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Articles containing the keyword 'fiber'

Category: Article

article id 5147, category Article
J. Eriksson, J. Bergholm, K. Kvist. (1981). Injury to vegetation caused by industrial emissions of boron compounds. Silva Fennica vol. 15 no. 4 article id 5147. https://doi.org/10.14214/sf.a15374
Keywords: Betula pendula; boron; soil; Sweden; toxicity; emissions; air pollution; leaves; fiberclass factory
Abstract | View details | Full text in PDF | Author Info

At immediate surroundings of a fiberglass plant in Central Sweden, vegetation shows toxicity symptoms. Soils and birch (Betula pendula Roth) leaves were sampled. The soil was analysed for water soluble and organic bound boron, carbon, nitrogen, and pH. Vegetation was analysed for total boron. Both fractions of boron in the soils increased towards the factory. Organic bound boron increased irregularly because of its strong correlation to carbon content which varied in the area. The C/N ratio increased nearer the industry due to the harmful effect of boron on the decomposition of organic matter. No relation between pH and the distance from the emission source was visible, but B/C ratio was found to increase with increasing pH of the soil. Boron levels in birch leaves were elevated very much close to the factory. The geographical distribution of high levels of boron in birch, corresponded well with high values in soils, and also with the main wind directions. The limit values for visible injury on birch were found to be around 5 ppm of water-soluble boron in soil and around 200 ppm in leaves.

  • Eriksson, E-mail: je@mm.unknown (email)
  • Bergholm, E-mail: jb@mm.unknown
  • Kvist, E-mail: kk@mm.unknown
article id 5097, category Article
K. M. Bhat, Ari Ferm, Matti Kärkkäinen. (1981). On the properties of one-year shoots of Betula pubescens Ehrh. and Salix spp. Silva Fennica vol. 15 no. 1 article id 5097. https://doi.org/10.14214/sf.a15038
Keywords: Betula pubescens; wood properties; bark; basic density; willows; vessels; fibers; Salix sp.; shoots
Abstract | View details | Full text in PDF | Author Info

Downy birch (Betula pubescens Ehrh.) trees growing on a drained peatland were cut during dormancy. The properties of the one-year old shoots produced by the stumps were measured in the autumn after one growing season. The one-year old willow shoots (a mixture of Salix phylicifolia L., S. pentandra L. and S. caprea L.) were collected from an abandoned field.

The basic density of unbarked shoots was 443 kg/m3 for birch and 346 kg/m3 for willow. The basic density of the bark was much higher than that of the wood. The effect of shoot length on the properties was small with the exception of cellular proportions. The fibre percentage increased and vessel percentage decreased with increasing shoot length.

The PDF includes a summary in Finnish.

  • Bhat, E-mail: kb@mm.unknown (email)
  • Ferm, E-mail: af@mm.unknown
  • Kärkkäinen, E-mail: mk@mm.unknown
article id 5095, category Article
K. M. Bhat, Matti Kärkkäinen. (1981).  . Silva Fennica vol. 15 no. 1 article id 5095. https://doi.org/10.14214/sf.a15036
English title: Variation in structure and selected properties of Finnish birch wood. III.
Keywords: Betula pendula; silver birch; branches; wood anatomy; parenchyma; stem; vessels; fibers
Abstract | View details | Full text in PDF | Author Info

Variation of cellular proportion within the same growth rings counted from the pith of the stems and branches in four trees of Betula pendula Roth was studied. The fibre percentage decreased from breast height to the crown and then increased in the branches. The reverse trend was found in the percentage of vessels and parenchyma, although the latter varied relatively little. No statistically significant differences were found in the percentages of fibres, vessels and rays within the same growth rings counted from the pith between the stems and branches. In both the stem and the branches, the proportion of fibres increased and that of vessels and rays decreased from the pith to the surface. Even crown formed wood differed from that of stem formed. 

The PDF includes a summary in Finnish. 

