scholarly journals Specific gravity of woody tissue from lowland Neotropical plants: differences among forest types

Ecology ◽  
2017 ◽  
Vol 98 (5) ◽  
pp. 1474-1474 ◽  
Author(s):  
Luisa Fernanda Casas ◽  
Ana María Aldana ◽  
Francisco Henao-Diaz ◽  
Boris Villanueva ◽  
Pablo R. Stevenson
Keyword(s):  
Specific Gravity ◽  
Forest Types ◽  
Woody Tissue ◽  
Neotropical Plants

WOOD CHARACTERISTICS OF AMAZON FOREST TYPES

IAWA Journal ◽  
2000 ◽  
Vol 21 (3) ◽  
pp. 277-292 ◽  
Author(s):  
D.W. Woodcock ◽  
G. Dos Santos ◽  
C. Reynel
Keyword(s):  
Specific Gravity ◽  
Vessel Diameter ◽  
Floodplain Forest ◽  
Small Samples ◽  
Vessel Element ◽  
Amazon Forest ◽  
Forest Types ◽  
Swamp Forest ◽  
Climate Controls ◽  
Pattern Of Variation

The Tambopata region of the southern Peruvian Amazon supports a high diversity of both woody plants and forest types. Woods collected from low riverside vegetation, floodplain forest, clay-soil forest on an upper terrace, sandy-soil forest, and swamp forest provide an opportunity to test for significant differences in quantitative anatomical characters among forest types. Vessel-element length in floodplain-forest trees is significantly greater than in the other forest types. Specific gravity is lower in the two early-successional associations (low riverine forest and mature floodplain forest). Vessel diameter and density do not show significant differences among forest types and may be responding to overall climate controls. These two characters, however, show a pattern of variation within a transect extending back from the river along a gradient of increasing substrate and forest age; in addition, sites characterized by frequent flooding or presence of standing water lack vessels in the wider-diameter classes. The six characters analyzed show distributions that are, with the exception of wood specific gravity, significantly nonnormally distributed, a consideration that may be important in representing characteristics of assemblages of taxa. The degree of variability seen in some of the quantitative characters shows the importance of either basing analysis on adequate sample sizes or identifying robust indicators that can be used with small samples.

scholarly journals Wood specific gravity of trees and forest types in the southern Peruvian Amazon

2000 ◽  
Vol 30 (4) ◽  
pp. 589-589 ◽  
Author(s):  
Deborah W. WOODCOCK
Keyword(s):  
Specific Gravity ◽  
Tropical Forest ◽  
Alluvial Soil ◽  
Peruvian Amazon ◽  
Forest Age ◽  
Forest Types ◽  
High Terrace ◽  
Carbon Stores ◽  
High Degree ◽  
Terrestrial Biomass

Estimates of terrestrial biomass depend critically on reliable information about the specific gravity of the wood of forest trees. The study reported on here was carried out in the southern Peruvian Amazon and involved collection of wood samples from trees (70 spp.) in intact forest stands. Results demonstrate the high degree of variability in specific gravity (ovendry weight/green volume) in trees at single locations. Three forest types (swamp, high terrace forest with alluvial soil, and sandy-soil forest) had values close to the average reported for tropical forest woods (.69). Two early successional forest types, which make up as much as 12% of the total vegetated area in this part of the Amazon, had values significantly lower (.40). An increase in specific gravity with increasing age of the tree, which has been reported in some spe cies of tropical-forest woods, is seen in a positive relationship between specific gravity and di ameter for a species prevalent in one plot. Increases in specific gravity with tree and forest age may be significant in estimating changes in carbon stores over time.

Wood Specific Gravity of Trees in Amazonian White-Water Forests in Relation to Flooding

IAWA Journal ◽  
2006 ◽  
Vol 27 (3) ◽  
pp. 255-268 ◽  
Author(s):  
Florian Wittmann ◽  
Jochen Schöngart ◽  
Pia Parolin ◽  
Martin Worbes ◽  
Maria T. F. Piedade ◽  
...  
Keyword(s):  
Specific Gravity ◽  
Amazon Basin ◽  
Wood Properties ◽  
Forest Types ◽  
Terra Firme ◽  
Canopy Tree ◽  
Wood Specific Gravity ◽  
Core Section ◽  
White Water ◽  
Várzea Forests

