The Relationship between Longitudinal Growth Strain, Tree Form and Tension Wood at the Stem Periphery of Ten- to Eleven-Year-Old Eucalyptus globulus Labill.

Holzforschung ◽  
2003 ◽  
Vol 57 (3) ◽  
pp. 308-316 ◽  
Author(s):  
R. Washusen ◽  
J. Ilic ◽  
G. Waugh
Keyword(s):  
Eucalyptus Globulus ◽  
Tension Wood ◽  
High Growth ◽  
Normal Wood ◽  
Growth Strain ◽  
Strain Measurements ◽  
Tree Form ◽  
Remote Locations ◽  
Multiple Measurements ◽  
The Relationship

Summary The potential for growth strain measurements for detection of tension wood was assessed in trees from two plantations of 10- to 11-year-old Eucalyptus globulus. Tension wood had commonly developed at or near the stem periphery of straight, vertical and dominant trees. At a localized level growth strain was found to be a good indicator of tension wood. However, in some cases moderate to low growth strain was also detected in some trees where tension wood had been overgrown with small amounts of normal wood. On a whole tree basis the relationship was not as clear. In this case growth strain values determined from multiple measurements appear to be influenced primarily by tissue close to the site of measurements and not by wood at relatively remote locations. In some cases low growth strain values were found in trees with significant tension wood and in others high growth strain values where little tension wood had developed.

Relationships between Density, Shrinkage, Extractives Content and Microfibril Angle in Tension Wood from Three Provenances of 10-Year-Old Eucalyptus globulus Labill

Holzforschung ◽  
2001 ◽  
Vol 55 (2) ◽  
pp. 176-182 ◽  
Author(s):  
R. Washusen ◽  
P. Ades ◽  
R. Evans ◽  
J. Ilic ◽  
P. Vinden
Keyword(s):  
Wood Density ◽  
Eucalyptus Globulus ◽  
Tension Wood ◽  
Microfibril Angle ◽  
Positive Association ◽  
Normal Wood ◽  
X Ray Diffraction ◽  
X Ray ◽  
Saturation Method ◽  
Improvement Programs

Summary Density and microfibril angle (MFA) of tension wood and normal wood were assessed in the sapwood and heartwood, from three provenanaces of 10-year-old Eucalyptus globulus Labill. Density was measured using a modified saturation method that also enabled the calculation of the extractives lost during saturation. Microdensity and MFA were determined by SilviScan 2, a rapid X-ray densitometry and X-ray diffraction system developed at CSIRO. Significant differences were found in density and extractives between provenances and also density between the sapwood and adjacent heartwood from each provenance. This result may explain some of the drying differences between provenances found in an earlier study (Washusen and Ilic 2000). Sapwood samples with high percentages of tension wood fibres had high density and a significant positive correlation was found between microdensity and tension wood fibre percentage. MFA was found to be very low in normal wood in the sapwood, where most tension wood was found, so tension wood could not be identified by MFA. The positive association between tension wood and wood density suggests that caution should be taken when selecting trees for high wood density in tree improvement programs.

Analysis of Protein Expression along the Normal to Tension Wood Gradient in Eucalyptus gunnii

Holzforschung ◽  
2003 ◽  
Vol 57 (4) ◽  
pp. 353-358 ◽  
Author(s):  
C. Plomion ◽  
C. Pionneau ◽  
H. Baillères
Keyword(s):  
Protein Expression ◽  
Tension Wood ◽  
Lignin Content ◽  
Polyacrylamide Gel Electrophoresis ◽  
Wood Formation ◽  
Computer Assisted ◽  
Normal Wood ◽  
Growth Strain ◽  
Silver Nitrate Staining ◽  
Xylem Tissue

Abstract This paper examines the contribution of various xylem proteins to wood formation in Eucalyptus gunnii. Proteins were extracted from differentiating xylem harvested from a crooked tree, separated by high-resolution two-dimensional polyacrylamide gel electrophoresis, visualised by silver nitrate staining and analysed with a computer-assisted system for single protein spot quantification. Growth strain measurements allowed xylem samples to be classified quantitatively from tension wood to normal wood. Regression of lignin content on growth strain showed that a decrease in lignin content corresponded to decreasing growth strain values, i.e., presence of tension wood. Out of the 140 studied protein spots, 12 were significantly associated with growth strain: 7 being less abundant in tension wood and 5 being more abundant in tension wood. A clustered-correlation analysis was performed to study protein expression simultaneously along the gradient of gravistimulated stressed xylem tissue. Proteins were found to form “expression clusters”.

