scholarly journals Tension Wood and Oppositewood in 21 Tropical Rain Forest Species

IAWA Journal ◽  
2006 ◽  
Vol 27 (4) ◽  
pp. 341-376 ◽  
Author(s):  
Julien Ruelle ◽  
Bruno Clair ◽  
Jacques Beauchêne ◽  
Marie Françoise Prévost ◽  
Meriem Fournier
Keyword(s):  
Rain Forest ◽  
Tropical Rain Forest ◽  
Tension Wood ◽  
Fibre Diameter ◽  
Microfibril Angle ◽  
Ultrastructural Level ◽  
Growth Stress ◽  
Opposite Wood ◽  
Two Samples ◽  
French Guyana

The anatomy of tension wood and opposite wood was compared in 21 tropical rain forest trees from 21 species belonging to 18 families from French Guyana. Wood specimens were taken from the upper and lower sides of naturally tilted trees. Measurement of the growth stress level ensured that the two samples were taken from wood tissues in a different mechanical state: highly tensile-stressed wood on the upper side, called tension wood and normally tensile-stressed wood on the lower side, called opposite wood. Quantitative parameters relating to fibres and vessels were measured on transverse sections of both tension and opposite wood to check if certain criteria can easily discriminate the two kinds of wood. We observed a decrease in the frequency of vessels in the tension wood in all the trees studied. Other criteria concerning shape and surface area of the vessels, fibre diameter or cell wall thickness did not reveal any general trend. At the ultrastructural level, we observed that the microfibril angle in the tension wood sample was lower than in opposite wood in all the trees except one (Licania membranacea).

scholarly journals Tension Wood and Opposite Wood in 21 Tropical Rain Forest Species

IAWA Journal ◽  
2006 ◽  
Vol 27 (3) ◽  
pp. 329-338 ◽  
Author(s):  
Bruno Clair ◽  
Julien Ruelle ◽  
Jacques Beauchêne ◽  
Marie Françoise Prévost ◽  
Meriem Fournier
Keyword(s):  
Rain Forest ◽  
Tropical Rain Forest ◽  
Tension Wood ◽  
Reaction Wood ◽  
Forest Species ◽  
Growth Stresses ◽  
Opposite Wood ◽  
Two Samples ◽  
Key Factor ◽  
French Guyana

Wood samples were taken from the upper and lower sides of 21 naturally tilted trees from 18 families of angiosperms in the tropical rain forest in French Guyana. The measurement of growth stresses ensured that the two samples were taken from wood tissues in a different mechanical state: highly tensile stressed wood on the upper side, called tension wood, and lower tensile stressed wood on the lower side, called opposite wood. Eight species had tension wood fibres with a distinct gelatinous layer (G-layer). The distribution of gelatinous fibres varied from species to species. One of the species, Casearia javitensis (Flacourtiaceae), showed a peculiar multilayered secondary wall in its reaction wood. Comparison between the stress level and the occurrence of the G-layer indicates that the G-layer is not a key factor in the production of high tensile stressed wood.

scholarly journals GROWTH STRAINS AND RELATED WOOD STRUCTURES IN THE LEANING TRUNKS AND BRANCHES OF TROCHODENDRON ARALIOIDES - A VESSEL-LESS DICOTYLEDON

IAWA Journal ◽  
2007 ◽  
Vol 28 (2) ◽  
pp. 211-222 ◽  
Author(s):  
Ling-Long Kuo-Huang ◽  
Shin-Shin Chen ◽  
Yan-San Huang ◽  
Shiang-Jiuun Chen ◽  
Yi-In Hsieh
Keyword(s):  
Microfibril Angle ◽  
Wall Layer ◽  
Growth Stress ◽  
Lower Side ◽  
Wood Structures ◽  
Opposite Wood ◽  
Gelatinous Fibers ◽  
Percentage Area ◽  
Gelatinous Fiber ◽  
The Difference

Leaning trunks and branches of Trochodendron aralioides Sieb. & Zucc., a primitive vessel-less dicotyledon, show increased radial growth and gelatinous fibers on the upper side similar to the features found in dicotyledons with vessels. The patterns of peripheral longitudinal growth strain are variable among trees but similar at different heights within the same leaning trunk. Growth strains on the lower side of the trunks are very small but they are relatively large on the lower side of the branches. Growth stress in the branches is partly affected by the gravitational bending stress, which would be exerted mostly on the lower side. Large spring back strains of branches are associated with large surface strains. Both the microfibril angle (MFA) and the percentage area of gelatinous fiber show positive relationships with the measured strains. The MFA of the S2 wall layer in tracheids in the opposite wood is 24.6 ± 2.2°, whereas the MFA of gelatinous layer in the tension wood is only 14.2 ± 2.7°. The difference of MFA between the gelatinous fibers and the opposite wood is one of the factors accounting for the large contracting force for reorientation.

