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  • 1.
    Bergsten, U
    et al.
    SLU.
    Lindeberg, Johan
    SLU.
    Rindby, A
    Evans, R
    Batch measurements of wood density on intact or prepared drill cores using x-ray microdensitometry2001In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 35, p. 435-452Article in journal (Refereed)
    Abstract [en]

    The performance of a batch scanning x-ray densitometer for measuring wood density without sample preparation, i.e., on intact drill cores, or on rectangular samples prepared from drill cores, was analysed. Effects of x-ray intensity, sample thickness and fiber direction, as well as extractives content, were evaluated for young (mainly sapwood) and old (mainly heartwood) wood from Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.). The x-ray power level used as standard (1.4 kW; 40 kV and 35 mA) seemed appropriate for the tested species and specimen thickness. The density of intact drill cores could be determined with a mean standard deviation of 1.6% for each sample, with a single machine run, if the cores were mounted with a fixed fiber direction and calibrations were made for each wood type. The corresponding precision for rectangular samples was 1.0%. Further improvements are attainable by using standard reference samples in each machine run and batch-wise analysis. For the chosen wood types and measurement technique, a sample thickness of 5 mm should give the best precision. However, for species with very narrow rings, thinner samples would improve the spatial resolution when ring boundaries are angled or curved. Extractives should be removed, especially for pine, but possibly also for spruce, if high precision in density determination is required.

  • 2.
    Hallingbäck, Henrik R.
    et al.
    Swedish University of Agricultural Sciences.
    Högberg, Karl-Anders
    The Forestry Research Institute of Sweden.
    Säll, Harald
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Lindeberg, Johan
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Marie
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Jansson, Gunnar
    The Forestry Research Institute of Sweden.
    Optimal timing of early genetic selection for sawn timber traits in Picea abies2018In: European Journal of Forest Research, ISSN 1612-4669, E-ISSN 1612-4677, Vol. 137, no 4, p. 553-564Article in journal (Refereed)
    Abstract [en]

    In breeding Norway spruce, selection for improved growth and survival is performed at age 10-15 years in order to optimize genetic gain per year. We investigated whether a selection based on wood traits such as density and grain angle, measured under bark in the field at the same age would be informative enough with respect to structural quality traits of sawn boards. To achieve this objective, a sawing study was conducted on the butt logs of 401 trees from a 34-year-old Norway spruce progeny trial situated in southern Sweden. Stem discs were excised from the top of the logs and radial profile data of grain angle, and wood density was recorded for specific annual rings. The sawn and dried boards were assessed for structural traits such as twist, board density, bending stiffness (static modulus of elasticity, sMoE) and bending strength (modulus of rupture, MoR). Additive genetic correlations (r (a)) between single annual ring density measurements and board density, sMoE and MoR were consistently strong (r (a)> 0.7) for annual rings 5-13. Genetic correlations of similar magnitude between grain angle and board twist were estimated for all investigated annual rings (from 2 to around 26 under bark). Consequently, it was found that indirect selection for wood density and grain angle at the tree age 10-16 years would result in more genetic gain per year than selection at later ages. This makes it feasible to perform simultaneous selection of progeny in the field for both growth and wood traits at similar ages.

  • 3.
    Jones, Grace
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Liziniewicz, Mateusz
    Swedish Forestry Research Institute, Sweden.
    Lindeberg, Johan
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Nondestructive wood density testing in downy birch and silver birch genetics field trial, southern Sweden2019In: 21st International Nondestructive Testing and Evaluation of Wood Symposium,: Freiburg, Germany, 2019 / [ed] Wang, Xiping; Sauter, Udo H.; Ross, Robert J.,, U.S. Department of Agriculture (USDA) , 2019, p. 79-86Conference paper (Refereed)
    Abstract [en]

    Non-destructive testing of wood density, as is already done for Eucalyptus, can allow for earlyselection of birch trees for breeding programmes and stands for harvesting. In this work, external stemquality traits were visually assessed in a family trial of downy (Betula pendula) and silver (B.pubescens) birch in southern Sweden. A subsample of trees was measured for wood density using thePilodyn resistometer portable NDT tool. An X-ray microdensitometric analysis of the subsample oftrees was completed using the Itrax X-ray machine for increment cores taken from the south face,through the pith to the north bark at 1.3 m stem height. The Pearson’s r value for Itrax density andPilodyn density was high (0.580 for downy birch and 0.795 for silver birch), and this correlationmeans Pilodyn should provide a good estimate of average birch wood density. Neither species hadstable wood density values at age 13 and both species’ density increased over time from pith to bark.Ring width influence on stem density was minor or non-existant, and may vary between birch species

