Dalarna University's logo and link to the university's website

du.sePublikasjoner
Endre søk
Begrens søket
12 1 - 50 of 64
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1. Ahman, Birgitta
    et al.
    Svensson, Kristin
    Rönnegård, Lars
    Högskolan Dalarna, Akademin Industri och samhälle, Statistik.
    High female mortality resulting in herd collapse in free-ranging domesticated reindeer (Rangifer tarandus tarandus) in Sweden2014Inngår i: PLOS ONE, E-ISSN 1932-6203, Vol. 9, nr 10, artikkel-id e111509Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reindeer herding in Sweden is a form of pastoralism practised by the indigenous Sami population. The economy is mainly based on meat production. Herd size is generally regulated by harvest in order not to overuse grazing ranges and keep a productive herd. Nonetheless, herd growth and room for harvest is currently small in many areas. Negative herd growth and low harvest rate were observed in one of two herds in a reindeer herding community in Central Sweden. The herds (A and B) used the same ranges from April until the autumn gathering in October-December, but were separated on different ranges over winter. Analyses of capture-recapture for 723 adult female reindeer over five years (2007-2012) revealed high annual losses (7.1% and 18.4%, for herd A and B respectively). A continuing decline in the total reindeer number in herd B demonstrated an inability to maintain the herd size in spite of a very small harvest. An estimated breakpoint for when herd size cannot be kept stable confirmed that the observed female mortality rate in herd B represented a state of herd collapse. Lower calving success in herd B compared to A indicated differences in winter foraging conditions. However, we found only minor differences in animal body condition between the herds in autumn. We found no evidence that a lower autumn body mass generally increased the risk for a female of dying from one autumn to the next. We conclude that the prime driver of the on-going collapse of herd B is not high animal density or poor body condition. Accidents or disease seem unlikely as major causes of mortality. Predation, primarily by lynx and wolverine, appears to be the most plausible reason for the high female mortality and state of collapse in the studied reindeer herding community.

    Fulltekst (pdf)
    fulltext
  • 2. Anglart, D
    et al.
    Emanuelson, U
    Rönnegård, Lars
    Högskolan Dalarna, Institutionen för information och teknik, Statistik.
    Sandgren, C Hallén
    Detecting and predicting changes in milk homogeneity using data from automatic milking systems.2021Inngår i: Journal of Dairy Science, ISSN 0022-0302, E-ISSN 1525-3198, Vol. 104, nr 10, s. 11009-11017Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To ensure milk quality and detect cows with signs of mastitis, visual inspection of milk by prestripping quarters before milking is recommended in many countries. An objective method to find milk changed in homogeneity (i.e., with clots) is to use commercially available inline filters to inspect the milk. Due to the required manual labor, this method is not applicable in automatic milking systems (AMS). We investigated the possibility of detecting and predicting changes in milk homogeneity using data generated by AMS. In total, 21,335 quarter-level milk inspections were performed on 5,424 milkings of 624 unique cows on 4 farms by applying visual inspection of inline filters that assembled clots from the separate quarters during milking. Images of the filters with clots were scored for density, resulting in 892 observations with signs of clots for analysis (77% traces or mild cases, 15% moderate cases, and 8% heavy cases). The quarter density scores were combined into 1 score indicating the presence of clots during a single cow milking and into 2 scores summarizing the density scores in cow milkings during a 30-h sampling period. Data generated from the AMS, such as milk yield, milk flow, conductivity, and online somatic cell counts, were used as input to 4 multilayer perceptron models to detect or predict single milkings with clots and to detect milking periods with clots. All models resulted in high specificity (98-100%), showing that the models correctly classified cow milkings or cow milking periods with no clots observed. The ability to successfully classify cow milkings or cow periods with observed clots had a low sensitivity. The highest sensitivity (26%) was obtained by the model that detected clots in a single milking. The prevalence of clots in the data was low (2.4%), which was reflected in the results. The positive predictive value depends on the prevalence and was relatively high, with the highest positive predictive value (72%) reached in the model that detected clots during the 30-h sampling periods. The misclassification rate for cow milkings that included higher-density scores was lower, indicating that the models that detected or predicted clots in a single milking could better distinguish the heavier cases of clots. Using data from AMS to detect and predict changes in milk homogeneity seems to be possible, although the prediction performance for the definitions of clots used in this study was poor.

    Fulltekst (pdf)
    fulltext
  • 3. Anglart, D.
    et al.
    Hallén-Sandgren, C.
    Emanuelson, U.
    Rönnegård, Lars
    Högskolan Dalarna, Akademin Industri och samhälle, Statistik. SLU.
    Comparison of methods for predicting cow composite somatic cell counts2020Inngår i: Journal of Dairy Science, ISSN 0022-0302, E-ISSN 1525-3198, Vol. 103, nr 9, s. 8433-8442Artikkel i tidsskrift (Fagfellevurdert)
    Fulltekst (pdf)
    fulltext
  • 4.
    Berglund, Torkel
    et al.
    Kungliga Tekniska högskolan.
    Borg-Karlsson, Anna Karin
    Kungliga Tekniska högskolan.
    Lindström, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Ohlsson, Anna
    Kunliga Tekniska högskolan.
    Hellqvist, Claes
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Slutrapport, fält- och laboratorietest av substanser för aktivering av det egna försvaret hos gran- och tallplantor2012Rapport (Annet vitenskapelig)
  • 5.
    Berglund, Torkel
    et al.
    KTH.
    Lindström, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Aghelpasand, Hooman
    KTH.
    Stattin, Eva
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Ohlsson, Anna B.
    KTH.
    Protection of spruce seedlings against pine weevil attacks by treatment of seeds or seedlings with nicotinamide, nicotinic acid and jasmonic acid2016Inngår i: Forestry (London), ISSN 0015-752X, E-ISSN 1464-3626, Vol. 89, nr 2, s. 127-135Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

    Fulltekst (pdf)
    fulltext
  • 6.
    Blomberg, Jonas
    Högskolan Dalarna, Akademin Industri och samhälle, Materialteknik.
    Elastic strain at semi-isostatical compression of Scots pine (pinus sylvestris L.)2005Inngår i: Journal of Wood Science, ISSN 1435-0211, E-ISSN 1611-4663, Vol. 51, nr 4, s. 401-404Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Quarter-sawn and plain-sawn specimens of Scots pine were semi-isostatically compressed at 5, 15, 50, and 140MPa in a Quintus press. Elastic strain was measured using a telescope device that was pushed together when wood was compressed and remained in this position at release of pressure. Delayed elastic and plastic strains were assessed through repeated callipering during 5 years after densification. At 140MPa, wood reached an almost compact structure (rho approximate to 1450kg/m(3)) but as a result of elastic springback the density decreased to just below 1000kg/m(3). At 140MPa, the elastic and delayed elastic strains were 14.6% and 1.8%, respectively, in quarter-sawn specimens, and were 13.1% and 0.8%, respectively, in plain-sawn specimens. The higher elastic strains in quarter-sawn specimens can be attributed to elastic springback in the tangentially deformed latewood bands.

  • 7.
    Blomberg, Jonas
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Träteknologi.
    Persson, Bengt
    Högskolan Dalarna, Akademin Industri och samhälle, Träteknologi.
    An algorithm for comparing density in CT-images taken before and after compression of Pinus sylvestris2005Inngår i: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 63, nr 1, s. 23-29Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ten plain-sawn boards of Scots pine (Pinus sylvestris L.) were compressed semi-isostatically according to the CaLignum process in a Quintus press at 25 C and 140 MPa. X-ray computerised tomography images of the same cross-sections were captured before and after compression and compared using a transformation algorithm. In the algorithm the shape of compressed cross-sections were converted to the same shape as non-compressed using the density variation between pixels. Density after compression and the increase in density were analysed using PLS regression. The regressor variables described position in the cross-section and wood properties of each pixel. Heartwood and other resinous wood were less compressed than sapwood, particularly in boards with high resin content. Density also increased little close to the press table, especially in whorls with large knots. Higher original density gives lower degree of compression but still higher density after compression.

  • 8.
    Blomberg, Jonas
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Träteknologi.
    Persson, Bengt
    Högskolan Dalarna, Akademin Industri och samhälle, Träteknologi.
    Plastic deformation in small clear pieces of Scots Pine (Pinus sylvestris L.) during densification with the Calignum® process2004Inngår i: Journal of Wood Science, ISSN 1435-0211, E-ISSN 1611-4663, Vol. 50, nr 4, s. 307-314Artikkel i tidsskrift (Fagfellevurdert)
  • 9.
    Blomberg, Jonas
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Persson, Bengt
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Swelling pressure of semi-isostatically densified wood under different mechanical restraints2007Inngår i: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 41, nr 5, s. 401-415Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Semi-isostatically densified and native wood samples of Scots pine and European birch were soaked in water. The swelling coefficients as well as the swelling pressure, that arose when the specimens were restrained in some way prior to the swelling, were measured using a universal testing machine equipped with a high resolution load-cell and an external extensometer. As densified wood swells, the native structure is almost restored and the swelling pressure became twice as high as for native wood in the most compressed directions (radial for pine and birch). That cell-shape recovery increases the swelling pressure can explain the problems with imbalance in laminated constructions where densified wood is used. The possibility to predict the swelling pressure from basic material properties was evaluated. The correlations between swelling pressure and material properties were strong enough to yield good predictive models.

