Published by De Gruyter

Volume 56 Issue 4

Issue of Holzforschung

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Contents
Journal Overview

June 1, 2005

Characteristics of Attack of Coastal Timbers by Pselactus spadix (Herbst) (Col.: Curc.: Cossoninae) and an Investigation of its Life History

P. Oevering, A.J. Pitman

Page range: 335-359

Abstract

Pselactus spadix attack of marine timbers was characterised by circular emergence holes 1.48±0.05 mm in diameter and adult tunnels (1.49±0.34 mm) breaking through the wood surface. Larval tunnels measured 0.407–1.892 mm in diameter, initiated from adult tunnels and increased in diameter away from the adult tunnel terminating in frass free pupal chambers (1.6±0.3 mm × 3.5±0.7 mm). Observations of larval tunnel locations indicated oviposition occurred inside the adult tunnels. P. spadix life history was investigated in Scots pine ( Pinus sylvestris ) heartwood at 22±2 °C and 99±1% r.h. Mean adult longevity was 11.5±6.5 months, with mean post-mating longevity for males (11.7±2.9 months) significantly longer than for females (6.3±1.1 months). Adults of at least 2–3 months old were found mating in galleries, which, with observations of the larval tunnel pattern, indicated P. spadix can complete its life cycle without emerging from wood. Five larval instars were identified by measurement of 1722 head capsule widths and application of Dyar's law. Mean development time from 2nd instar to adult emergence was 70.5±6.9 weeks and pupation took 14.6±5.8 days. Development from 2nd instar to reproductive adult took between 17–20 months, with life cycle approximating 24 months at 22±2 °C and 99±1%

June 1, 2005

Bacterial Cellulose Production Using Monosaccharides Derived from Hemicelluloses in Water-Soluble Fraction of Waste Liquor from Atmospheric Acetic Acid Pulping

Y. Uraki, M. Morito, T. Kishimoto, Y. Sano

Page range: 341-347

Abstract

The water-soluble fraction (WS) from waste liquor of atmospheric acetic acid pulping was analyzed in order to explore its potential utilization as a carbon source for bacterial cellulose (BC) production. The unpurified WS that contained colored compounds had appreciable antibacterial activity and was therefore not used as a carbon source for BC production with the bacteria Acetobacter xylinum ATCC 10245 and 53582. However, the bacteria produced BC from purified WS of both fir and birch after activated carbon treatment. The yields of BC were much lower compared to those using glucose as a typical carbon source in the Hestrin-Schramm (HS) medium. In order to improve the cellulose production, monosaccharides derived from hemicellulose sugars in WS were modified. The WS from softwood was reduced by catalytic reduction, i.e. mannose, the major component of softwood monosaccharides derived from hemicelluloses, was converted to mannitol. In the case of hardwood WS, xylose was isomerized with glucose isomerase to xylulose. The yield of BC was considerably enhanced by both modifications of the WS. The yield of BC using the modified WS from the pulping of fir was superior to that using glucose as carbon source.

June 1, 2005

Birch (Betula pendula) Wood Discolouration during Drying. Effect of Environmental Factors and Wood Location in the Trunk

K. Luostarinen, V. Möttönen, A. Asikainen, J. Luostarinen

Page range: 348-354

Abstract

Birch wood discolours during artificial drying, which is a considerable problem for the use of birch as raw material in the mechanical wood industry. In this investigation sample boards of Betula pendula were sawn to the dimensions used as raw material for parquet billets. The variables studied were those that may affect wood discolouration: growing site, felling date, length of the storage period for logs and location of the wood in the trunk. Discoloration of birch wood was studied in conventional and vacuum drying processes. The wood layer of about 2–5 mm under the yellow surface of conventionally dried boards remained light-coloured, while the inner wood of the boards became discoloured. During vacuum drying, however, the inner wood of sample boards clearly became discoloured. The radial location of the wood in the trunk affected the colour of dried wood more than the longitudinal location did. To keep the colour of dry wood as light as possible, it may be best to fell birch in winter and store the wood for several weeks before conventional drying. On the other hand, the lightest coloured wood obtained during vacuum drying was from autumnfelled five weeks stored birches, which may indicate differences in the process of discoloration in these two drying methods.