A Study of Eucalyptus Grandis and Eucalyptus Globulus Branch wood Microstructure

IAWA Journal ◽  
2005 ◽  
Vol 26 (2) ◽  
pp. 203-210 ◽  
Author(s):  
Russell Washusen ◽  
Robert Evans ◽  
Simon Southerton
Keyword(s):  
Tension Wood ◽  
Microfibril Angle ◽  
Eucalyptus Grandis ◽  
Local Variation ◽  
Experimental Measurements ◽  
X Ray ◽  
Stem Wood ◽  
Opposite Wood ◽  
Cellulose Crystallite ◽  
Branch Wood

Experimental measurements of cellulose crystallite width and microfibril angle (MFA) by X-ray diffractometry on SilviScan-2 and by conventional microtechniques revealed that the branch wood of the two species exhibited very similar trends in cellulose crystallite width and MFA. Cellulose crystallite width was greater on the upper side of the branches. Tension wood, as defined by the occurrence of gelatinous fibres, was found where cellulose crystallite width was greater than 3.0 nm and 3.1 nm in Eucalyptus grandis and E. globulus respectively. In the tension wood zones, MFA was lower than in the rest of the samples and so could be used to differentiate tension wood. On the lower side of the branches MFA determined from X-ray diffractometry unexpectedly exceeded 40° and fibres were often buckled in both the tangential and radial directions in both species. This local variation in the direction of the fibre axes contributed only slightly to the magnitude of the MFA determined by SilviScan-2. Even given this misalignment, the additional evidence gained from pit angles and cracks in fibre walls suggested that the MFA was indeed around 40° in the lower radius of the branches. This MFA is considerably larger than would be expected for eucalypt stem wood and it is suggested that opposite wood in eucalypt branches may provide a complimentary structural role to that of the tension wood. Experimental measurements of crystallite width produced by SilviScan-2 may be used to accurately locate tension wood zones in both species.

The Effects of a Tropical rain Forest Cover on Airborne Gamma-Ray Spectrometry

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Enio B. Pereira ◽  
Daniel J.R. Nordemann
Keyword(s):  
Rain Forest ◽  
Tropical Rain Forest ◽  
Forest Cover ◽  
Gamma Ray ◽  
Gamma Ray Spectrometry

Para solicitação de resumo, entrar em contato com editor-chefe ([email protected]). 

scholarly journals (5d RG-flow) trees in the tropical rain forest

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Marieke van Beest ◽  
Antoine Bourget ◽  
Julius Eckhard ◽  
Sakura Schäfer-Nameki
Keyword(s):  
Large Class ◽  
Rain Forest ◽  
Tropical Rain Forest ◽  
Field Theories ◽  
Flavor Symmetry ◽  
Superconformal Field Theories ◽  
Hasse Diagrams ◽  
Flavor Symmetries ◽  
Rank 2 ◽  
Mass Deformation

Abstract 5d superconformal field theories (SCFTs) can be obtained from 6d SCFTs by circle compactification and mass deformation. Successive decoupling of hypermultiplet matter and RG-flow generates a decoupling tree of descendant 5d SCFTs. In this paper we determine the magnetic quivers and Hasse diagrams, that encode the Higgs branches of 5d SCFTs, for entire decoupling trees. Central to this undertaking is the approach in [1], which, starting from the generalized toric polygons (GTPs) dual to 5-brane webs/tropical curves, provides a systematic and succinct derivation of magnetic quivers and their Hasse diagrams. The decoupling in the GTP description is straightforward, and generalizes the standard flop transitions of curves in toric polygons. We apply this approach to a large class of 5d KK-theories, and compute the Higgs branches for their descendants. In particular we determine the decoupling tree for all rank 2 5d SCFTs. For each tree, we also identify the flavor symmetry algebras from the magnetic quivers, including non-simply-laced flavor symmetries.

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