scholarly journals Wood Density Profiles and Their Corresponding Tissue Fractions in Tropical Angiosperm Trees

Forests ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 763 ◽  
Author(s):  
Tom De Mil ◽  
Yegor Tarelkin ◽  
Stephan Hahn ◽  
Wannes Hubau ◽  
Victor Deklerck ◽  
...  
Keyword(s):  
Wood Density ◽  
Density Profile ◽  
Growth Ring ◽  
Random Effect ◽  
Average Density ◽  
Congo Basin ◽  
Life Strategy ◽  
Density Profiles ◽  
Automated Method ◽  
Profile Variation

Wood density profiles reveal a tree’s life strategy and growth. Density profiles are, however, rarely defined in terms of tissue fractions for wood of tropical angiosperm trees. Here, we aim at linking these fractions to corresponding density profiles of tropical trees from the Congo Basin. Cores of 8 tree species were scanned with X-ray Computed Tomography to calculate density profiles. Then, cores were sanded and the outermost 3 cm were used to semi-automatically measure vessel lumen, parenchyma and fibre fractions using the Weka segmentation tool in ImageJ. Fibre wall and lumen widths were measured using a newly developed semi-automated method. An assessment of density variation in function of growth ring boundary detection is done. A mixed regression model estimated the relative contribution of each trait to the density, with a species effect on slope and intercept of the regression. Position-dependent correlations were made between the fractions and the corresponding wood density profile. On average, density profile variation mostly reflects variations in fibre lumen and wall fractions, but these are species- and position-dependent: on some positions, parenchyma and vessels have a more pronounced effect on density. The model linking density to traits explains 92% of the variation, with 65% of the density profile variation attributed to the three measured traits. The remaining 27% is explained by species as a random effect. There is a clear variation between trees and within trees that have implications for interpreting density profiles in angiosperm trees: the exact driving anatomical fraction behind every density value will depend on the position within the core. The underlying function of density will thus vary accordingly.

Growth-ring boundaries of tropical tree species: aiding delimitation by long histological sections and wood density profiles

2021 ◽  
pp. 125878
Author(s):  
Manolo Trindade Quintilhan ◽  
Luiz Santini ◽  
Daigard Ricardo Ortega Rodriguez ◽  
Joannès Guillemot ◽  
Gabriella Hita Marangom Cesilio ◽  
...  
Keyword(s):  
Wood Density ◽  
Tree Species ◽  
Growth Ring ◽  
Tropical Tree ◽  
Density Profiles ◽  
Tropical Tree Species ◽  
Histological Sections

Measurement of intra-ring wood density by means of imaging VIS/NIR spectroscopy (hyperspectral imaging)

Holzforschung ◽  
2013 ◽  
Vol 67 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Armando Fernandes ◽  
José Lousada ◽  
José Morais ◽  
José Xavier ◽  
João Pereira ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Wood Density ◽  
Mean Squared Error ◽  
Growth Ring ◽  
Nir Spectroscopy ◽  
Spectroscopic Technique ◽  
Coefficient Of Determination ◽  
Density Profiles ◽  
Squared Error ◽  
Density Values

Abstract This paper reports a novel application of hyperspectral imaging (a spectroscopic technique) for measuring wood density profiles at the growth ring scale. The measurements were performed with a spatial resolution of 79 µm. In the present case, hyperspectral imaging was used to measure wood sample reflectance for light in the wavelength range between 380 and 1028 nm, with a resolution of approximately 0.6 nm. The work was performed with 34 samples collected from 34 trees of Pinus pinea. A total of 34,093 density points were used to create and validate a partial least-squares (PLS) regression that converts spectroscopic reflectance data into density values. The coefficient of determination value between the present method and X-ray microdensitometry is 0.810 with a root mean squared error of 6.54×10-2 g.cm-3.

scholarly journals A numerical fit of analytical to simulated density profiles in dark matter haloes

2005 ◽  
pp. 13-32 ◽  
Author(s):  
R. Caimmi ◽  
C. Marmo ◽  
T. Valentinuzzi
Keyword(s):  
High Resolution ◽  
Density Profile ◽  
Geometrical Parameters ◽  
Density Profiles ◽  
Mean Values ◽  
Geometrical Properties ◽  
Best Fitting ◽  
Definition Of ◽  
Additional Support ◽  
Open Question