Wood specific gravity (SG) was analysed from wood cores of 180 individuals belonging to 58 common upper canopy tree species of late successional white water (várzea) forests in the Mamirauá Sustainable Development Reserve, Central Amazon Basin. We tested for a SG gradient of trees along the flood gradient. Mean SG in the low várzea was 0.62 g cm-3, in the high várzea 0.57 g cm-3. SG tended to increase with height and duration of flooding. In the two species that occurred in both forest types (Hevea spruceana, Tabebuia barbata) SG was significantly lower in the high várzea trees. Therefore, height and duration of flooding seem to be important factors influencing growth and wood properties in várzea trees. In addition, SG variation depended on the core section and to a lesser extent on tree diameter and height. Compared to trees in Amazonian upland ecosystems, SG of the várzea trees was lower than SG in Central and Eastern Amazonian terra firme, but was within the same range reported for Western Amazonian terra firme.

Valence electron spectroscopy of inhomogeneous media

1992 ◽  
Vol 50 (2) ◽  
pp. 1150-1151
Author(s):  
A. Howie ◽  
D.W. McComb
Keyword(s):  
Specific Gravity ◽  
Loss Function ◽  
Electron Spectroscopy ◽  
Valence Electron ◽  
Peak Height ◽  
Loss Functions ◽  
Loss Peak ◽  
High Energies ◽  
Valence Electron Density ◽  
Electron Microscopist

The bulk loss function Im(-l/ε (ω)), a well established tool for the interpretation of valence loss spectra, is being progressively adapted to the wide variety of inhomogeneous samples of interest to the electron microscopist. Proportionality between n, the local valence electron density, and ε-1 (Sellmeyer's equation) has sometimes been assumed but may not be valid even in homogeneous samples. Figs. 1 and 2 show the experimentally measured bulk loss functions for three pure silicates of different specific gravity ρ - quartz (ρ = 2.66), coesite (ρ = 2.93) and a zeolite (ρ = 1.79). Clearly, despite the substantial differences in density, the shift of the prominent loss peak is very small and far less than that predicted by scaling e for quartz with Sellmeyer's equation or even the somewhat smaller shift given by the Clausius-Mossotti (CM) relation which assumes proportionality between n (or ρ in this case) and (ε - 1)/(ε + 2). Both theories overestimate the rise in the peak height for coesite and underestimate the increase at high energies.

Float for Specific Gravity Determinations

1895 ◽  
Vol 39 (1011supp) ◽  
pp. 16162-16162
Author(s):  
T. Lohnstein
Keyword(s):  
Specific Gravity

On the Effect of 2-Layer Thickness by High-Specific Gravity Armor Blocks on Wave Reflection

1999 ◽  
Author(s):  
Masahiro Ito ◽  
Yuitch Iwagaki ◽  
Hiroshi Murakami ◽  
Kenji Nemoto ◽  
Masato Yamamoto ◽  
...  
Keyword(s):  
Specific Gravity ◽  
Layer Thickness ◽  
Wave Reflection ◽  
High Specific Gravity

Influence of anatomy on the adhesion performance of four wood species

2020 ◽  
Vol 9 (4) ◽  
pp. e31942727
Author(s):  
João Gabriel Missia da Silva ◽  
Pedro Nicó de Medeiros ◽  
Denise Ransolin Soranso ◽  
Vinicius Peixoto Tinti ◽  
José Tarcísio da Silva Oliveira ◽  
...  
Keyword(s):  
Shear Strength ◽  
Specific Gravity ◽  
Wood Species ◽  
Tectona Grandis ◽  
Glue Line ◽  
Anatomical Characteristics ◽  
Ray Cells ◽  
Adhesion Performance ◽  
Adhesion Process

The aim of this study was to evaluate the influence of anatomical characteristics on the adhesion performance of Vatairea sp., Paulownia sp., Aspidosperma populifolium and Tectona grandis wood. Specimens for anatomical, physical and mechanical analyzes were produced from tangentially oriented boards. The treatments were joint glued from pieces of the same anatomical orientation (radial and tangential), evaluated for shear strength and glue line failure. The Vatairea sp wood had the highest specific gravity (0.74 g cm-3) and the Paulownia sp (0.34 g cm-3) wood was smaller. Aspidosperma populifolium species showed the highest shear strength in the glue line in the tangential and radial faces. The anatomical variables with higher influence on the wood adhesion process were pith ray cells and especially fibers that exhibit the greatest correlation with the shear strength of the glue line.

New Method of Determining Specific Gravity

1955 ◽  
Vol 5 (1) ◽  
pp. 47-54
Author(s):  
J. Hammes
Keyword(s):  
Specific Gravity ◽  
New Method
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