Basic Specific Gravity Research Articles

Construction of a Dicotomous Key for Common Local and Imported Timber Species in Sri Lanka

Proper timber identification mechanism is essential today than ever before as lesser knownlocal and imported timber species are coming to timber market in present. In Sri Lanka thereare over 400 different timber species of commercial use, which show a remarkably widerange of variation in their physical properties as well as their anatomical structures. Hencetimber identification is a highly important task to confirm its authenticity. Scientific woodidentification is based on microscopic evaluation of anatomical properties.The objective is of this research is to develop a timber identification key for common localand imported timber species used in Sri Lanka to facilitate scientific identification of timberspecies based on anatomical features in IAWA (International Association of WoodAnatomist) list of 1989.Timber samples of local and imported timber species were collected from various floristicregions in Sri Lanka. Authentic timber samples were collected from Research Division of theState Timber Corporation. Transverse section (T.S), Radial Longitudinal Section (R.L.S.) andTangential Longitudinal Section (T.L.S.) were obtained using the Microtome. Microscopicslides were prepared for sixty seven timber species and photographic representations andanatomical details were presented. Anatomical features of rays, parenchyma and vessels werestudied. Tangential vessel diameter and ray height were also measured. Values of the meanvessel diameter were categorized according to IAWA: category 1(<=50 μm), Category 2,(50-100 μm), Category 3 (100-200 μm) and Category 4 (>=200 μm).The highest mean vessel diameter value was observed in Garcinia spp (Kandis) and secondhighest value was observed in Azadirachta indica (Margosa) timber species. The lowestMean Vessel Diameter value was observed in Elaeodendron glaucum (Neralu) timberspecies.Specific gravity values were taken from previous research and publications. Specific gravityare categorized three categories according to IAWA features: low (<=0.40), medium (0.40 -0.75) and high (>= 0.75). The highest basic specific gravity value was observed in Diospyrosebenum (Ebony) (1.12) and second highest value was observed in Palu (1.1) timber species.The lowest basic specific gravity values were observed in Lunumidella and Rukattana timberspecies.Mean ray height of 67 timber species were measured using Micrometrics SE premium 4software available at research division in the State Timber Corporation.A dichotomous key on timber identification was prepared using 56 common local timberspecies and 11 major imported timber species mostly used in Sri Lanka to facilitate scientificidentification of timber species based on anatomical features of IAWA (InternationalAssociation of Wood Anatomist) List 1989.

Monitoring of moisture content and basic specific gravity in black spruce logs using a hand-held MEMS-based near-infrared spectrometer

Our study presents results of a test of a hand-held micro-electro-mechanical system (MEMS)-based near-infrared (NIR) spectrometer to estimate moisture content and basic specific gravity of black spruce frozen and unfrozen logs. The spectra were acquired on sapwood and heartwood as well as on tangential and transversal log sections. Partial least square regression was used to develop and validate the models that relate NIR spectral data to the log properties. Models were developed for the frozen and unfrozen logs separately (temperature-specific models) and for both kinds of logs together (generalized model). Both model types gave similar prediction accuracy and there were no temperature condition effects on the PLS model, for both moisture content and basic specific gravity estimation. This implies that the NIR spectrometer can be used whatever the log temperature conditions, even under freezing conditions.

CONTRACCIONES Y PROPIEDADES FÍSICAS DE ACACIA MANGIUM, TECTONA GRANDIS Y TERMINALIA AMAZONIA, MADERAS DE PLANTACIÓN EN COSTA RICA

De acuerdo con las normas ASTM D 2395-02 y D 143-94, se determinó la contracción total y normal en dirección radial (CR), tangencial (CT) y volumétrica (CV) y el coeficiente CT/ CR total y normal de Acacia mangium Willd., Tectona grandis L. f. y Terminalia amazonia A. Chev, maderas provenientes de plantación. También se determinaron algunas propiedades físicas como peso específico básico (PEB), PE12% y PEanhidro, densidad verde (DV) y normal (DN), punto de saturación de la fibra (PSF) y contenido de humedad (CH). Algunos criterios de clasificación, propuestos por otros investigadores, se aplicaron para categorizar la estabilidad dimensional y propiedades físicas de estas especies. Se encontró que la CR, CT, CV totales y CTtotal/CRtotal tienen diferencias significativas entre especies, al igual que las propiedades físicas PEB y PSF. El índice CTtotal/CRtotal indicó que T. grandis tiene mejor estabilidad dimensional. La relación lineal (R2= 0.7769) indicó que el PSF es un buen indicador de la magnitud de la CVtotal. Las especies de plantación de este estudio comparadas con las del bosque natural tienen estabilidad dimensional similar pero menor PEB.