June 1, 2005

Immuno Electron Microscopic Localization of Peroxidases in the Differentiating Xylem of Populus spp.

Y.S. Kim, S.-G. Wi, C. Grünwald, U. Schmitt

Page range: 355-359

Abstract

Peroxidases were localized in differentiating xylem cells of Populus spp. by means of immunogold labelling in combination with transmission electron microscopy (TEM). Polyclonal antibodies raised in rabbits against horseradish peroxidase were used for these experiments. Within the cytoplasm, TEM revealed a distinct labelling of the dictyosomes, indicating that these organelles are involved in the transport of peroxidases to the plasma membrane. During the formation of primary and secondary walls, cell corner regions became distinctly labelled, the developing secondary wall layers to a much lesser degree. Significant differences in the immunogold labelling between the intercorner middle lamella and the secondary cell wall layers were not observed. According to the immunogold labelling, peroxidases are incorporated into the secondary wall more or less simultaneously with deposition of polysaccharides. Correlations between peroxidase incorporation and lignification are discussed.

June 1, 2005

Vanilloyl Acetic Acid as an Unstable Intermediate from β-Hydroxypropiovanillone to Acetovanillone

M. Niwa, Y. Saburi

Page range: 360-362

June 1, 2005

Study of Lewis Acid-Base Properties of Wood by Contact Angle Analysis

M. E. P. Wålinder

Page range: 363-371

Abstract

In the present work, an attempt is made to study the Lewis acid-base properties of wood by contact angle analysis. Using contact angle data for extracted, non-extracted, fresh and aged pine wood veneer samples, the Lewis acid-base contribution to the work of adhesion ( W a AB ) and the Lewis acid-base components of the surface free energy of the wood samples were determined by basic wetting theory, and by the so-called van Oss-Chaudhury-Good (vOCG) model. Results show, on the one hand, that W a AB between water and the non-extracted wood decreases with increasing aging time. This indicates that extractives migrate from the interior of wood to its exterior surface during the aging, creating a hydrophobic wood surface. On the other hand, W a AB between the non-extracted wood and ethylene glycol tends to increase with longer aging times. No such trends are observed for extracted samples. If water is considered to be predominantly Lewis acidic, and ethylene glycol predominantly Lewis basic, the changes in W a AB with longer aging times, indicate that the acidity and the basicity of non-extracted wood in these cases increases and decreases, respectively. This is presumably due to the presence of the extractives, and to reorientation of functional groups and oxidation at the wood/extractives-air interface. The acid-base characterization by the vOCG model also indicates that the acidity and the basicity of the non-extracted wood increases and decreases, respectively, with increasing aging time. However, there seems to be a similar trend even for extracted wood, presumably due to reorientation of functional groups at the wood-air interface. In the vOCG model, considerably higher base/acid ratios are obtained when using probe liquid parameters according to van Oss compared to those obtained by using liquid parameters according to Della Volpe and Siboni.

June 1, 2005

Lipophilic Extractives of the Inner and Outer Barks of Eucalyptus globulus

C. S. R. Freire, A. J. D. Silvestre, C. Pascoal Neto, J.A.S. Cavaleiro

Page range: 372-379

Abstract

The chemical compositions of the dichloromethane extracts of inner and outer barks of E. globulus were studied by gas chromatography-mass spectrometry. The two fractions show very different chemical compositions: triterpenic acids, such as betulinic, ursolic and oleanolic acids, were the major components of the outer bark extract, whereas β-sitosterol and β-amirin along with palmitic, linoleic and oleic acids predominate in the inner bark extract. Several α-and β-hydroxy fatty acids, recently reported for the first time as E. globulus wood components, were also identified in the outer and inner barks. In the outer bark extract, minor amounts of ferulic acid esters, also previously reported to occur in E. globulus wood were identified. In general, the inner bark lipophilic extractives resemble more closely that of E. globulus wood.

