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  • 151.
    Ostovar, Ahmad
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Division of Forestry and Forest Resources, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, 1431 Ås, Norway.
    Talbot, Bruce
    Division of Forestry and Forest Resources, Norwegian Institute of Bioeconomy Research (NIBIO).
    Puliti, Stefano
    Division of Forestry and Forest Resources, Norwegian Institute of Bioeconomy Research (NIBIO).
    Rasmus, Astrup
    Division of Forestry and Forest Resources, Norwegian Institute of Bioeconomy Research (NIBIO).
    Ringdahl, Ola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Using RGB images and machine learning to detect and classify Root and Butt-Rot (RBR) in stumps of Norway spruce2019Inngår i: Forest Operations in Response to Environmental Challenges: Proceedings of the Nordic-Baltic Conference on Operational Research (NB-NORD), June 3-5, Honne, Norway / [ed] Simon Berg & Bruce Talbot, Norsk institutt for bioøkonomi (NIBIO) , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Root and butt-rot (RBR) has a significant impact on both the material and economic outcome of timber harvesting. An accurate recording of the presence of RBR during timber harvesting would enable a mapping of the location and extent of the problem, providing a basis for evaluating spread in a climate anticipated to enhance pathogenic growth in the future. Therefore, a system to automatically identify and detect the presence of RBR would constitute an important contribution in addressing the problem without increasing workload complexity for the machine operator. In this study we developed and evaluated an approach based on RGB images to automatically detect tree-stumps and classify them as to the absence or presence of rot. Furthermore, since knowledge of the extent of RBR is valuable in categorizing logs, we also classify stumps to three classes of infestation; rot = 0%, 0% < rot < 50% and rot ≥50%. We used deep learning approaches and conventional machine learning algorithms for detection and classification tasks. The results showed that tree-stumps were detected with precision rate of 95% and recall of 80%. Stumps without and with root and butt-rot were correctly classified with accuracy of 83.5% and 77.5%. Classifying rot into three classes resulted in 79.4%, 72.4% and 74.1% accuracy respectively. With some modifications, the algorithm developed could be used either during the harvesting operation to detect RBR regions on the tree-stumps or as a RBR detector for post-harvest assessment of tree-stumps and logs.

  • 152. Palmroth, Sari
    et al.
    Bach, Lisbet H
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Lindh, Marie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Kolari, Pasi
    Nordin, Annika
    Palmqvist, Kristin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Nitrogen supply and other controls of carbon uptake of understory vegetation in a boreal Picea abies forest2019Inngår i: Agricultural and Forest Meteorology, ISSN 0168-1923, E-ISSN 1873-2240, Vol. 276, artikkel-id 107620Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In boreal forests, carbon (C) uptake by understory may be too large to be ignored and too variable in space to be assumed a constant fraction of the ecosystem gross primary production. To improve estimates of understory production in these ecosystems, we need to better account for its main controls. In this study, we estimated C uptake of field-layer vegetation, dominated by Vaccinium myrtillus, V. vitis-idaea, and Deschampsia flexuosa, in a boreal Picea abies stand in northern Sweden. Nitrogen (N) availability in the stand has been manipulated through annual N additions since 1996 at the rates of 0, 12.5, and 50 kg N ha(-1) yr(-1). To assess the relative importance of N supply, and interannual fluctuations in leaf biomass and weather, in controlling field-layer photosynthetic production, we calculated C uptake over eight growing seasons using a canopy photosynthesis model. Without N additions, tree leaf area index (L) was already high (8.5) and field-layer C uptake was small, 27 g Cm-2 (or similar to 3% of stand C uptake). An increase in tree L with N additions further reduced light availability for the understory, yet the concurrent increase in the relative abundance of the more physiologically active D. flexuosa sustained the contribution of the field-layer to stand photosynthetic production. Based on a literature survey, in which site quality or stand age generated a wide range in L, understory contribution to ecosystem C uptake increases linearly with the fraction of available light reaching the forest floor across high latitude forests. Understory contributes only similar to 5% to ecosystem C uptake where trees intercept similar to 80% of incoming light, increasing to 100% after clearcut tree harvest. While the availability of solar energy, both spatially and temporally, is the primary driver of understory production, our analyses suggest that the predicted increases in drought severity and frequency at high latitudes may affect understory communities more than trees. Future empirical and modeling studies should focus on functional and ecological responses to drought of not only trees but also understory species, which contribute to biodiversity and convert their photosynthates to important non-timber products.

  • 153. Pencik, Ales
    et al.
    Casanova-Sáez, Ruben
    Pilarova, Veronika
    Zukauskaite, Asta
    Pinto, Rui
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Luis Micol, José
    Ljung, Karin
    Novák, Ondrej
    Ultra-rapid auxin metabolite profiling for high-throughput mutant screening in Arabidopsis2018Inngår i: Journal of Experimental Botany, ISSN 0022-0957, E-ISSN 1460-2431, Vol. 69, nr 10, s. 2569-2579Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Auxin (indole-3-acetic acid, IAA) plays fundamental roles as a signalling molecule during numerous plant growth and development processes. The formation of local auxin gradients and auxin maxima/minima, which is very important for these processes, is regulated by auxin metabolism (biosynthesis, degradation, and conjugation) as well as transport. When studying auxin metabolism pathways it is crucial to combine data obtained from genetic investigations with the identification and quantification of individual metabolites. Thus, to facilitate efforts to elucidate auxin metabolism and its roles in plants, we have developed a high-throughput method for simultaneously quantifying IAA and its key metabolites in minute samples (<10 mg FW) of Arabidopsis thaliana tissues by in-tip micro solid-phase extraction and fast LC-tandem MS. As a proof of concept, we applied the method to a collection of Arabidopsis mutant lines and identified lines with altered IAA metabolite profiles using multivariate data analysis. Finally, we explored the correlation between IAA metabolite profiles and IAA-related phenotypes. The developed rapid analysis of large numbers of samples (>100 samples d(-1)) is a valuable tool to screen for novel regulators of auxin metabolism and homeostasis among large collections of genotypes.

  • 154.
    Persson, Erik
    Sveriges Lantbruksuniversitet.
    Report from a Socratic Dialogue on the Concept of Risk2005Inngår i: URMAF 2005: Uncertainty and Active Risk Management and Forestry : May 25-26, 2005 Alnarp Sweden : proceedings of the International Conference Uncertainty and Active Risk Management and Forestry / [ed] Kristina Blennow, Alnarp: Institutionen för sydsvensk skogsvetenskap, SLU , 2005Konferansepaper (Annet vitenskapelig)
  • 155.
    Pesquet, Edouard
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Arrhenius Laboratories, Department of Ecology, Environment and Plant Sciences (DEEP), Stockholm University, Sweden.
    The COST action FP1105: a research network to understand wood cell wall structure, biopolymer interaction and composition2016Inngår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 70, nr 12, s. 1103-1104Artikkel i tidsskrift (Annet vitenskapelig)
  • 156. Pettersson, Maria
    et al.
    Strömberg, Caroline
    Keskitalo, E. Carina H.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för geografi och ekonomisk historia.
    Possibility to implement invasive species control in Swedish forests2016Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 45, s. 214-222Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Invasive alien species constitute an increasing risk to forestry, as indeed to natural systems in general. This study reviews the legislative framework governing invasive species in the EU and Sweden, drawing upon both a legal analysis and interviews with main national level agencies responsible for implementing this framework. The study concludes that EU and Sweden are limited in how well they can act on invasive species, in particular because of the weak interpretation of the precautionary principle in the World Trade Organisation and Sanitary and Phytosanitary agreements. In the Swedish case, this interpretation also conflicts with the stronger interpretation of the precautionary principle under the Swedish Environmental Code, which could in itself provide for stronger possibilities to act on invasive species.