  • 10. Boonstra, M. J.
    et al.
    Blomberg, Jonas
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Semi-isostatic densification of heat-treated radiata pine2007Inngår i: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 41, nr 7, s. 607-617Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Semi-isostatic densification is a useful method to increase the density and to improve the mechanical properties of fast-grown softwood species like radiata pine. A major disadvantage of this method is the almost complete recovery of the original dimensions when densified wood is exposed to moisture. Heat treatment improves the dimensional stability of wood and might be a useful method to prevent this shape-recovery after densification. However, no or only a limited effect on the shape-recovery was found when densified radiata pine was exposed to moisture.

  • 11. Brännström, Mattias
    et al.
    Westin, Jerker
    Högskolan Dalarna, Akademin Industri och samhälle, Datateknik.
    Classification of structural timber by decision trees: a comparison to the certified method2009Inngår i: Forest Products Journal, ISSN 0015-7473, Vol. 59, nr 3, s. 53-61Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work is an example of how to adapt a classification method, in this case a classification tree, to the present standardized method for the development of settings for strength grading machines. Data from commercially available industrial strength grading equipment were used on a large sample (approximately 1440 pieces) of Norway spruce (Picea abies (L. Karsten)) in various sawn dimensions. The equipment is a multisensor scanning device combining planar X-ray and resonance frequency measurement. Destructive testing was done according to European standard EN408. The goal was to make the classification, based on machine data, as close as possible to the optimum grading, which was done according to standard. Two different approaches for classification by cost-sensitive decision trees were applied to the data and compared to classification accredited according to EN14081. Classification accuracy increased from 64% correctly classified to 73%, and a reduction from 33% False Negative to 23% was achieved. False Positive increased from 3% to 4%. The outcome was an increase in value for the producer by 0.9%–2.1% at 2007 average price level. The improvement came mainly from an in-yield increase in C30 by 10%.

  • 12.
    Chiatante, Donato
    et al.
    Università degli Studi dell'Insubria.
    Radoglou, Kalliopi
    Democritus University of Thrace.
    Sismanis, Nikos
    Democritus University of Thrace.
    Smirnakou, Sonia
    Democritus University of Thrace.
    Mattsson, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Hernandez Velasco, Marco
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Schirone, Bartolomeo
    Universita degli Studi della Tuscia.
    Marras, Tatiana
    Universita degli Studi della Tuscia.
    Mechilli, Manuela
    Universita degli Studi della Tuscia.
    Ortolani, Maria Raffaella
    Universita degli Studi della Tuscia.
    Vessella, Federico
    Universita degli Studi della Tuscia.
    Terzaghi, Mattia
    Università degli Studi dell'Insubria.
    Fulgaro, Nicoletta
    Università degli Studi dell'Insubria.
    Montagnoli, Antonio
    Università degli Studi dell'Insubria.
    Càtia, Freitas
    Azorina S.A.
    Pietrzak, Malgorzata
    Azorina S.A.
    Casimiro, Pedro
    Azorina S.A.
    Ferreira, Raquel
    Azorina S.A.
    ZEPHYR Project – Deliverable D3.3: Final report on growth tests and biological validation2015Rapport (Annet vitenskapelig)
  • 13.
    Conti, Eugenio
    Högskolan Dalarna, Institutionen för kultur och samhälle, Turismvetenskap.
    Guides as Forest Experience Co-creators: Lessons Learned at Fulufjället National Park, Sweden2021Inngår i: Managing Visitor Experiences in Nature-based Tourism / [ed] J. Albrecht, CABI Publishing, 2021Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    This chapter explores the role of tour guides as human experience brokers of naturalness in forest areas. After outlining conceptual discussions around the role and tasks of the guide as experience broker, empirical findings from Fulufjället National Park (Sweden) are presented, showing the guide as a pivotal forest experience co-creator. Implications are discussed, with particular emphasis on how the guide's personal valuations of the forest, background and personal aims are reflected in the guide's pathfinding, storytelling and staging strategies, and on how tourists are positively impacted by unexpected and different ways of valuing, mapping and interpreting the forest landscape.

    Fulltekst (pdf)
    fulltext
  • 14.
    Derakhshan, Reza
    et al.
    Högskolan Dalarna, Institutionen för information och teknik.
    Yousefzadeh Boroujeni, Soroush
    Högskolan Dalarna, Institutionen för information och teknik.
    Body Rumen Fill Scoring of Dairy Cows Using Digital Images2024Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The research presented in this thesis focuses on an innovative use of digital imaging, and the machine learning techniques to assess the body rumen fill scoring in dairy cows. This study aims to enhance the efficiency of monitoring and managing dairy cow health, which is crucial for the dairy industry's productivity and sustainability.

    The primary objective was to develop an automated annotation system fore valuating rumen fill status in dairy cows using digital images extracted from recorded videos. This system leverages advanced machine learning algorithms and neural networks, aiming to mimic manual assessments by veterinarians and specialists on farms. To achieve the above objectives, this thesis made use of already existing video records from a Swedish dairy farm hosting mainly the Swedish Redand the Swedish Holstein breeds. A subset of these images were then processed, manually classified using a modified rumen fill scoring system based on visual assessment, and supervised classification algorithms were trained on 277 manually annotated images.

    The thesis explored various machine learning techniques for classifying these images, including Logistic Regression, Support Vector Machine (SVM), and a Deep Neural Network using the VGG16 architecture. These models were trained, validated, and tested with a dataset that included variations in cow color patterns, aiming to determine the most effective approach for automated rumen fill scoring.The results indicated that while each model had its strengths and weaknesses, the simple logistic model was performing the best in terms of test accuracy and F1 score.

    This research contributes to the field of precision livestock farming, particularly in the context of dairy farming. By automating the process of rumen fill scoring, the study aims to provide dairy farmers with a reliable, efficient, and cost-effective tool for monitoring cow health. This tool has the potential to enhance dairy cow welfare, improve milk production, and support the sustainability of dairy farming operations. However, at the current state, the model accuracy of the best model was only moderate. There is a need for further improvement of the prediction performance possibly by adding more cow images, using improved image processing, and feature engineering.

    Fulltekst (pdf)
    fulltext
  • 15. Fedderwitz, F.
    et al.
    Björklund, N.
    Anngren, R.
    Lindström, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Nordlander, G.
    Can methyl jasmonate treatment of conifer seedlings be used as a tool to stop height growth in nursery forest trees?2020Inngår i: New forests, ISSN 0169-4286, E-ISSN 1573-5095, Vol. 51, s. 379-394Artikkel i tidsskrift (Fagfellevurdert)
    Fulltekst (pdf)
    fulltext
  • 16.
    Felleki, Majbritt
    Högskolan Dalarna, Akademin Industri och samhälle, Statistik. Swedish University of Agricultural Sciences.
    Genetic Heteroscedasticity for Domestic Animal Traits2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Animal traits differ not only in mean, but also in variation around the mean. For instance, one sire’s daughter group may be very homogeneous, while another sire’s daughters are much more heterogeneous in performance. The difference in residual variance can partially be explained by genetic differences. Models for such genetic heterogeneity of environmental variance include genetic effects for the mean and residual variance, and a correlation between the genetic effects for the mean and residual variance to measure how the residual variance might vary with the mean.

    The aim of this thesis was to develop a method based on double hierarchical generalized linear models for estimating genetic heteroscedasticity, and to apply it on four traits in two domestic animal species; teat count and litter size in pigs, and milk production and somatic cell count in dairy cows.

    The method developed is fast and has been implemented in software that is widely used in animal breeding, which makes it convenient to use. It is based on an approximation of double hierarchical generalized linear models by normal distributions. When having repeated observations on individuals or genetic groups, the estimates were found to be unbiased.

    For the traits studied, the estimated heritability values for the mean and the residual variance, and the genetic coefficients of variation, were found in the usual ranges reported. The genetic correlation between mean and residual variance was estimated for the pig traits only, and was found to be favorable for litter size, but unfavorable for teat count.