  • Bhat, E-mail: kb@mm.unknown (email)
  • Kärkkäinen, E-mail: mk@mm.unknown

Category: Article

article id 7511, category Article
Jukka Tyrväinen. (1995). Wood and fiber properties of Norway spruce and its suitability for thermomechanical pulping. Silva Fennica vol. 0 no. 249 article id 7511. https://doi.org/10.14214/aff.7511
Keywords: Picea abies; wood properties; pulpwood; fiber properties; thermomechanical pulping; pulp properties
Abstract | View details | Full text in PDF | Author Info

In the first part of the study, the selected wood and fiber properties were investigated in terms of their occurrence and variation in wood, as well as their relevance for thermomechanical pulping process and related end-products. It was concluded that the most important factors were the fiber dimensions, juvenile wood content, and in some cases, the content of heartwood being associated with extremely dry wood with low permeability in spruce. The following pulpwood assortments of which pulping potential was assumed to vary were formed: wood from regeneration cuttings, first-thinnings wood, and sawmill chips.

In the experimental part of the study, the average wood and fibre characteristics and their variation were determined for the raw material groups. Subsequently, each assortment – equalling about 1,500 m3 roundwood – was pulped separately for 24 h period. The properties of obtained newsgrade thermomechanical pulps were then determined.

Thermomechanical pulping (TMP) from sawmill chips had the highest proportion of long fibres, smallest proportion of fines, and had generally the coarsest and longest fibers. TMP from first-thinned wood was the opposite, whereas that from regeneration cuttings fell in between these two. High proportion of dry heartwood in wood originating from regeneration cuttings produced a slightly elevated shives content. However, no differences were found in pulp specific energy consumption. The obtained pulp tear index was clearly the best in TMP made from sawmill chips and poorest in pulp from first-thinned wood, which had generally inferior strength properties. No big differences in any of the strength properties were found between pulp from sawmill residual wood and regeneration cuttings. Pulp optical properties were superior in TMP from first-thinnings. No noticeable differences were found in sheet density, bulk, air permeance or roughness between the three pulps.

The most important wood quality factors were the fibre length, fibre cross-sectional dimensions and percentage juvenile wood. Differences found in the quality of TMP assortments suggest that they could be segregated and pulped separately to obtain specific product characteristics and to minimize unnecessary variation in the raw material and pulp quality.

  • Tyrväinen, E-mail: jt@mm.unknown (email)

Category: Research article

article id 7822, category Research article
Mulualem Tigabu, Annika M. Felton. (2018). Multivariate calibration of near infrared spectra for predicting nutrient concentrations of solid moose rumen contents. Silva Fennica vol. 52 no. 1 article id 7822. https://doi.org/10.14214/sf.7822
Keywords: Alces alces; lignin; NIRS; acid-detergent fiber; crude protein; microbial-N; neutral detergent fiber
Highlights: Multivariate calibrations were established for predicting nutrient concentrations of solid moose rumen contents by near infrared spectroscopy (NIRS); Crude protein, available protein and ash contents were accurately predicted; Prediction of microbial nitrogen, ash, acid-detergent fiber, neutral detergent fiber and lignin were satisfactory; The results demonstrate that NIRS offers quick and inexpensive procedure to quantify nutrient concentrations of solid rumen contents.
Abstract | Full text in HTML | Full text in PDF | Author Info

This study aimed at establishing calibrations to predict nutrient concentrations of solid moose (Alces alces L.) rumen content using near infrared spectroscopy (NIRS), as an alternative to expensive chemical analyses. NIR reflectance spectra of 148 dry pulverized samples were recorded. The scanned samples were then analyzed for crude protein, available protein, microbial nitrogen (N), ash, acid-detergent fiber (ADF), neutral detergent fiber (NDF) and lignin contents following standard chemical analysis procedures. The calibration models were derived by Orthogonal Projection to Latent Structure (OPLS) and validated using external prediction sets. The calibration models accurately predicted crude protein, available protein and ash contents (R2 = 0.99, 0.96, and 0.92, prediction error = 0.39, 0.72 and 0.53% dry matter, respectively) while NDF (R2 = 0.92; prediction error = 2.23% dry matter) and ADF (R2 = 0.89; prediction error = 1.94% dry matter) were predicted with sufficient accuracy and that of microbial-N (R2 = 0.81; prediction error = 1.25 mg yeast-RNA g–1 dry matter) and lignin (R2 = 0.84; prediction error = 1.05% dry matter) were acceptable. The ratio of performance to deviation values were > 3.0 for crude protein and available protein, between 3.0 and 2.5 for ADF, NDF and lignin, and 2.32 for microbial-N; attesting the robustness of the calibration models. It can be concluded that NIR spectroscopy offers a quick and inexpensive procedure for prediction of nutrient concentrations of solid rumen contents in wild herbivores.