  • 157.
    Rani, Raffaele
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Abramowicz, Konrad
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Falster, Daniel S.
    Sterck, Frank
    Brännström, Åke
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik. Evolution and Ecology Program, International Institute for Applied Systems Analysis, Laxenburg, Austria.
    Effects of bud-flushing strategies on tree growth2018Inngår i: Tree Physiology, ISSN 0829-318X, E-ISSN 1758-4469, Vol. 38, nr 9, s. 1384-1393Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Allocation of carbohydrates between competing organs is fundamental to plant development, growth and productivity. Carbohydrates are synthesized in mature leaves and distributed via the phloem vasculature to developing buds where they are consumed to produce new biomass. The distribution and mass-allocation processes within the plant remain poorly understood and may involve complex feedbacks between different plant functions, with implications for the emergent structure of the plant. Here, we investigate how the order in which dormant buds are flushed affects the development of tree size and reproductive output during the first 20 years of growth in full light and shaded canopy environments. We report the following findings: (i) Bud-flushing strategies strongly affect the temporal dynamics of height, mass and the size of reproduction pool, as well as the resulting architectures. (ii) Bud-flushing strategies affect tree growth by altering the rate of growth and final size of trees. (iii) No single bud-flushing strategy performs best when both the size and allocation for reproduction of the resulting trees are compared. However, we observe that the strategy that optimizes the net carbon gain for the entire tree architecture always results in a high reproduction output. (iv) Branch turnover and meristem regeneration enhance the performance of certain strategies with respect to the measured quantities. These results highlight the importance of employing generic models of architecture (i.e., non-species-specific) to identify general mechanisms of carbon allocation and the spatial distribution of newly formed biomass in growing trees.

  • 158. Rigal, Adeline
    et al.
    Yordanov, Yordan S.
    Perrone, Irene
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik.
    Karlberg, Anna
    Tisserant, Emilie
    Bellini, Catherine
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Busov, Victor B.
    Martin, Francis
    Kohler, Annegret
    Bhalerao, Rishi
    Legue, Valerie
    The AINTEGUMENTA LIKE1 Homeotic Transcription Factor PtAIL1 controls the formation of Adventitious Root Primordia in Poplar2012Inngår i: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 160, nr 4, s. 1996-2006Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Adventitious rooting is an essential but sometimes rate-limiting step in the clonal multiplication of elite tree germplasm, because the ability to form roots declines rapidly with age in mature adult plant tissues. In spite of the importance of adventitious rooting, the mechanism behind this developmental process remains poorly understood. We have described the transcriptional profiles that are associated with the developmental stages of adventitious root formation in the model tree poplar (Populus trichocarpa). Transcriptome analyses indicate a highly specific temporal induction of the AINTEGUMENTA LIKE1 (PtAIL1) transcription factor of the AP2 family during adventitious root formation. Transgenic poplar samples that overexpressed PtAIL1 were able to grow an increased number of adventitious roots, whereas RNA interference mediated the down-expression of PtAIL1 expression, which led to a delay in adventitious root formation. Microarray analysis showed that the expression of 15 genes, including the transcription factors AGAMOUS-Like6 and MYB36, was overexpressed in the stem tissues that generated root primordia in PtAIL1-overexpressing plants, whereas their expression was reduced in the RNA interference lines. These results demonstrate that PtAIL1 is a positive regulator of poplar rooting that acts early in the development of adventitious roots.

  • 159.
    Ringdahl, Ola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Automation in forestry: development of unmanned forwarders2011Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    For the last 50 year, forestry operations have become more and more mechanized. In modern forestry in Europe two machines are typically used; a harvester that fells, debranches and cross-cuts the trees into logs and a forwarder that transports them to the nearest road. These machines are technically advanced and quite expensive, but have a very high production rate. In fact, the productivity is so high that the human operator risks becoming a bottleneck if the machines become even more efficient. One way of solving this is to change working methods such that some work tasks are not needed anymore. In this way, efficiency is improved without increasing the workload. Another way to solve the problem is to develop (semi-)autonomous vehicles. One part of the work described in this thesis is an analysis of the economical performance of four potential systems based on the concept of integrated loading. Two of these systems use autonomous forest machines. Results from simulations with large amounts of real forest data show that a promising system is an autonomous forwarder switching loads with a manned harwarder, a combination of harvester and forwarder. Autonomous forwarders able to do the same work as conventional forwarders would be even more profitable than any of the other systems analyzed in this study.The development of techniques and algorithms for autonomous navigation of forwarders that transport logs from the harvesting site to the nearest transportation road is a major part of the thesis. A novel path-tracking algorithm is introduced that is able to accurately guide a forest machine along a previously demonstrated path with high accuracy. To avoid obstacles, the VFH+ algorithm was modified to work on forest machines. However, tests with a forwarder showed that this algorithm performs unsatisfactory when there are narrow passages to negotiate with obstacles close to both sides of the vehicle. This led us to develop a real-time path-planner for off-road vehicles using a simulator to predict collisions in a window forward in time. The path-planner is able to safely navigate a forest machine around obstacles on and close to the path in a way that is hard or impossible to achieve with regular obstacle-avoidance algorithms that do not take the shape of the vehicle into account. To handle a multitude of sensors, actuators, and other hardware in a systematic and uniform way and to enable communication between software modules, a software framework (often called robotics middleware) was developed. The system can be distributed over a network of computers if some software modules require more computing power. The framework has shown to be a powerful tool for research and development of autonomous vehicles.A problem in forestry operations is wheel slip causing ground damage and reducing trafficability of forest machines. Using data collected during experiments with the autonomous forest machine, a method for measuring slip was developed. It can be used to detect excessive wheel slip and may ultimately be used to control the machine transmission to reduce the amount of slip.

  • 160.
    Ringdahl, Ola
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hellström, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindroos, Ola
    Dept. of Forest Resource Management, Swedish University of Agricultural Sciences.
    Potentials of possible machine systems for directly loading logs in cut-to-length harvesting2012Inngår i: Canadian Journal of Forest Research, ISSN 0045-5067, E-ISSN 1208-6037, Vol. 42, nr 5, s. 970-985Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In conventional mechanized cut-to-length systems, a harvester fells and cuts trees into logs that are stored on the ground until a forwarder picks them up and carries them to landing sites. A proposed improvement is to place logs directly into the load spaces of transporting machines as they are cut. Such integrated loading could result in cost reductions, shorter lead times from stump to landing, and lower fuel consumption. However, it might also create waiting times for the machines involved, whereas multifunctional machines are likely to be expensive. Thus, it is important to analyze whether or not the advantages of any changes outweigh the disadvantages. The conventional system was compared with four potential systems, including two with autonomous forwarders, using discrete-event simulation with stochastic elements in which harvests of more than 1000 final felling stands (containing in total 1.6 million m3) were simulated 35 times per system. The results indicate that harwarders have substantial potential (less expensive on ≥80% of the volume and fuel consumption decreased by ≥18%) and may become competitive if key innovations are developed. Systems with cooperating machines have considerably less potential, limited to very specific stand conditions. The results conform with expected difficulties in integrating processing and transporting machines’ work in variable environments.

  • 161.
    Ringdahl, Ola
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hellström, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Wästerlund, Iwan
    Dept. of Forest Resource Management, Swedish University of Agricultural Sciences.
    Lindroos, Ola
    Dept. of Forest Resource Management, Swedish University of Agricultural Sciences.
    Estimating wheel slip for a forest machine using RTK-DGPS2012Inngår i: Journal of terramechanics, ISSN 0022-4898, E-ISSN 1879-1204, Vol. 49, nr 5, s. 271-279Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wheel slip may increase the risk for wheel rutting and tear up ground vegetation and superficial roots and thereby decreasing the bearing capacity of the ground, but also reducing the growth of nearby standing forest trees. With increased slip, more energy is consumed for making wheel ruts in the ground, with increased fuel consumption as a result. This paper proposes a novel method for measuring slip in an uneven forest terrain with an 8WD forestry machine. This is done by comparing the wheel velocity reported by the machine and velocity measured with an accurate DGPS system. Field tests with a forestry machine showed that slip could be calculated accurately with the suggested method. The tests showed that there was almost no slip on asphalt or gravel surfaces. In a forest environment, 10–15% slip was common. A future extension of the method enabling estimation of the slip of each wheel pair in the bogies is also suggested.