    Fulltekst (pdf)
    Kappa of thesis
  • 17.
    Felleki, Majbritt
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Statistik.
    Lee, Dongwhan
    Department of Statistics, Seoul National University, Seoul 151-747, Korea .
    Lee, Youngjo
    Department of Statistics, Seoul National University, Seoul 151-747, Korea .
    Gilmour, Arthur R.
    School of Mathematics and Applied Statistics, Faculty of Informatics, University of Wollongong, Wollongong, NSW 2522, Australia.
    Rönnegård, Lars
    Högskolan Dalarna, Akademin Industri och samhälle, Statistik.
    Estimation of breeding values for mean and dispersion, their variance and correlation using double hierarchical generalized linear models2012Inngår i: Genetics Research, ISSN 0016-6723, Vol. 94, nr 6, s. 307-317Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The possibility of breeding for uniform individuals by selecting animals expressing a small response to environment has been studied extensively in animal breeding. Bayesian methods for fitting models with genetic components in the residual variance have been developed for this purpose, but have limitations due to the computational demands. We use the hierarchical (h)-likelihood from the theory of double hierarchical generalized linear models (DHGLM) to derive an estimation algorithm that is computationally feasible for large datasets. Random effects for both the mean and residual variance parts of the model are estimated together with their variance/covariance components. An important feature of the algorithm is that it can fit a correlation between the random effects for mean and variance. An h-likelihood estimator is implemented in the R software and an iterative reweighted least square (IRWLS) approximation of the h-likelihood is implemented using ASReml. The difference in variance component estimates between the two implementations is investigated, as well as the potential bias of the methods, using simulations. IRWLS gives the same results as h-likelihood in simple cases with no severe indication of bias. For more complex cases, only IRWLS could be used, and bias did appear. The IRWLS is applied on the pig litter size data previously analysed by Sorensen & Waagepetersen (2003) using Bayesian methodology. The estimates we obtained by using IRWLS are similar to theirs, with the estimated correlation between the random genetic effects being −0·52 for IRWLS and −0·62 in Sorensen & Waagepetersen (2003).

  • 18.
    Felleki, Majbritt
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Statistik. Sveriges Lantbruksuniversitet.
    Lundeheim, Nils
    Sveriges Lantbruksuniversitet.
    Genetic Control of Residual Variance for Teat Number in Pigs2013Inngår i: Proc. Assoc. Advmt. Anim. Breed. Genet., AAABG , 2013, s. 538-541Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The genetic improvement in litter size in pigs has been substantial during the last 10-15 years. The number of teats on the sow must increase as well to meet the needs of the piglets, because each piglet needs access to its own teat. We applied a genetic heterogeneity model on teat numberin sows, and estimated medium-high heritability for teat number (0.5), but low heritability for residual variance (0.05), indicating that selection for reduced variance might have very limited effect. A numerically positive correlation (0.8) between additive genetic breeding values for mean and for variance was found, but because of the low heritability for residual variance, the variance will increase very slowly with the mean.

    Fulltekst (pdf)
    Genetic Control of Residual Variance for Teat Number in Pigs
  • 19.
    Felleki, Majbritt
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Statistik.
    Lundeheim, Nils
    Sveriges lantbruksuniversitet, Institutionen för husdjursgenetik.
    Genetic Heteroscedasticity for Teat Count in PigsManuskript (preprint) (Annet vitenskapelig)
  • 20.
    Felleki, Majbritt
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Statistik.
    Lundeheim, Nils
    SLU.
    Genetic heteroscedasticity of teat count in pigs2015Inngår i: Journal of Animal Breeding and Genetics, ISSN 0931-2668, E-ISSN 1439-0388, Vol. 132, nr 5, s. 392-398Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The genetic improvement in pig litter size has been substantial. The number of teats on the sowmust thus increase as well to meet the needs of the piglets, because each piglet needs access to itsown teat. We applied a genetic heterogeneity model to teat counts in pigs, and estimated a mediumheritability for teat counts (0.35), but found a low heritability for residual variance (0.06),indicating that selection for reduced residual variance might have a limited effect. A numericallypositive correlation (0.8) was estimated between the breeding values for the mean and the residualvariance. However, because of the low heritability of the residual variance, the residual variance will probably increase very slowly with the mean.

  • 21.
    Gullberg, Tomas
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Företagsekonomi.
    Johansson, Jerry
    Högskolan Dalarna, Akademin Industri och samhälle, Företagsekonomi.
    A method for integrated extraction of logging residues and soil scarification on a small scale2006Inngår i: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 30, nr 12, s. 1035-1042Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new method for integrated haulage of logging residues and soil scarification on a small-scale has been evaluated. The base machine was a farm tractor to which a grapple loader trailer was attached. The grapple loader had an attachment on the grapple used for the integrated recovery of forest energy from logging residues and soil scarification. The machine was in this case, when hauling the logging residues fresh, also used for hauling round wood. It may even be used for, e.g. spreading wood ashes (only simulated). Conventional machine systems with special machines for all four types of work result in very high fixed costs for moving, etc. which makes cost unacceptable for many small sites. Effective time per dry ton of logging residues was 28.4min in the integrated method, of which soil scarification was 14.3min. Average load size was about 1.3ton dry matter (about 2.9m3 solid). The soil scarification plots covered 12% of the surface. Cost calculations show that the integration of several activities results in substantially lower costs for small harvesting sites. For sites of about 1.5ha the cost is about the same as for conventional machines. The studied method creates new possibilities for self-employed forest owners to do the work themselves and, in case of lower personal cost and no moving cost, reduce cost further.

  • 22. Hallén Sandgren, C
    et al.
    Anglart, D
    Klaas, I C
    Rönnegård, Lars
    Högskolan Dalarna, Institutionen för information och teknik, Statistik.
    Emanuelson, U
    Homogeneity density scores of quarter milk in automatic milking systems.2021Inngår i: Journal of Dairy Science, ISSN 0022-0302, E-ISSN 1525-3198, Vol. 104, nr 9, s. 10121-10130Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Milk quality and clinical mastitis in dairy cows are monitored by detecting visually abnormal milk. A standardized method to evaluate clots in milk and studies of the incidence and dynamics of clots in milk at the quarter level are lacking. We validated a method to score clot density in quarter milk samples and describe the prevalence and dynamics of the density scores between consecutive samplings and periods in 4 farms with automatic milking systems. Using in-line filters, we collected quarter milk samples at each milking during 3 periods of 30 h each in each farm. Clot density was scored based on coverage of the filter area as 0 (negative), 1 (trace), 2 (mild), 3 (moderate), 4 (heavy), and 5 (very heavy). The score for a specific quarter and milking is referred to as the quarter milking score (QMS). Three assessors independently scored 902 images of filter samples with a Fleiss kappa value of 0.72. In total, 21,202 quarter milk samples from 5,398 milkings of 621 cows were collected. Of the quarter filter samples, 2.4% had visible clots, distributed as mild (1.4%), moderate (0.6%), heavy (0.3%), and very heavy (<0.1%, n = 8). Cases with a cow period sum of QMS ≥ 4, corresponding to 9.4% of all periods, harbored 86% and 94% of all QMS of 2 to 5 and 3 to 5, respectively. Of these cases, cows sampled in all 3 periods and clots in only 1 period had a quarter period sum score ≥ 1 in 1.8 different quarters in average. Corresponding numbers for the cows with clots or traces in 2 or 3 periods were 2.2 and 2.5 different quarters, respectively. A QMS of 2 to 5 in the preceding milking increased the chance of a QMS >1 in the following milking, with an average chance of 38%. The probability of a QMS > 1 increased with increasing previous QMS, a higher sum of QMS during the milking period, longer milking interval, and higher lactation number, but decreased with increasing days in milk. Our study showed that the method of clot-density scoring is feasible to perform and reproducible for investigating the occurrence and dynamics of clots in milk. Elevated clot-density scores clustered within certain cows and cow periods and appeared in new quarters of the cows over time. The low recurrence of QMS of 1 and 2 within quarters indicated that QMS 3 could be a reasonable threshold for detecting quarters with abnormal milk that require further attention.

    Fulltekst (pdf)
    fulltext
  • 23.
    Hansson, I
    et al.
    Swedish University of Agricultural Sciences, Uppsala.
    Silvera, A
    Swedish University of Agricultural Sciences, Uppsala.
    Ren, K
    Swedish University of Agricultural Sciences, Uppsala.
    Woudstra, S
    University of Copenhagen, Frederiksberg, Denmark.
    Skarin, A
    Swedish University of Agricultural Sciences, Uppsala.
    Fikse, W F
    Swedish University of Agricultural Sciences, Uppsala.
    Nielsen, P P
    RISE Research Institute of Sweden, Lund.
    Rönnegård, Lars
    Högskolan Dalarna, Institutionen för information och teknik, Statistik. Swedish University of Agricultural Sciences, Uppsala.
    Cow characteristics associated with the variation in number of contacts between dairy cows2023Inngår i: Journal of Dairy Science, ISSN 0022-0302, E-ISSN 1525-3198, Vol. 106, nr 4, s. 2685-2699Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In modern freestall barns where large groups of cows are housed together, the behavior displayed by herd mates can influence the welfare and production of other individuals. Therefore, understanding social interactions in groups of dairy cows is important to enhance herd management and optimize the outcomes of both animal health and welfare in the future. Many factors can affect the number of social contacts in a group. This study aimed to identify which characteristics of a cow are associated with the number of contacts it has with other group members in 2 different functional areas (feeding and resting area) to increase our understanding of the social behavior of dairy cows. Inside 2 herds housed in freestall barns with around 200 lactating cows each, cow positions were recorded with an ultra-wideband real-time location system collecting all cows' positions every second over 2 wk. Using the positioning data of the cows, we quantified the number of contacts between them, assuming that cows spending time in proximity to one another (within a distance of 2.5 m for at least 10 min per day) were interacting socially. We documented in which barn areas these interactions occurred and used linear mixed models to investigate if lactation stage, parity, breed, pregnancy status, estrus, udder health, and claw health affect the number of contacts. We found variation in the number of contacts a cow had between individuals in both functional areas. Cows in later lactation had more contacts in the feeding area than cows in early lactation. Furthermore, in one herd, higher parity cows had fewer contacts in the feeding area than first parity cows, and in the other herd, cows in third parity or higher had more contacts in the resting area. This study indicates that cow characteristics such as parity and days in milk are associated with the number of contacts a cow has daily to its herd mates and provides useful information for further research on social interactions of dairy cows.