  • Tigabu, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Box 49, SE-230 53 Alnarp, Sweden ORCID http://orcid.org/0000-0003-2471-1168 E-mail: mulualem.tigabu@slu.se (email)
  • Felton, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Box 49, SE-230 53 Alnarp, Sweden E-mail: annika.felton@slu.se
article id 1611, category Research article
Ilpo Ervasti. (2016). Wood fiber contents of different materials in the paper industry material chain expressed in roundwood equivalents (RWEs). Silva Fennica vol. 50 no. 4 article id 1611. https://doi.org/10.14214/sf.1611
Keywords: pulpwood; paper production; raw materials; roundwood equivalent (RWE); wood pulp; recycled fiber; recovered paper; material recycling
Highlights: The paper industry material recycling chain consists of different material streams; Consumed paper products form a huge fiber source for industry. However, a reliable measuring system should be developed to quantify these fiber volumes; Converting factors are introduced to quantify the wood fiber contents of different paper industry-related materials of the chain, namely, wood pulp, paper and recovered paper; By using these conversion factors it is possible to convert for example global recovered paper utilization volumes into wood fiber volumes expressed in roundwood equivalents (RWEs).
Abstract | Full text in HTML | Full text in PDF | Author Info

At present, there are no means for reliably comparing the wood fiber contents of different material streams within the paper industry material chain with each other. The aim of this article is to introduce conversion factors that make it possible to quantify the volume of wood expressed in roundwood equivalent (RWE) values for different paper industry-related materials in the material chain. These conversion factors apply to wood pulp, paper, and recovered paper. European data are used in quantifying the paper industry material streams and calculating the RWE conversion factors. The introduced conversion factors can be used to estimate RWE volumes at a global scale. With assumption that paper recycling did not occur and that paper production volume remained unchanged, an additional volume of 666 million m3 RWEs would be required globally per annum to produce 167 million tons of virgin wood pulp to replace 222 million tons of recovered paper utilized by the paper industry in 2010. This volume is approximately the same as 1.6 times the total removal of wood in Europe (EU27), or the total annual removal of wood in the USA, Canada, and Brazil combined.

