarily been adapted for hand-held electric saws, which utilise higher cutting velocities. Fundamental studies in wood cutting mechanics suggest that a cutting velocity of up to 50 m s−1 has negligible effect on the cutting forces acting on an orthogonal cutting tool. There is a lack of research on the mechanisms involved in the use of native handsaw teeth for wood cutting. This study investigates how cutting velocity affects the forces acting on four bevel-ground cross-cutting teeth extracted from a handsaw blade. Conditioned specimens of Norway spruce [Picea abies (L.) Karst.] were used in the tests. The mean densities of wood specimens were assessed using X-ray computed tomography. Cutting tests were performed on a pre-existing, custom-made cutting-force test machine. Cutting data were collected using piezoelectric dynamometers linked to a data acquisition system. Cutting velocity was controlled by the rotational speed of the arm holding the wood specimen. A customised software application logged and processed the forces acting on the teeth. The results show that the mean resultant force does not vary significantly within a 2.5–15 m s−1 velocity range. The current study suggests that velocity is nearly independent of the system mean cutting force acting on bevelled handsaw teeth cutting across the grain. The findings are particularly relevant for developing cutting tools for wood applications since knowledge from handsaw tooth geometry can be adapted for the design of cutting blades for power tools.

  • 32.
    Finy, Peter
    et al.
    Eotvos Lorand Univ, Hungary;Hungarian Mycol Soc, Hungary.
    Jeppson, Mikael
    University of Gothenburg, Sweden.
    Knapp, Daniel
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Eotvos Lorand Univ, Hungary.
    Papp, Viktor
    Hungarian Univ Agr & Life Sci, Hungary.
    Albert, Laeszlo
    Hungarian Mycol Soc, Hungary.
    Olvedi, Istvaen
    Hungarian Mycol Soc, Hungary.
    Boka, Kaeroly
    Eotvos Lorand Univ, Hungary.
    Varga, Dora
    Eotvos Lorand Univ, Hungary.
    Kovacs, Gaebor M.
    Eotvos Lorand Univ, Hungary.
    Dima, Baelint
    Eotvos Lorand Univ, Hungary.
    Exploring diversity within the genus Tulostoma (Basidiomycota, Agaricales) in the Pannonian sandy steppe: four fascinating novel species from Hungary2023Ingår i: MycoKeys, ISSN 1314-4057, E-ISSN 1314-4049, nr 100, s. 153-170Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Steppe vegetation on sandy soil in Hungary has recently been revealed as one of the hot spots in Europe for the stalked puffballs (genus Tulostoma). In the framework of the taxonomic revision of gasteroid fungi in Hungary, four Tulostoma species are described here as new to science: T. dunense, T. hungaricum, T. sacchariolens and T. shaihuludii. The study is based on detailed macro-and micromorphological investigations (including light and scanning electron microscopy), as well as a three-locus phylogeny of nrDNA ITS, nrDNA LSU and tef1-alpha sequences. The ITS and LSU sequences generated from the type specimen of T. cretaceum are provided and this resolved partly the taxonomy of the difficult species complex of T. aff. cretaceum.

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  • 33. Bari, Ehsan
    et al.
    Ghorbanian Far, Mohammad
    Moradi, N
    Morrell, Jefry J
    Daniel, Geoffrey
    Mohebby, Behbod
    Hosseinpourpia, Reza
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Humar, M
    Failure characteristics of thermally modified poplar wood subjected to mechanical tests2023Ingår i: IRG documents database and compendium, International Research Group of Wood Protection , 2023, artikel-id 23-40983Konferensbidrag (Refereegranskat)
    Abstract [en]