    Fulltekst (pdf)
    fulltext
  • 24.
    Hernandez Velasco, Marco
    Högskolan Dalarna, Institutionen för information och teknik, Energiteknik.
    Enabling Year-Round Cultivation in the Nordics-Agrivoltaics and Adaptive LED Lighting Control of Daily Light Integral2021Inngår i: Agriculture, E-ISSN 2077-0472, Vol. 11, nr 12, s. 1255-1255Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High efficacy LED lamps combined with adaptive lighting control and greenhouse integrated photovoltaics (PV) could enable the concept of year-round cultivation. This concept can be especially useful for increasing the production in the Nordic countries of crops like herbaceous perennials, forest seedlings, and other potted plants not native of the region, which are grown more than one season in this harsh climate. Meteorological satellite data of this region was analyzed in a parametric study to evaluate the potential of these technologies. The generated maps showed monthly average temperatures fluctuating from −20 °C to 20 °C throughout the year. The natural photoperiod and light intensity also changed drastically, resulting in monthly average daily light integral (DLI) levels ranging from 45–50 mol·m−2·d−1 in summer and contrasting with 0–5 mol·m−2·d−1 during winter. To compensate, growth room cultivation that is independent of outdoor conditions could be used in winter. Depending on the efficacy of the lamps, the electricity required for sole-source lighting at an intensity of 300 µmol·m−2·s−1 for 16 h would be between 1.4 and 2.4 kWh·m−2·d−1. Greenhouses with supplementary lighting could help start the cultivation earlier in spring and extend it further into autumn. The energy required for lighting highly depends on several factors such as the natural light transmittance, the light threshold settings, and the lighting control protocol, resulting in electric demands between 0.6 and 2.4 kWh·m−2·d−1. Integrating PV on the roof or wall structures of the greenhouse could offset some of this electricity, with specific energy yields ranging from 400 to 1120 kWh·kW−1·yr−1 depending on the region and system design.

    Fulltekst (pdf)
    fulltext
  • 25.
    Hernandez Velasco, Marco
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Treatments for induction of cold hardiness in Picea abies (L.) Karst. and Pinus sylvestris L. seedlings pre-cultivated under light-emitting diodes–impact of photoperiod and temperature including energy consumption and seedling quality after cold storage2020Inngår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 35, nr 1-2, s. 46-58Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In Nordic climates, the weather allows a narrow time window during spring and summer for forest seedlings to be transplanted from indoor growth to outdoor conditions. If a new method for year-round cultivation under LED lamps is to be successfully introduced in forest nurseries, a cold storage phase for batches produced outside of the vegetation period needs to be included in the concept. Different short-day treatments for induction of cold hardiness in very young seedlings of Picea abies and Pinus sylvestris cultivated solely under LED lamps were investigated. The study compared a combination of two photoperiods (5 h or 8 h) at three different temperatures (5°C, 10°C or 20°C) applied during five weeks. Chlorophyll fluorescence, shoot electrolyte leakage and molecular testing for gene expression of cold acclimation were used to assess the treatments. After a period of three months in cold storage at 2°C, the vitality of the seedlings was evaluated using a root growth capacity test. Lower temperatures during the treatments, especially for Pinus sylvestris, had a significant effect on inducing cold hardiness. The results showed that the photoperiod should not be overly reduced to allow photosynthesis and generation of carbohydrate reserves but it could be optimized to reduce electricity consumption. © 2020, © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

    Fulltekst (pdf)
    fulltext
  • 26.
    Hernandez Velasco, Marco
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Kotilainen, Titta
    Valoya Ltd.
    New technology for pre-cultivation of forest seedlings under LED lamps – modification of light conditions to mitigate light shock stress after transplanting to open land2014Inngår i: 2nd Restoring Forests Conference Abstracts, 2014Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Forest restoration aims to cope with the increasing demand on forest products, as well as an aid in fighting climate change and compensating for accelerated deforestation. Funded by the European Commission under the Seventh Framework Program (FP7), the Zephyr project aims to introduce a zero-impact incubator for the pre-cultivation of forest regeneration materials. The consortium, involving 14 organizations of 10 different European countries, is developing innovative and cost-efficient technologies that will allow the production of standardized high quality forest seedlings ready to be transplanted. The technologies will be integrated into a functional and transportable unit not affected by the outdoor conditions and producing minimal emissions. To achieve this, the system will be powered mainly by solar energy and will recycle the water used. Specifically developed devices such as wireless sensors and LED lamps will be used to monitor and enhance the cultivation process, reduce the energy consumption and decrease the overall cost due to their high efficiency, long lifetime and low maintenance.

    The LED grow lights used have a continuous spectrum that has been selected and specifically tailored to the plants’ needs. Nevertheless, seedlings pre-cultivated under LED lights could face UV stress after transplanting to open land as these wavelengths are not included in the light spectrum used in the growth chamber. Moreover, light intensity levels during indoor cultivation are usually much lower compared to the outdoor conditions, which can cause a light shock to the plants. Juvenile plants are less efficient in the utilization of the absorbed light, and therefore, prone to photoinhibition by radiation fluxes that usually do not harm mature plants. Plant protective mechanisms against UV radiation and high PAR (400-700nm) light intensity are partly overlapping. Hence, exposure to UV or high light intensity before transplanting, or introducing a transient phase by using shading cloths during transplantation period could help to reduce this stress.

    The aim was to reduce the transplanting stress of Picea abies and Pinus sylvestris seedlings grown under LED-lamps for the first 5 weeks of cultivation. We investigated how different methods; UV-A pre-treatment or high irradiance during the indoor cultivation or usage of shading cloths for the first week(s) after transplanting outdoors can be used to mitigate light shock stress. Different methods and exposure times showed varying ability in ensuring good seedling growth and survival.

  • 27.
    Hernandez Velasco, Marco
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Mattsson, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    A silvicultural practice to facilitate forest restoration: a new seedling cultivation technology for regeneration establishment2014Inngår i: The International Forestry Review Vol.16 (5), 2014 / [ed] John A. Parrotta, Cynthia F. Moser, Amy J. Scherzer, Nancy E. Koerth and Daryl R. Lederle, The Commonwealth Forestry Association, www.cfa-international.org , 2014, Vol. 16, nr 5, s. 129-Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Forest restoration has become a primary task, not only to cope with an increasing demand on forest products, but also to fi ghtclimate change and compensate for an accelerated global deforestation. However, many of the current practices used in forestrynurseries to produce forest planting stock have adverse effects on the environment. The main objective of the ZEPHYR project,funded by the European Commission under the Seventh Framework Programme (FP7), is to develop an innovative zero-impacttechnology for the pre-cultivation of forest regeneration materials that is not affected by the outdoor climate. Among the maincomponents to be improved are artifi cial lighting sources used for cultivation. Traditional fl uorescence lamps are to be replacedby LED grow lights with spectra tailored to the seedlings’ needs. The present work investigates biological responses of Piceaabies and Pinus sylvestris to six different light spectra. The pre-cultivation has been done following standard growth protocolsduring 5 weeks with a photoperiod of 16 h at 100 μmol/m2/s. This has been done under controlled closed conditions with a roomtemperature of 20 °C and a relative humidity of 60%. The analyses have shown clear differences among the treatments and theiradapting capacity when transplanted.

  • 28.
    Hernandez Velasco, Marco
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Mattsson, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Cultivation of forest regeneration materials under artificial radiant sources—effects of light intensity on energy consumptionand seedling development2014Inngår i: The International Forestry Review Vol.16 (5), 2014 / [ed] John A. Parrotta, Cynthia F. Moser, Amy J. Scherzer, Nancy E. Koerth and Daryl R. Lederle, 2014, Vol. 16, nr 5, s. 300-300Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In times of major environmental challenges and increasing demand for forest products, planted forests have acknowledgedadvantages compared to other land uses. Despite not being able to completely take the place of natural forests, planted ones have,if properly managed, great potential to contribute in addressing these problems. Besides the ecological benefi ts such as carbonsequestration, planted forests can help meet the demand for wood products without further depletion of the natural forest. Forestrestoration, rehabilitation, and reforestation are limited by the capacity for producing forest regeneration materials. Often, asproduction is intensifi ed at forest nurseries, the practices begin to have an adverse impact on the environment and stop being trulysustainable. One of the main issues in nurseries is the energy consumption for grow lights during periods of short daylight.By using high-effi ciency LED grow lamps and adjusting the light intensity, this study aimed to reduce the energy consumptionfrom lighting per seedling without compromising seedling development. The precultivation of Picea abies and Pinus sylvestrisseedlings was done during 5 weeks under controlled conditions at 20 °C and a relative humidity of 60%. The photoperiod was16 hours at an intensity ranging from 50 to 350 μmol/m2/s in intervals of 50 μmol/m2/s intervals.