June 1, 2005

Thick-Target PIXE Analysis of Trace Elements in Wood Incoming to a Pulp Mill

K.-E. Saarela, L. Harju, J.-O. Lill, J. Rajander, A. Lindroos, S.-J. Heselius, K. Saari

Page range: 380-387

Abstract

Trunk-wood samples of wood raw material incoming to a pulp mill were analysed by thick-target particle induced X-ray emission (PIXE). The tree species studied were pine and spruce from Finland, birch from Finland and Poland and eucalyptus from Uruguay. The wood samples were dry ashed to 550 °C prior to the analysis in order to increase the sensitivity of the method. The method was calibrated and validated using some wood based certified reference materials. The elements determined with the method were P, S, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Pb, Sr, Rb, Ba and F. The concentrations of the main elements P, S, K, Ca and Mn exceeded 50 ppm in most wood samples. The concentrations of heavy metal ions like Cu, Ni and Pb in the samples studied were below or close to 1 ppm. The ash content of birch, pine and spruce wood were in the range 0.2–0.4% and that of eucalyptus ca 0.5%.

June 1, 2005

Formation of Aliphatic Carboxylic Acids during Soda-AQ Pulping of Kenaf Bark

Z. Feng, R. Alén, K. Niemelä

Page range: 388-394

Abstract

The formation of aliphatic carboxylic acids during soda-AQ pulping of kenaf bark was studied. In addition to formic and acetic acids, a variety of hydroxy monocarboxylic and dicarboxylic acids were monitored. The results showed that the formation of hydroxy acids and formic acid significantly depend, in contrast to acetic acid, on the cooking conditions employed. Detailed gas chromatographic studies revealed that the most abundant hydroxy carboxylic acids were glucoisosaccharinic, lactic, glycolic, 3-deoxypentonic, 2-hydroxybutanoic, xyloisosaccharinic, 3,4-dideoxypentonic, 2-hydroxyglutaric, and glucoisosaccharinaric acids. The total amount of aliphatic carboxylic acids corresponded to 12–16% of o.d. kenaf bark.

June 1, 2005

Comparing Mechanical Properties of Normal and Compression Wood in Norway Spruce: The Role of Lignin in Compression Parallel to the Grain

W. Gindl

Page range: 395-401

Abstract

Cell-wall lignin content and composition, as well as microfibril angle of normal and compression wood samples were determined prior to mechanical testing in compression parallel to the grain. No effect of increased lignin content on the Young's modulus in compression wood was discernible because of the dominating influence of microfibril angle. In contrast, compressive strength of compression wood was not negatively affected by the high microfibril angle. It is proposed that the observed high lignification in compression wood increases the resistance of the cell walls to compression failure. An increased percentage of p-hydroxyphenylpropane units observed in compression wood lignin may also contribute to the comparably high compressive strength of compression wood.

June 1, 2005

Oxidative Ammonolysis of Technical Lignins. Part 3. Effect of Temperature on the Reaction Rate

E. A. Capanema, M. Y. Balakshin, C.-L. Chen, J. S. Gratzl, A. G. Kirkman

Page range: 402-415

Abstract

The effect of the reaction temperature on the kinetics and the reaction mechanism of oxidative ammonolysis of Repap organosolv lignin have been studied. The reaction was conducted in 0.8 M Nh4oh solution under oxygen pressure of 12 bar and at three different temperatures, 70 °C, 100 °C and 130 °C. The resulting N -modified lignins were analyzed by elemental and methoxyl group. About 20–25% of maximum nitrogen content is incorporated into the lignin very fast, in 1–2 min of the reaction. The reaction kinetics then follows a pseudo-first order reaction law and consists of two phases. The activation energies for nitrogen incorporation and lignin solubilization are rather low, in the range of 33–34 kJ/mol. Linear correlation between nitrogen incorporated into the lignin and molecular oxygen uptake, oxygen incorporation, CO 2 formation, O-demethylation and total carbon loss was analyzed at the different reaction temperatures. On the basis of kinetic data obtained so far, we have postulated that the reaction temperature affects the reaction rate, but not the reaction pathways. The reaction temperature also affects the ratios between different reaction pathways, though the effect is not very strong. The results obtained are discussed in the terms of competitive reactions of lignin oxidation followed by nitrogen incorporation and lignin deactivation involving nitrogen