    Poplar (Populus spp.) are among the fastest growing timber species and have been widely planted for use in plywood, composites, pallets, furniture components and paper production. However, the low density of the wood limits many structural applications and the wood has little resistance to biodegradation. Thermal modification represents one approach to improving durability by changing the moisture behavior of the wood, but it can also have adverse effects on structural performance. Understanding the potential effects of thermal treatment on poplar properties can help define the most appropriate applications for these materials. Poplar timbers from Iran were subjected to 30 or 60 min of thermal treatment at temperatures ranging from 110 to 220 °C. Samples were then evaluated for mass loss during treatment, changes in flexural properties, e.g., modulus of elasticity (MOE) and modulus of rupture (MOR), the degree of polymerization, and water absorption characteristics. MOR of controls subjected to 100 °C were similar to those exposed to 160 °C, while MOE was more variable with a slight upward trend for samples exposed to a given heating regime for only 30 min. The increases in MOE may be related to changes in cellulose crystallinity. Mass losses increased with increasing temperature exposure while moisture absorption decreased as expected with longer thermal exposure. The degree of polymerization remained similar for samples exposed up to 170 °C and then increased at higher temperatures. The increases may reflect the complete destruction of shorter chain polymers, leaving only the heat-resistant longer chain polymers. The results suggest that poplar can be thermally modified within limited parameters to improve some performance attributes without adversely affecting its structural capacity.

  • 34.
    Svensson, Carl
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Bader, Martin K.-F.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Löf, Magnus
    Swedish University of Agricultural Sciences, Sweden.
    Johansson, Ulf
    Swedish University of Agricultural Sciences, Sweden.
    Bergh, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Linnéuniversitetet, Kunskapsmiljöer Linné, Grön hållbar utveckling.
    Fertilisation and irrigation have no effects on growth of oak (Quercus robur, Q. petraea) stands on abandoned farmland in southwest Sweden2023Ingår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 529, artikel-id 120700Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Low nutrient availability often limits productivity in northern forests. In a nutrient optimisation trial, we investigated the effects of fertilisation and irrigation on soil moisture, leaf area index (LAI) as well as height and radial growth in 25-year-old stands of pedunculate and sessile oak (Quercus robur L., Q. petraea (Matt.) Liebl.) growing on abandoned farmland in southwestern Sweden. Control (C), fertilisation (F), irrigation (I), and irrigation +fertilisation (IF) treatments were arranged in a randomized complete block design. End of growing season analysis of foliar nutrients guided the quantitative composition of next year’s fertiliser mix. Volumetric soil moisture (VWC) was significantly higher in the I and IF treatments compared to the C and F treated stands of both oak species. We did not observe a fertiliser-related reduction in VWC (except for 2015, when VWC in F- treated Q. robur stands was significantly lower than the control by about 18 %). This is in line with the unaffected LAI estimates (5.3–5.9) suggesting no stimulation of leaf production that could drive increases in transpiration with subsequent soil moisture depletion. There was no treatment ×year interaction for any of the growth-related variables. Treatments had no significant effects on basal area growth, which increased annually by 1.72 and 1.54 m2 ha-1 on average for Q. petraea and Q. robur, respectively. Pre-treatment height differences in Q. petraea stands (7–12 % taller trees in the C and IF plots) persisted throughout the study resulting in significant effects, while no significant differences in height occurred in Q. robur. Periodic annual volume increment varied more strongly following drier periods but there were no significant differences among treatments. Our findings indicate that fertilisation causes no or only minor increases in oak water use, suggesting that nutrient addition in oak stands within this precipitation regime does not require simultaneous irrigation. Most importantly, our data implies that the soil nutrient legacies of past agricultural use suffice to maximise the productivity of oak stands on abandoned farmland typical of the main oak growing region in southwestern Sweden.