  • 162.
    Ringdahl, Ola
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hohnloser, Peter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hellström, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Holmgren, Johan
    Dept. of Forest Resource Management, Swedish University of Agricultural Sciences.
    Lindroos, Ola
    Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences.
    Enhanced Algorithms for Estimating Tree Trunk Diameter Using 2D Laser Scanner2013Inngår i: Remote Sensing, ISSN 2072-4292, E-ISSN 2072-4292, Vol. 5, nr 10, s. 4839-4856Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Accurate vehicle localization in forest environments is still an unresolved problem. Global navigation satellite systems (GNSS) have well known limitations in dense forest, and have to be combined with for instance laser based SLAM algorithms to provide satisfying accuracy. Such algorithms typically require accurate detection of trees, and estimation of tree center locations in laser data. Both these operations depend on accurate estimations of tree trunk diameter. Diameter estimations are important also for several other forestry automation and remote sensing applications. This paper evaluates several existing algorithms for diameter estimation using 2D laser scanner data. Enhanced algorithms, compensating for beam width and using multiple scans, were also developed and evaluated. The best existing algorithms overestimated tree trunk diameter by ca. 40%. Our enhanced algorithms, compensating for laser beam width, reduced this error to less than 12%.

  • 163.
    Ringvall, Anna
    et al.
    SLU.
    Snäll, Tord
    University of Colorado at Boulder, USA.
    Ekström, Magnus
    Centre of Biostochastics, Swedish University of Agricultural Sciences, S-901 83 Umeå, Sweden.
    Ståhl, Göran
    SLU.
    Unrestricted guided transect sampling for surveying sparse species2007Inngår i: Canadian Journal of Forest Research, ISSN 0045-5067, E-ISSN 1208-6037, Vol. 37, nr 12, s. 2575-2586Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a modification of an earlier presented method using prior auxiliary information in the layout of survey strips. The idea is to imitate a skilled surveyor who purposively seeks the species of interest. Yet, the method “unrestricted guided transect sampling” (UGTS) is a probability sampling method. In comparison with a strip survey using no auxiliary information, UGTS gave 11%–64% lower standard errors for estimates of species population size in three simulated forest types. In a test in six stands where European aspen (Populus tremula L.) and an epiphytic moss (Orthotrichum speciosum Nees) had been mapped, UGTS gave a small improvement in some stands but considerably higher standard errors in other stands with kNN estimates of volume of deciduous trees derived from satellite images as covariate values. With covariates values simulated from aspen basal area, UGTS gave 8%–75% lower standard error than a strip survey using no auxiliary information. The study shows a gain in precision by using auxiliary information both in the design and in estimation when surveying sparse species but also that the correlation between the covariate and the variable of interest has to be relatively strong to make the method worthwhile.

  • 164. Rist, Lucy
    et al.
    Moen, Jon
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Sustainability in forest management and a new role for resilience thinking2013Inngår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 310, s. 416-427Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Forest management faces a substantial challenge with ever-more-pervasive anthropogenic impacts and growing demands on forests coupled with the increasing certainty of global change. If the capacity of forests to provide valued ecological goods and services in the future is to be maintained, new tools and approaches will be needed. Several approaches have been influential in dealing with sustainability challenges in forest management and forestry to date, two of the most notable being the ecosystem approach and adaptive management. Resilience-based approaches have now emerged as a new paradigm to deal with these challenges. This paper considers how resilience thinking might inform forest management by exploring its conceptual basis in comparison with the ecosystem approach and adaptive management as two earlier influences. We identify three novel conceptual contributions and outline some of the key challenges encountered when applying resilience thinking to the management of forests. Resilience thinking offers new conceptual contributions for dealing with large and uncertain changes, the relationships between social and ecological components of forest systems, and a new perspective on sustainability. However, there are several barriers to it informing forest management in a practical way, including means by which resilience can be measured and valued within a management context, and most importantly, how resilience can be maintained and enhanced within systems focused on resource production or service provision. Resilience thinking's contributions are largely conceptual at this stage and offer more in terms a problem-framing approach than analytical or practical tools. Decision-relevant, science-based, and solution-oriented approaches are required to tackle future forest management challenges. Resilience thinking, if developed to become more solution-orientated could offer a needed complement to current management paradigms.

    (C) 2013 Elsevier B.V. All rights reserved.

  • 165.
    Roberge, Jean-Michel
    et al.
    Sveriges lantbruksuniversitet, SLU.
    Laudon, Hjalmar
    Sveriges lantbruksuniversitet, SLU.
    Björkman, Christer
    Sveriges lantbruksuniversitet, SLU.
    Ranius, Thomas
    Sveriges lantbruksuniversitet, SLU.
    Sandström, Camilla
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statsvetenskapliga institutionen.
    Felton, Adam
    Swedish Univ Agr Sci SLU, Southern Swedish Forest Res Ctr, Rorsjovagen 1,Box 49, S-23053 Alnarp, Sweden.
    Sténs, Anna
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Nordin, Annika
    Sveriges lantbruksuniversitet, SLU.
    Granström, Anders
    Sveriges lantbruksuniversitet, SLU.
    Widemo, Fredrik
    Swedish University of Agricultural Sciences (SLU).
    Bergh, Johan
    Linnéuniversitetet.
    Sonesson, Johan
    Skogforsk.
    Stenlid, Jan
    Swedish University of Agricultural Sciences (SLU).
    Lundmark, Tomas
    Swedish University of Agricultural Sciences (SLU).
    Socio-ecological implications of modifying rotation lengths in forestry2016Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 45, s. 109-123Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The rotation length is a key component of even-aged forest management systems. Using Fennoscandian forestry as a case, we review the socioecological implications of modifying rotation lengths relative to current practice by evaluating effects on a range of ecosystem services and on biodiversity conservation. The effects of shortening rotations on provisioning services are expected to be mostly negative to neutral (e.g. production of wood, bilberries, reindeer forage), while those of extending rotations would be more varied. Shortening rotations may help limit damage by some of today's major damaging agents (e.g. root rot, cambium-feeding insects), but may also increase other damage types (e.g. regeneration pests) and impede climate mitigation. Supporting (water, soil nutrients) and cultural (aesthetics, cultural heritage) ecosystem services would generally be affected negatively by shortened rotations and positively by extended rotations, as would most biodiversity indicators. Several effect modifiers, such as changes to thinning regimes, could alter these patterns.

  • 166. Roche, Jessica
    et al.
    Turnbull, Matthew H.
    Guo, Qianqian
    Novak, Ondrej
    Späth, Jana
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Swedish Metabolomics Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences KBC, Umeå University, Linnéus vag, SE-90182 Umeå, Sweden.
    Gieseg, Steven P.
    Jameson, Paula E.
    Love, Jonathan
    Coordinated nitrogen and carbon remobilization for nitrate assimilation in leaf, sheath and root and associated cytokinin signals during early regrowth of Lolium perenne2017Inngår i: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 119, nr 8, s. 1353-1364Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background and Aims The efficiency of N assimilation in response to defoliation is a critical component of plant regrowth and forage production. The aim of this research was to test the effect of the internal C/N balance on NO3- assimilation and to estimate the associated cytokinin signals following defoliation of perennial ryegrass (Lolium perenne L. 'Grasslands Nui') plants. Methods Plants, manipulated to have contrasting internal N content and contrasting availability of water soluble carbohydrates (WSCs), were obtained by exposure to either continuous light or short days (8: 16 h light-dark), and watered with modified N-free Hoagland medium containing either high (5 mM) or low (50 mu M) NO3- as sole N source. Half of the plants were defoliated and the root, sheath and leaf tissue were harvested at 8, 24 and 168 h after cutting. The spatiotemporal changes in WSCs, synthesis of amino acids and associated cytokinin content were recorded after cutting. Key Results Leaf regrowth following defoliation involved changes in the low-and high-molecular weight WSCs. The extent of the changes and the partitioning of the WSC following defoliation were dependant on the initial WSC levels and the C and N availability. Cytokinin levels varied in the sheath and root as early as 8 h following defoliation and preceded an overall increase in amino acids at 24 h. Subsequently, negative feedback brought the amino acid response back towards pre-defoliation levels within 168 h after cutting, a response that was under control of the C/N ratio. Conclusions WSC remobilization in the leaf is coordinated with N availability to the root, potentially via a systemic cytokinin signal, leading to efficient N assimilation in the leaf and the sheath tissues and to early leaf regrowth following defoliation.