June 1, 2005

The Erythro/Threo Ratio of β-O-4 Structures as an Important Structural Characteristic of Lignin. Part 2. Changes in Erythro/Threo (E/T) Ratio of β-O-4 Structures during Delignification Reactions

T. Sugimoto, T. Akiyama, Y. Matsumoto, G. Meshitsuka

Page range: 416-421

Abstract

The ozonation method was applied to an analysis of the changes in erythro and threo (E/T) ratio of arylglycerol-β-aryl ether (β-O-4) structures in the residual lignins of delignified wood samples. When delignified by alkali cook, not only the total yield of erythronic and threonic acids per lignin decreased, but also the E/T ratio decreased with the progress of delignification. These results indicate that residual lignin of alkali-delignified wood contain only a small amount of arylglycerol-β-aryl ether structures and/or glycerol side chains, which are relatively rich in the threo form. A suggested reason for this, in addition to the stereo-preferential degradation of the erythro β-O-4 structure, is the increasing contribution of topologically-inert lignin and/or chemically-inert lignin structures with a low original E/T ratio. In contrast, when the wood samples are delignified by NaClO 2 treatment, no significant change is observed in the E/T ratio. This confirms that the NaClO 2 delignification proceeds without the residual lignin retaining special configurational characteristics in its side chains.

June 1, 2005

The Effect of HS- Ions in 1-mol/l NaOH Solutions on the Ion Diffusion in Wood Calculated as the Steady State Diffusion and the Drift Speed

M. Törnqvist, T. Hurme, J. B. Rosenholm

Page range: 422-427

Abstract

Diffusion tests in pine, birch and spruce were done with different Na 2 S fractions of 1-mol/l NaOH solutions. The steady state diffusion was found to be dependent on the original moisture content present in the wood samples and the concentration of the electrolyte, but not the HS − ions. The drift speed was dependent on the mobility of the HS − ions, reducing the flux as compared to the OH − flux in pure NaOH solutions. The moisture content originally present inside the wood samples affected the migration, especially in the longitudinal direction due to structural effects.

June 1, 2005

Industrial Kiln Drying and its Effect on Microstructure, Impregnation and Properties of Scots Pine Timber Impregnated for Above Ground Use. Part 1. Effects of Initial, Final Dryings and Preservative on Impregnation and Timber Quality

N. Terziev

Page range: 428-433

Abstract

Scots pine ( Pinus sylvestris L.) planks were dried in industrial progressive, conventional batch and high temperature kilns. The quality of drying was assessed by measuring the final moisture content and its gradient, deformations, checks and internal stress of planks. The timber was rearranged in three charges and impregnated in an industrial autoclave with copper-based preservatives for above ground use (class AB):Kemwood ACQ 1900, Tanalith E and Wolmanit CX-8. The moisture content was determined after impregnation and the planks were divided into two charges; the first was dried in an industrial conventional batch kiln while the second was air dried. Assessment of the final product quality after kiln and air drying was carried out as after the initial drying. The penetration of preservatives was measured as well. The data were analysed by a statistical mixed model to ascertain the effects of drying and preservatives on the impregnation and timber quality. A strong relationship was found between the initial drying of Scots pine timber and its quality after impregnation and drying. The conventional batch and high temperature kiln drying ensured similar drying quality regarding the final moisture content and gradient, bow, twist and checks, but the high temperature drying provided significantly better (94.4%of the total sapwood area) penetration of the preservatives tested. It is suggested that changes in wood structure could be provoked during the high temperature drying, thus improving the subsequent impregnation and secondary drying. The progressive and conventional batch kiln drying led to similar penetration of the preservatives; the conventional batch kiln drying ensured significantly lower final moisture content, less twist and surface checks of the timber than the progressive kiln drying. Wolmanit CX-8 penetrated significantly better into the pine sapwood (96.3%) than Kemwood ACQ 1900 and Tanalith E (83.5 and 88.5%, respectively). The planks impregnated with Wolmanit CX-8 achieved the best quality regarding the final moisture content, its gradient and cup. The planks impregnated with Kemwood ACQ 1900 and Tanalith E showed similar quality regarding the penetration and some deformations after drying, but Kemwood ACQ 1900 impregnated planks had highest moisture content and gradient.