  • 29.
    Hernandez Velasco, Marco
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Mattsson, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Energy efficiency in intensified production of forest regeneration materials – design of a photovoltaic system for sustainably powering an innovative forestry incubator2014Inngår i: The International Forestry Review Vol.16 (5), 2014 / [ed] John A. Parrotta, Cynthia F. Moser, Amy J. Scherzer, Nancy E. Koerth and Daryl R. Lederle, 2014, Vol. 16, nr 5, s. 393-393Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Planted forests can contribute addressing problems of global concern such as climate change mitigation, biodiversity lost and pressure on ecosystems due to high demand of forestry products. However, in order to be able to profit from these benefits sustainably, production rates of forest regeneration materials should be higher than the harvesting rates. Nevertheless, intensive production methods often bring along adverse consequences for the environment. In the frame of the ZEPHYR project, funded by the European Commission under the Seventh Framework Programme (FP7), innovative and cost-friendly technologies for the pre-cultivation are being developed. They will be integrated into a functional and transportable system for a large scale production of seedlings, with zero-impact on the environment and not affected by outdoor conditions. To achieve this, high efficiency devices with low energy consumption will be used and the incubator will be powered by solar energy. This work aims to present the efforts made to reduce the energy loads and optimize the photovoltaic (PV) system. The power system will also be capable of connecting to the electricity grid, using a diesel generator as a back-up, and a battery bank with at least one day of autonomy (up to 7 kWh/day) in central European latitudes.   

  • 30.
    Hernandez Velasco, Marco
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. Uppsala Universitet.
    Mattsson, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Light shock stress after outdoor sunlight exposure in seedlings of picea abies (L.) Karst. and Pinus sylvestris L. pre-cultivated under LEDs-possible mitigation treatments and their energy consumption2020Inngår i: Forests, E-ISSN 1999-4907, Vol. 11, nr 3, artikkel-id 354Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Year-round cultivation under light emitting diodes (LEDs) has gained interest in boreal forest regions like Fenno-Scandinavia. This concept offers forest nurseries an option to increase seedling production normally restricted by the short vegetation period and the climate conditions. In contrast to some horticultural crops which can be cultivated entirely under LEDs without sunlight, forest seedlings need to be transplanted outdoors in the nursery at a very young age before being outplanted in the field. Juvenile plants are less efficient using absorbed light and dissipating excess energy making them prone to photoinhibition at conditions that usually do not harm mature plants. The outdoor transfer can cause stress in the seedlings due to high sunlight intensity and exposure to ultraviolet (UV) radiation not typically present in the spectra of LED lamps. This study tested possible treatments for mitigating light shock stress in seedlings of Picea abies (L.) Karst. and Pinus sylvestris L. transplanted from indoor cultivation under LEDs to outdoor sunlight exposure. Three sowings were carried out in 2014 (May and June) and 2015 (May) cultivating the seedlings during five weeks under LED lights only. Afterwards, higher light intensity or UV radiation treatments were applied during one week in order to adapt the seedlings to natural outdoor conditions. After transplanting a transition phase was introduced using shading cloths for one or three weeks as outdoor treatments for light shock mitigation. Chlorophyll fluorescence (ChlF) levels and CO2 assimilation rates were measured before transplanting and followed outdoors during 5 weeks. The ChlF results revealed stress symptoms in the photoreceptors during the first days after transplanting. After five weeks outdoors the ChlF levels had recovered and the light saturation points had shifted, allowing higher CO2 assimilation rates. By the end of the vegetation period the morphological attributes showed no major differences between treatments. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

    Fulltekst (pdf)
    fulltext
  • 31.
    Hernandez Velasco, Marco
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Mattsson, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Long night treatment for induction of cold hardiness using artificial lights: effects of photoperiod on seedling storabilityand energy consumption2014Inngår i: The International Forestry Review Vol.16 (5), 2014 / [ed] John A. Parrotta, Cynthia F. Moser, Amy J. Scherzer, Nancy E. Koerth and Daryl R. Lederle, 2014, Vol. 16, nr 5, s. 379-379Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Human-assisted forest regeneration in Nordic climates is considerably limited by the harsh outdoor conditions. There is onlya small open window of time during the summer when the weather is favorable for transplantation and establishment ofpre-cultivated seedlings in open land. Greenhouses and modern growth chambers help to cope with this limitation by allowingyear-round seedling cultivation. Nonetheless, production levels are constrained to the cold storage capacity during the nontransplantingseason. This storage is in turn dependent on the ability of the conifer to adapt to freezing temperatures and withstand theoverall stress associated with cold hardening. Long night treatments can induce dormancy with cessation of growth and terminalbuds initiation, leading to a better cold resistance. When growing forest regeneration materials under artifi cial lights, the lengthsof the long night treatment and the photoperiod will have a signifi cant impact not only on the biological response of the seedlingsbut also on the energy consumption, and thus on the CO2 emissions. The aim of this work was to explore different long nighttreatment regimes for induction of cold hardiness in Picea abies and Pinus sylvestris seedlings using artifi cial lights. This wasdone with the purpose of studying the relationship between the energy consumption and the biological responses.

  • 32.
    Hernandez Velasco, Marco
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Mattsson, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Nuevas tecnologías para el pre-cultivo de plantas forestales - diseño de una incubadora sustentable para minimizar el impacto ambiental2014Inngår i: VI Congreso Forestal Latinoamericano: Latinoamérica unida en armonia por la sustentabilidad de los recursos forestales, 2014Konferansepaper (Annet vitenskapelig)
    Abstract [es]

    Los bosques plantados pueden contribuir a combatir problemas globales como el cambio climático, la erosión del suelo y la presión en los ecosistemas debido a la alta demanda de productos forestales. Para que este beneficio sea sustentable, la producción del material para la regeneración forestal tiene que ser mayor a la velocidad en que se tala. Las técnicas intensivas en los viveros forestales puede traer efectos adversos al ambiente como el uso de fertilizantes, pesticidas y alto consumo energético de los invernaderos. 

    Financiado por Séptimo Programa de Investigación y Desarrollo de la Unión Europea, el proyecto ZEPHYR está enfocado a desarrollar nuevas tecnologías para el pre-cultivo de plantas forestales de una manera sustentable y económicamente viable. Estas innovaciones estarán integradas en una incubadora transportable y totalmente funcional para la producción a gran escala. El cuarto de crecimiento será independiente de las condiciones exteriores y tendrá un mínimo impacto ambiental. Para lograr esto se usaran aparatos de alta eficiencia y bajo consumo energético como lámparas LED y todo funcionará con un sistema solar fotovoltaico.

  • 33.
    Hernandez Velasco, Marco
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Mattsson, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Outdoor performance of forest seedlings pre-cultivated under artificial lights: effects of the light spectra used for pre-cultivation on the future establishment and development2015Inngår i: Rainforest challenges: Book of abstracts / [ed] Vladan Ivetić and Tatjana Ćirković‐Mitrović , 2015, s. 20-20Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Forest nurseries are essential for producing good quality seedlings, thus being a key element in the reforestation process. With increasing climate change awareness, nursery managers are looking for new tools that can help reduce the effects of their operations on the environment. The ZEPHYR project, funded by the European Commission under the Seventh Framework Programme (FP7), has the objective of finding new alternatives for nurseries by developing innovative zero-impact technologies for forest plant production. Due to their direct relationship to the energy consumption of the nurseries, one of the main elements addressed are the grow lights used for the pre-cultivation. New LED luminaires with a light spectrum tailored to the seedlings’ needs are being studied and compared against the traditional fluorescent lamps. Seedlings of Picea abies and Pinus sylvestris were grown under five different light spectra (one fluorescent and 4 LED) during 5 weeks with a photoperiod of 16 hours at 100 μmol∙m-2∙s-1 and 60% humidity. In order to evaluate if these seedlings were able cope with real field stress conditions, a forest field trial was also designed. The terrain chosen was a typical planting site in mid-Sweden after clear-cutting. Two vegetation periods after the outplanting, the seedlings that were pre-cultivated under the LED lamps have performed at least as well as those that were grown under fluorescent lights. These results show that there is a good  potential for lightning substitution in forestry nurseries.