  • 167. Rosvall, Ola
    et al.
    Bradshaw, Richard H. W.
    Egertsdotter, Ulrika
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC). Department of Forest Genetics and Plant Physiology, Swedish Agricultural University, Umeå, Sweden.
    Ingvarsson, Par K.
    Wu, Harry
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC). Swedish University of Agricultural Sciences, Umeå, Sweden.
    Using Norway spruce clones in Swedish forestry: introduction2019Inngår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 34, nr 5, s. 333-335Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    In this introductory paper, we briefly review the history of using clones in Swedish forestry. The different approaches of using clones are defined as: (1) "clonal forestry", the deployment of tested selected clones, and (2) "family forestry" with vegetative multiplication of crosses between elite parents. Clones of Norway spruce may be deployed as rooted cuttings or as propagules produced via somatic embryogenesis (SE). The speed and flexibility of using clones is compared with the traditional deployment of reforestation stock raised from seed orchard seed. The key questions addressed in this special issue are presented: (1) what are the benefits and risks of using clones in forestry, (2) what physiological and genetic effects are introduced by the SE propagation technology, (3) what are the long-term genetic consequences of changing genetic diversity by using clones, (4) what are the environmental consequences of using clones, and (5) what are the management implications from vegetatively propagated nursery stock?

  • 168. Rosvall, Ola
    et al.
    Bradshaw, Richard H. W.
    Egertsdotter, Ulrika
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC). Department of Forest Genetics and Plant Physiology, Swedish Agricultural University, Umeå, Sweden.
    Ingvarsson, Pär K.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC). Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Mullin, Tim J.
    Wu, Harry
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC). Swedish University of Agricultural Sciences, Umeå, Sweden.
    Using Norway spruce clones in Swedish forestry: implications of clones for management2019Inngår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 34, nr 5, s. 390-404Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    This final paper of the series discusses implications of various aspects of using clones in forestry. Benefits from using clones are considerable. A large benefit arises from the ability to deploy genetic gain much sooner than is possible through conventional seed orchards. This benefit applies even to the use of clones to implement family forestry, even though the clones themselves are not tested. The requirement for genetic diversity at both the stand and landscape levels requires active management to ensure that diversity is conserved. This is achieved partly through the management of breeding populations, as well as by managing the genetic diversity and number of genotypes deployed in clone mixtures. A numerical example is given comparing diversity of clone and seed orchard deployment over time. Many aspects of managing concerns about using clones are about communication to clarify public perceptions and establishing a code of practice.

  • 169.
    Sandström, Camilla
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statsvetenskapliga institutionen.
    Beland Lindahl, Karin
    Sténs, Anna
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Comparing forest governance models2017Inngår i: Forest Policy and Economics, ISSN 1389-9341, E-ISSN 1872-7050, Vol. 77, s. 1-5Artikkel i tidsskrift (Fagfellevurdert)
  • 170.
    Sandström, Camilla
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statsvetenskapliga institutionen.
    Carlsson-Kanyama, Annika
    Beland Lindahl, Karin
    Mossberg Sonnek, Karin
    Mossing, Annika
    Nordin, Annika
    Nordstrom, Eva-Maria
    Räty, Riitta
    Understanding consistencies and gaps between desired forest futures: An analysis of visions from stakeholder groups in Sweden2016Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 45, s. S100-S108Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Conflicting perspectives on forests has for a long time challenged forest policy development in Sweden. Disagreements about forest futures create intractable deadlocks when stakeholders talk past each other. The purpose of this study is to move beyond this situation through the application of participatory backcasting. By comparing visions of the future forest among stakeholder groups, we highlight contemporary trajectories and identify changes that were conceived as desirable. We worked with four groups: the Biomass and Bioenergy group, the Conservation group, the Sami Livelihood group and the Recreation and Rural Development group; in total representatives from 40 organizations participated in workshops articulating the groups' visions. Our results show well-known tensions such as intrinsic versus instrumental values but also new ones concerning forests' social values. Identified synergies include prioritization of rural development, new valued-added forest products and diversified forest management. The results may feed directly into forest policy processes facilitating the process and break current deadlocks.

  • 171.
    Sandström, Camilla
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statsvetenskapliga institutionen.
    Sandström, Per
    SLU Umeå.
    Jougda, Leif
    Swedish forest agency.
    Mitigating conflicts through collaborative learning: the case of forestry and reindeer husbandry in northern Sweden2009Konferansepaper (Annet vitenskapelig)
  • 172.
    Sandström, Camilla
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statsvetenskapliga institutionen.
    Sténs, Anna
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Dilemmas in forest policy development: the Swedish forestry model under pressure2015Inngår i: The future use of nordic forests: a global perspective / [ed] Erik Westholm, Karin Beland Lindahl, Florian Kraxner, Springer, 2015, s. 145-158Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    This chapter brings back the discussion to the Swedish situation and describes the forest policy dilemmas related to a transition of forest governance. The expected transition implies a shift in forest policy and practice in developed countries with a reduced "emphasis on timber production relative to the provision of environmental goods and services". The chapter describes a number of dilemmas and concludes that Swedish forestry policy has not managed to handle the gap between key stakeholders. Now this gap seems too wide to expect any joint contribution to the development of Swedish forest policy. Instead, the disagreements have resulted in putting pressure on the Swedish forestry model 

  • 173. Sandström, Per
    et al.
    Sandström, Camilla
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statsvetenskapliga institutionen.
    Svensson, Johan
    Jougda, Leif
    Baer, Karin
    Participatory GIS to mitigate conflicts between reindeer husbandry and forestry in Vilhelmina Model Forest, Sweden2012Inngår i: Forestry Chronicle, ISSN 0015-7546, Vol. 88, nr 3, s. 254-260Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To improve communication between reindeer-herders and other land users, we developed and implemented a system to produce reindeer husbandry plans together with Sami reindeer-herding communities. A central component of our communications strategy was the introduction and use of a participatory GIS (pGIS). We evaluated the potential and limitations of pGIS as a tool for collaborative learning. We concluded that by merging traditional and scientific knowledge in a pGIS, the process of spatial communication has contributed to a more inclusive planning process, and to improved knowledge-sharing. Furthermore, the process has contributed to a more efficient long-term perspective where land use planning focuses on key areas but with solutions applied to the landscape. The Model Forest offered an appropriate platform to facilitate the process.

  • 174.
    Sarneel, Judith M.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Ecology and Environmental Sciences, Utrecht University, Utrecht, The Netherlands.
    Bejarano, Maria D.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Natural Resources Department, Technical University of Madrid, Madrid, Spain.
    van Oosterhout, Martin
    Nilsson, Christer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Local flooding history affects plant recruitment in riparian zones2019Inngår i: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 30, nr 2, s. 224-234Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aims: Many rivers across the globe are severely impacted by changed flooding regimes, resulting in drastic shifts in vegetation, but the processes driving the exchange of flood‐sensitive and flood‐tolerant species are understood less. We studied the role of long‐term and recent flooding histories for riparian plant recruitment in response to various changes in flooding regime.

    Location: Vindel River catchment (Northern Sweden).

    Methods

    We experimentally changed long‐term flooding regimes by transplanting turfs between high and low elevations in 2000 and in 2014 (= 8 per treatment). We sowed seeds of five riparian species in both transplanted turfs and non‐transplanted controls and counted seedling numbers over two growing seasons. Further, we inventoried natural seedling frequencies in 190 plots in 19 reaches in 2013 and 2014, and related natural seedling numbers to plot flooding history in the period 2012–2014.

    Results: We observed effects of long‐term flooding history in the second year of the transplantation study (2015), but not in the first year. In 2015, turfs transplanted to locations with less flooding resulted in higher plant recruitment while transplantation to sites with more frequent flooding reduced recruitment compared to the controls. Since these differences were only found in recently transplanted turfs and not in older turfs, the legacy effect of long‐term flooding history can be transient. In the field seedling survey, similar differences were found between flooding‐history categories in 2013, but not in 2014, when the moisture conditions of the most recent year determined flooding. Further, lowest seedling numbers were observed when the previous flooding occurred in winter, and higher seedling numbers when floods occurred in spring or not at all.