Analytical and geometrical properties of generalized power-law (GPL) density profiles are investigated in detail. In particular, a one-to-one correspondence is found between mathematical parameters (a scaling radius, r0, a scaling density, ?0, and three exponents, ?, ?, ?), and geometrical parameters (the coordinates of the intersection of the asymptotes, xC, yC, and three vertical intercepts, b, b?, b?, related to the curve and the asymptotes, respectively): (r0,?0,?,?,?) ? (xC,yC,b,b?,b?). Then GPL density profiles are compared with simulated dark haloes (SDH) density profiles, and nonlinear least-absolute values and least-squares fits involving the above mentioned five parameters (RFSM5 method) are prescribed. More specifically, the sum of absolute values or squares of absolute logarithmic residuals, Ri=log?SDH(ri) ? log?GPL(ri), is evaluated on 10 points making a 5dimension hypergrid, through a few iterations. The size is progressively reduced around a fiducial minimum, and superpositions on nodes of earlier hypergrids are avoided. An application is made to a sample of 17 SDHs on the scale of cluster of galaxies, within a flat ?CDM cosmological model (Rasia et al. 2004). In dealing with the mean SDH density profile, a virial radius, Rvir, averaged over the whole sample, is assigned, which allows the calculation of the remaining parameters. Using a RFSM5 method provides a better fit with respect to other methods. The geometrical parameters, averaged over the whole sample of best fitting GPL density profiles, yield (?, ?, ?) ? (0.6,3.1,1.0), to be compared with (?, ?, ?) = (1,3,1), i.e. the NFW density profile (Navarro et al. 1995, 1996, 1997), (?, ?, ?) = (1.5,3, 1.5) (Moore et al. 1998, 1999), (?, ?, ?) = (1,2.5,1) (Rasia et al. 2004); and, in addition, ? ? 1.5 (Hiotelis 2003), deduced from the application of a RFSM5 method, but using a different definition of scaled radius, or concentration; and ? ? 1.21.3 deduced from more recent high-resolution simulations (Diemand et al. 2004, Reed et al. 2005). No evident correlation is found between SDH dynamical state (relaxed or merging) and asymptotic inner slope of the fitting logarithmic density profile or (for SDH comparable virial masses) scaled radius. Mean values and standard deviations of some parameters are calculated, and in particular the decimal logarithm of the scaled radius, ?vir, reads < log?vir >= 0.74 and ?slog?vir = 0.150.17, consistent with previous results related to NFW density profiles. It provides additional support to the idea, that NFW density profiles may be considered as a convenient way to parametrize SDH density profiles, without implying that it necessarily produces the best possible fit (Bullock et al. 2001). A certain degree of degeneracy is found in fitting GPL to SDH density profiles. If it is intrinsic to the RFSM5 method or it could be reduced by the next generation of high-resolution simulations, still remains an open question. .

Contact Value Formulae for the Density Profiles of the Electric Double Layer

2008 ◽  
Vol 73 (4) ◽  
pp. 558-574 ◽  
Author(s):  
Douglas J. Henderson ◽  
Lutful B. Bhuiyan
Keyword(s):  
Computer Simulations ◽  
Density Profile ◽  
Physical Interpretation ◽  
Electric Double Layer ◽  
Reasonable Agreement ◽  
Hard Wall ◽  
Density Profiles ◽  
Sum Rule ◽  
Recent Computer ◽  
Local Expression

An exact sum rule, due to Henderson, Blum, and Lebowitz, for the contact value of the density profile of ions in a primitive model electrolyte next to a planar, nonpolarizable charged hard wall, has been known for some years. This result has a pleasing physical interpretation and is local. It has been useful in assessing the accuracy of theoretical approximations. However, a sum rule for the contact value of the charge profile for the same system has, until recently, not been known. A few years ago, Boda and Henderson proposed what they thought might be a useful, but approximate, local expression for the contact value of the charge profile at a weakly charged electrode. Very recent computer simulations indicate that this expression may well be exact at low electrode charge. Recently, Holovko, Badiali, and di Caprio have obtained a more general, but nonlocal, sum rule for the contact value of the charge profile that is valid for all electrode charge. In this paper, we develop an alternative, nonlocal, but nonrigorous expression for this quantity. Both the expression of Holovko et al. and our new expression are examined by means of computer simulations. The Holovko et al. expression is exact and, within numerical uncertainties, seems supported by our simulations. Although admittedly nonrigorous, our simpler expression is in seemingly reasonable agreement with simulation and thus appears to be useful. The relation between the two expressions has not been established.

Analysis of the influence of particle and poplar fibres share on selected properties of particle-fibre boards

2020 ◽  
Vol 112 ◽  
pp. 22-31
Author(s):  
Karol Zaraziński ◽  
Piotr Boruszewski
Keyword(s):  
Density Profile ◽  
Modulus Of Elasticity ◽  
Internal Bond ◽  
Average Density ◽  
Raw Material ◽  
Thickness Swelling ◽  
Pine Wood ◽  
Poplar Hybrid ◽  
Control Variant ◽  
Positive Effect

