scholarly journals Inter-Tracheid and Cross-Field Pitting in Compression Wood and Opposite Wood of Norway Spruce (Picea abies L.)

2011 ◽  
Vol 3 (2) ◽  
pp. 145-151 ◽  
Author(s):  
Asghar TARMIAN ◽  
Mohammad AZADFALLAH ◽  
Hadi GHOLAMIYAN ◽  
Mahdi SHAHVERDI
Keyword(s):  
Picea Abies ◽  
Norway Spruce ◽  
Compression Wood ◽  
Microfibril Angle ◽  
Air Permeability ◽  
Sem Images ◽  
Aperture Diameter ◽  
Opposite Wood ◽  
Bordered Pits ◽  
S2 Layer

Inter-tracheid and cross-filed pit specifications in compression wood and opposite wood of Norway spruce (Picea abies) were determined. Fewer pits of a smaller size and a smaller aperture diameter were observed in compression wood. In contrast to the uniseriate arrangement of bordered pit pairs in compression wood, both uniseriate and biseriate pits were observed in opposite wood. In contrast to the circular view of the pit aperture in opposite wood, a slit-like pit aperture was often observed in compression wood. SEM images showed a number of helical fissures on the tracheid walls and bordered pits of compression wood along the microfibril angle in the S2 layer. The cross-field pits in compression wood were dominantly piceoid but sometimes cupressoid and occasionally taxodioid, whereas they were mostly piceoid and occasionally cupressoid in opposite wood. Overall, some significant differences in the inter-tracheid and cross-field pitting between the compression wood and opposite wood can give some explanations for their different air permeability and drying kinetics found in the previous studies.

Effect of abnormal fibres on the mechanical properties of paper made from Norway spruce, Picea abies (L.) Karst.

Holzforschung ◽  
2008 ◽  
Vol 62 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Nasko Terziev ◽  
Geoffrey Daniel ◽  
Ann Marklund
Keyword(s):  
Mechanical Properties ◽  
Picea Abies ◽  
Norway Spruce ◽  
Cell Walls ◽  
Compression Wood ◽  
Morphological Changes ◽  
Mechanical Processing ◽  
Opposite Wood ◽  
Tear Index ◽  
Control Samples

Abstract The aim of the present study was to determine the effect of a variety of abnormal fibres on the mechanical properties of paper made from Norway spruce, Picea abies (L.) Karst. Fibres representing abnormality were obtained from trees treated by irrigation and fertilisation. Moreover, fibres from compression wood and its accompanying opposite wood were isolated. The effect of dislocations on paper quality was studied on four mixtures (20, 40, 60 and 80% fibres with induced dislocations) of untreated/compressed fibres. Two more groups consisting of control untreated samples and samples with 100%-induced dislocations were also included in the test. The mechanical properties of the paper were tested and the results were compared to those of control samples. Abnormal fibres reduced the desired mechanical properties of the final paper concerning tensile strength, modulus of elasticity and tear-tensile index. Irrespective of the type of treatment, all morphological changes introduced in fibre cell walls appear to directly affect changes in the mechanical properties of the paper. Control samples had a tear index of 25 compared to 10 mN m2 g-1 of samples containing 100% dislocations. It is obvious that 20% of dislocations, an amount that is expected to be induced in pulp under mechanical processing and transport, will contribute to a decrease in tear index with an average of 3 mN m2 g-1, i.e., 10% of the total value.

Air permeability in longitudinal and radial directions of compression wood of Picea abies L. and tension wood of Fagus sylvatica L.

Holzforschung ◽  
2009 ◽  
Vol 63 (3) ◽  
Author(s):  
Asghar Tarmian ◽  
Patrick Perré
Keyword(s):  
Picea Abies ◽  
Fagus Sylvatica ◽  
Tension Wood ◽  
Compression Wood ◽  
Air Permeability ◽  
Normal Wood ◽  
Reaction Wood ◽  
Anatomical Point ◽  
Bordered Pits ◽  
The Difference

Abstract The air permeability in longitudinal and radial directions of compression wood in spruce (Picea abies) and tension wood in beech (Fagus sylvatica) was compared with that of the corresponding normal wood. The primary aim of the present study was to explain why the reaction woods dry more slowly than the normal woods in the domain of free water. A number of boards conventionally dried to an average final moisture content of 12% were chosen to perform the measurements. Bordered pits on the radial walls of longitudinal tracheids in the compression and normal wood and intervessel or intervascular pits in the tension and normal wood were also examined. The reaction wood of both species is less permeable than the normal wood, both in longitudinal and radial directions. The difference in permeability was more pronounced between compression and normal wood of spruce, especially in longitudinal direction. From an anatomical point of view, this is likely related to some differences in anatomical characteristics affecting the airflow paths, such as the pit features. Such results can explain the difference in drying kinetics of the reaction and normal woods in the capillary regime of drying.