  • 4. Lestander, A
    et al.
    Lindeberg, Johan
    Eriksson, Daniel
    Bergsten, Urban
    Prediction of Pinus sylvestris clear-wood properties using NIR spectroscopy and biorthogonal partial least squares regression2008In: Canadian Journal of Forest Research, ISSN 0045-5067, E-ISSN 1208-6037, Vol. 38, p. 2052-2062Article in journal (Refereed)
    Abstract [en]

    Thirteen wood parameters were predicted using near infrared (NIR) spectra in the range 780-2380 nm modelled by biorthogonal partial least squares regression. The analysis of parameters and NIR measurements was done on clear-wood samples from the base and midstem of Scots pine (Pinus sylvestris L.) from trees at two sites. Calibrations based oil the measured parameters at seven growth rings (cambial age ranging between 6 and 42 years) could be divided into three groups: (i) the best accuracy was found for longitudinal modulus of elasticity (r > 0.9) followed by bending, compression, and cell length (0.8 < r < 0.9); (ii) microfibril angle, longitudinal hardness, proportion of latewood, and creep with correlations in the range of 0.7-0.8; and (iii) tangential hardness, cell diameter, and cell wall thickness with 0.4 < r < 0.7. It was also shown that juvenile (cambial age : 20 years) and mature wood can be classified using NIR techniques.

  • 5. Persson, E
    et al.
    Lindeberg, J
    Changes in metal concentrations during dry- and wet-storage of Norway spruce pulpwood2001In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 16, p. 327-332Article in journal (Refereed)
    Abstract [en]

    The changes in concentrations and radial distribution of Ca, Fe and Mn in Norway spruce (Picea abies) pulpwood after three months of storage were evaluated. Three different storage alternatives were tested: dry storage, sprinkling with an intensity corresponding to the rate of evaporation and sprinkling with an intensity corresponding to twice the rate of the evaporation. The analyses were performed using energy dispersive x-ray fluorescence (EDXRF) and atomic absorption spectroscopy (AAS). In the dry-stored logs, the AAS analyses revealed a tendency for decreased concentrations of Ca and Fe after three months storage. The tendency in the sprinkled logs was, according to the AAS analyses, a small increase in Ca and Mn contents after three months storage. The EDXRF analyses indicated that the radial distribution of Ca and Mn might have been affected during storage.

  • 6. Quist, E
    et al.
    Nasholm, T
    Lindeberg, Johan
    Johannisson, C
    Hogbom, L
    Hogberg, P
    Responses of a nitrogen-saturated forest to a sharp decrease in nitrogen input1999In: Journal of Environmental Quality, ISSN 0047-2425, E-ISSN 1537-2537, Vol. 28, p. 1970-1977Article in journal (Refereed)
    Abstract [en]

    The reversibility of induced N saturation was investigated in a 46- yr-old pine (Pinus sylvestris L.) forest in northern Sweden Ammonium nitrate has been applied annually since 1971 to plots (30 by 30 m) at average dosages of 36 (N1), 72 (N2), and 108 (N3) kg N ha(-1) yr(-1): with or without P and K addition (background N deposition is <4 kg ha(-1) yr(-1)). In 1990, after two decades of treatment, the largest N application (N3) was suspended, while N1 and N2 still received ammonium nitrate applications. Seven gears after the last application in N3, the N availability measured as N concentration in plants spine roots and needles and in leaves of the grass Deschampsia flexuosa (L.) Trin.] and activity of the enzyme nitrate reductase in leaves of D. flexuosa, and N-15 uptake by excised pine roots, was at the same levels as in N1, although more than twice the amount of N has been applied in total to N3. The arginine concentrations in pine needles, concentrations of exchangeable mineral N in the organic layer and the uppermost 20 cm of the mineral soil were at the same levels as in the control plots. Thus, an experimentally induced N excess was, according to these measurements, to a high degree reversed 7 yr after the last N application. However, the composition of the understory vegetation still differed markedly from the untreated control 8 yr after the last N3 application.

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