A comparison of static bending, compression and tension parallel to grain and toughness properties of compression wood and normal wood of a giant sequoia

1973 ◽  
Vol 7 (4) ◽  
pp. 241-250 ◽  
Author(s):  
R. A. Cockrell ◽  
R. M. Knudson
Keyword(s):  
Compression Wood ◽  
Normal Wood ◽  
Giant Sequoia

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.

Contribution of lignin to the stress transfer in compression wood viewed by tensile FTIR loading

Holzforschung ◽  
2020 ◽  
Vol 74 (5) ◽  
pp. 459-467 ◽  
Author(s):  
Hui Peng ◽  
Lennart Salmén ◽  
Jiali Jiang ◽  
Jianxiong Lu
Keyword(s):  
Compression Wood ◽  
Microfibril Angle ◽  
Stress Transfer ◽  
Direct Coupling ◽  
Normal Wood ◽  
Static Tensile Loading ◽  
Static Tensile ◽  
Lower Load ◽  
Dynamic Loading Conditions ◽  
Molecular Deformation

AbstractTo achieve efficient utilization of compression wood (CW), a deeper insight into the molecular interactions is necessary. In particular, the role of lignin in the wood needs to be better understood, especially concerning how lignin contributes to its mechanical properties. For this reason, the properties of CW and normal wood (NW) from Chinese fir (Cunninghamia lanceolata) have been studied on a molecular scale by means of polarized Fourier transform infrared (FTIR) spectroscopy, under both static and dynamic loading conditions. Under static tensile loading, only molecular deformations of cellulose were observed in both CW and NW. No participation of lignin could be detected. In relation to the macroscopic strain, the molecular deformation of the cellulose C-O-C bond was greater in NW than in CW as a reflection of the higher microfibril angle and the lower load taken up by CW. Under dynamic deformation, a larger contribution of the lignin to stress transfer was detected in CW; the molecular deformation of the lignin being highly related to the amplitude of the applied stress. Correlation analysis indicated that there was a direct coupling between lignin and cellulose in CW, but there was no evidence of such a direct coupling in NW.

Deposition of Lignin in Differentiating Xylem Cell Walls of Normal and Compression Wood of Buxus microphylla var. insularis Nakai

Holzforschung ◽  
1999 ◽  
Vol 53 (2) ◽  
pp. 156-160 ◽  
Author(s):  
Nobuo Yoshizawa ◽  
Hiromi Ohba ◽  
Junko Uchiyama ◽  
Shinso Yokota
Keyword(s):  
Visible Light ◽  
Cell Walls ◽  
Compression Wood ◽  
Outer Region ◽  
Cell Types ◽  
Deposition Process ◽  
The Other ◽  
Normal Wood ◽  
Long Period ◽  
Buxus Microphylla

Summary The deposition process of lignins within differentiating xylem walls of normal and compression wood of Buxus microphylla var. insularis Nakai was examined by visible-light microspectrophotometry coupled with the Wiesner and Mäule reactions. Buxus formed compression wood on the underside of the leaning stems. The secondary walls of the vessels and fibre tracheids in compression wood showed an intense lignification in the outer region of S2 layer. The spectra of tissues after Mäule and Wiesner reactions showed absorption maxima of around 515 nm and 570 nm, respectively. In differentiating xylem cells of normal wood, lignin composed of both guaiacyl and syringyl units was deposited mainly during the S2 thickening and after formation of the S3 layer in fibre tracheids, whereas in vessels it was actively deposited mainly during the S2 thickening. In compression wood, the deposition of the lignin composed of guaiacyl units was observed for a long period from the early stages of the S2 thickening. Lignification was becoming particularly active at the outer portion of S2 layer after completion of the S2 thickening in both vessels and fibre tracheids. On the other hand, the syringyl units were deposited mainly during the S2 thickening in both cell types.

Helical Thickenings in Normal and Compression Wood of Some Softwoods

IAWA Journal ◽  
1985 ◽  
Vol 6 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Nobuo Yoshizawa ◽  
Takao Itoh ◽  
Ken Shimaji
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Secondary Wall ◽  
Compression Wood ◽  
Normal Wood ◽  
Additional Layer ◽  
Innermost Layer ◽  
Inner Surface ◽  
Helical Thickenings ◽  
Scanning Electron

Compression wood in some softwoods having helical thickenings on the inner surface of normal wood tracheids were examined using a scanning electron microscope. Helical thickenings of Taxus, Torreya and Cephalotaxus have narrow bases, and are loosely attached to the innermost layer of the secondary wall, while those of Pseudotsuga, Picea and Larix have broad bases blended tightly with the microfibrils of the S3 layer in normal wood. The transition from normal to compression wood entails a preservation of the thickenings in Taxus, Torreya and Cephalotaxus, while they are replaced by helical ridges and cavities in Pseudotsuga, Picea and Larix. The direction of helical thickenings gradually changes from an S- to a Z-helix, or a Z- to an S-helix in the course of the transition from normal to compression wood, or vice versa in Taxus, Torreya and Cephalotaxus. Helical checks never occur in these species. In Pseudotsuga, however, helical thickenings can be deposited as an additional layer on the helical ridges. The results obtained in the present investigation revealed that the orientation of the thickenings did not always coincide with that of the innermost microfibrils of the secondary wall layers, indicating that helical thickenings may be considered as a layer independent of the secondary wall.

Lignin distribution in mild compression wood of Pinus radiata

1999 ◽  
Vol 77 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Lloyd A Donaldson ◽  
Adya P Singh ◽  
Arata Yoshinaga ◽  
Keiji Takabe
Keyword(s):  
Cell Wall ◽  
Fluorescence Microscopy ◽  
Pinus Radiata ◽  
Compression Wood ◽  
Middle Lamella ◽  
Confocal Fluorescence Microscopy ◽  
Interference Microscopy ◽  
Normal Wood ◽  
Lignin Distribution ◽  
Confocal Fluorescence

Lignin distribution in the tracheid cell wall of mild compression wood in Pinus radiata D. Don was examined by interference microscopy, confocal fluorescence microscopy, and ultraviolet (UV) microscopy. Two anatomically different samples of mild compression wood were compared with a sample of normal wood using quantitative interference microscopy and microdensitometry combined with confocal fluorescence microscopy to estimate the quantitative or semiquantitative lignin distribution in the S2 and S2L regions of the secondary cell wall and of the cell corner middle lamella (CCML). One of these samples was briefly examined by UV microscopy for comparison. Quantitative interference microscopy provided information on lignin concentration in different regions of the cell wall with values of 26, 46, and 57%, respectively, for the S2, S2L, and CCML regions of sample 1 and 20, 29, and 46%, respectively, for the same regions of sample 2. Microdensitometry of confocal fluorescence images provided semiquantitative information on the relative lignin distribution based on lignin autofluorescence. Comparison between the two compression wood samples using autofluorescence gave results that were in partial agreement with interference microscopy with respect to the relative lignification levels in the S2, S2L, and CCML regions. Some improvement was achieved by using calibration values for hemicellulose rather than holocellulose for interference data in the S2L region. Results for UV microscopy performed on sample 1 indicated that the lignification of the CCML region was comparable with that of the S2L region in this sample but with some variation among cells. All three techniques indicated significant variation in lignification levels of the S2L and CCML regions among adjacent cells and a significant reduction in the lignification of the CCML region compared to normal wood.Key words: lignin distribution, interference microscopy; confocal fluorescence microscopy, UV microscopy, mild compression wood, Pinus radiata D. Don.

scholarly journals Fluorescence-Detected Linear Dichroism of Wood Cell Walls in Juvenile Serbian Spruce: Estimation of Compression Wood Severity

2016 ◽  
Vol 22 (2) ◽  
pp. 361-367 ◽  
Author(s):  
Aleksandar Savić ◽  
Aleksandra Mitrović ◽  
Lloyd Donaldson ◽  
Jasna Simonović Radosavljević ◽  
Jelena Bogdanović Pristov ◽  
...  
Keyword(s):  
Cross Sections ◽  
Cell Walls ◽  
Compression Wood ◽  
Linear Dichroism ◽  
Normal Wood ◽  
Qualitative Comparison ◽  
Cellulose Fibril ◽  
Cellulose Fibrils ◽  
Picea Omorika ◽  
Serbian Spruce

AbstractFluorescence-detected linear dichroism (FDLD) microscopy provides observation of structural order in a microscopic sample and its expression in numerical terms, enabling both quantitative and qualitative comparison among different samples. We applied FDLD microscopy to compare the distribution and alignment of cellulose fibrils in cell walls of compression wood (CW) and normal wood (NW) on stem cross-sections of juvenile Picea omorika trees. Our data indicate a decrease in cellulose fibril order in CW compared with NW. Radial and tangential walls differ considerably in both NW and CW. In radial walls, cellulose fibril order shows a gradual decrease from NW to severe CW, in line with the increase in CW severity. This indicates that FDLD analysis of cellulose fibril order in radial cell walls is a valuable method for estimation of CW severity.

Detection and Classification of Norway Spruce Compression Wood in Reflected Light by Means of Hyperspectral Image Analysis

IAWA Journal ◽  
2009 ◽  
Vol 30 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Philipp Duncker ◽  
Heinrich Spiecker
Keyword(s):  
Image Analysis ◽  
Norway Spruce ◽  
Tree Ring ◽  
Compression Wood ◽  
Hyperspectral Image ◽  
Normal Wood ◽  
Cross Sectional ◽  
Spectral Angle Mapper ◽  
Hyperspectral Image Analysis ◽  
Reflected Light

A methodology has been developed based on reflected light to detect compression wood in stem cross sections of Norway spruce (Picea abies [L.] Karst.). In addition to quantify the spatial distribution of compression wood, the chronological pattern of its formation is recorded by cross linking the pixel classification to the tree ring sequence. An imaging spectrometer is used to record the spectral characteristics in the visible light and near infrared of the cross-sectional surface. Cross-sectional areas are classified by hyperspectral image analysis into severe compression wood, moderate compression wood, normal wood, and background/cracks. The classification is performed by the Spectral Angle Mapper algorithm, which compares the standardized spectrum of each pixel with reference spectra stored in a spectral library. The reference spectra are obtained from selected training areas of the different compression wood severity classes identified by cell characteristics under a light microscope. The tree ring boundaries are located in a grey scale image which shows the spatial information at wavelength 435 nm and the annual radial increment is measured. The classification accuracy is tested by a confusion matrix and cross-analysed with High-Frequency Densitometry.

scholarly journals In situ observation of shrinking and swelling of normal and compression Chinese fir wood at the tissue, cell and cell wall level

2021 ◽  
Author(s):  
Tianyi Zhan ◽  
Jianxiong Lyu ◽  
Michaela Eder
Keyword(s):  
Cell Wall ◽  
Compression Wood ◽  
Chinese Fir ◽  
Fine Tuning ◽  
Tissue Cell ◽  
In Situ Observation ◽  
Normal Wood ◽  
Moisture Variation ◽  
Hierarchical Levels

AbstractThe shrinking and swelling of wood due to moisture changes are intrinsic material properties that control and limit the use of wood in many applications. Herein, hygroscopic deformations of normal and compression wood of Chinese fir (Cunninghamia lanceolata [Lamb.] Hook.) were measured during desorption and absorption processes. The dimensional changes were observed in situ by an environmental scanning electron microscope and analyzed at different hierarchical levels (tissue, cell and cell wall). The relationship between moisture variation and hygroscopic deformation was measured. During initial desorption periods from 95 to 90 or 75% RH, an expansion of the lumen and a shrinkage of the cell wall were observed, revealing a non-uniform and directional deformation of single wood cells. The variation of shrinking or swelling at different hierarchical levels (tissue, cell and cell wall) indicates that the hygroscopic middle lamella plays a role in the deformation at the tissue level. Higher microfibril angles and helical cavities on the cell wall in compression wood correlate with a lower shrinking/swelling ratio. Normal wood showed a more pronounced swelling hysteresis than compression wood, while the sorption hysteresis was almost the same for both wood types. This finding is helpful to elucidate effects of micro- and ultrastructure on sorption. The present findings suggest that the sophisticated system of wood has the abilities to adjust the hygroscopic deformations by fine-tuning its hierarchical structures.

scholarly journals The Nature of Reaction Wood III. Cell Division and Cell Wall Formation in Conifer Stems

1952 ◽  
Vol 5 (4) ◽  
pp. 385 ◽  
Author(s):  
ABW Ardrop ◽  
HE Dadswell
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Secondary Wall ◽  
Compression Wood ◽  
Normal Wood ◽  
Reaction Wood ◽  
Primary Wall ◽  
Wall Formation ◽  
Tracheid Length ◽  
Secondary Wall Formation

Cell division, the nature of extra-cambial readjustment, and the development of the secondary wall in the tracheids of conifer stems have been investigated in both compression wood and normal wood. It has been shown that the reduction in tracheid length, accompanying the development of compression wood and, in normal wood, increased radial growth after suppression, result from an increase in the number of anticlinal divisions in the cambium. From observations of bifurcated and otherwise distorted cell tips in mature tracheids, of small but distinct terminal canals connecting the lumen to the primary wall in the tips of mature tracheids, and of the presence of only primary wall at the tips of partly differentiated tracheids, and from the failure to observe remnants of the parent primary walls at the ends of differentiating tracheids, it has been concluded that extra-cambial readjustment of developing cells proceeds by tip or intrusive growth. It has been further concluded that the development of the secondary wall is progressive towards the cell tips, on the bases of direct observation of secondary wall formation in developing tracheids and of the increase found in the number of turns of the micellar helix per cell with increasing cell length. The significance of this in relation to the submicroscopic organization of the cell wall has been discussed. Results of X-ray examinations and of measurements of� tracheid length in successive narrow tangential zones from the cambium into the xylem have indicated that secondary wall formation begins before the dimensional changes of differentiation are complete.

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