  • Ervasti, Aalto University, Industrial Engineering and Management, Maarintie 8, 02150 Espoo, Finland E-mail: ilervasti@gmail.com (email)
article id 257, category Research article
Nadir Ayrilmis. (2008). Effect of compression wood on dimensional stability of medium density fiberboard. Silva Fennica vol. 42 no. 2 article id 257. https://doi.org/10.14214/sf.257
Keywords: compression wood; linear expansion; linear contraction; thickness swelling; thickness shrinkage; medium density fiberboard; dimensional stability
Abstract | View details | Full text in PDF | Author Info
This study evaluated the effect of compression wood on dimensional stability of medium density fiberboards (MDF) manufactured from fiber furnishes of pine (Pinus nigra Arnold var. pallasiana) containing compression wood. Two panel types were manufactured from two different compression wood (CW) portion / normal wood (NW) portions in the furnish, 75/25 and 10/90, respectively. Linear and thickness variations of the panels exposed to various relative humidites at 20 °C, linear expansion/contraction and thickness swelling/shrinkage, were measured according to the procedures defined by DIN EN 318 (2005) standard test method. Panels made from fiber furnish containing 75% the CW had higher linear expansion and linear contraction values with an average value of 0.286% and 0.247% than those of panels made from fiber furnish containing 10% the CW with an average value of 0.184% and 0.152%, respectively. As for thickness swelling and thickness shrinkage properties, panels made from fiber furnish containing 75% the CW had the thickness swelling and thickness shrinkage values with an average of 5.042% and 4.402% while panels made from fiber furnish containing 10% the CW had the values with 3.621% and 2.861%, respectively. Consequently, based on the findings obtained from this study, expansion and swelling properties of the MDF panels were negatively affected by compression wood increase.
  • Ayrilmis, University of Istanbul, Faculty of Forestry, Department of Wood Mechanics and Technology, Bahcekoy, TR-34473 Istanbul, Turkey E-mail: nadiray@istanbul.edu.tr (email)
article id 358, category Research article
Turgay Akbulut, Nadir Ayrilmis. (2006). Effect of compression wood on surface roughness and surface absorption of medium density fiberboard. Silva Fennica vol. 40 no. 1 article id 358. https://doi.org/10.14214/sf.358
Keywords: compression wood; medium density fiberboard; surface properties; surface analysis
Abstract | View details | Full text in PDF | Author Info
Compression wood is undoubtedly one of the most important raw material variables in wood based panel manufacturing. This study evaluated effect of compression wood on surface roughness and surface absorption (flow distance) of medium density fiberboards (MDF) manufactured from furnishes of pine (Pinus nigra Arnold var. pallasiana) containing compression wood. Panels were manufactured from two different portions of the furnish, one of the portions having a compression wood/normal wood ratio of 75/25, and the other having a ratio of 10/90. Surface absorption and surface roughness were determined according to (EN 382-1) and (ISO 4287), respectively. It was found that panels made from furnish with a 75/25 ratio had a significantly lower surface absorption value (255.78 mm) than panels made from furnish with a 10/90 ratio (317.95 mm). Surface roughness measurements based on three roughness parameters, average roughness (Ra), mean peak-to-valley height (Rz), and maximum peak-to-valley height (Ry) were considered to evaluate the surface characteristics of the panels and supported the above findings as the panels made from furnish with a 75/25 ratio had slightly rougher surface with average values of 4.15 µm (Ra). From the tests performed, we conclude that increasing of the compression wood portion increased the surface roughness and decreased the surface absorption value.
  • Akbulut, Istanbul University, Faculty of Forestry, Bahcekoy, TR-34473 Istanbul, Turkey E-mail: ta@nn.tr
  • Ayrilmis, Istanbul University, Faculty of Forestry, Bahcekoy, TR-34473 Istanbul, Turkey E-mail: nadiray@istanbul.edu.tr (email)
article id 494, category Research article
Antero Varhimo, Soili Kojola, Timo Penttilä, Raija Laiho. (2003). Quality and yield of pulpwood in drained peatland forests: pulpwood properties of Scots pine in stands of first commercial thinnings. Silva Fennica vol. 37 no. 3 article id 494. https://doi.org/10.14214/sf.494
Keywords: Pinus sylvestris; peatland; thinning; silviculture; pulpwood; fiber; pulping
Abstract | View details | Full text in PDF | Author Info
The inherent structural dynamics of drained peatland forests may result in a great variation in various wood and fiber properties. We examined variation in fiber and pulp properties i) among stands, ii) among trees within stands, and iii) within trees in young stands dominated by Scots pine (Pinus sylvestris L.). The stands, selected to cover a maximal range of the potential variation, were all at a stage of development where the first commercial thinnings would be feasible. Differences in the processability of the thinning removals were small. In similar kraft cooking conditions, a 5-unit variation in the kappa number of unbleached pulp was observed among the stands. Stand origin had no effect on pulp bleaching. The wood formed prior to drainage had a higher density, shorter fibers, was slightly slower delignified by cooking, and its yield was slightly lower than that of post-drainage wood. These properties, except for high density, are typical for juvenile wood in general, and at stand level they did not correlate with the proportion of pre-drainage wood. When the variation in fiber and pulp properties was broken down into its components, most of it was derived from tree-level in all the cases. On average, the fiber and pulp properties did not differ from those observed for first-thinning pulpwood from upland sites. Consequently, peatland-grown pulpwood may be mixed with other pulpwood in industrial processes. It would probably be best suited as the raw material for pulps with high bonding requirements, e.g. in the top ply of multi-ply board grades or in some specialty grades.
  • Varhimo, KCL, P.O. Box 70, FIN-02151 Espoo, Finland E-mail: antero.varhimo@kcl.fi (email)
  • Kojola, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: sk@nn.fi
  • Penttilä, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: sp@nn.fi
  • Laiho, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: raija.laiho@helsinki.fi

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