    Fulltekst (pdf)
    fulltext
  • 34.
    Hernandez Velasco, Marco
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Mattsson, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Swedish experiences and visions on the production of containerized seedlings2016Inngår i: / [ed] Palle Madsen, 2016Konferansepaper (Annet vitenskapelig)
  • 35.
    Hernandez Velasco, Marco
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Pérez-Mora, Nicolás
    University of Balearic Islands and Sampol Ingenieria y Obras.
    Marras, Tatiana
    Universita degli Studi della Tuscia.
    Using Hybrid Solar Photovoltaic + Combined Heat and Power Systems (PV+CHP) to Enable Industrial Scale Indoor Plant Cultivation: a Feasibility Study2016Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    A rapid population growth linked to intensive agriculture has originated several problems such as soil degradation, groundwater depletion, forestland transformation, and eutrophication of aquatic systems. Vertical farming offers an alternative for producing plants indoors in a resources and space efficient manner, reducing leakage of chemicals, optimizing water and land use, and allowing year-round cultivation. Controlled environment agriculture (CEA) also enables urban residents to access locally grown plants that would have otherwise been imported from far away, reducing transport and storage emissions. This comes with a caveat: the energy loads increase to provide artificial illumination and keep an optimal climate. To address this issue, the present work studies the feasibility of using a hybrid photovoltaics and combined heat and power system (PV+CHP) to satisfy the energy demands of an industrial-sized growth room. For this, different European locations and climates have been considered as well as various growth protocols.

  • 36.
    Hernandez Velasco, Marco
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    R Pamidi, Sreenivaasa
    Exergy Ltd..
    The Zephyr concept and the energetic autonomy2014Inngår i: CAFFEINA 2014: Il Futuro e le Radici - The Future and the Roots, 2014Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Currently, forest ecosystems are facing many sustainability problems due to drastic climate changes and extreme exploitation of their resources. Planted forests can contribute to more sustainable practices and help addressing some of these issues. In order to be able to profit from these benefits sustainably, production rates of forest regeneration materials should be higher than the harvesting rates. Nevertheless, intensive production methods often bring along adverse consequences for the environment.

    At the moment, there exist several options such as greenhouses or plant growth chambers that allow producing forest materials more rapidly. Unfortunately these systems consume considerable high amounts of energy for lighting, acclimatization and irrigation having a negative impact on the environment.

    The Zephyr project aims to introduce an innovative technology built on pre-cultivation of forest regeneration materials in a zero-impact and cost-friendly production unit. The project will integrate several technologies into a functional and transportable system for large scale production of pre-cultivated forest regeneration materials adapted to transplanting and further growth at forest nurseries.

    A transportable and closed incubator independent from the outdoor climate provides a better control on the seedlings production. The plants can be produced directly at the place where they are needed avoiding further transportation to the reforestation/afforestation zone. The closed-climate allows seedlings pre-cultivation in places where it would not be possible otherwise (e.g. near deserts). Additionally, it extends the production time throughout the whole year even during the winter. Moreover, it will allow a certified and standardized production of reforestation materials, with a noticeable increasing of the efficiency of the reforestation operations.

    Specially developed LED growth lamps and wireless sensors will be used to reduce energy consumption and monitor the cultivation process. The main part of the energy will be provided by solar PV-panels, depending from the geographic and climatic area the power system should be able to provide at least one day of autonomy (in central Europe). The energy savings will result in a reduction of greenhouse gas emissions; moreover, since the LED lamps do not produce additional warming, there will be further energy saving through the reduction of air conditioning costs.

    The PV system is designed based on the load specifications of the different subsystems involved for advanced state-of-art pre-cultivation of forest seedlings. It will be further evaluated based on the changes in the load profiles as the growth protocols for different species are defined.  The main objectives are to maximize the power/energy flow delivered to the load and to investigate feasible options for an external backup power source whilst considering options to reduce the overall load of the system.

  • 37. Hogberg, Karl-Anders
    et al.
    Persson, Bengt
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Hallingback, Henrik R.
    Jansson, Gunnar
    Relationships between early assessments of stem and branch properties and sawn timber traits in a Pinus sylvestris progeny trial2010Inngår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 25, nr 5, s. 421-431Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A sample of 162 trees was harvested from a 36-year-old Scots pine (Pinus sylvestris L.) progeny trial to evaluate correlations between early measurements of branch diameter, and other stem and branch traits, with sawn timber traits, and hence their potential utility for predicting wood quality. The sample trees were assigned to three genetic groups of small, medium and large branch diameter, based on parental breeding values. Bottom logs were cut and sawn, and several important traits for the visual quality of the boards were assessed. Phenotypic correlations were then estimated between these traits and measurements of the height, diameter, branch diameter, branch angle, stem crookedness, number of branches and grain angle under bark of the corresponding trees when they were 16 and 36 years old. The diameter of the coarsest knot in the board was correlated with the branch diameter at the age of 16 years (0.50), and there were significant differences in this trait among the genetic branch diameter groups. In addition, the board twist was correlated with the grain angle under bark at the age of 36 years (0.54). Thus, the field assessments of branch diameter and grain angle under bark show relevance for the visual quality of centrally sawn small timber.

  • 38.
    Jonsdottir, Rakel J.
    et al.
    Norðurlandsskógar, Krókeyri, IS-600, Akureyri, Iceland.
    Sigurdsson, Bjarni D.
    Faculty of Environmental Sciences, Agricultural University of Iceland, Hvanneyri, IS-311, Borgarnes, Iceland.
    Lindström, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik. School for Forest Management, Swedish University of Agricultural Sciences, Box 43, 739 21 Skinnskatteberg, Sweden.
    Effects of nutrient loading and fertilization at planting on growth and nutrient status of Lutz spruce (Picea x lutzii) seedlings during the first growing season in Iceland2013Inngår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 28, nr 7, s. 631-641Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The low availability of nitrogen (N) is believed to be one of the major limiting factors of forest regeneration inIceland and frequently under Boreal conditions. Lutz spruce (Picea x lutzii Littl.) seedlings were nutrient loadedusing four fertilization regimes in the end of nursery rotation in autumn 2008 and planted in the following spring,with or without a single dose of fertilizer, on two treeless sites in N-Iceland with contrasting soil fertility.Measurements were made after one growing season. The highest loading level without additional field fertilizationincreased new needle mass by 122% and 152%, for the poor and more fertile site, respectively. The highest loadinglevel with field fertilization increased new needle mass equally, by 188% and 189%, for the poor and more fertilesite, respectively. Retranslocation of N, from old needles to current needles, increased with more loading.However, it was clear that nutrient loading could not replace field fertilization, as the seedlings generally showedan additive response to field fertilization and nutrient loading; doing both always gave the best results in seedlingperformance. As the study only covers field establishment during the first year, the long-term effect of nutrientloading of Lutz spruce cannot be predicted. However, it was concluded that loading might provide an additionalinput for faster plantation establishment during the first growing season after planting.

  • 39. Joosen, R.V.L.
    et al.
    Lammers, M.
    Balk, P.
    Brönnum, P.
    Konings, M.C.J.M.
    Perks, M.
    Stattin, Eva
    Högskolan Dalarna, Akademin Industri och samhälle, Träteknologi.
    van Wordragen, M.F.
    Geest, L.H.M.
    Correlating gene expression to physiological parameters and environmental conditions during cold acclimation of Pinus sylvestris, identification of molecular markers using cDNA microarrays2006Inngår i: Tree Physiology, ISSN 0829-318X, E-ISSN 1758-4469, Vol. 26, nr 10, s. 1297-1313Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Scots pine (Pinus sylvestris L.) seedlings were grown under different conditions (three field locations, two seasons and two climate room regimes), and then analyzed for freezing tolerance of shoots and roots and for transcript abundance in apical buds based on a cDNA microarray containing about 1500 expressed sequence tags (ESTs) from buds of cold-treated Scots pine seedlings. In a climate room providing long daily photoperiods and high temperatures, seedlings did not develop freezing tolerance, whereas seedlings in a climate room set to provide declining temperatures and day lengths developed moderate freezing tolerance. Control seedlings grown outside under field conditions developed full freezing tolerance. Differences in physiological behavior of the different seedling groups, combined with molecular analysis, allowed identification of a large group of genes, expression of which changed during the development of freezing tolerance. Transcript abundance of several of these genes was highly correlated with freezing tolerance in seedlings differing in provenance, field location or age, making them excellent candidate marker genes for molecular tests for freezing tolerance.