June 1, 2005

Industrial Kiln Drying and its Effect on Microstructure, Impregnation and Properties of Scots Pine Timber Impregnated for Above Ground Use. Part 2. Effect of Drying on Microstructure and Some Mechanical Properties of Scots Pine Wood

N. Terziev, G. Daniel

Page range: 434-439

Abstract

Scots pine ( Pinus sylvestris L.) planks were dried in industrial progressive, conventional batch and high temperature kilns. The timber was further impregnated in an industrial autoclave with three preservatives used for above ground use. Samples dried by the three test methods and control samples were thereafter processed for scanning electron microscopy observations. Small clear specimens were sawn for determination of impact bending strength, modulus of elasticity and rupture (MOE and MOR) and hardness. The high temperature dried wood (at 115 °C) was characterised by partially damaged apertures in some bordered pits and nano- (10–20 nm) and micro checks (1–2 μm) in the warty and S3 layers of the cell walls. It is probable that certain modifications in the structure of the wood polymer complex also occurred due to hemicellulose thermal degradation. The above-mentioned structural changes facilitated the penetration of the preservative during impregnation and its evacuation during the final stage of vacuum. The industrial progressive and conventional batch kiln drying had no visible effect on the microstructure of Scots pine wood. There was no critical reduction of the impact bending strength, hardness and MOE of the dried untreated wood regardless of the drying method. MOR was significantly decreased after the conventional kiln drying, but not following high temperature drying. Impregnation with Tanalith E and conventional batch kiln drying aggravated the MOE and MOR of the high temperature dried wood, but both MOE and MOR did not differ significantly from those of progressive and conventional batch kiln dried samples.

June 1, 2005

Study on Gypsum-Bonded Particleboard Reinforced with Jute Fibres

Y. Deng, T. Furuno

Page range: 440-445

Abstract

This paper deals with the influence of length and content (based on a percentage of wood particles) of jute fibers on the physical and mechanical properties of gypsum-bonded particleboard (GPB). The length and amount of jute fibers had a significant effect on the internal bond strength (IB) and the modulus of rupture (MOR) of GPB. The addition of jute fibers did not obviously influence the modulus of elasticity (MOE), the thickness swelling (TS) or water absorption (WA). The values of IB were prominently high at the 3 mm length and 9–12% contents of jute fibers. The highest value of MOR was attained when the board was made with fibers 12 mm in length and a fiber content of 15%. The optimal amount of jute fibers reinforced the mechanical properties of GPB to achieve high performance. However, too much jute fiber reduced the IB, MOR (except for 12 mm length), and MOE of GPB. The values of TS and WA decreased gradually with an increase in the fiber content for all fiber lengths. In addition, the GPB gave very low weight loss on exposure to wood-decaying fungi of both Tyromyces palustris (TYP) and Coriolus versicolor (COV) as compared with untreated wood. It was concluded that the combination of 3 mm length and 9–12% content or 12 mm length and 15% content of jute fibers was the optimum for producing good performance of

June 1, 2005

Literature Reports

Page range: 446-447

About this journal

Objective
Holzforschung (HF) is an international scholarly journal that publishes cutting-edge research on the biology, chemistry, physics and technology of wood and wood components. High quality papers about biotechnology and tree genetics are also welcome. Rated year after year as one of the top scientific journals in the category of Pulp and Paper (ISI Journal Citation Index), Holzforschung represents innovative, high quality basic and applied research. The German title reflects the journal's origins in a long scientific tradition, but all articles are published in English to stimulate and promote cooperation between experts all over the world. Ahead-of-print publishing ensures fastest possible knowledge transfer.

Topics

Biology, chemistry, physics and technology of wood and wood components
Biotechnology and tree genetics

Article formats
Original articles, Reviews, Short notes

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