Sifat Anatomi dan Sifat Fisika Kayu Mindi (Melia azedarach Linn) dari Hutan Rakyat di Yogyakarta

Anatomical and Physical Properties of Mindi Wood (Melia azedarach Linn) from Community Forest in YogyakartaInformation about mindi wood characteristics is very limited while utilisation of this wood on our society is very extensive. Better knowledge on anatomical and physical wood properties of mindi wood optimizes its utilization. Therefore, this study aims to identify anatomical (macroscopic and microscopic) and physical (moisture content, specific gravity and dimensional changes) wood properties of mindi taken from community forests around Yogyakarta. The macroscopic structural characteristics results showed that annual ring appeared clearly at transversal surface, having single vessel, vasicentric and diffuse parenchyma, rough texture, straight fiber direction, and no resin canal. Cell proportion of wood showed that fibers occupy more than 44%, followed by vessel (20%), parenchyma (19%) and rays (15%). Wood fiber dimension showed fiber length of 0.83 mm, fiber diameter of 14.57µ, and cell wall thickness of 2.50µ. Physical wood properties showed that mindi has 31% moisture content and 0.416 of basic specific gravity. Wood shrinkage from green to kilndry on longitudinal was 3.94 %, tangensial 5.74 %, and radial 2.60 %, with T/R ratio 2.38. Based on T/R ratio value, mindi wood is not recommended for wood construction due to its low dimensional stability. Furthermore, mindi wood also has high longitudinal wood shrinkage and low specific gravity indicating juvenility.

Caracterização anatômica, química e física da madeira de candeia (Eremanthus erythropappus (DC.) Macleish)

Neste trabalho, objetivou-se a caracterização anatômica, química e física da madeira de candeia (Eremanthus erythropappus (DC.) Macleish). Coletaram-se cinco árvores na região de Carrancas-MG, e retirados discos ao DAP para confecção dos corpos-deprova. Realizou-se a descrição e mensuração dos principais elementos anatômicos da madeira (fibras, vasos e parênquima radial). Para a análise química, determinou-se a quantidade de extrativos totais, holocelulose, lignina e constituintes inorgânicos. O estudo físico consistiu na determinação da densidade básica e aparente da madeira e assim como a determinação das contrações tangencial, radial e volumétrica total, dos coeficientes de anisotropia e de retratibilidade. Os principais resultados encontrados para características macroscópicas foram: odor desagradável, decorrente da presença de óleo-resina, grã revessa e dura ao corte; características microscópicas: parênquima axial escasso e radial bastante fino, elementos de vasos com pontoações numerosas e muito pequenas, placas de perfuração simples, fibras libriformes curtas com parede celular espessa e presença de células de óleo no raio. Composição química: 20,89% de extrativos totais; 50,52% de holocelulose; 28,59% de lignina e 0,39% de constituintes inorgânicos. A densidade aparente foi de 0,98 g/cm³ e a básica de 0,79 g/cm³. O coeficiente de anisotropia foi igual a 1,91 e o coeficiente de retratibilidade volumétrica, 0,28%.

Allometric equations for tree species and carbon stocks for forests of northwestern Mexico