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  • 35.
    Aksoy, Samet
    et al.
    Istanbul Technical University, Türkiye.
    Hasan Al Shwayyat, Shouq Zuhter
    Marmara University, Türkiye.
    Nur Topgül, Şule
    Istanbul Technical University, Türkiye.
    Sertel, Elif
    Istanbul Technical University, Türkiye.
    Ünsalan, Cem
    Marmara University, Türkiye.
    Salo, Jari
    University of Helsinki, Finland.
    Holmström, Anton
    Katam Technologies, Sweden.
    Wallerman, Jörgen
    Swedish University of Agricultural Sciences, Sweden.
    Nilsson, Mats
    Swedish University of Agricultural Sciences, Sweden.
    Fransson, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Forest Biophysical Parameter Estimation via Machine Learning and Neural Network Approaches2023Ingår i: IGARSS 2023 - 2023 IEEE International Geoscience and Remote Sensing Symposium: Pasadena, CA, USA, 2023, IEEE, 2023, s. 2661-2664Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents the first results of the ongoing development of new forest mapping methods for the Swedish national forest mapping case using Airborne Laser Scanning (ALS) data, utilizing the recent findings in machine learning (ML) and Artificial Intelligence (AI) techniques. We used Random Forest (RF) and eXtreme Gradient Boosting (XGBoost) as ML models. In addition, Neural networks (NN) based approaches were utilized in this study. ALS derived features were used to estimate the stem volume (V), above-ground biomass (AGB), basal area (B), tree height (H), stem diameter (D), and forest stand age (A). XGBoost ML algorithm outperformed RF 1 % to 3 % in the R² metric. NN model performed similar to ML model, however it is superior in the estimation of V, AGB, and B parameters.

  • 36.
    Haesen, Stef
    et al.
    Katholieke Univ Leuven, Belgium.
    Lembrechts, Jonas J.
    Univ Antwerp, Belgium.
    De Frenne, Pieter
    Univ Ghent, Belgium.
    Lenoir, Jonathan
    Univ Picardie Jules Verne, France.
    Aalto, Juha
    Finnish Meteorol Inst, Finland;Univ Helsinki, Finland.
    Ashcroft, Michael B.
    Univ Wollongong, Australia.
    Kopecky, Martin
    Czech Acad Sci, Czech Republic;Czech Univ Life Sci Prague, Czech Republic.
    Luoto, Miska
    Univ Helsinki, Finland.
    Maclean, Ilya
    Univ Exeter, UK.
    Nijs, Ivan
    Univ Antwerp, Belgium.
    Niittynen, Pekka
    Univ Helsinki, Finland.
    van den Hoogen, Johan
    Swiss Fed Inst Technol, Switzerland.
    Arriga, Nicola
    European Commiss, Italy.
    Bruna, Josef
    Czech Acad Sci, Czech Republic.
    Buchmann, Nina
    Swiss Fed Inst Technol, Switzerland.
    Ciliak, Marek
    Tech Univ Zvolen, Slovakia.
    Collalti, Alessio
    Natl Res Council Italy CNR ISAFOM, Italy.
    De Lombaerde, Emiel
    Univ Ghent, Belgium.
    Descombes, Patrice
    Univ Lausanne, Switzerland;Musee & Jardins Bot Cantonaux, Switzerland.
    Gharun, Mana
    Swiss Fed Inst Technol, Switzerland;Univ Munster, Germany.
    Goded, Ignacio
    European Commiss, Italy.
    Govaert, Sanne
    Univ Ghent, Belgium.
    Greiser, Caroline
    Stockholm University, Sweden.
    Grelle, Achim
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Gruening, Carsten
    European Commiss, Italy.
    Hederova, Lucia
    Czech Acad Sci, Czech Republic.
    Hylander, Kristoffer
    Stockholm University, Sweden.
    Kreyling, Juergen
    Univ Greifswald, Germany.
    Kruijt, Bart
    Wageningen Univ & Res, Netherlands.
    Macek, Martin
    Czech Acad Sci, Czech Republic.
    Malis, Frantisek
    Tech Univ Zvolen, Slovakia.
    Man, Matej
    Czech Acad Sci, Czech Republic.
    Manca, Giovanni
    European Commiss, Italy.
    Matula, Radim
    Czech Univ Life Sci Prague, Czech Republic.
    Meeussen, Camille
    Univ Ghent, Belgium.
    Merinero, Sonia
    Univ Rey Juan Carlos, Spain.
    Minerbi, Stefano
    Forest Serv, Italy.
    Montagnani, Leonardo
    Forest Serv, Italy;Free Univ Bolzano, Italy.
    Muffler, Lena
    Georg August Univ Goettingen, Germany.
    Ogaya, Roma
    CREAF CSIC UAB, Spain.
    Penuelas, Josep
    CREAF CSIC UAB, Spain.
    Plichta, Roman
    Mendel Univ Brno, Czech Republic.
    Portillo-Estrada, Miguel
    Univ Antwerp, Belgium.
    Schmeddes, Jonas
    Univ Greifswald, Germany.
    Shekhar, Ankit
    Swiss Fed Inst Technol, Switzerland.
    Spicher, Fabien
    Univ Picardie Jules Verne, France.
    Ujhazyova, Mariana
    Tech Univ Zvolen, Slovakia.
    Vangansbeke, Pieter
    Univ Ghent, Belgium.
    Weigel, Robert
    Georg August Univ Göttingen, Germany;CREAF CSIC UAB, Spain.
    Wild, Jan
    Czech Acad Sci, Czech Republic.
    Zellweger, Florian
    Swiss Fed Inst Forest Snow & Landscape Res WSL, Switzerland.
    Van Meerbeek, Koenraad
    Katholieke Univ Leuven, Belgium.
    ForestClim: Bioclimatic variables for microclimate temperatures of European forests2023Ingår i: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 29, nr 11, s. 2886-2892Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Microclimate research gained renewed interest over the last decade and its importance for many ecological processes is increasingly being recognized. Consequently, the call for high-resolution microclimatic temperature grids across broad spatial extents is becoming more pressing to improve ecological models. Here, we provide a new set of open-access bioclimatic variables for microclimate temperatures of European forests at 25 x 25 m2 resolution.