THE ASSOCIATION BETWEEN CELLULOSE CRYSTALLITE WIDTH AND TENSION WOOD OCCURRENCE IN EUCALYPTUS GLOBULUS

IAWA Journal ◽  
2001 ◽  
Vol 22 (3) ◽  
pp. 235-243 ◽  
Author(s):  
Russell Washusen ◽  
Robert Evans
Keyword(s):  
Eucalyptus Globulus ◽  
Tension Wood ◽  
Rapid Assessment ◽  
Solid Wood ◽  
Normal Wood ◽  
X Ray Diffraction ◽  
Cellulose Crystallite ◽  
Hardwood Species ◽  
Commercially Important ◽  
Diffraction Patterns

The association between cellulose crystallite width and the occurrence of tension wood was assessed for Eucalyptus globulus Labill., a commercially important plantation hardwood species. Crystallite width (uncorrected for instrumental broadening) was determined from X-ray diffraction patterns collected on SilviScan-2, an instrument developed for the rapid assessment of wood microstructure. Comparisons of crystallite widths were made using 66 samples of tension wood and normal wood selected randomly from one tree known to have abundant tension wood. Tension wood was found to have significantly wider crystallites than normal wood. The mean crystallite widths were 3.6 nm for tension wood and 3.2 nm for normal wood. The normal wood crystallite widths were consistent with those reported in previous studies, allowing for an experimental broadening equivalent to about 0.5 nm in this work. This study demonstrates that SilviScan-2 is useful for the detection of tension wood in solid wood samples such as increment cores.

The nature of reaction wood. IV. Variations in cell wall organization of tension wood fibres

1955 ◽  
Vol 3 (2) ◽  
pp. 177 ◽  
Author(s):  
AB Wardrop ◽  
HE Dadswell
Keyword(s):  
Cell Wall ◽  
Tension Wood ◽  
Secondary Wall ◽  
Degree Of Crystallinity ◽  
Tropical Species ◽  
Normal Wood ◽  
Reaction Wood ◽  
Gelatinous Layer ◽  
Wood Fibres ◽  
Cell Wall Organization

The cell wall organization, the cell wall texture, and the degree of lignification of tension wood fibres have been investigated in a wide variety of temperate and tropical species. Following earlier work describing the cell wall structure of tension wood fibres, two additional types of cell wall organization have been observed. In one of these, the inner thick "gelatinous" layer which is typical of tension wood fibres exists in addition to the normal three-layered structure of the secondary wall; in the other only the outer layer of the secondary wall and the thick gelatinous layer are present. In all the tension wood examined the micellar orientation in the inner gelatinous layer has been shown to be nearly axial and the cellulose of this layer found to be in a highly crystalline state. A general argument is presented as to the meaning of differences in the degree, of crystallinity of cellulose. The high degree of crystallinity of cellulose in tension wood as compared with normal wood is attributed to a greater degree of lateral order in the crystalline regions of tension wood, whereas the paracrystalline phase is similar in both cases. The degree of lignification in tension wood fibres has been shown to be extremely variable. However, where the degree of tension wood development is marked as revealed by the thickness of the gelatinous layer the lack of lignification is also most marked. Severity of tension wood formation and lack of lignification have also been correlated with the incidence of irreversible collapse in tension wood. Such collapse can occur even when no whole fibres are present, e.g. in thin cross sections. Microscopic examination of collapsed samples of tension wood has led to the conclusion that the appearance of collapse in specimens containing tendon wood can often be attributed in part to excessive shrinkage associated with the development of fissures between cells, although true collapse does also occur. Possible explanations of the irreversible shrinkage and collapse of tension wood fibres are advanced.