Analysis of the influence of particle and poplar fibres share on selected properties of particle-fibre boards. As a part of the study, one-layer particle-fibre boards with 12 mm thick and of average density 650 kg/m3 were manufactured from plantation poplar ‘Hybrid 275’ wood.. For the control variant a typical industrial raw material (pine wood) was used. The following properties were determined for the boards: modulus of rapture (MOR), density profile, modulus of elasticity at static bending (MOE), internal bond (IB), thickness swelling (TS) after 2h and 24h soaking in water. On the basis of conducted study, it was found that the addition of poplar fibers to particle-fibre boards in most cases has a positive effect on the values of determined properties – an increase in strength was noted, except for internal bond (IB). In the case of thickness swelling of the boards after 24 h soaking in water, it was noted that with the increase in the share of poplar fibers in the boards, the value of the tested property decreased (which was not clear in the case of thickness swelling of boards after 2 h soaking in water).

scholarly journals Improving spatial synchronization between X-ray and near-infrared spectra information to predict wood density profiles

2020 ◽  
Vol 54 (5) ◽  
pp. 1151-1164 ◽  
Author(s):  
Ana Alves ◽  
Andrea Hevia ◽  
Rita Simões ◽  
Juan Majada ◽  
Ricardo Alia ◽  
...  
Keyword(s):  
Wood Density ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Spatial Synchronization ◽  
Density Profiles ◽  
X Ray ◽  
Near Infrared Spectra

Leaf area – sapwood cross-sectional area relationships in repressed stands of lodgepole pine

1987 ◽  
Vol 17 (3) ◽  
pp. 205-209 ◽  
Author(s):  
M. G. Keane ◽  
G. F. Weetman
Keyword(s):  
Hydraulic Conductivity ◽  
Leaf Area ◽  
Wood Density ◽  
Lodgepole Pine ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Density Profiles ◽  
Individual Tree ◽  
Individual Trees

To better understand the phenomenon of growth "stagnation" in high-density lodgepole pine (Pinuscontorta Dougl. ex Loud.), leaf area and its relationship with sapwood cross-sectional area were examined on both an individual tree and stand basis. Leaf areas of individual trees in a 22-year-old stand varied from 30.8 m2 (dominants in stands of low stocking) to 0.05 m2 (suppressed trees in stands of high stocking). Leaf area indices ranged from 13.4 to 2.3 m2 m−2 between low and high stocking levels, respectively. Over the same stocking range, the ratio of leaf area to sapwood cross-sectional area was reduced from 0.3 to 0.15 m2 cm−2. Intraring wood density profiles showed that ovendry density increased from 0.52 to 0.7 g cm−3 and the proportion of early wood decreased over a stocking level range of 6500–109 000 trees/ha. A reduction in hydraulic conductivity in the stems of stagnant trees, suggested by the greater proportion of narrow-diameter tracheids present, may lead to a greater resistance to water transport within the boles of trees from stagnant stands, leading to low leaf areas.

Climate signals from intra-annual wood density fluctuations in Abies durangensis

IAWA Journal ◽  
2019 ◽  
Vol 40 (2) ◽  
pp. 276-287 ◽  
Author(s):  
Marcos González-Cásares ◽  
Marín Pompa-García ◽  
Alejandro Venegas-González
Keyword(s):  
Wood Density ◽  
Drought Index ◽  
Growth Ring ◽  
Ring Width ◽  
Climatic Conditions ◽  
Density Fluctuations ◽  
Growth Ring Width ◽  
Density Values ◽  
Climate Signals ◽  
Hydroclimatic Variables

ABSTRACTOngoing climate change is expected to alter forests by affecting forest productivity, with implications for the ecological functions of these systems. Despite its great dendrochronological potential, little research has been conducted into the use of wood density as a proxy for determining sensitivity to climate variability in Mexico. The response of Abies durangensis Martínez, in terms of wood density and growth ring width, to monthly climatic values (mean temperature, accumulated precipitation and the drought index SPEI) was analyzed through correlation analysis. Abies durangensis presents a high response, in terms of radial growth, to climatic conditions. Tree-ring widths are more sensitive to hydroclimatic variables, whereas wood density values are more sensitive to temperature. In particular, mean (MeanD) and minimum (MND) wood density values are more sensitive to climate than maximum (MXD). We found very marked spatial variations that indicate that A. durangensis responds differently to drought conditions depending on the indices of density.

Non-linear effects in a Rayleigh–Bénard experiment

1970 ◽  
Vol 42 (1) ◽  
pp. 161-175 ◽  
Author(s):  
D. R. Caldwell
Keyword(s):  
Rayleigh Number ◽  
Heat Flow ◽  
Density Profile ◽  
Critical Rayleigh Number ◽  
Temperature Drop ◽  
Density Profiles ◽  
Heating Curve ◽  
Linear Effects ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard

Observations of temperature drop as a function of heat flow in Rayleigh–Bénard convection with curved density profiles show: (1) reversal of slope in the heating curve, (2) oscillations with time, (3) history dependence, and (4) an increase in critical Rayleigh number as the curvature of the density profile is increased. Some of the results are quite similar to the predictions of Busse.

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