  • 37.
    Fransson, Johan
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Sertel, Elif
    Istanbul Technical University, Türkiye.
    Ünsalan, Cem
    Marmara University, Türkiye.
    Salo, Jari
    University of Helsinki, Finland.
    Holmström, Anton
    Katam Technologies, Sweden.
    Wallerman, Jörgen
    Swedish University of Agricultural Sciences, Sweden.
    Nilsson, Mats
    Swedish University of Agricultural Sciences, Sweden.
    ForestMap: Mapping Forest Attributes Across the Globe - First Case Study2023Ingår i: IGARSS 2023 - 2023 IEEE International Geoscience and Remote Sensing Symposium, IEEE, 2023, s. 3395-3397Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents the project ForestMap – a project aiming to develop and distribute new methods, which provide the benefits of accurate forest maps to a global audience. Using the recent developments in remote sensing, machine learning, and Artificial Intelligence (AI) the goal is to export the Scandinavian success stories to a wide range of stakeholders in the world.

  • 38.
    Grelle, Achim
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Hedwall, Per-Ola
    Swedish University of Agricultural Sciences, Sweden.
    Strömgren, Monika
    Swedish University of Agricultural Sciences, Sweden.
    Håkansson, Charlotta
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Bergh, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Linnéuniversitetet, Kunskapsmiljöer Linné, Grön hållbar utveckling.
    From source to sink: recovery of the carbon balance in young forests2023Ingår i: Agricultural and Forest Meteorology, ISSN 0168-1923, E-ISSN 1873-2240, Vol. 330, artikel-id 109290Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We analyzed ecosystem carbon fluxes from eddy-covariance measurements in five young forests in southernSweden where the previous stand had been harvested by clear-cutting or wind-felled: three stands with Norwayspruce (Picea abies (L.) Karst.), one with Scots pine (Pinus sylvestris) and one with Larch (Larix x eurolepis A.Henry). One of the spruce stands had the stumps harvested, one was fertilized and one without any specialtreatments. These stands returned from positive (sources) to negative (sinks) annual carbon fluxes 8–13 yearsafter disturbance, depending on site productivity and management. This corresponds to approximately 15% ofthe rotation periods at these sites. Extrapolation in combination with chronosequence data suggests thatconventionally regenerated stands reach a neutral carbon balance after approximately 30% of the rotationperiod. The lowest carbon emissions and shortest recovery time was observed in a stand where the stumps of thetrees, in addition to the stems and logging residues, were removed after harvest. This stand not only returned to acarbon sink within this time period but the total carbon gains since disturbance also equaled the total losses afteronly 11 years. These results stress that production stands in southern Sweden are carbon sources during arelatively small part of the rotation period, and that this part can be considerably shortened by measures thatincrease productivity or reduce the amount of woody debris left after disturbance.