    Conclusions: Both long‐term and recent flooding histories can affect plant recruitment, and their influence should be taken into account when designing restoration projects.

  • 175. Schelker, J
    et al.
    Kuglerová, Lenka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Eklöf, K
    Bishop, K
    Laudon, H
    Hydrological effects of clear-cutting in a boreal forest: snowpack dynamics, snowmelt and streamflow responses2013Inngår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 484, s. 105-114Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigated the effects of forest clear-cutting on snow accumulation, melt dynamics and associated stream responses in a paired catchment experiment in northern Sweden. Two boreal first-order streams, of which one was clear-cut harvested in 2006, were compared during the 2005-2011 study period. Clear-cutting increased snow accumulation expressed as snow water equivalents (SWEs) on average by 29 mm (27%). Further snow melt occurred earlier in the clear-cut resulting in more rapid stream responses of the harvested catchment during some, but not all years (2008, 2009 and 2010). Snowmelt runoff increased by 39% and 27% in the clear-cut (reference = 144 mm and 121 mm) during 2008 and 2009, respectively, whereas no significant difference in runoff was observed during spring 2010 and 2011. The results indicate that stream responses to snowmelt, primarily governed by sensible heat transfer through air temperature, radiation and turbulent heat fluxes, are controlled by three main processes: (i) interception in the forest canopy, reducing SWE; (ii) sublimation directly from the snowpack; and (iii) additional losses of melt water as, for example, evaporation during the melt. The year-to-year variation in these processes determines the stream response to clear-cutting during snowmelt. Overall this study underlines the large inter-annual variation in spring snowmelt responses of managed boreal catchments, which may have hydrological and biochemical implications for downstream locations.

  • 176. Segura, Javier H.
    et al.
    Nilsson, Mats B.
    Sparrman, Tobias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Serk, Henrik
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Schleucher, Juergen
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Tolu, Julie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Öquist, Mats G.
    Boreal tree species affect soil organic matter composition and saprotrophic mineralization rates2019Inngår i: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 441, nr 1-2, s. 173-190Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aims: To investigate how different tree species affect the composition of SOM and its mineralization in boreal forest ecosystems.

    Methods: We used pyrolysis GC-MS for molecular-level characterization of the SOM formed under five common boreal tree species at a replicated field experiment similar to 50years after plantation. We incubated soil samples at 4, 9, 14 and 19 degrees C and measured inherent CO2 production and substrate-induced respiration. We then evaluated if the saprotrophic microbial activity and its temperature sensitivity was controlled by the SOM composition.

    Results: The molecular composition of the SOM emerged as key factor influencing SOM properties in plots with different tree species. Most of the variance in the SOM content was explained by the organo-chemical composition of the SOM. More importantly, the fraction of the microbial community able to utilize the native SOM was largely controlled by the SOM organo-chemical composition. Temperature sensitivity of CO2 production (Q(10)) was not explained by SOM composition. However, the microbial access to different SOM pools varied with temperature.

    Conclusions: These results bridge the gap between the paradigms of short-term litter and long-term SOM decomposition showing that, on an intermediate timescale (similar to 50 years), boreal tree species affect SOM molecular composition and saprotrophic mineralization rates.

  • 177.
    Servin, Martin
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Backman, Anders
    HPC2N (Högpresterande beräkningscentrum norr).
    Bodin, Kenneth
    HPC2N (Högpresterande beräkningscentrum norr).
    Bergsten, Urban
    Bergström, Dan
    Löfgren, Björn
    Nordfjell, Tomas
    Wästerlund, Iwan
    Visual Simulation of Machine Concepts for Forest Biomass Harvesting2008Inngår i: VRIC '08 Laval Virtual: 10th Virtual Reality International Conference, 2008, s. 211-215Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    We present work-in-progress of applying simulator technology for developing, demonstrating and evaluating new machine concepts and work methods in off-road environments. In particular we consider a new concept machine for making efficient biomass harvesting in the process of thinning in dense forest stands and we describe how this machine concept is realized in a virtual environment and plan for simulator experiments.

  • 178.
    Seyfferth, Carolin
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Wessels, Bernard A.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Gorzsás, András
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Love, Jonathan W.
    Rüggeberg, Markus
    Delhomme, Nicolas
    Vain, Thomas
    Antos, Kamil
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Tuominen, Hannele
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik.
    Sundberg, Björn
    Felten, Judith
    Ethylene Signaling Is Required for Fully Functional Tension Wood in Hybrid Aspen2019Inngår i: Frontiers in Plant Science, ISSN 1664-462X, E-ISSN 1664-462X, Vol. 10, artikkel-id 1101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tension wood (TW) in hybrid aspen trees forms on the upper side of displaced stems to generate a strain that leads to uplifting of the stem. TW is characterized by increased cambial growth, reduced vessel frequency and diameter, and the presence of gelatinous, cellulose-rich (G-)fibers with its microfibrils oriented parallel to the fiber cell axis. Knowledge remains limited about the molecular regulators required for the development of this special xylem tissue with its characteristic morphological, anatomical, and chemical features. In this study, we use transgenic, ethylene-insensitive (ETI) hybrid aspen trees together with time-lapse imaging to show that functional ethylene signaling is required for full uplifting of inclined stems. X-ray diffraction and Raman microspectroscopy of TW in ETI trees indicate that, although G-fibers form, the cellulose microfibril angle in the G-fiber S-layer is decreased, and the chemical composition of S- and G-layers is altered than in wild-type TW. The characteristic asymmetric growth and reduction of vessel density is suppressed during TW formation in ETI trees. A genome-wide transcriptome profiling reveals ethylene-dependent genes in TW, related to cell division, cell wall composition, vessel differentiation, microtubule orientation, and hormone crosstalk. Our results demonstrate that ethylene regulates transcriptional responses related to the amount of G-fiber formation and their properties (chemistry and cellulose microfibril angle) during TW formation. The quantitative and qualitative changes in G-fibers are likely to contribute to uplifting of stems that are displaced from their original position.

  • 179.
    Sonntag-Öström, Elisabet
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Nordin, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Slunga Järvholm, Lisbeth
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Lundell, Ylva
    Brännström, Rigmor
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Dolling, Ann
    Can the boreal forest be used for rehabilitation and recovery from stress-related exhaustion? A pilot study.2011Inngår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 26, nr 3, s. 245-256Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It has been suggested that humans suffering from mental exhaustion recover better in environments that do not demand directed attention. Hence, we hypothesized that forests have restorative effects and examined whether the boreal forest in northern Sweden can be used for rehabilitation from stress-related exhaustion in a pilot study. Six participants suffering from stress-related exhaustion were offered visits twice a week, for 11 weeks, in six different forest settings: pine forest, mixed forest, spruce forest, forest by the lake, the forest with a small stream and rock outcrops. The participants chose one forest setting prior to each visit, and the mental state of each participant was evaluated before and after each visit. Interviews focusing on the experience of the forest were conducted after the 22 visits. Solitude and forest settings with light were identified as positive factors for recovery. Despite the limited amount of data, the results showed that the forest visits had significant positive effects on the participants' mental state. The interviews also indicated that the concept is suitable for use in larger randomized studies and that it is important to provide various forest settings to meet individual preferences of the participants and to offer the possibility of solitude.

  • 180. Soolanayakanahally, Raju Y
    et al.
    Guy, Robert D
    Street, Nathaniel R
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Robinson, Kathryn M
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Silim, Salim N.
    Albrectsen, Benedicte R
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Jansson, Stefan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Comparative physiology of allopatric Populus species: geographic clines in photosynthesis, height growth, and carbon isotope discrimination in common gardens2015Inngår i: Frontiers in Plant Science, ISSN 1664-462X, E-ISSN 1664-462X, Vol. 6, artikkel-id 528Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Populus species with wide geographic ranges display strong adaptation to local environments. We studied the clinal patterns in phenology and ecophysiology in allopatric Populus species adapted to similar environments on different continents under common garden settings. As a result of climatic adaptation, both Populus tremula L. and Populus balsamifera L. display latitudinal clines in photosynthetic rates (A), whereby high-latitude trees of P. tremula had higher A compared to low-latitude trees and nearly so in P. balsamifera (p = 0.06). Stomatal conductance (g(S)) and chlorophyll content index (CCI) follow similar latitudinal trends. However, foliar nitrogen was positively correlated with latitude in P. balsamifera and negatively correlated in P. tremula. No significant trends in carbon isotope composition of the leaf tissue (delta C-13) were observed for both species; but, intrinsic water-use efficiency (WUEi) was negatively correlated with the latitude of origin in P. balsamifera. In spite of intrinsically higher A, high-latitude trees in both common gardens accomplished less height gain as a result of early bud set. Thus, shoot biomass was determined by height elongation duration (HED), which was well approximated by the number of days available for free growth between bud flush and bud set. We highlight the shortcoming of unreplicated outdoor common gardens for tree improvement and the crucial role of photoperiod in limiting height growth, further complicating interpretation of other secondary effects.

