1,720,971 research outputs found
Wood anatomical characteristics and chemical composition of Prosopis laevigata grown in the Northeast of Mexico
No full textStructural heartwood characteristics for Prosopis laevigata (Humb. & Bonpl. exWilld.) M.C. Johnst., including a histometrical evaluation, were obtained by light microscopy coupled with a digitised image analysis system. The growth ring boundaries of the semi-ring-porous or diffuse-porous wood are often marked by a marginal parenchyma band. Average fibre length is 975 mu m, the fibres are thick-walled with a single cell wall thickness of 13 mu m on average. Average diameter of the vessels which are arranged in non-specific patterns differs significantly between earlywood (116 mu m) and latewood (44 mu m). The topochemical distribution of lignin and phenolic deposits in the tissue was investigated by means of scanning UV microspectrophotometry (UMSP). Thereby, in heartwood tissue the deposition of extractives in vessels, pit canals, parenchyma cells, fibre lumina and partly also in the S-2 layers of the fibres was detected. Monosaccharides were qualitatively and quantitatively determined by borate complex anion exchange chromatography. Holocellulose content is between 61.5 and 64.7 % and Klason lignin content between 29.8 and 31.4%. Subsequent extraction of the soluble compounds was performed with petrolether, acetone/water and methanol/water by accelerated solvent extraction (ASE). Total extractives content in heartwood ranges between 14 to 16 % on a dry weight basis. Major compounds in acetone/water extracts were identified as (-)-epicatechin, (+)-catechin and taxifolin, and quantitatively determined by liquid chromatography (RP-HPLC-UV)
Treatability And Penetration Indices Of Four Lesser-Used Myanmar Hardwoods
No full textDepletion of Myanmar's top commercial timbers has grown the attention towards lesser-used timbers, which present: low durability and require protection against biodegradation. This research tested the treatability of four nondurable Myanmar hardwoods: Bombax ceiba, Bombax insigne, Spondias pinnata and Tetrameks nudiflora. Conditioned heartwood samples were pressure-treated according to standard schedules using a staining solution. Solution uptake, penetration depths, and percent of each cell type penetrated were determined and discussed according to wood anatomical characteristics. B. ceiba, B. insigne and S. pinnata had high uptakes and good penetration making them promising for protective treatment. T nudiflora was also classified as easy to treat based on its penetration index but as generally difficult to treat according to retention and depth of penetration. This different behavior was attributed to the tyloses occluding its vessels. The results are useful for the development of specific treatment schedules to achieve the retentions and penetration required for the effective protection of these lesser-used hardwoods
Treatability And Penetration Indices Of Four Lesser-Used Myanmar Hardwoods
No full textDepletion of Myanmar's top commercial timbers has grown the attention towards lesser-used timbers, which present: low durability and require protection against biodegradation. This research tested the treatability of four nondurable Myanmar hardwoods: Bombax ceiba, Bombax insigne, Spondias pinnata and Tetrameks nudiflora. Conditioned heartwood samples were pressure-treated according to standard schedules using a staining solution. Solution uptake, penetration depths, and percent of each cell type penetrated were determined and discussed according to wood anatomical characteristics. B. ceiba, B. insigne and S. pinnata had high uptakes and good penetration making them promising for protective treatment. T nudiflora was also classified as easy to treat based on its penetration index but as generally difficult to treat according to retention and depth of penetration. This different behavior was attributed to the tyloses occluding its vessels. The results are useful for the development of specific treatment schedules to achieve the retentions and penetration required for the effective protection of these lesser-used hardwoods
Timber Grade Oriented Analysis of Abies Grandis Trees' Ovendry Density with Different Growth Rates Part I.: Experimental Design
No full textThe variability of ovendry density on 12 giant fir (Abies grandis) logs was investigated. Statistical analysis also was made. The wood was checked for compression wood, "coloured heartwood", knots and annual ring width. However, giant fir has usually no coloured heartwood in some investigated logs discolouration of the heartwood was detectable. The mean ovendry density (at MC of 0 %) of all specimens was 0.357 g.cm(-3). The statistical analysis showed significant differences between ovendry density of the sapwood (mean = 0.417 g.cm(-3)) and those of visible (mean = 0.335 g.cm(-3)) and non-visible (mean = 0.336 g.cm(-3)) heartwood ovendry densities. The ovendry density was higher in compression wood than in normal wood in case of heartwood and sapwood as well. The ovendry density at 1.5 m height the highest was, and decreased constantly with increasing tree heights at 7.0, 14.0 and 20 m