Properties of chemically and mechanically isolated fibres of spruce (Picea abies[L.] Karst.). Part 2: Twisting phenomena

Holzforschung ◽  
2005 ◽  
Vol 59 (2) ◽  
pp. 247-251 ◽  
Author(s):  
Ingo Burgert ◽  
Klaus Frühmann ◽  
Jozef Keckes ◽  
Peter Fratzl ◽  
Stefanie Stanzl-Tschegg
Keyword(s):  
Cell Wall ◽  
Picea Abies ◽  
Microfibril Angle ◽  
Cell Wall Assembly ◽  
Opposite Wood ◽  
Wood Compression ◽  
Mechanical Isolation ◽  
Wall Assembly ◽  
S2 Layer ◽  
Lateral Cell

Abstract The twisting behaviour of chemically and mechanically isolated fibres of spruce (Picea abies[L.] Karst.) was examined. Mechanical isolation was carried out using very fine tweezers to obtain fibres with an unmodified cell wall assembly. Chemical isolation was achieved using hydrogen peroxide and glacial acetic acid, leading to partial degradation of lignin and hemicelluloses. Besides normal adult wood, compression wood and opposite wood fibres were investigated. Fibre twisting while drying increased with higher microfibril angles in the S2 layer, and was significantly less pronounced for mechanically isolated compared to chemically macerated fibres. A simple model is introduced that takes into account the interdependency between lateral cell-wall shrinkage and the microfibril angle in the S2 cell wall.

Microfibril angle of Norway spruce [Picea abies (L.) Karst.] compression wood: comparison of measuring techniques

2000 ◽  
Vol 46 (5) ◽  
pp. 343-349 ◽  
Author(s):  
Seppo Andersson ◽  
Ritva Serimaa ◽  
Mika Torkkeli ◽  
Timo Paakkari ◽  
Pekka Saranpää ◽  
...  
Keyword(s):  
Picea Abies ◽  
Norway Spruce ◽  
Compression Wood ◽  
Microfibril Angle ◽  
Measuring Techniques

MICROFIBRIL ANGLE OF THE S1 CELL WALL LAYER OF NORWAY SPRUCE COMPRESSION WOOD TRACHEIDS

IAWA Journal ◽  
2004 ◽  
Vol 25 (4) ◽  
pp. 415-423 ◽  
Author(s):  
Jonas Brändström
Keyword(s):  
Norway Spruce ◽  
Compression Wood ◽  
Microfibril Angle ◽  
Soft Rot ◽  
Wall Layer ◽  
Thermomechanical Pulp ◽  
Ultrastructural Organization ◽  
Normal Wood ◽  
Cell Wall Layer ◽  
Fracture Characteristics

The ultrastructural organization of the outer layer of the secondary wall (i.e. S1 layer) of Norway spruce (Picea abies (L.) Karst.) compression wood tracheids was investigated with emphasis on the microfibril angle. Light microscopy was used to study the orientation of soft rot cavities (viz. microfibril angle) in compression wood tracheids from macerated soft rot degraded wood blocks. In addition, surface and fracture characteristics of compression wood tracheids selected from a thermomechanical pulp were investigated using scanning electron microscopy (SEM). Results showed that the orientation of soft rot cavities varied little between tracheids and the angles were also consistent along the length of individual tracheids. The average S1 microfibril angle in two selected annual rings was 90.0° ± 2.7° and 88.9° ± 2.4° respectively. SEM observations of the compression wood tracheids from the pulp showed distinct fractures between S1 and S2 or within S1 and these fractures were oriented perpendicular to the tracheid axis. It was concluded that the microfibril angle of the S1 layer of compression wood tracheids is higher and less variable than normal wood tracheids. This is considered an adaptation for restraining the compressive forces that act on leaning conifer stems or branches.

scholarly journals Genetic control of transition from juvenile to mature wood with respect to microfibril angle in Norway spruce (Picea abies) and lodgepole pine (Pinus contorta)

2018 ◽  
Vol 48 (11) ◽  
pp. 1358-1365 ◽  
Author(s):  
Haleh Hayatgheibi ◽  
Nils Erik Gustaf Forsberg ◽  
Sven-Olof Lundqvist ◽  
Tommy Mörling ◽  
Ewa J. Mellerowicz ◽  
...  
Keyword(s):  
Picea Abies ◽  
Genetic Control ◽  
Norway Spruce ◽  
Pinus Contorta ◽  
Juvenile Wood ◽  
Lodgepole Pine ◽  
Microfibril Angle ◽  
Mature Wood ◽  
Direct Selection ◽  
Narrow Sense Heritability

