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- Adamopoulos, Stergios, et al.
(author)
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Ring width, latewood proportion and dry density in stems of Pinus brutia Ten
- 2009
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In: European Journal of Wood and Wood Products. - : Springer Science and Business Media LLC. - 0018-3768 .- 1436-736X. ; 67:4, s. 471-477
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Journal article (peer-reviewed)abstract
- This study examined basic characteristics of stem wood produced in Pinus brutia Ten. reforestations in Northeastern Greece. Sixteen dominant trees growing at good and medium site qualities were felled at 14–22 years. Site quality classification was based on site quality surrogates and confirmed by using site index curves that were created for a neighbouring area. Discs were taken at three stem positions (base, middle, top) to study variations in ring width, latewood proportion and dry density. Generally, at both good and medium sites, ring width was found to increase towards the top of the stems while latewood proportion and dry density showed a negative relationship with stem height. Radial variability trends were similar at all heights, and at both sites, revealing a rapid increase for ring width in the first 3–6 annual rings followed by a decrease towards the bark, a gradual increase for latewood proportion and no specific change for dry density. Comparisons between wood material produced during the same growth period (2005–2001) showed statistically significant differences among sampling heights in all cases except for dry density in medium sites. At the base of the stems, mean ring width and dry density were significantly (P ≤0.05) higher at good sites (3.6 mm and 0.53 g/cm3) than at medium sites (3.0 mm and 0.50 g/cm3). However, the differences between the sites are of small magnitude and therefore have limited practical impact on wood processing. The availability of such data is useful in utilising small-dimension timber of brutia pine.
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- Adamopoulos, Stergios, et al.
(author)
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Strength properties of juvenile and mature wood in black locust (Robinia pseudoacacia L.)
- 2007
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In: Wood and Fiber Science. - : Society of Wood Science and Technology. - 0735-6161. ; 39:2, s. 241-249
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Journal article (peer-reviewed)abstract
- This study was undertaken to investigate the strength properties of juvenile and mature wood in black locust (Robinia pseudoacacia L.). Wood specimens were prepared from various stem heights, up to 9 m, of five naturally-grown black locust trees, 21-37 years old. Mechanical properties tested included moduli of rupture (MOR) and elasticity (MOE), and pure modulus of elasticity (PMOE) in static bending, stress wave modulus of elasticity (SWMOE) in dynamic strength, axial compression, and toughness. Comparisons between juvenile and mature wood specimens of similar densities (0.667-0.894 g/cm3 and 0.682-0.892 g/cm3, respectively) showed that juvenile wood had a statistically significant lower mean MOR (138.78 N/mm2), MOE (13,936 N/mm2), PMOE (18,125 N/mm2), SWMOE (16,813 N/mm2) and toughness strength (155.25 KJ/m2) than the mature wood (148.29 N/mm2, 14,747 N/mm2, 19,498 N/mm2, 17,635 N/mm2 and 181.27 KJ/m2, respectively). On the contrary, no statistically significant differences were found for the mean strength in axial compression among juvenile (63.75 N/mm2) and mature wood (66.65 N/mm2). Fractured surfaces of juvenile and mature wood specimens in static bending and toughness were classified into the "splintering tension" type of failure, while compression failures were of the "shearing type" according to ASTM D 143-83 standards. Lower strength of juvenile wood in most of the properties examined may be attributed to anatomical and chemical properties rather than density of wood specimens. The adverse influence of juvenile wood on strength properties should be considered for effective management (e.g. longer rotation age and other genetic and forest or plantation management measures that reduce juvenile wood content) and utilization of the species.
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- Adamopoulos, Stergios, et al.
(author)
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Variation of certain chemical properties within the stemwood of black locust (Robinia pseudoacacia L.)
- 2005
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In: European Journal of Wood and Wood Products. - : Springer. - 0018-3768 .- 1436-736X. ; 63:5, s. 327-333
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Journal article (peer-reviewed)abstract
- From the bottom, middle, and top of three mature 35 to 37-year old black locust tree discs were cut and analysed to determine the variation within the stem of certain chemical properties. Hot-water extractive content was greater in heartwood than in sapwood, while the reverse occurred for the dichloromethane extractive content. Vertical stem analysis of hot-water extractives showed that they increased in heartwood but decreasedin sapwood from the bottom to the top of the stems while the reversal occurred for dichloromethane extractive content of sapwood. At the bottom and the middle of the stems, ash content was greater in sapwood than in heartwood, but at the top no difference was found between heartwood and sapwood. Ash content of both heartwood and sapwood was found to increase in the axial direction with respective values of 0.36% (bottom) and 0.76% (top) for heartwood and of 0.65% (bottom) and 0.76% (top) for sapwood. Ash analysis showed that considerable variations were found for the inorganic elements K and P being greater in sapwood than in heartwood. Heartwood was more acid than sapwood except for the top of the stems. Acidity mean values were found to increase from the bottom to the top of the stems in heartwood while they slightly decreased in sapwood. Total buffering capacity of heartwood was greater than that of sapwood and total buffering capacity of sapwood exhibited an inverse relationship to height. Very small acid equivalent values were determined only in sapwood. At the bottom, lignin content in heartwood (25.73%) was greater than in sapwood (18.13%). Lignin content of heartwood decreased from 25.73% at the bottom to 18.33% at the top, while that of sapwood was 18.13% at the bottom, 21.42% at the middle and 19.64% at the top.
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- Passialis, Costas, et al.
(author)
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Extractives, acidity, buffering capacity, ash and inorganic elements of black locust wood and bark of different clones and origin
- 2008
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In: European Journal of Wood and Wood Products. - : Springer. - 0018-3768 .- 1436-736X. ; 66:6, s. 395-400
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Journal article (peer-reviewed)abstract
- Chemical properties of black locust wood and bark from Greece, Bulgaria and Hungary (clones NY, U and J) were investigated. Disks at breast height were taken from 25 black locust trees (five trees per origin and clone) and were divided into separate biomass components (juvenile heartwood, mature heartwood, sapwood and bark). Hot water soluble (HWSE) and dichloromethane soluble extractives (DSE), acidity (pH), buffering capacity, ash content and inorganic elements were determined according to standard laboratory techniques. Bark had the highest extractive content for both HWSE (9.25–13.49%) and DSE (3.09–4.03%). Differences of extractive contents in wood were found to exist between trees of different origin and between the three clones and ranged in heartwood between 5.04–10.10% for HWSE and 0.53–1.83% for DSE and in sapwood between 3.33–6.76% for HWSE and 0.48– 1.47% for DSE. The higher values of pH occurred in sapwood (4.92–5.35), while the differences between bark (4.44–5.12) and heartwood (4.35–4.92) were small. Acid (ABC) and base (BBC) buffering capacities from the initial to pH 10 for ABC and to pH 3 for BBC were greater in bark (ABC 0.0172–0.0219 ml/ml and BBC 0.0079– 0.0141 ml/ml) than in the other wood components (for heartwood ABC 0.0069–0.0159 ml/ml and BBC 0.0022– 0.0096 ml/ml and for sapwood ABC 0.00330.0066 ml/ml and BBC 0.00330.0049 ml/ml). The total ash content was greater in bark (7.24–8.56%) than in other biomass components (for heartwood 0.34–0.89% and for sapwood 0.72– 1.24%). The content of the main inorganic elements (Ca, K, Mg, Na, P) were also found to be much higher in bark while sapwood values were greater than heartwood.
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