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  • 39.
    Håkansson, Charlotta
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Greenhouse Gas Fluxes and Carbon Sequestration in Young Norway Spruce Stands: The Effects of Fertilization2023Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Den stora utmaningen med de pågående klimatförändringarna har sedan Kyotoprotokollet 1997 diskuterats med en ökande intensitet eftersom dessa har en avgörande inverkan på livet på jorden. Skogen har en viktig roll att spela då växterna genom sin fotosyntes tar upp koldioxid (CO2) från atmosfären och det växande trädet binder in kol (C). Ju högre tillväxten är, desto större är kolinlagringen och klimatnyttan. Efterfrågan på trä och träprodukter liksom den pågående debatten om skogsskötsel intensifierats. Därför är alternativa skogsskötselmetoder för att öka virkesproduktionen intressanta att studera liksom deras påverkan på klimatförändringarna. Med detta som bakgrund behandlar denna avhandling effekten av gödsling avseende skogens kolbalans, närmare bestämt tillväxt i ungskog samt flöden av växthusgaserna, CO2, metan (CH4) och lustgas (N2O) från skogsmark. Dessutom behandlar den tillförlitligheten i och jämförbarheten av olika mätmetoder med avseende på skogens kolbalans.

    Studierna har genomförts i ett ungt blandbestånd av gran (Picea abies(L.) Karst) och björk (Betula pendula and Betula pubescens) på ett ca 60 hektar stort område, utanför Ljungby i Kronobergs län, som blåste ned istormen Gudrun år 2005. Under åren 2013 till 2021 genomfördes redovisade kammarmätningar av markflöden av växthusgaser, eddyfluxmätningar av växthusgasers nettoflöden på beståndsnivå, skogsuppskattning av trädslag, höjd och diameter samt insamling av björkblad. Mätningarna var delvis överlappande i tid. En del av området gödslades ett långtidsförsök med 150 kg kväve (N) per hektar vartannat år från 2014. Den andra delen behölls ogödslad. På en del av den ogödslade delen inrättades 2016 ett giveförsök där 0, 150, 300 och 450 kg N per hektar tillfördes för att undersöka de olika nivåernas påverkan på växthusgasflödena från marken.

    Resultaten visar att även om flödet av koldioxid från marken intitialt ökar efter en första standardgödsling så avtar effekten snabbt. När kolinbindningen i växternas fotosyntes läggs till utflödena från marken blir bestånden kolsänkor, dvs de visar ett nettoupptag, redan åtta år efter stormfällningen. För skogsmark på mineraljord gäller att den generellt ären sänka för metan. I långtidsförsöket minskade denna sänka efter första gödslingen medan i det i giveförsöket behövdes dubbel kvävedos för att minskningen skulle bli signifikant. I samtliga fall fortsatte skogsmarken emellertid att ta upp metan. Flödena av lustgas från marken ökade direkt efter gödsling i försöket med upprepade gödslingar men ingen skillnad syntes åren efter. I giveförsöket var skillnaden inte signifikant även om bilden visar en uppåtgående trend med ökad gödselgiva. I markens flöden av växthusgaser utgör CH4 och N2O endast en bråkdel i jämförelse med CO2.