Genetic control of microfibril angle (MFA) transition from juvenile wood to mature wood was evaluated in Norway spruce (Picea abies (L.) Karst) and lodgepole pine (Pinus contorta Douglas ex Loudon). Increment cores were collected at breast height (1.3 m) from 5664 trees in two 21-year-old Norway spruce progeny trials in southern Sweden and from 823 trees in two lodgepole pine progeny trials, aged 34–35 years, in northern Sweden. Radial variations in MFA from pith to bark were measured for each core using SilviScan. To estimate MFA transition from juvenile wood to mature wood, a threshold level of MFA 20° was considered, and six different regression functions were fitted to the MFA profile of each tree after exclusion of outliers, following three steps. The narrow-sense heritability estimates (h2) obtained for MFA transition were highest based on the slope function, ranging from 0.21 to 0.23 for Norway spruce and from 0.34 to 0.53 for lodgepole pine, while h2 were mostly non-significant based on the logistic function, under all exclusion methods. Results of this study indicate that it is possible to select for an earlier MFA transition from juvenile wood to mature wood in Norway spruce and lodgepole pine selective breeding programs, as the genetic gains (ΔG) obtained in direct selection of this trait were very high in both species.

WITHIN-TREE VARIATION IN ANATOMICAL PROPERTIES OF COMPRESSION WOOD IN RADIATA PINE

IAWA Journal ◽  
2004 ◽  
Vol 25 (3) ◽  
pp. 253-271 ◽  
Author(s):  
Lloyd A. Donaldson ◽  
Jenny Grace ◽  
Geoff M. Downes
Keyword(s):  
Wall Thickness ◽  
Compression Wood ◽  
Microfibril Angle ◽  
Basic Density ◽  
Radiata Pine ◽  
Lumen Diameter ◽  
Normal Wood ◽  
Lignin Distribution ◽  
Opposite Wood ◽  
Anatomical Properties

Two trees of radiata pine, one showing severe lean, the other growing almost vertically, were assessed for the presence and anatomical properties of compression wood, including anatomy, lignin distribution, microfibril angle, basic density, radial and tangential lumen diameter and cell wall thickness. Both trees contained significant amounts of compression wood although the severity and amount of compression wood was greater in the leaning tree. Changes in lignin distribution seem to be characteristic of the mildest forms of compression wood with reduced lignification of the middle lamella representing the earliest change observed from normal wood. An increase in microfibril angle was associated with both mild and severe compression wood although examples of severe compression wood with the same or smaller microfibril angles than opposite wood, or with very small microfibril angles, were found. When segregated into mild and severe compression wood the average difference in microfibril angle was 4° and 8° respectively compared with opposite wood. Within-ring distribution of microfibril angle was different in severe compression wood compared to opposite wood with higher angles in the latewood.Severe compression wood showed a 22% increase in basic density compared to mild compression wood and opposite wood. The increased density was accounted for in terms of a 26% increase in tracheid wall thickness throughout the growth ring, offset by a 9% increase in radial lumen diameter, slightly greater in the latewood. There were no significant changes in density or cell dimensions in mild compression wood compared with opposite wood.

A comprehensive analysis of the relation of cellulose microfibril orientation and lignin content in the S2 layer of different tissue types of spruce wood (Picea abies (L.) Karst.)

Holzforschung ◽  
2008 ◽  
Vol 62 (4) ◽  
Author(s):  
Karin Jungnikl ◽  
Gerald Koch ◽  
Ingo Burgert
Keyword(s):  
Picea Abies ◽  
Cellulose Microfibril ◽  
Lignin Content ◽  
Microfibril Angle ◽  
Structural Features ◽  
X Ray Diffraction ◽  
Spruce Wood ◽  
Cellulose Microfibril Orientation ◽  
The Individual ◽  
S2 Layer

Abstract A possible relation between cellulose microfibril angle and lignin content in the S2 layer was investigated by X-ray diffraction and cellular UV microspectrophotometry on spruce tissues [Picea abies] with different structural features and chemical composition. A strong correlation was not found, neither for the individual tissue types nor for the compiled data of all tissues. As the data did not confirm the findings in former studies, further examinations are necessary concerning a possible general interrelation between microfibril angle and lignin content.

Properties of young Araucaria heterophylla (Norfolk Island pine) reaction and normal wood

Holzforschung ◽  
2014 ◽  
Vol 68 (7) ◽  
pp. 817-821 ◽  
Author(s):  
Monika Sharma ◽  
Clemens Michael Altaner
Keyword(s):  
Pinus Radiata ◽  
Modulus Of Elasticity ◽  
Compression Wood ◽  
Microfibril Angle ◽  
Normal Wood ◽  
Opposite Wood ◽  
Araucaria Heterophylla ◽  
Norfolk Island ◽  
Anatomical Properties

Abstract Young Araucaria heterophylla (Salisb.) Franco seedlings have been grown tilted to obtain compression wood (CW), opposite wood (OW), and normal wood (NW). Mechanical and anatomical properties of these wood tissues have been assessed. CW had characteristics associated with low severity. OW and NW did not differ significantly in their properties and were found to have a considerably lower microfibril angle and higher modulus of elasticity than those of juvenile corewood of Pinus radiata D. Don.

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