  • 181.
    Sténs, Anna
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Ja till förskönade landskap, nej till reglering2014Inngår i: Västerbottenskuriren, ISSN 1104-0246Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 182.
    Sténs, Anna
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Skogens estetik: Anna Sténs presenterar sin forskning2015Inngår i: Norra Skogsmagasinet, ISSN 1653-5154, nr 1, s. 30-Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [sv]

    Skogsbrukets anpassning till estetiska och upplevelsemässiga värden förknippas ofta med tätortsnära skogar och tätbefolkade områden med mycket turism. Anna Sténs vid Future Forests vände på perspektivet och tog reda på hur skogsägare i ett glesbefolkat och skogsrikt Västerbotten tänker.

  • 183.
    Sténs, Anna
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Skogens skönhetsvärden växer i vikt2014Inngår i: Idéer och värderingar: rapport från Future Forests 2009-2012 / [ed] Erland Mårald och Christer Nordlund, Umeå: SLU, Future Forests , 2014, , s. 2s. 28-29Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 184.
    Sténs, Anna
    et al.
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Kardell, Örjan
    Umeå universitet, Humanistiska fakulteten, Institutionen för språkstudier.
    Oenigheten består om skogsgödsling2014Inngår i: Idéer och värderingar: rapport från Future Forests 2009-2012 / [ed] Erland Mårald och Christer Nordlund, Umeå: SLU, Future Forests , 2014, , s. 2s. 26-27Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 185.
    Sténs, Anna
    et al.
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Kardell, Örjan
    Umeå universitet, Humanistiska fakulteten, Institutionen för språkstudier.
    Skogsdödens "uppgång och fall": vad har vi lärt oss?2014Inngår i: Idéer och värderingar: rapport från Future Forests 2009-2012 / [ed] Erland Mårald och Christer Nordlund, Umeå: SLU, Future Forests , 2014, , s. 4s. 22-25Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 186.
    Sténs, Anna
    et al.
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Mårald, Erland
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Managing forest aesthetics in the boreal fringe2014Inngår i: International forestry review, ISSN 1465-5489, E-ISSN 2053-7778, Vol. 16, nr 5, s. 52-Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    The value and management of forest aesthetics have been heavily studied since the early 1970s. However, studies moving outsideof urban areas are less frequent. This also holds for Sweden. Previous research has focused on the southern, urban parts of thecountry rather than the sparsely populated, forest dependent, northern interior. However, to increase the quality of livelihood inthese areas, an aesthetically attractive environment is an important component. This paper discusses the attitudes to aestheticalconsiderations among forest owners and consultants in the northern parts of Sweden. It raises questions such as: Whichconsiderations have been taken to aesthetical values in boreal forests? What policies lay behind and what was gained from theseconsiderations? What are the attitudes to forest aesthetics today and who will be responsible for the preservation and creationof aesthetical values in the future? The study has been conducted through a qualitative literary review of previous research andinterviews with present stakeholders. Preliminary results show that the societal interest in forest aesthetics is high, but policiesregulating these values have become more vague. There also seem to be a discrepancy between forest owner’s and consultant’sattitudes when discussing aesthetical considerations in boreal productive forests.

  • 187.
    Sténs, Anna
    et al.
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Sandström, Camilla
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statsvetenskapliga institutionen.
    Allemansrätten och bären: vem ska äga "skogens guld"2014Inngår i: Idéer och värderingar: rapport från Future Forests 2009-2012 / [ed] Erland Mårald och Christer Nordlund, Umeå: SLU, Future Forests , 2014, , s. 2s. 20-21Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 188. Svensson, Johan
    et al.
    Sandström, Per
    Sandström, Camilla
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statsvetenskapliga institutionen.
    Jougda, Leif
    Baer, Karin
    Sustainable landscape management in the Vilhelmina Model Forest, Sweden2012Inngår i: Forestry Chronicle, ISSN 0015-7546, Vol. 88, nr 3, s. 291-297Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this paper is to outline current foundations for sustainable landscape management in the Vilhelmina Model Forest, northwest Sweden. A case study revealed that the remaining patches of undisturbed or less disturbed boreal forest ecosystems comprise multiple values and, thus, constitute the basis for landscape planning. By identifying these patches, it is also possible to construct a spatial planning infrastructure for implementing sustainable management and land use. A more comprehensive toolbox needs to be developed, however, including monitoring and inventory schemes for relevant biophysical and socio-economic data, better temporal resolution for cause and effect analyses, and functioning scale-flexible planning and governance instruments.

  • 189.
    Talbot, Patricia
    et al.
    bLaurentian Forestry Centre, Canadian Forest Service, Natural Resources Canada, 1055 rue du PEPS, Québec, QC G1V 4C7, Canada.
    Thompson, Stacey Lee
    bLaurentian Forestry Centre, Canadian Forest Service, Natural Resources Canada, 1055 rue du PEPS, Québec, QC G1V 4C7, Canada.
    Schroeder, William
    cAgroforestry Development Centre, AAFC Agri-Environment Services Branch, P.O. Box 940, No. 2 Government Road, Indian Head, SK S0G 2K0, Canada.
    Isabel, Nathalie
    bLaurentian Forestry Centre, Canadian Forest Service, Natural Resources Canada, 1055 rue du PEPS, Québec, QC G1V 4C7, Canada.
    An efficient single nucleotide polymorphism assay to diagnose the genomic identity of poplar species and hybrids on the Canadian prairies2011Inngår i: Canadian Journal of Forest Research, ISSN 0045-5067, E-ISSN 1208-6037, Vol. 41, nr 5, s. 1102-1111Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hybridization frequently occurs among poplars, both naturally and artificially, hindering identification. Over 32 million clonal poplars, predominantly hybrids, have been planted throughout the Canadian prairies over the past century, making confirmation of genomic identity important. We developed a genotyping assay that rapidly diagnoses four compatible Populus species (Populus balsamifera L. and Populus deltoides Bartr. ex Marsh.: indigenous, Populus laurifolia Ledeb. and Populus nigra L.: exotics) and their hybrids found throughout this ecozone. First, we sequenced 23 genes from representative provenances of the four Populus species to discover single nucleotide polymorphisms (SNPs). Second, we developed and validated a medium-throughput genotyping assay of 26 diagnostic SNPs within these genes. We used this assay to genotype 198 trees from natural populations as well as 30 clones (pure species and hybrids), including those broadly distributed by Agriculture and Agri-Food Canada's Agroforestry Development Centre since 1910. This suite of SNPs has the resolving power to correctly identify pure species and hybrids of Populus. We confirmed the identity of clones of well-documented origin, complex hybrids with exotic components, and paternity of open-pollinated progenies from breeding programs. This diagnostic tool should prove useful for efficient molecular fingerprinting of breeding material and for further studies of interspecific gene flow on the Canadian prairies.