Durability of wood of Prosopis laevigata and the effect of its extractives on wood-decaying fungus
No full textThe natural durability of mezquite wood (Prosopis laevigata) from four localities in Northeast Mexico was determined using two test, a) terrestrial microcosm (European pre-norm 807) during 32 weeks on a non sterilized vertisol soil and, b) laboratory conditions according to the modify European Norm 113, the wood was exposed by 16 weeks to Basidiomycetes Trametes versicolor, Coniophora puteana, Irpex lacteus and Pleurotus ostreatus. The natural durability of two methods were determined by mass loss and by the dynamic modulus of elasticity loss (MOEdyn). Additionally the inhibition effect of wood extracts obtained from wood sawdust in either hot water, ethanol or acetone at 100 parts per million (ppm), 1 000 ppm, 5 000 ppm and 10 000 ppm on growth of C. puteana and T. versicolor was also determined. The results showed that P. laevigata wood from the four sites is similar and very resistant to soil contact; the mass lost was ranging from (9 +/- 2)% to (17 +/- 5)%. The MOEdin lost of P. laevigata was ranging from (20 +/- 4)% to (39 +/- 11)%, the control species showed values of (91 +/- 13)% and (62 +/- 15)% respectively. The second method (modify european norm 113) showed mass loss of P. laevigata for the four localities and the four fungi ranging from (0,7 +/- 0,5)% to (2,6 +/- 3,2)%, placed this species as a class 1 (i.e. very durable) according to the European Norm 350-1. The MOEdyn losses was from (3,8 +/- 4,2)% to (19,9 +/- 5,6)%. The hot water extracts at 1 0000 ppm concentration inhibited growth of C. puteana and T. versicolor by (83 +/- 8)% and (93 +/- 6)% respectively
Timber Grade Oriented Analysis of Abies Grandis Trees' Ovendry Density with Different Growth Rates Part I.: Experimental Design
No full textThe variability of ovendry density on 12 giant fir (Abies grandis) logs was investigated. Statistical analysis also was made. The wood was checked for compression wood, "coloured heartwood", knots and annual ring width. However, giant fir has usually no coloured heartwood in some investigated logs discolouration of the heartwood was detectable. The mean ovendry density (at MC of 0 %) of all specimens was 0.357 g.cm(-3). The statistical analysis showed significant differences between ovendry density of the sapwood (mean = 0.417 g.cm(-3)) and those of visible (mean = 0.335 g.cm(-3)) and non-visible (mean = 0.336 g.cm(-3)) heartwood ovendry densities. The ovendry density was higher in compression wood than in normal wood in case of heartwood and sapwood as well. The ovendry density at 1.5 m height the highest was, and decreased constantly with increasing tree heights at 7.0, 14.0 and 20 m
Wood anatomical characteristics and chemical composition of Prosopis laevigata grown in the Northeast of Mexico
No full textStructural heartwood characteristics for Prosopis laevigata (Humb. & Bonpl. exWilld.) M.C. Johnst., including a histometrical evaluation, were obtained by light microscopy coupled with a digitised image analysis system. The growth ring boundaries of the semi-ring-porous or diffuse-porous wood are often marked by a marginal parenchyma band. Average fibre length is 975 mu m, the fibres are thick-walled with a single cell wall thickness of 13 mu m on average. Average diameter of the vessels which are arranged in non-specific patterns differs significantly between earlywood (116 mu m) and latewood (44 mu m). The topochemical distribution of lignin and phenolic deposits in the tissue was investigated by means of scanning UV microspectrophotometry (UMSP). Thereby, in heartwood tissue the deposition of extractives in vessels, pit canals, parenchyma cells, fibre lumina and partly also in the S-2 layers of the fibres was detected. Monosaccharides were qualitatively and quantitatively determined by borate complex anion exchange chromatography. Holocellulose content is between 61.5 and 64.7 % and Klason lignin content between 29.8 and 31.4%. Subsequent extraction of the soluble compounds was performed with petrolether, acetone/water and methanol/water by accelerated solvent extraction (ASE). Total extractives content in heartwood ranges between 14 to 16 % on a dry weight basis. Major compounds in acetone/water extracts were identified as (-)-epicatechin, (+)-catechin and taxifolin, and quantitatively determined by liquid chromatography (RP-HPLC-UV)