Allometric equations were developed and applied to forest inventory data to estimate biomass and carbon stocks for temperate species and forests of Durango and Chihuahua and for tropical dry forests of Sinaloa, Mexico. A total of 872 trees were harvested and dissected into their component parts: leaves and branches, boles, and coarse roots. Coarse roots of 40 temperate trees ranging in diameter at breast height (DBH) from 6.0 to 52.9 cm were excavated in their entirety (i.e., >0.5 cm diameter). The species sampled (number of trees) in tropical dry forests (39) were Lysiloma divaricata (Jacq) Macbr. (10), Haematoxylon brasiletto Karst. (10), Cochlospermum vitifolium (Wild.) (5), Ceiba acuminata (S. Watson) Rose (5), Bursera penicillata ( B. inopinnata) (5), and Jatropha angustifolia Mull. Arg. (4) and in temperate forests (833) were Quercus spp. (118) ( Q. rugosa Neé, 15, Quercus sideroxylla Humb. & Bonpl, 51, Quercus spp., 52), Pinus herrerae Martinez 1940 (19), Pinus oocarpa Schiede ex Schlectendal 1838 (31), Pinus engelmannii Carriere 1854 (7), Psudotsuga menziesii (Mirb.) Franco (19), Pinus leiophylla Schiede ex Schlectendal et Chamisso 1831 (27), Pinus teocote Schiede ex Schlectendal et Chamisso (55), Pinus ayacahuite Ehrenb. ex Schltdl. (58), Pinus cooperi Blanco (48), Pinus durangensis Martinez 1942 (385), and Pinus arizonica Engelmann 1879 (66). Allometric equations having only DBH as an independent variable were developed for each component of each species. Since Pinus herrerae, Pinus engelmannii, Pinus oocarpa and Pseudotsuga menziensii had a small number of trees, an individual allometric equation was developed for these species. We used non-linear regression to fit parameters of the typical allometric power equation. The resulting 31 equations (10 species or groups of species, three biomass components; bole, branch and leaves, and total aerial; and the generalized equation for coarse roots) fit the data well and enable the user to predict biomass by component for each of the 10 different groups of species or each of six temperate species. A single allometric equation that incorporates the basic specific gravity for aboveground biomass of all temperate tree species also fit the data well, and this equation provides both the detail and the accuracy supplied by species-specific, plant-part-specific equations. Biomass equations coupled with forest inventory data for temperate (637 circular, 1/10 ha plots) and tropical dry forests (166 20 m × 20 m-quadrats) of northwestern Mexico predict a mean (confidence intervals) of 130 Mg ha −1 (4.2 Mg ha −1) and 73 Mg ha −1 (7.1 Mg ha −1) for total tree and total aboveground biomass, respectively. Large sample sizes and the economic and ecological importance of the species studied make this data set uniquely useful for biomass estimations and for understanding the inherent heterogeneity of tree structure in dynamic tropical and temperate environments of northwestern Mexico.

Comparison of Pinus taeda L. whole-tree wood property calibrations using diffuse reflectance near infrared spectra obtained using a variety of sampling options

A necessary objective for tree-breeding programs, with a focus on wood quality, is the measurement of wood properties on a whole-tree basis, however, the time and cost involved limits the numbers of trees sampled. Near infrared (NIR) spectroscopy provides an alternative and recently, it has been demonstrated that calibrations based on milled increment cores and whole-tree data can provide good estimates of whole-tree properties. Several options exist for sampling standing trees and the aim of this study was to compare wood property calibrations based on NIR spectra collected from samples obtained using different sampling methods. Calibrations for whole-tree lignin and basic specific gravity based on NIR spectra from whole-tree chips (milled or intact) had the strongest statistics, calibrations based on NIR spectra from milled increment cores were similar. Other options for sampling the tree (drill shavings, etc.) gave errors that were too large for practical applications. If an increment core is going to be used to estimate whole-tree properties, it is recommended that it be dried and milled prior to analysis.

Above-ground biomass estimation in ten tropical dry evergreen forest sites of peninsular India

Abstract The present study aims to estimate the above-ground biomass (AGB) distribution in ten 1-ha permanent plots, established in five sites each in inland and coastal tropical dry evergreen forests of peninsular India. Two linear regression equations, one using basal area (BA, Method 1) and the other using BA and height (Method 2) were followed. On using method 1, the AGB varied from 39.69 to 170.02 Mg ha −1 and by method 2, it varied from 73.06 to 173.10 Mg ha −1 . The relationship between BA and AGB yielded a positive correlation for all the five sites of inland and coastal areas. The basic wood specific gravity of 41 tree species determined by oven-dry weight by volume, ranged from 0.46 to 0.92 g cm −3 for inland sites and 0.47 to 0.89 g cm −3 for the coastal sites. The AGB estimation obtained in this study represents a more realistic picture of biomass of tropical dry evergreen forests, because a relatively large area was sampled.

Estimates of genetic parameters of wood traits for sawn timber production in Eucalyptus grandis

In this study, the breeding perspectives of 41 open-pollinated progenies of Eucalyptus grandis were evaluated based on their wood traits. The progenies were distributed in two experiments in a randomized complete block design, with three replicates and linear plots containing six plants each. The traits were assessed at eight years of age. Two trees from each plot were selected for this assessment based on better growth, stem form and phytosanity. Significant differences in basic density, sapwood/heartwood ratio, bowing, specific gravity, parallel compression and static bending were detected among the progenies. These traits were potentially promising for breeding programs, with heritability coefficients that varied from 0.34 to 0.61 on a progeny mean basis. There was no genetic variation in the moisture content, board end-splitting, log volume under bark, log eccentricity, bark content, crooking, and shear strength of the progenies. Intermediate to highly significant genetic correlations were detected among the physical and mechanical properties, as well as between pairs of traits such as basic density and log end-splitting, basic density and bowing, specific gravity and bowing, sapwood/heartwood ratio and bowing, log volume and bowing, and log volume and log end-splitting. These results show that the levels of growth stress in trees can be reduced by selection using indirect traits such as the sapwood/heartwood ratio and bowing.