  • 190.
    Tan, Biyue
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Stora Enso AB.
    Genomic selection and genome-wide association studies to dissect quantitative traits in forest trees2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The convergence of quantitative genetics of complex traits with genomic technologies is quickly becoming an innovative approach to explore fundamental genetic questions and also have practical consequences for implementations in tree breeding. In this thesis, I used genomic selection and genome-wide association studies (GWAS) to dissect the genetic basis of quantitative traits, i.e. growth, phenology and wood property traits. I also assessed the importance of dominance and epistatic effects in hybrid Eucalyptus. Both dominance and epistasis are important in hybrids, as they are the likely contributing to the genetic basis of heterosis. To successfully implement genomic selection models, several important factors have to be considered. I found that for a good model establishment, both the size and composition of the training population, as well as the number of SNPs to be important considered. Based on the optimal models, additive, dominance and epistasis genetic effects of growth and wood traits have been estimated to evaluate genetic parameters and how these influence the prediction accuracy, which can be used in selecting elite breeding individuals or clones. I also addressed the advantage of genotyping-based analyses by showing that we could accurately correct pedigree information errors. More importantly, genotyping-based analyses capture both Mendelian segregation variation within full-sib families and cryptic genetic links through unknown common ancestors, which are not available from traditional pedigree data. GWAS were used to analyse growth and phenology related traits. Using a single-trait GWAS method, we identified a region strongly associated with the timing of bud set in Populus tremula, a trait with high heritability. For the growth related traits, we found that a multi-traits GWAS approach was more powerful than single-trait analyses as it identified more associated SNPs in hybrid Eucalyptus. Moreover, many more novel associated SNPs were identified from considering over-dominance effects in the GWAS analyses. After annotating the associated SNPs I show that these functional candidate genes were related to growth and responding to abiotic and biotic stress. In summary, the results of genomic selection and GWAS provided a deeper understanding of the genetic backgrounds of quantitative traits in forest trees.

  • 191.
    Tan, Biyue
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Biomaterials Division, Stora Enso AB, SE-131 04, Nacka, Sweden.
    Grattapaglia, Dario
    Wu, Harry X.
    Ingvarsson, Pär K.
    Genomic relationships reveal significant dominance effects for growth in hybrid Eucalyptus2018Inngår i: Plant Science, ISSN 0168-9452, E-ISSN 1873-2259, Vol. 267, s. 84-93Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Non-additive genetic effects can be effectively exploited in control-pollinated families with the availability of genome-wide markers. We used 41,304 SNP markers and compared pedigree vs. marker-based genetic models by analysing height, diameter, basic density and pulp yield for Eucalyptus urophylla x E.grandis control-pollinated families represented by 949 informative individuals. We evaluated models accounting for additive, dominance, and first-order epistatic interactions (additive by additive, dominance by dominance, and additive by dominance). We showed that the models can capture a large proportion of the genetic variance from dominance and epistasis for growth traits as those components are typically not independent. We also showed that we could partition genetic variances more precisely when using relationship matrices derived from markers compared to using only pedigree information. In addition, phenotypic prediction accuracies were only slightly increased by including dominance effects for growth traits since estimates of non-additive variances yielded rather high standard errors. This novel result improves our current understanding of the architecture of quantitative traits and recommends accounting for dominance variance when developing genomic selection strategies in hybrid Eucalyptus.

  • 192.
    Tan, Biyue
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Stora Enso AB.
    Ingvarsson, Pär K.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Department of Plant Biology, Swedish University of Agricultural Sciences.
    Multivariate genome-wide association identify loci for complex growth traits by considering additive and over-dominance effects in hybrid EucalyptusManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Genome-wide association studies are a powerful and widely used approach to decipher the genetic control of quantitative traits. One of the major challenges for traits in hybrid forest trees, such as hybrid Eucalyptus, is dissecting also non-additive effects for complex traits using a traditional linear mixed model. These non-additive effects, especially over-dominance effects, are one of most important hypotheses for the genetic basis of heterosis. In this study, we used a population including 949 F1 hybrids and their 174 parents, that were phenotyped for circumference at breast height and height at age of three years and six years, and also genotyped at 37,832 informative SNPs. Here we use and compare single-trait and multi-trait association models by accounting for additive and over-dominance effects, to evaluate genomic regions associated with the growth traits. For additive effect-based association model, nine significant SNPs were observed in multi-trait analyses, whereas only two unique SNPs were detected in single-trait analyses. These two SNPs were also identified in the multi-trait model. When evaluating over-dominance effects, 17 and 13 SNPs were identified from multi-trait and single-trait models, respectively. Moreover, more phenotypic variation can be explained by SNPs identified from multi-trait GWAS when including over-dominance effects. Overall, this study shows the added values of including over-dominance and considering multiple traits for identifying genomic regions that control traits of interest and that could contribute to heterosis in hybrids.

  • 193. Tao, Yi
    et al.
    Ferrer, Jean-Luc
    Ljung, Karin
    Pojer, Florence
    Hong, Fangxin
    Long, Jeff A
    Li, Lin
    Moreno, Javier E
    Bowman, Marianne E
    Ivans, Lauren J
    Cheng, Youfa
    Lim, Jason
    Zhao, Yunde
    Ballaré, Carlos L
    Sandberg, Göran
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Noel, Joseph P
    Chory, Joanne
    Rapid synthesis of auxin via a new tryptophan-dependent pathway is required for shade avoidance in plants2008Inngår i: Cell, ISSN 0092-8674, E-ISSN 1097-4172, Vol. 133, nr 1, s. 164-176Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Plants grown at high densities perceive a decrease in the red to far-red (R:FR) ratio of incoming light, resulting from absorption of red light by canopy leaves and reflection of far-red light from neighboring plants. These changes in light quality trigger a series of responses known collectively as the shade avoidance syndrome. During shade avoidance, stems elongate at the expense of leaf and storage organ expansion, branching is inhibited, and flowering is accelerated. We identified several loci in Arabidopsis, mutations in which lead to plants defective in multiple shade avoidance responses. Here we describe TAA1, an aminotransferase, and show that TAA1 catalyzes the formation of indole-3-pyruvic acid (IPA) from L-tryptophan (L-Trp), the first step in a previously proposed, but uncharacterized, auxin biosynthetic pathway. This pathway is rapidly deployed to synthesize auxin at the high levels required to initiate the multiple changes in body plan associated with shade avoidance.

  • 194.
    Thompson, Stacey Lee
    et al.
    Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055, rue du P.E.P.S., c.p. 10380 Succursale Sainte-Foy, Québec QC G1V 4C7 Canada.
    Bérubé, Yanik
    Department of Forest Sciences, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada.
    Bruneau, Anne
    Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Sherbrooke Est, Montréal QC H1X 2B2, Canada.
    Ritland, Kermit
    Department of Forest Sciences, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada.
    Three-gene identity coefficients demonstrate that clonal reproduction promotes inbreeding and spatial relatedness in yellow-cedar, Callitropsis nootkatensis2008Inngår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 62, nr 10, s. 2570-2579Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Asexual reproduction has the potential to promote population structuring through matings between clones as well as through limited dispersal of related progeny. Here we present an application of three-gene identity coefficients that tests whether clonal reproduction promotes inbreeding and spatial relatedness within populations. With this method, the first two genes are sampled to estimate pairwise relatedness or inbreeding, whereas the third gene is sampled from either a clone or a sexually derived individual. If three-gene coefficients are significantly greater for clones than nonclones, then clonality contributes excessively to genetic structure. First, we describe an estimator of three-gene identity and briefly evaluate its properties. We then use this estimator to test the effect of clonality on the genetic structure within populations of yellow-cedar (Callitropsis nootkatensis) using a molecular marker survey. Five microsatellite loci were genotyped for 485 trees sampled from nine populations. Our three-gene analyses show that clonal ramets promote inbreeding and spatial structure in most populations. Among-population correlations between clonal extent and genetic structure generally support these trends, yet with less statistical significance. Clones appear to contribute to genetic structure through the limited dispersal of offspring from replicated ramets of the same clonal genet, whereas this structure is likely maintained by mating among these relatives.