Timber Grade Oriented Analysis of Abies Grandis Trees' Ovendry Density with Different Growth Rates Part Ii.: Effect of the Trees' Social Position in the Forest on the Variability of Ovendry Density
No full textThe variability of ovendry density on 12 giant fir logs (Abies grandis) was investigated. Statistical analysis was made also. The variation of the ovendry density was determined regarding to the different Kraft classes, heights and radial wood zones (sapwood, heartwood and compression wood). The difference between the ovendry density of the trees from the Kraft class 1 and 3 is not significant. According to the determined radial gradients the highest ovendry density was always measured in the outermost parts (next to the cambium) while the lowest ovendry density was measured in the innermost part of the heartwood (juvenile wood). In longitudinal direction the ovendry density showed at 1.5 m tree height the highest and at 7.5 and 14.0 m the lowest values. The density of the heartwood was lower than the density of the sapwood and compression wood at all investigated tree heights. The ovendry density of the compression wood reached values between the heartwoods and the sapwoods density, at all investigated tree heights. The test results provide a solid and practical basis for the timber grading of the giant fir logs.EU [TAMOP-4.2.2.A-11/1/KONV-2012-0068]; European Social Foundatio
Durability of wood of Prosopis laevigata and the effect of its extractives on wood-decaying fungus
No full textThe natural durability of mezquite wood (Prosopis laevigata) from four localities in Northeast Mexico was determined using two test, a) terrestrial microcosm (European pre-norm 807) during 32 weeks on a non sterilized vertisol soil and, b) laboratory conditions according to the modify European Norm 113, the wood was exposed by 16 weeks to Basidiomycetes Trametes versicolor, Coniophora puteana, Irpex lacteus and Pleurotus ostreatus. The natural durability of two methods were determined by mass loss and by the dynamic modulus of elasticity loss (MOEdyn). Additionally the inhibition effect of wood extracts obtained from wood sawdust in either hot water, ethanol or acetone at 100 parts per million (ppm), 1 000 ppm, 5 000 ppm and 10 000 ppm on growth of C. puteana and T. versicolor was also determined. The results showed that P. laevigata wood from the four sites is similar and very resistant to soil contact; the mass lost was ranging from (9 +/- 2)% to (17 +/- 5)%. The MOEdin lost of P. laevigata was ranging from (20 +/- 4)% to (39 +/- 11)%, the control species showed values of (91 +/- 13)% and (62 +/- 15)% respectively. The second method (modify european norm 113) showed mass loss of P. laevigata for the four localities and the four fungi ranging from (0,7 +/- 0,5)% to (2,6 +/- 3,2)%, placed this species as a class 1 (i.e. very durable) according to the European Norm 350-1. The MOEdyn losses was from (3,8 +/- 4,2)% to (19,9 +/- 5,6)%. The hot water extracts at 1 0000 ppm concentration inhibited growth of C. puteana and T. versicolor by (83 +/- 8)% and (93 +/- 6)% respectively
Wood Anatomy and Topochemistry of Bombax ceiba L. and Bombax insigne Wall.
No full textWood anatomical characteristics, content of phenolic extractives, and topochemistry of two lesser known and underutilised hardwood species, Bombax ceiba and Bombax insigne were studied. Heartwood and sapwood material was obtained from logs originating from natural forests of Pyinmana District, Myanmar. The basic qualitative anatomical features agreed with descriptions reported for the species in other regions (e. g. India, Bangladesh, Southeast Asia). However, there were some light differences in the quantitative wood anatomical data among the regions due to the influence of environmental conditions. The amount of phenolic extractives obtained by gradual extraction with acetone-water was almost the same in heartwood and sapwood (about 1.2%) in B. insigne, while heartwood showed a higher amount (2.8%) than sapwood (2.5%) in B. ceiba. Topochemical distribution of lignin and phenolic deposits in heartwood tissues investigated by scanning UV microspectrophotometry (UMSP) revealed that B. insigne is more highly lignified than B. ceiba. For both species, a lower UV-absorbance by the fiber and ray cell wall as compared to that of the cell wall of vessels was observed. Also, phenolic compounds were mostly deposited in the lumina of parenchyma cells and vessels rather than in cell walls. The results further improve the knowledge on the wood anatomy and chemistry of the species and in this respect are useful in future research to broaden their utilisation potential
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