    Mätningar av trädens tillväxt visade att både björk och gran svarar på upprepad ungskogsgödsling med ökad tillväxt, granen (4,2 m3 per hektar och år) i högre utsträckning än björken (2,1 m3 per hektar och år). Våra resultat visar också att gödslingen 12 och 15 år efter beståndsanläggningen ökat kolinlagringen i beståndet med 4,7 respektive 8,7 ton kol per hektar och år.

    Jämförelse av mätresultat från Eddy-flux teknikens nettoflöden och kammarmätningarna av markrespiration tillsammans med trädens tillväxt visar på vikten av att kalibrera mätmetoderna när resultaten senare ska användas i modellering av framtida klimatscenarier.

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  • 40.
    Lerink, Bas J. W.
    et al.
    Wageningen Univ & Res, Netherlands.
    Schelhaas, Mart-Jan
    Wageningen Univ & Res, Netherlands.
    Schreiber, Roland
    Bayer Landesanstalt Wald & Forstwirtschaft, Germany.
    Aurenhammer, Peter
    Bayer Landesanstalt Wald & Forstwirtschaft, Germany.
    Kies, Uwe
    InnovaWood, Belgium.
    Vuillermoz, Morgan
    Inst Technol FCBA, France.
    Ruch, Philippe
    Inst Technol FCBA, France.
    Pupin, Cyrille
    Cooperat Forets & Bois Est Agence Troyes, France.
    Kitching, Andrew
    South Scotland Conservancy, UK.
    Kerr, Gary
    Forest Res, UK.
    Sing, Louise
    Forestry & Land Scotland, UK.
    Calvert, Amanda
    Small Woods Assoc, UK.
    Ni Dhubhain, Aine
    Univ Coll Dublin, Ireland.
    Nieuwenhuis, Maarten
    Univ Coll Dublin, Ireland.
    Vayreda, Jordi
    CREAF, Spain.
    Reumerman, Patrick
    BTG Biomass Technol Grp BV, Netherlands.
    Gustavsonn, Göran
    Energikontor Sydost AB, Sweden.
    Jakobsson, Rikard
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Little, Daragh
    Veon Ltd, Ireland.
    Thivolle-Cazat, Alain
    Inst Technol FCBA, France.
    Orazio, Christophe
    Inst Europeen Foret Cultivee, France.
    Nabuurs, Gert-Jan
    Wageningen Univ & Res, Netherlands.
    How much wood can we expect from European forests in the near future?2023Ingår i: Forestry (London), ISSN 0015-752X, E-ISSN 1464-3626, Vol. 96, nr 4, s. 434-447Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The demand for wood in Europe is expected to increase in the coming decades. However, any theoretical maximum supply will be affected by sustainability constraints, the motivations of forest owners and regional factors, such as incentives, species and assortments. However, the influence of these factors on supply is changeable. In this study, we quantify what might be realistically available as additional wood supply from currently existing European forests, based on a combination of results of the forest resource model EFISCEN-Space and a literature review of national supply projections. Wood mobilization scenarios for 10 representative Model Regions in Europe that assume forest owners and managers in the simulated regions will adapt their behaviour to alternative behaviour as recorded from other regions were projected with the EFISCEN-Space model. The realistic additional potential based on the literature review is 90 million m(3) yr(-1). This potential should be attainable within 10-20 years. However, the simulations in the Model Regions found potentials to be lower in 7 out of 10 cases as compared with the country they are located in. On average, the model regions reached less than half of the potential as compared with the literature review. This suggests that the realistic additional potential at the European scale may well be lower if all mobilization barriers are taken into account in more detail, but also highlights the uncertainty surrounding these estimates. We conclude from the analyses that although there are large differences in potential between regions and the analysis method employed, there are no 'hotspots' where a large pool of accessible wood can be quickly mobilized using existing infrastructure for nearby industries. An increase in harvest would therefore only be possible with a large effort that spans the whole chain, from forest owners' behaviour to capacity building, financial incentives and matching resources to harvesting capacity. The additionally available wood can most likely only be mobilized against higher marginal costs and will thus only become available in times of higher stumpage prices. The largest potential lies in privately owned forests which often have a fragmented ownership but will most likely be able to supply more wood, though mostly from deciduous species. In the long term (more than 20 years), additional wood, compared with the amounts we found for short term, can only be made available through investments in afforestation, forest restoration, improved forest management and more efficient use of raw material and recycled material.