  • 40.
    Kroese, Adrien
    et al.
    Swedish University of Agricultural sciences, Uppsala.
    Alam, Moudud
    Högskolan Dalarna, Institutionen för information och teknik, Statistik.
    Hernlund, Elin
    Swedish University of Agricultural sciences, Uppsala.
    Berthet, David
    Sony Nordic, Lund.
    Tamminen, Lena-Mari
    Swedish University of Agricultural sciences, Uppsala.
    Fall, Nils
    Swedish University of Agricultural sciences, Uppsala.
    Högberg, Niclas
    Swedish University of Agricultural sciences, Uppsala.
    3-Dimensional pose estimation to detect posture transition in freestall-housed dairy cows2024Inngår i: Journal of Dairy Science, ISSN 0022-0302, E-ISSN 1525-3198, Vol. 107, nr 9, s. 6878-6887Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Freestall comfort is reflected in various indicators, including the ability for dairy cattle to display unhindered posture transition movements in the cubicles. To ensure farm animal welfare, it is instrumental for the farm management to be able to continuously monitor occurrences of abnormal motions. Advances in computer vision have enabled accurate kinematic measurements in several fields such as human, equine and bovine biomechanics. An important step upstream to measuring displacement during posture transitions is to determine that the behavior is accurately detected. In this study, we propose a framework for detecting lying to standing posture transitions from 3D pose estimation data. A multi-view computer vision system recorded posture transitions between Dec. 2021 and Apr. 2022 in a Swedish stall housing 183 individual cows. The output data consisted of the 3D coordinates of specific anatomical landmarks. Sensitivity of posture transition detection was 88.2% while precision reached 99.5%. Analyzing those transition movements, breakpoints detected the timestamp of onset of the rising motion, which was compared with that annotated by observers. Agreement between observers, measured by intra-class correlation, was 0.85 between 3 human observers and 0.81 when adding the automated detection. The intra-observer mean absolute difference in annotated timestamps ranged from 0.4s to 0.7s. The mean absolute difference between each observer and the automated detection ranged from 1.0s to 1.3s. There was a significant difference in annotated timestamp between all observer pairs but not between the observers and the automated detection, leading to the conclusion that the automated detection does not introduce a distinct bias. We conclude that the model is able to accurately detect the phenomenon of interest and that it is equatable to an observer.

    Fulltekst (pdf)
    fulltext
  • 41. Kännaste, Astrid
    et al.
    Zhao, Tao
    Lindström, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Stattin, Eva
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Långström, Bo
    Borg-Karlson, Anna-Karin
    Odors of Norway spruce (Picea abies L.) seedlings: differences due to age and chemotype2013Inngår i: Trees, ISSN 0931-1890, E-ISSN 1432-2285, Vol. 27, nr 1, s. 149-159Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Small conifer seedlings (mini-seedlings) are less damaged by the large pine weevil Hylobius abietis (L.) (Coleoptera: Curculionidae) compared to conventional seedlings. Chemical difference between the seedling types is one possible explanation for this phenomenon. In the present paper, the emissions of volatile organic compounds (VOC) of 7- to 43-week-old Norway spruce [Picea abies (L.) Karst.] seedlings were analyzed. Collection and identification of the volatiles was made by solid phase micro-extraction and gas chromatography mass spectrometry (SPME–GC–MS). The enantiomers of α-pinene and limonene were separated in a two-dimensional GC (2D-GC). Most of the seedlings represented either a limonene- or a bornyl acetate-chemotype. Only minor changes in the volatile composition of the two types of seedlings were found during the first year. Age-related changes, however, were found in the volatiles released by wounded phloem where green leaf volatiles (GLVs) and borneol were the dominated VOC for young seedling. The attractive compound for the pine weevil, α-pinene, was first detected in the phloem emissions of 18- to 22-week-old seedlings. Different storage conditions of the seedlings during the winter/early spring-phase influenced the volatile composition in the phloem. High amount of GLVs was characteristic for the 43-week-old seedlings stored in naturally changing outdoor temperature, but not present in the seedlings winter-stored at a constant temperature of −4 °C. The possible role of these observed differences in odor emissions between seedlings of different age and physiological status for the feeding preferences of the large pine weevil is discussed.

  • 42.
    Lindahl, Cecilia
    et al.
    Department of Agriculture and Food, RISE Research Institutes of Sweden.
    Bergman Bruhn, Åsa
    Högskolan Dalarna, Institutionen för kultur och samhälle, Arbetsvetenskap.
    Andersson, Ing-Marie
    Högskolan Dalarna, Institutionen för kultur och samhälle, Arbetsvetenskap.
    Occupational Safety Climate in the Swedish Equine Sector2022Inngår i: Animals, E-ISSN 2076-2615, Vol. 12, nr 4, s. 438-438Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Swedish equine sector is considered a high-risk work environment, with relatively high injury rates and high severity of injuries. General safety research has identified a correlation between the safety performance and safety culture, but little is known about the intricacies of the safety culture in the Swedish equine sector, especially concerning managers’ and employees’ perceptions of their work environment. The safety climate assessment is recognised as an effective tool for identifying potential problems in the workplace, thus enhancing safety behaviour and decreasing the frequency and severity of injuries. The aim was to evaluate the safety climate at riding schools and trotting stables through the Nordic Safety Climate Questionnaire (NOSACQ-50) diagnostic tool, and to get a better understanding of the workers’ perceptions regarding safety and safety management at their workplace through complementary interviews. The results showed that the safety climate was generally positive and that employees were aware of the risks relating to their work. Riding schools commonly had routines in place for risk assessment and work environment management, but such routines were often lacking at trotting stables, indicating inadequate prioritisation of safety by the management. The main area that should be targeted to improve safety in the sector is employees’ prioritisation and non-acceptance of risks. Proactive instead of reactive safety management should be promoted, where safety is an integral part of daily work and all employees are encouraged to identify factors contributing to occupational injuries and develop strategies for injury prevention.

    Fulltekst (pdf)
    fulltext
  • 43.
    Lindström, Anders
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Hellqvist, Claes
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik. Sveriges Lantbruksuniversitet.
    Etablering, tillväxt och skador för plantor odlade i såddrör (Tubesprout™) - resultat efter två säsonger i fält2013Rapport (Annet vitenskapelig)
    Abstract [sv]

    Försöket visade på mycket god överlevnad för plantor odlade i såddrören, Tubesprout™. Efter två år var överlevnaden för dessa 91 % för tall och 79 % för gran. För miniplantorna odlade i Jiffy varierade överlevnaden efter två år mellan 84 (tall) och 64 % (gran). Lägst överlevnad efter både det första och andra året hade de större referensplantorna. Av dessa levde 67 % av tallplantorna och endast 45 % av granplantorna. Bidragande till den goda överlevelsen hos Tubesprout™-odlade plantor var få snytbaggeskador och nästan inga skador av torka. Det andra miniplantsystemet, Jiffy 18, klarade snytbaggen nästan lika bra som Tubesprout™, men drabbades istället av stora avgångar beroende på torka. Hylsan tycks förhindra uttorkning av plantan som annars är ett stort problem vid plantering på torra marker av små plantor. För de äldre täckrotsodlade referensplantorna var den mesta plantdöden orsakad av kraftiga snytbaggeskador. Granen var värst drabbad med drygt 50 % snytbaggedödade plantor efter två år, medan den plantavgång hos tall som var orsakad av snytbagge var 26 %. Några plantor som stod i Tubesprout™ på försöksytan blev dock uppryckta, sannolikt av kråkfåglar.

    Fulltekst (pdf)
    fulltext
  • 44.
    Lindström, Anders
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik. School for Forest Management, Swedish University of Agricultural Sciences, Skinnskatteberg.
    Stattin, Eva
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Gräns, Daniel
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik. School for Forest Management, Swedish University of Agricultural Sciences, Skinnskatteberg.
    Wallin, Elisabeth
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. School for Forest Management, Swedish University of Agricultural Sciences, Skinnskatteberg.
    Storability measures of Norway spruce and Scots pine seedlings and assessment of post storage vitality by measuring shoot electrolyte leakage2014Inngår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 29, nr 8, s. 717-724Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As indoor frozen storage is increasing in forest tree nurseries it is important to have accurate methods for assessing seedling storability in autumn and methods to determine post-storage vitality. Storability of spruce (Picea abies (L.) Karst.) and pine (Pinus sylvestris L.) seedlings can be based on determination of dry matter content (DMC) of seedling shoots or by freezing shoots at -25 degrees C and thereafter measure electrolyte leakage (SELdiff-25). To compare these two methods we stored 1-year-old spruce and pine seedlings at different occasions during the autumn. To test if leakage of electrolytes from shoots (SEL) could indicate deteriorated vitality, we measured SEL at the end of storage. After storage seedling viability was determined in a three-week growth test, measuring shoot and root growth capacity (RGC). Determination of freezing tolerance (SELdiff-25) before storage had a better ability to predict the outcome of storage compared to the DMC test. Measuring SEL at the end of the frozen storage period accurately indicated seedling vitality. Seedlings with SEL of 0-5% had a high survival rate whereas SEL over 10% indicated low survival and growth capacity after storage. The SEL method has a potential to become a screening test for identifying batches of seedlings that have been damaged during storage in the nursery.