Some Tree Growth – Wood Property Relationships of Eucalypts

1975 ◽  
Vol 5 (3) ◽  
pp. 424-432 ◽  
Author(s):  
J. E. Nicholson ◽  
W. E. Hillis ◽  
N. Ditchburne
Keyword(s):  
Wood Property ◽  
Basic Density ◽  
Wood Properties ◽  
Reaction Wood ◽  
Growth Strain ◽  
Fiber Structure ◽  
Tree Crown ◽  
Stem Form ◽  
The Relationship ◽  
Longitudinal Growth Strain

The relationship between level of longitudinal growth strain and stress, modulus of elasticity, basic density, volumetric shrinkage, fiber classification, and stem form was investigated with 10 Eucalyptusregnans regrowth trees. Close relationships were observed. It is suggested that variations in these properties within trees are closely controlled, possibly to enable optimum positioning of the tree crown in relation to its immediate environment. The concept of fiber structure varying as a response to environment is supported by the observed variation in wood properties within and between trees of this species. The often-reported association between eccentric radial growth and reaction wood was not substantiated in this study.The data indicate that if economically justifiable, it would be possible to segregate trees that are likely to contain material that is hard to season.

scholarly journals An Analysis of the Entrepreneurial Ecosystem of Malawi: The Global Entrepreneurship Index (GEI) Approach

2021 ◽  
Vol 8 (1) ◽  
pp. 224-238
Author(s):  
Frederick Pobee ◽  
Thuso Mphela
Keyword(s):  
New Technologies ◽  
High Growth ◽  
Gdp Per Capita ◽  
Risk Capital ◽  
Entrepreneurial Ecosystem ◽  
Start Up ◽  
Depth Analysis ◽  
Per Capita ◽  
Global Entrepreneurship ◽  
The Relationship

The research paper provides an in-depth analysis of the entrepreneurial ecosystem of Malawi. Employing the Global Entrepreneurship Index (GEI) methodology, the findings reveal a weak entrepreneurial ecosystem with a GEI score of 12.2 out of a possible 100. The relationship between the GDP per capita and the three entrepreneurship sub-indices, thus, attitude, ability, and aspiration are very weak and fall well below global average trends. Unfortunately, despite the high total entrepreneurship activities (TEA) in Malawi, this leads to little contribution to the country's GDP per-capita – a common phenomenon in many developing countries. At the pillar level, Malawi’s performance is a mixed bag, however, with most pillars performing not only poorly but below world averages. Despite the general positive perception of entrepreneurship by citizens, the country’s weak entrepreneurial ecosystem has failed to harness the propensity to develop new products and adopt new technologies for innovation and high growth entrepreneurship. From a policy intervention perspective, Malawi needs to focus most of its efforts and investments in five areas that include start-up skills, risk acceptance, high growth, risk capital, and human capital to improve the country's GEI score by 0.02.

scholarly journals Uma revisão bibliográfica do tipo scopping/mapping sobre a Agricultura Urbana e Periurbana

2020 ◽  
Vol 12 (6) ◽  
pp. 1242
Author(s):  
Victor Bueno Sellin ◽  
Tania Pereira Christopoulos
Keyword(s):  
Urban Areas ◽  
High Growth ◽  
Well Being ◽  
Urban Dynamics ◽  
Academic Literature ◽  
Sustainable Urbanization ◽  
The Subject ◽  
Definition Of ◽  
Periurban Agriculture ◽  
The Relationship

The world is undergoing an accelerated urbanization process marked by social and environmental imbalances. In this context, urban and periurban agriculture (UPA) emerges as an alternative to sustainable urbanization mainly due to its contribution to food security, reduction of environmental impact, revitalization of urban areas, integration of households and physical and psychological well-being increasing. The purpose of this paper is to understand how academic literature deals with urban and periurban agriculture. For that, a scoping / mapping literature review was carried out and its results were presented after identification of relevant scientific studies on UPA, its main aspects, ways in which the term has been defined; and discussion about themes from the selected articles. After this review, the conclusions are: the scientific production on the subject is undergoing high growth rates in recent years; the relationship between UPA and urban dynamics is more important for the definition of UPA than the location of agriculture; and that the aspects that authors found most interesting are: concept and panorama, urban planning and governance, quantitative potential, environment, risk of contamination and techniques and productivity.

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