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  • 41.
    Aquino, Caroline
    et al.
    University of Minho, Portugal.
    Rodrigues, Leonardo
    University of Nottingham, UK.
    Kržan, Meta
    Slovenian National Building and Civil Engineering Institute, Slovenia.
    Schweigler, Michael
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Li, Zheng
    Tongji University, China.
    Branco, Jorge
    University of Minho, Portugal.
    Influence of Test Methods on the Parallel to Grain Embedment Strength and Foundation Modulus Characterization2023Ingår i: Proceedings from the 13th World Conference on Timber Engineering 2023: 19-22 June, 2023, Oslo / [ed] Anders Q. Nyrud, Kjell Arne Malo, Kristine Nore, Oslo, Norway: World Conference on Timber Engineering (WCTE) , 2023, s. 3667-3674Konferensbidrag (Refereegranskat)
    Abstract [en]

    Different test setups have been reported in the literature for the determination of the embedment strengthin timber elements. These variances hinder a straightforward comparison between available test data. It is difficult todetermine if the source of variability lies in intrinsic timber properties or is related to the test protocol used. This paperaims to provide a better insight into the influence of embedment strength test methods, comparing experimental resultsfrom different test setups within the guidelines of EN 383 and ASTM D 5764-97a for Scots pine wood (Pinus sylvestris)and Spruce (Picea Abies). A robust statistical analysis was performed to identify statistically significant differencesbetween the groups evaluated. The analysis of the parallel to grain embedment strength showed that the results differedbetween standards, pointing out the potential bias inserted in the embedment properties given their evaluation method.Moreover, the thickness of the specimen tests also proved to influence the yield and ultimate embedment strength for thewood species tested.

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  • 42.
    Johansson, Jimmy
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Nilsson, Daniel
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Lennartsson, Torbjörn
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Ramsö, John
    Energikontor Norra Småland, Sweden.
    Gustavsson, Göran
    Energikontor Syd, Sweden.
    Kaskadanvändning och cirkulära perspektiv på skogsbränslen och biprodukter2023Rapport (Övrigt vetenskapligt)
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  • 43.
    Peichl, Matthias
    et al.
    Swedish University of Agricultural Sciences, Sweden.
    Martinez-Garcia, Eduardo
    Swedish University of Agricultural Sciences, Sweden.
    Fransson, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Swedish University of Agricultural Sciences, Sweden.
    Wallerman, Jörgen
    Swedish University of Agricultural Sciences, Sweden.
    Laudon, Hjalmar
    Swedish University of Agricultural Sciences, Sweden.
    Lundmark, Tomas
    Swedish University of Agricultural Sciences, Sweden.
    Nilsson, Mats B.
    Swedish University of Agricultural Sciences, Sweden.
    Landscape-variability of the carbon balance across managed boreal forests2023Ingår i: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 29, nr 4, s. 1119-1132Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Boreal forests are important global carbon (C) sinks and, therefore, considered as a key element in climate change mitigation policies. However, their actual C sink strength is uncertain and under debate, particularly for the actively managed forests in the boreal regions of Fennoscandia. In this study, we use an extensive set of biometric- and chamber-based C flux data collected in 50 forest stands (ranging from 5 to 211 years) over 3 years (2016-2018) with the aim to explore the variations of the annual net ecosystem production (NEP; i.e., the ecosystem C balance) across a 68 km(2) managed boreal forest landscape in northern Sweden. Our results demonstrate that net primary production rather than heterotrophic respiration regulated the spatio-temporal variations of NEP across the heterogeneous mosaic of the managed boreal forest landscape. We further find divergent successional patterns of NEP in our managed forests relative to naturally regenerating boreal forests, including (i) a fast recovery of the C sink function within the first decade after harvest due to the rapid establishment of a productive understory layer and (ii) a sustained C sink in old stands (131-211 years). We estimate that the rotation period for optimum C sequestration extends to 138 years, which over multiple rotations results in a long-term C sequestration rate of 86.5 t C ha(-1) per rotation. Our study highlights the potential of forest management to maximize C sequestration of boreal forest landscapes and associate climate change mitigation effects by developing strategies that optimize tree biomass production rather than heterotrophic soil C emissions.