  • 45.
    Lindström, Anders
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Stattin, Eva
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Widemo Sandvik, Maria
    Analys av granvitalitet efter översvämning2009Rapport (Annet vitenskapelig)
    Fulltekst (pdf)
    fulltext
  • 46. Malmqvist, C.
    et al.
    Wallin, Elisabeth
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Lindström, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Säll, H.
    Differences in bud burst timing and bud freezing tolerance among interior and coastal seed sources of Douglas fir2017Inngår i: Trees, ISSN 0931-1890, E-ISSN 1432-2285, Vol. 31, nr 6, s. 1987-1998Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The need for species that will grow well through ongoing climate change has increased the interest in Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] in Sweden. One of the most common problems seen in plantations of Douglas fir seedlings is damage caused by late spring frost, known to be highly correlated with the timing of bud burst. The objective of this study was to investigate spring-related bud development under Nordic conditions of seven Douglas fir provenances and to compare data with a local provenance of Norway spruce (Picea abies (L.) Karst). Results from a field trial and a greenhouse-based study were compared. The interior Douglas fir provenances exhibited an earlier bud burst than coastal provenances, both in the greenhouse and in the field trial. When comparing differences within the groups of interior and coastal Douglas fir provenances, no differences could be found. The local Norway spruce, only grown in the greenhouse, showed an intermediate bud development profile similar to the interior Douglas fir provenance Three Valley. We therefore suggest that Three Valley could be planted at the same locations as the investigated local provenance of Norway spruce in mid-Sweden. To avoid spring frost damage the Douglas fir seedlings need to be frozen stored and planted late in spring. Planting under shelterwood can also help protect the seedlings from spring frost damages. As similar results for bud development patterns of Douglas fir and Norway spruce provenances were obtained from the greenhouse and field trials, greenhouse tests could facilitate selection of provenances.

    Fulltekst (pdf)
    fulltext
  • 47.
    Malmqvist, Cecilia
    et al.
    Dept of Forestry and Wood technology, Linneus University, Växjö, Sweden.
    Wallertz, Kristina
    Asa Forest Research Station, Swedish University of Agricultural Sciences, Lammhult Sweden.
    Lindström, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Storability and freezing tolerance of Douglas fir and Norway spruce seedlings grown in mid-Sweden2017Inngår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 32, nr 1, s. 30-38Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Climate change provides new challenges to Nordic forestry. Use of non-native species, such as Douglas fir, can be a means of mitigating the effects of climate change and meeting the growing demand for biomass. When Douglas fir is grown in Sweden, it is several degrees of latitude north of its normal range, which can affect timing of growth cessation, hardening of seedlings, and seedling storability. The objective of this study was to investigate tolerance to freezing and sub-zero storability of seven Douglas fir provenances and make comparisons with the native Norway spruce. Freezing tolerance and storability were evaluated by measuring the electrolytic leakage of shoots and roots after freezing, complemented with a three-week cultivation test after storage. All provenances of Douglas fir used in this study were able to tolerate frozen storage at −4°C for about four months. Norway spruce and the interior Douglas fir provenance, Three Valley, could be stored earlier in the autumn than the southern coastal Douglas fir provenances. Consequently, it should be possible to store Douglas fir seedlings with the same routines as for Norway spruce.

    Fulltekst (pdf)
    fulltext
  • 48.
    Marina, H.
    et al.
    Swedish University of Agricultural Sciences, Uppsala.
    Nielsen, P. P.
    RISE Ideon, Lund.
    Fikse, W. F.
    Växa, Swedish University of Agricultural Sciences, Uppsala.
    Rönnegård, Lars
    Högskolan Dalarna, Institutionen för information och teknik, Statistik. Swedish University of Agricultural Sciences, Uppsala.
    Multiple factors shape social contacts in dairy cows2024Inngår i: Applied Animal Behaviour Science, ISSN 0168-1591, E-ISSN 1872-9045, Vol. 278, artikkel-id 106366Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cattle develop preferential relationships with other individuals in the herd. These social interactions between individuals have a significant impact on both animal welfare and production. Given the relevance of social behaviour in dairy cattle, scientific studies have focused on understanding social interactions among cattle. These may also be influenced by individual area preferences, particularly when animals are housed in confined spaces. Therefore, investigating the relationship between individual area preferences and social interactions is essential for understanding social behaviour in dairy cattle. Real-time location systems provide the opportunity to monitor individual area preferences and social contacts at the same time. This study aims to assess the impact of dairy cows' area preferences on their daily social contacts and to determine the potential implications of overlooking individual area preferences in social behaviour studies. The individual position of the lactating cows was automatically collected once per second for two months on a Swedish commercial farm housing dairy cows inside a free-stall barn. The location data of 243 lactating cows was used to construct the social networks and to estimate the similarity of the area utilisation distributions between these individuals. The effect of utilisation distribution similarity in social networks was investigated by applying separable temporal exponential random graph mixed models. The role of different cow characteristics in the similarity of the utilisation distributions was assessed through a linear mixed model. Our analyses stressed the importance of similarity of area preference, parity, kindergarten effect, and filial relatedness in shaping daily social contacts in dairy cattle. The kindergarten effect refers to the effect on cow behaviour of being grouped together in the early stages of their lives. Similarity of area preference was influenced by the kindergarten effect and relatedness by pedigree, which favoured interactions between these individuals. The described approach allowed to disassociate the area preference from the social contacts between cows, providing more accurate results of the importance of the cow's characteristics on their social behaviour.

    Fulltekst (pdf)
    fulltext
  • 49.
    Marina, Héctor
    et al.
    Swedish University of Agricultural Sciences, Uppsala.
    Ren, Keni
    Swedish University of Agricultural Sciences, Uppsala.
    Hansson, Ida
    Swedish University of Agricultural Sciences, Uppsala.
    Fikse, Freddy
    Swedish University of Agricultural Sciences, Uppsala.
    Nielsen, Per Peetz
    RISE Research Institute of Sweden; RISE Ideon, Lund.
    Rönnegård, Lars
    Högskolan Dalarna, Institutionen för information och teknik, Statistik. Swedish University of Agricultural Sciences, Uppsala.
    New insight into social relationships in dairy cows, and how time of birth, parity and relatedness affect spatial interactions later in life2024Inngår i: Journal of Dairy Science, ISSN 0022-0302, E-ISSN 1525-3198, Vol. 107, nr 2, s. 1110-1123Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Social interactions between cows play a fundamental role in the daily activities of dairy cattle. Real-time location systems provide on a continuous and automated basis information about the position of individual cows inside barns, offering a valuable opportunity to monitor dyadic social contacts. Understanding dyadic social interactions could be applied to enhance the stability of the social structure promoting animal welfare and to model disease transmission in dairy cattle. This study aimed to identify the impact of different cow characteristics on the likelihood of the formation and persistence of social contacts in dairy cattle. The individual position of the lactating cows was automatically collected once per second for 2 weeks, using an ultra-wideband system on a Swedish commercial farm consisting of nearly 200 dairy cows inside a free-stall barn. Social networks were constructed using the position data of 149 cows with available information on all characteristics during the study period. Social contacts were considered as a binary variable indicating whether a cow pair was within 2.5 m of each other for at least 10 min per day. The role of cow characteristics in social networks was studied by applying separable temporal exponential random graph models. Our results revealed that cows of the same parity interacted more consistently, as well as those born within 7 d of each other or are closely related by pedigree. The repeatability of the topological parameters indicated a consistent short-term stability of the individual animal roles within the social network structure. Additional research is required to elucidate the underlying mechanisms governing the long-term evolution of social contacts among dairy cattle and to investigate the relationship between these networks and the transmission of diseases in the dairy cattle population.

    Fulltekst (pdf)
    fulltext
  • 50.
    Mattsson, Anders
    Högskolan Dalarna, Akademin Industri och samhälle, Skog- och träteknik.
    Reforestation challenges in Scandinavia2016Inngår i: Reforesta, ISSN 2466-4367, nr 1, s. 67-85Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the keynote, major reforestation challenges in Scandinavia will be highlighted. The following countries make up Scandinavia: Iceland, Norway, Sweden, Finland and Denmark. For Iceland, with only a forest cover of 2%, a major reforestation challenge is the deforestation and overgrazing in combination with land degradation and extensive soil erosion. The challenges include the conflicts with livestock farmers. For centuries the commons were used for sheep and horse grazing. However, more and more of farmer grazing land have been fenced up, allowing the regeneration of birch and plantations of other species to increase. With a forest cover of 37% and 69% respectively, for decades a major reforestation challenge in Norway and Sweden has been the risk of seedling damages from the pine weevil. Unprotected seedlings can have a survival rate of less than 25% after being planted. Pine weevils feed on the bark of planted young seedlings at regeneration sites. If the seedling is girdled, it will not survive. In Sweden, and soon in Norway, pesticides have been forbidden. In the keynote, new methods and technology will be presented based on non-chemical protection. In Finland, with a forest cover of 75%, a major reforestation challenge is linked to the forest structure. The structure of Finnish forestry includes many private forests in combination with small regeneration sites. This implies a situation where logistics and methods for lifting and field storage provide a major challenge in order to preserve seedling quality until the planting date. Due to this situation, new logistic systems and technologies are being developed in Finland, including new seedling cultivation programs (including cultivation under Light Emitting Diodes (LEDs)) to match the access of fresh planting stock to different planting dates. In Denmark, with a forest cover of 13%, a major reforestation challenge is the possibility of future plantations based on a wide range of relevant species. For this to become a realistic option, new methods and technology have to be developed in reforestation activities that support this possibility. These methods and technology should make it possible to not be limited to certain species due to problems and restrictions during field establishment. This due to the prospect of establishing stable, healthy, and productive stands of various forest species that can be adapted to future climate change.

    Fulltekst (pdf)
    fulltext
12 1 - 50 of 64
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf