Comparison of basic density and longitudinal shrinkage in tension wood and opposite wood in young stems of Populus euramericana cv. Ghoy when subjected to a gravitational stimulus

2001 ◽  
Vol 31 (10) ◽  
pp. 1676-1683 ◽  
Author(s):  
B. Jourez ◽  
A. Riboux ◽  
A. Leclercq
Keyword(s):  
Tension Wood ◽  
Basic Density ◽  
Longitudinal Shrinkage ◽  
Populus Euramericana ◽  
Opposite Wood

Comparison of basic density and longitudinal shrinkage in tension wood and opposite wood in young stems of Populus euramericana cv. Ghoy when subjected to a gravitational stimulus

2001 ◽  
Vol 31 (10) ◽  
pp. 1676-1683 ◽  
Author(s):  
B Jourez ◽  
A Riboux ◽  
A Leclercq
Keyword(s):  
Physical Properties ◽  
Tension Wood ◽  
Basic Density ◽  
Small Samples ◽  
Longitudinal Shrinkage ◽  
Wood Tissue ◽  
Populus Euramericana ◽  
Opposite Wood ◽  
Gelatinous Fibers ◽  
Poplar Cuttings

In a greenhouse, under controlled conditions, young shoots, taken from poplar cuttings (Populus euramericana (Dole) Guinier cv. Ghoy), were artificially bent to quantify the modifications of physical properties induced by a gravitational stimulus. At the end of the growing season, basic density and longitudinal shrinkage were measured on very small samples taken from pure tension wood tissue observed on the upper face of the inclined axis and compared with opposite wood tissue, free of gelatinous fibers, developed on the opposite lower face. In a second step, shoots bent at two different lean intensities were analyzed. In young poplar wood, gravitational stimulus was found to have a significant effect on physical properties. Relations between basic density and longitudinal shrinkage are different depending on the types of wood considered. Shrinkage appears more sensitive to lean intensity in the range considered here.

Wood quality in artificially inclined 1-year-old trees of Eucalyptus regnans — differences in tension wood and opposite wood properties

2011 ◽  
Vol 41 (5) ◽  
pp. 930-937 ◽  
Author(s):  
Shakti S. Chauhan ◽  
John C.F. Walker
Keyword(s):  
Tension Wood ◽  
Wood Quality ◽  
Basic Density ◽  
Wood Properties ◽  
Acoustic Velocity ◽  
Volumetric Shrinkage ◽  
Longitudinal Shrinkage ◽  
Eucalyptus Regnans ◽  
New Approach ◽  
Opposite Wood

This paper presents a new approach to assess wood quality in 1-year-old Eucalyptus regnans F. Muell. Twenty-two seedlings were grown tilted to induce tension wood and acoustic velocity, basic density, longitudinal shrinkage, and volumetric shrinkage of both opposite wood and tension wood were assessed subsequently. Longitudinal growth strains were also estimated in the leaning stems by sawing along the length through the pith and measuring the bending of the two halves. The derived longitudinal growth strain, which varied from 708 to 2319 µε, was uncorrelated with stem and wood characteristics. Wood characteristics differed significantly between upper-side wood (predominantly tension wood) and lower-side wood (opposite wood). Tension wood was characterized by a higher acoustic velocity (high stiffness), basic density, and volumetric shrinkage compared with opposite wood. Tension wood also exhibited significant collapse and dimensional distortion such as twisting. Longitudinal shrinkage exhibited a significant negative relationship with acoustic velocity in opposite wood and a positive relationship with the basic density in tension wood. This new approach has potential in early selection of breeding material with superior normal wood properties from 1-year-old material by isolating the influence of tension wood. This approach can also be useful in understanding the variability in propensity of tension wood production in breeding populations.

scholarly journals Influência do lenho de tração nas propriedades físicas da madeira de Eucalyptus sp.

2010 ◽  
Vol 1 (1) ◽  
pp. 6-11
Author(s):  
Thiago Campos Monteiro ◽  
Renato da Silva Vieira ◽  
José Tarcísio Lima ◽  
Edy Eime Pereira Baraúna ◽  
Duam Matosinhos de Carvalho ◽  
...  
Keyword(s):  
Tension Wood ◽  
Basic Density ◽  
Eucalyptus Camaldulensis ◽  
Normal Wood ◽  
Reaction Wood ◽  
Opposite Wood ◽  
The Face ◽  
Eucalyptus Maculata ◽  
Shrinkage Coefficient

The reaction wood is formed in an attempt to remain upright tree in response to the action of forces such as winds, irregular crown or slope of the land that tend to incline it. In hardwoods, as in Eucalyptus, this type of wood is called tension wood and occurs in the region of the stem facing the face of force application. Indicative of the presence of this type of wood is the high shrinkage and basic density compared to normal wood. Once the basic density and shrinkage are parameters for determining the quality of the wood, this study aimed to evaluate the variation of basic density and shrinkage of opposite and tension wood along the radius in four species of Eucalyptus sp. Four tree species Eucalyptus camaldulensis, Eucalyptus maculata, Eucalyptus pilularis and Eucalyptus urophylla, with 32 years of age, were taken from an experimental planting of the Federal University of Lavras. Specimens were made to represent the diametrical variation of the opposite of tension wood in disks cut at the dbh. The results indicate that the properties of radial, tangential and volumetric shrinkage, coefficient of anisotropy and basic density did not differ statistically between the tensionand opposite wood.

ANATOMICAL CHARACTERISTICS OF TENSION WOOD AND OPPOSITE WOOD IN YOUNG INCLINED STEMS OF POPLAR (POPULUS EURAMERICANA CV 'GHOY')

IAWA Journal ◽  
2001 ◽  
Vol 22 (2) ◽  
pp. 133-157 ◽  
Author(s):  
B. Jourez ◽  
A. Riboux ◽  
A. Leclercq
Keyword(s):  
Cross Section ◽  
Tension Wood ◽  
Growth Ring ◽  
Growing Season ◽  
Lower Face ◽  
Wood Tissue ◽  
Populus Euramericana ◽  
Opposite Wood ◽  
Upper Face ◽  
Poplar Cuttings

Young shoots from poplar cuttings (Populus euramericana cv ʻGhoyʼ) were artificially inclined to 30° from vertical to quantify the anatomical modifications induced by this gravitational stimulus. At the end of the growing season, the tension wood tissue (from the upper face of the inclined axis) was compared to the opposite wood tissue (from the lower face), with radial position taken into account. On isolated elements after maceration, fibres and vessels were significantly longer in tension wood tissue. In the cross section, the gelatinous fibres had a smaller radial diameter than normal fibres in opposite wood. Vessel frequency and porosity were significantly lower in tension wood than in opposite wood. Solitary vessels in tension wood were less circular in cross section than in opposite wood, but their surface area did not differ. Rays were more numerous in tension wood than in opposite wood but their height did not differ between the two tissue types. Finally, there was a negative correlation between the proportion of vessel lumina (lowest in tension wood) and the proportion of fibre lumina including the G layer. The very controlled nature of this experiment (greenhouse, young clonal material, detailed anatomical observations within one growth ring) and the image analysis technology (allowing a large number of observations) enabled us to draw conclusions that may not have been seen in less-controlled experiments and /or those with smaller sample sizes.

scholarly journals QUALITY OF REACTION WOOD IN Eucalyptus TREES TILTED BY WIND FOR PULP PRODUCTION

CERNE ◽  
2017 ◽  
Vol 23 (3) ◽  
pp. 291-297
Author(s):  
Walter Torezani Neto Boschetti ◽  
Juarez Benigno Paes ◽  
Graziela Baptista Vidaurre ◽  
Marina Donária Chaves Arantes ◽  
João Gabriel Missia da Silva
Keyword(s):  
Chemical Composition ◽  
Chemical Constituents ◽  
Wood Quality ◽  
Basic Density ◽  
Kraft Pulping ◽  
Normal Wood ◽  
Reaction Wood ◽  
Opposite Wood ◽  
Holocellulose Content

ABSTRACT This study aims to evaluate the quality of normal, tension and opposite wood of eucalyptus trees lengthwise, in straight and inclined stems, affected by wind action. It also aims to explain the pulping parameters resultant from the quality of the wood. The trees were grouped into four tilt ranges, ranging from 0 to 50º, and the basic density, chemical composition of the wood, and performance in kraft pulping were assessed. Normal and tension wood had similar basic densities; while for opposite wood, the density was lower, being responsible for a decrease in reaction wood density. The chemical composition of the wood was influenced by the presence of reaction wood in the stem. Tension and opposite wood showed lower levels of extractives and lignin and higher holocellulose content when compared to normal wood, with favorable wood quality for pulping. The increase in holocellulose content and the reduction of lignin and extractives content contributed positively to a more delignified pulp and reduction of the Kappa number. However, after cooking the reaction wood under the same conditions as those of normal wood, reaction wood pulping tends to have a lower screen yields. Due to differences in basic density and chemical constituents between opposite and normal wood, it is recommended not to designate the opposite wood as normal wood.

Strength and stiffness of the reaction wood in five Eucalyptus species

Holzforschung ◽  
2019 ◽  
Vol 73 (2) ◽  
pp. 219-222
Author(s):  
Bruno Charles Dias Soares ◽  
José Tarcísio Lima ◽  
Selma Lopes Goulart ◽  
Claudineia Olímpia de Assis
Keyword(s):  
Mechanical Behavior ◽  
Tension Wood ◽  
Compression Wood ◽  
Vertical Position ◽  
Eucalyptus Species ◽  
Reaction Wood ◽  
Opposite Wood ◽  
Average Slope ◽  
Strength And Stiffness

AbstractTree stems deviating from the vertical position react by the formation of tension wood (TW) or compression wood (CW), which are called in general as reaction wood (RW), in which the cells are modified chemically and anatomically. The focus of the present work is the mechanical behavior of TW in five 37-year-oldEucalyptusspecies, which were grown on a planting area with an average slope of 28% leading to decentralized pith in the trees, which is an unequivocal indication of the presence of RW. TW and opposite wood (OW) samples were isolated and subjected to a compression-parallel-to-grain test. It was observed that TW is less resistant and less stiff than the OW.

scholarly journals Evidence that release of internal stress contributes to drying strains of wood

Holzforschung ◽  
2012 ◽  
Vol 66 (3) ◽  
Author(s):  
Bruno Clair
Keyword(s):  
Tension Wood ◽  
Drying Shrinkage ◽  
Cellulose Microfibrils ◽  
Internal Stresses ◽  
Schematic Model ◽  
Normal Wood ◽  
Longitudinal Shrinkage ◽  
Fibre Direction ◽  
Desorption Process ◽  
Chestnut Wood

Abstract Wood shrinks during drying, with the departure of bond water. Along the fibre direction, the magnitude of this shrinkage is mainly governed by the orientation of cellulose microfibrils (MF) in the cell wall. However, tension wood has an unexpectedly high longitudinal shrinkage considering the fact that MFs are oriented nearly parallel to the cell direction. This effect is thought to be caused by the gel collapse of the G-layer; however, some species producing a tension wood without a G-layer also exhibit a higher longitudinal shrinkage than normal wood. The aim of this study is to analyse the contribution of maturation stresses to drying shrinkage. Longitudinal and tangential drying shrinkage of tension wood and normal wood were measured on two sets of matched chestnut wood samples. The first set was directly oven-dried, whereas on the second set, a hygrothermal treatment released the maturation stress before oven-drying. The analysis of the strains during each step of the procedure revealed that part of the drying shrinkage is caused by the release of internal stresses during the desorption process. Finally, a tentative schematic model is proposed, taking into account the cumulative contributions to longitudinal drying shrinkage.

scholarly journals SIFAT FISIK BATANG DAN CABANG KAYU MAKADAMIA

PERENNIAL ◽  
2006 ◽  
Vol 2 (1) ◽  
pp. 16
Author(s):  
Andi Detti Yunianti
Keyword(s):  
Specific Gravity ◽  
Moisture Content ◽  
Physical Properties ◽  
Quality Indicators ◽  
Basic Density ◽  
Raw Material ◽  
Longitudinal Shrinkage ◽  
Wood Production ◽  
Efficient Utilization ◽  
Tangential Shrinkage

Since there have been a big difference between wood production and industrial need, wood diversification plays an important role in handling wood deficiencies. Wood raw material diversification could developed and increased throughout the use of whole parts of the tree including branch. The current study was aimed at understanding stem and branch physical properties (basic density, air-dry specific gravity, air-dry moisture content and shrinkage) of macadamia wood as quality indicators for efficient utilization in the future. For the purpose of the study, parts of stem and branch of the tree were taken from a macadamia tree. Test specimens of stem were cut 50 cm from the ground while that of branch were selected from the largest diameter at 10 cm distance from the main stem of the tree. All samples were tested for their physical properties according to ISO standards, 1975. Results showed that the basic density, air dry specific gravity and longitudinal shrinkage of the branchwood of macadamia were higher than those of the stem. The air-dry moisture content, radial and tangential shrinkage were low on the branchwood. Keywords : Wood Physical Properties, Branchwood , Macadamia Wood

scholarly journals The Nature of Reaction Wood

1948 ◽  
Vol 1 (1) ◽  
pp. 3 ◽  
Author(s):  
AB Wardrop ◽  
HE Dads Well
Keyword(s):  
Tensile Strength ◽  
Tension Wood ◽  
Reaction Wood ◽  
Fibre Structure ◽  
Longitudinal Shrinkage ◽  
High Tensile Strength ◽  
Wood Fibres

The structure of tension wood fibres is ofconsiderahle academic and practicalinterest, both in relation to considerations of the stimuli which produce them,and to studies of the influence of fibre structure on the properties of the wood asa whole. As is well known, the chief abnormal properties of tension wood lie inits unusually high longitudinal shrinkage, its high tensile strength, and its lowcompressive strength .

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