Radial Variation in Wood Properties of Naturally and Plantation Grown Light Red Meranti (Shorea, Dipterocarpaceae)

The wood quality parameters of cell wall percentage, tissue proportions and basic specific gravity were determined for three naturally and nine plantation grown trees of Light Red Meranti (Shorea leprosula and S. parvifolia).

Radial Variation in Wood Specific Gravity, Fibre Length and Vessel Area for Two Central American Hardwoods: Hyeronima Alchorneoides and Vochysia Guatemalensis: Natural and Plantation-Grown Trees

Natural-grown and young (5.5 year old) plantation-grown trees were sampled for two Central American hardwood species: Hyeronima alchorneoides and Vochysia guatemalensis in the Atlantic lowlands of Costa Rica. Increment cores extracted at a height of 1.3 m from trees were divided into 1cm segments from pith to bark. Basic specific gravity was calculated for each segment. Using the same cores, fibre length was measured from macerations for five natural and plantation-grown trees of each species. Number of vessels/mm2 and vessel tangential diameter were measured from segment cross sections for five natural-grown trees of each species.

Radial and Vertical Wood Specific Gravity in Ochroma pyramidale (Cav. ex Lam.) Urb. (Bombacaceae)

Radial (pith-to-bark) wood samples from Ochroma pyramidale sampled at breast height and at subsequent five meter height intervals were analyzed to determine basic specific gravity. Specific gravity increased linearly with radial distance at any given height. In multiple regressions both radial distance and height proved to be equally important independent variables in explaining variation in specific gravity. However, when radial distance was measured centripetally (barkto-pith) rather than centrifugally (pith-to-bark), the importance of height diminished drastically. These results suggest that the secondary xylem produced at any one time along the bole exhibits the same specific gravity. This timeconstant model is contrasted with the alternative extreme, the radius-constant model, where xylem at a given radial distance (pith-to-bark) would exhibit the same specific gravity. Both models present alternative developmental patterns for tropical wet forest species which commonly exhibit increases in specific gravity with distance from the pith.

Physical properties of black cottonwood and balsam poplar

The objective of this study was to characterize selected properties of black cottonwood and balsam poplar to determine whether these species should be distinguished in their utilization. At present, black cottonwood is excluded from the "northern aspen" species group embraced by the National Lumber Grading Agency grading rules for dimension lumber and from use as core material in softwood plywood. Samples of black cottonwood were obtained from three sites in British Columbia. Samples of balsam poplar were obtained from three sites in Alberta. Ten tres were randomly selected from each site and a single 130 cm long bolt was collected immediately above breast height (1.36 m) from each tree. From two trees on each site, three additional bolts of the same length were collected immediately above the height positions located at 25, 50, and 75% of total tree height. The average basic specific gravity of the two species did not differ significantly (black cottonwood, 0.338; balsam poplar, 0.337) in this study. However, differences do exist between site averages, at least for black cottonwood. The initial green moisture contents differ significantly (black cottonwood, 160.5%; balsam poplar, 120.6%) and may be expected to affect their drying requirements differentially. For both species, the specific gravity increases and the green moisture content decreases with increasing height position in the tree. The average fiber length of black cottonwood is significantly longer than that of balsam poplar. The bending properties of strength and stiffness for black cottonwood were found to be significantly greater than for balsam poplar. Variation of these properties with height position in the tree was studied. Fiber length was found to decrease with increasing height position, while the bending strength properties were not affected by height position.

Woody biomass of forest stands

Published data on the total aboveground woody biomass (stems and branches), W T, of 640 forest and woodland stands around the world (Cannell, 1982) were divided into 32 species groups. Differences between groups were examined in the relationship: WT = F( HG) D, where F was a stand form factor; H was mean tree height; G was basal area at breast height; and D was mean wood basic specific gravity. W T was linearly related to ( HG); broadleaved species, owing to their greater D, had greater regression coefficients than conifers. Regression coefficients and F factors tended to be smallest in groups having the smallest percentage biomass as branches and greatest in those having most branches. F factors of about 0.5 corresponded to groups having 5–10% branches. The shapes of the woody parts of trees in those groups would conform most closely to quadratic paraboloids as hypothesized by Dawkins (1963) and Gray (1966). But heavily branched broadleaved stands had F factors of 0.6–0.8, and the F factor of tapped Hevea rubber with 81% branches exceeded 1. Thus, for any given G and H, the greatest W T was contained in those forests which had the greatest proportion of branches.