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  • 44.
    Zarafshar, Mehrdad
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Linkages between forest dynamics, soil quality and soil microbial activity2023Ingår i: Frontiers in Forests and Global Change, E-ISSN 2624-893X, Vol. 6, artikel-id 1302871Artikel i tidskrift (Övrigt vetenskapligt)
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  • 45.
    Grubîi, Victor
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Dagbro, Ola
    Linnéuniversitetet, Universitetsbiblioteket.
    Measurement of surface-checking in sliced lamellae-based engineered wood flooring using digital image correlation2023Ingår i: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 81, s. 1427-1436Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The lack of quantitative methods for surface-checking measurements may hinder improving the product characteristics of engineered wood flooring products built with sliced top-layer lamellae. This study evaluated the digital image correlation method for its applicability to surface checking measurements in engineered wood flooring elements with the top-layer comprising the plain sliced lamellae of oak (Quercus spp.) species with nominal thicknesses of 1.5–4.5 mm. The method involves observing full-field surface displacements of the sliced lamellae-based wood flooring specimens subjected to an accelerated sorption/desorption cycle. Detection of surface checks relates to discontinuities in surface displacements which can be interpreted from the output strain data as strain peak regions. Additionally, a surface-checking index was defined to describe the extension of surface-checking. Exposure tests were performed on a combination of coating presence and a different number of testing cycles. The main findings provide insight into the method procedure parameters, such as exposure duration, climate conditions, analysis parameters and recommendations regarding the digital image correlation setup settings and specimen manufacturing.

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  • 46.
    Ahmed, Sheikh Ali
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Hosseinpourpia, Reza
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Michigan Technological University, USA.
    Adamopoulos, Stergios
    Swedish University of Agricultural Sciences, Sweden.
    Micro-Fibrillated Cellulose in Lignin–Phenol–Formaldehyde Adhesives for Plywood Production2023Ingår i: Forests, ISSN 1999-4907, E-ISSN 1999-4907, Vol. 14, nr 11, artikel-id 2249Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Petrochemical-based phenol–formaldehyde (PF) adhesives are widely used in plywood production. To substitute phenol in the synthesis of PF adhesives, lignin can be added due to its structural similarity to phenol. Moreover, micro-fibrillated cellulose (MFC) can further enhance the bond performance, mechanical properties, and toughness of adhesive systems. Thus, the aim of this study was to evaluate the adhesion performance of lignin–PF (LPF) adhesives reinforced with MFC. In LPF formulations, three levels of MFC (0, 15, and 30 wt% based on the total solid content of adhesives) were added to the homogenous adhesive mixture. Three-layer plywood panels from birch (Betula pendula Roth.) veneers were assembled after hot pressing at 130 °C under two pressing durations, e.g., 60 and 75 s/mm. Tensile shear strength was measured at dry (20 °C and 65% RH) and wet conditions (water soaked at room temperature for 24 h). The results indicated that the addition of lignin reduced the strength of LPF adhesives in both dry and wet conditions compared to the control PF adhesive. However, MFC reinforcement enhanced the shear strength properties of the plywood. Furthermore, a longer pressing time of 75 s/mm slightly increased the shear strength.

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  • 47.
    Bader, Thomas K.
    et al.