  • 195.
    Thompson, Stacey Lee
    et al.
    Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Sherbrooke Est, Montréal QC H1X 2B2, Canada.
    Lamothe, Manuel
    Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Sherbrooke Est, Montréal QC H1X 2B2, Canada.
    Meirmans, Patrick G
    Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Sherbrooke Est, Montréal QC H1X 2B2, Canada.
    Périnet, Pierre
    Ministère des Ressources naturelles et de la Faune du Québec, 2700 Einstein, Québec, QC G1P 3W8, Canada.
    Isabel, Nathalie
    Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Sherbrooke Est, Montréal QC H1X 2B2, Canada.
    Repeated unidirectional introgression towards Populus balsamifera in contact zones of exotic and native poplars.2010Inngår i: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 19, nr 1, s. 132-145Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As the evolutionary significance of hybridization is largely dictated by its extent beyond the first generation, we broadly surveyed patterns of introgression across a sympatric zone of two native poplars (Populus balsamifera, Populus deltoides) in Quebec, Canada within which European exotic Populus nigra and its hybrids have been extensively planted since the 1800s. Single nucleotide polymorphisms (SNPs) that appeared fixed within each species were characterized by DNA-sequencing pools of pure individuals. Thirty-five of these diagnostic SNPs were employed in a high-throughput assay that genotyped 635 trees of different age classes, sampled from 15 sites with various degrees of anthropogenic disturbance. The degree of admixture within sampled trees was then assessed through Bayesian clustering of genotypes. Hybrids were present in seven of the populations, with 2.4% of all sampled trees showing spontaneous admixture. Sites with hybrids were significantly more disturbed than pure stands, while hybrids comprised both immature juveniles and trees of reproductive age. All three possible F1s were detected. Advanced-generation hybrids were consistently biased towards P. balsamifera regardless of whether hybridization had occurred with P. deltoides or P. nigra. Gene exchange between P. deltoides and P. nigra was not detected beyond the F1 generation; however, detection of a trihybrid demonstrates that even this apparent reproductive isolation does not necessarily result in an evolutionary dead end. Collectively, results demonstrate the natural fertility of hybrid poplars and suggest that introduced genes could potentially affect the genetic integrity of native trees, similar to that arising from introgression between natives.

  • 196.
    Torimaru, Takeshi
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Hirosaki University, Hirosaki, Japan.
    Wennstrom, Ulfstand
    Andersson, Bengt
    Almqvist, Curt
    Wang, Xiao-Ru
    Reduction of pollen contamination in Scots pine seed orchard crop by tent isolation2013Inngår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 28, nr 8, s. 715-723Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study examined the differences in mating system between indoor versus outdoor Scots pine (Pinus sylvestris L.) seed orchard using DNA markers. By analyzing the paternities in seed crops from isolation tents, we found a significant reduction in contamination rate, from 23% in the outdoor open blocks to 0% inside the tents. Increase in selfing rate and a decrease in genetic diversity in the crops were also observed inside the tents. These undesirable effects can be mitigated to some extent by the supplementation of extra pollen genotypes, e.g. selfing rate decreased from 14.4% to 6.6% and the effective number of fathers increased from 6 to 11.4 in the tents without and with supplemental mass pollination, respectively. Our study showed that tent isolation may become an effective rescuer for seed orchards where pollen contamination is severe.

  • 197. Tylewicz, S.
    et al.
    Petterle, A.
    Marttila, S.
    Miskolczi, P.
    Azeez, A.
    Singh, R. K.
    Immanen, J.
    Mähler, Niklas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik.
    Hvidsten, Torgerir R.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
    Eklund, D. M.
    Bowman, J. L.
    Helariutta, Y.
    Bhalerao, R. P.
    Photoperiodic control of seasonal growth is mediated by ABA acting on cell-cell communication2018Inngår i: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 360, nr 6385, s. 212-214Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In temperate and boreal ecosystems, seasonal cycles of growth and dormancy allow perennial plants to adapt to winter conditions. We show, in hybrid aspen trees, that photoperiodic regulation of dormancy is mechanistically distinct from autumnal growth cessation. Dormancy sets in when symplastic intercellular communication through plasmodesmata is blocked by a process dependent on the phytohormone abscisic acid. The communication blockage prevents growth-promoting signals from accessing the meristem. Thus, precocious growth is disallowed during dormancy. The dormant period, which supports robust survival of the aspen tree in winter, is due to loss of access to growth-promoting signals.

  • 198.
    Vidalis, Amaryllis
    et al.
    Department of Forest Genetics and Forest Tree Breeding, University of Göttingen, Göttingen, Germany.
    Curtu, A. L.
    Department of Forest Genetics and Forest Tree Breeding, University of Göttingen, Göttingen, Germany and Department of Forest Sciences, University of Transilvania, Brasov, Romania .
    Finkeldey, R.
    Department of Forest Genetics and Forest Tree Breeding, University of Göttingen, Göttingen, Germany.
    Novel SNP development and analysis at a NADP+ -specific IDH enzyme gene in a four species mixed oak forest2013Inngår i: Plant Biology, ISSN 1435-8603, E-ISSN 1438-8677, Vol. 15, nr Supplement 1, s. 126-137Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Closely related Quercus species generally exhibit low levels of genetic differentiation despite their ecological and morphological differences. However, at a few so-called 'outlier' loci they seem to remain genetically distinct. Isocitrate dehydrogenases (IDH) are key enzymes involved in the metabolic pathway of the citrate cycle. IDH has also been characterised as an 'outlier' marker, significantly differentiating the closely related Q. robur and Q. petraea with the isozyme technique. This ability to differentiate the species was tested here at molecular level: 13 single nucleotide polymorphism (SNP) markers were identified and developed within a NADP(+) -specific IDH gene in Quercus spp. and applied as molecular markers in a four species mixed oak forest in eastern Europe, where Q. robur, Q. petraea, Q. pubescens and Q. frainetto naturally co-exist. From the 13 developed SNPs, three groups were formed: non-synonymous, synonymous and non-coding SNPs. The levels of total gene diversity were moderate for all species investigated. The non-synonymous SNPs showed lower levels of gene diversity. Overall, the four closely related Quercus spp. were significantly differentiated (except Q. petraea with Q. frainetto). Analysis of non-random association of alleles revealed no clear physical clustering of the SNP sites in significant linkage disequilibrium (LD). However, separate LD analysis for each species showed a lower number of sites in significant LD for Q. robur than for the other species, possibly reflecting the history of the species in this specific geographical site and less efficient recombination effect due to the larger effective population size of Q. robur. Eleven statistically significant associations were found between seven SNPs and morphological traits that are commonly used to differentiate oak species.

  • 199. Vincent, Andrea G
    et al.
    Ilstedt, Ulrik
    Vestergren, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Giesler, Reiner
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Persson, Per
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Gröbner, Gerhard
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Schleucher, Jürgen
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Phosphorus in forest soils: disentangling the chemistry of an essential nutrient2013Inngår i: Forest facts, nr 4Artikkel i tidsskrift (Fagfellevurdert)
  • 200. Väisänen, Maria
    et al.
    Martz, Françoise
    Kaarlejärvi, Elina
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Julkunen-Tiitto, Riitta
    Stark, Sari
    Phenolic responses of mountain crowberry (Empetrum nigrum ssp. hermaphroditum) to global climate change are compound specific and depend on grazing by reindeer (Rangifer tarandus)2013Inngår i: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 39, nr 11-12, s. 1390-1399Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Mountain crowberry (Empetrum nigrum ssp. hermaphroditum) is a keystone species in northern ecosystems and exerts important ecosystem-level effects through high concentrations of phenolic metabolites. It has not been investigated how crowberry phenolics will respond to global climate change. In the tundra, grazing by reindeer (Rangifer tarandus) affects vegetation and soil nutrient availability, but almost nothing is known about the interactions between grazing and global climate change on plant phenolics. We performed a factorial warming and fertilization experiment in a tundra ecosystem under light grazing and heavy grazing and analyzed individual foliar phenolics and crowberry abundance. Crowberry was more abundant under light grazing than heavy grazing. Although phenolic concentrations did not differ between grazing intensities, responses of crowberry abundance and phenolic concentrations to warming varied significantly depending on grazing intensity. Under light grazing, warming increased crowberry abundance and the concentration of stilbenes, but decreased e.g., the concentrations of flavonols, condensed tannins, and batatasin-III, resulting in no change in total phenolics. Under heavy grazing, warming did not affect crowberry abundance, and induced a weak but consistent decrease among the different phenolic compound groups, resulting in a net decrease in total phenolics. Our results show that the different phenolic compound groups may show varying or even opposing responses to warming in the tundra at different levels of grazing intensity. Even when plant phenolic concentrations do not directly respond to grazing, grazers may have a key control over plant responses to changes in the abiotic environment, reflecting multiple adaptive purposes of plant phenolics and complex interactions between the biotic and the abiotic factors.

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