Planing and Turning Characteristics of Gmelina arborea Grown in Two Ecological Zones in Ghana

Mitchual, Stephen Jobson; Minkah, Maxidite A.; Owusu, Francis Wilson; Okai, Reynolds

doi:10.9734/air/2018/39024

Cited by 3 publications

(8 citation statements)

References 3 publications

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“…The average oven-dry density of the top, middle and butt portions of Gmelina arborea obtained from the Daboase plantation in the WEFZ as reported by Mitchual et al [15] was 515 kg/m 3 , with a range of 413 kg/m 3 -599 kg/m 3 , while the one obtained from the Abofour plantation in the DSDFZ was 455 kg/m 3 , with a range of 390 kg/m 3 -500 kg/m 3 . On the average, the moisture content of the specimen before the sanding and shaping test was 15.5%.…”

Section: Gmelina Arboreamentioning

confidence: 73%

“…Before the sanding operation the boards were planed using a surfacing and thickness planer machine of type 610 x 230 mm DAA; knife with cutting angle 30 degrees and feed speed of 14 m/min. These cutting angle and feed speed were selected based on studies by Mitctual et al [15] and it was intended to generate more defective (chipped/ torn) samples for the sanding test. For each ecological zone the total number of boards sampled for the sanding test was 135.…”

Section: Sanding Quality Testmentioning

confidence: 99%

“…It is a deciduous tree and grows to 12-30 m in height and 60-100 cm in diameter. It is a medium-density timber species and has excellent strength, planing and turning properties [14,15]. Studies have indicated that Gmelina arborea wood is suitable for use as plywood, particleboard, mining props, timber and telecommunication transmission poles and also serves as a fuel source [14].…”

Section: Introductionmentioning

confidence: 99%

“…In Ghana, hectares of Gmelina arborea plantations have been established by individuals, CSIR-Forestry Research Institute of Ghana and the Forestry Commission, of which some have been cultivated by Subri Industrial Plantations Limited (SIPL) at Daboase near Sekondi-Takoradi. The Daboase Gmelina arborea plantation was originally cultivated to serve as a wood resource base for a proposed paper-processing factory in Ghana [15]. However, the factory was never established and the plantation was left unused.…”

Section: Introductionmentioning

confidence: 99%

“…It was later realised that Gmelina arborea could be used as timber in various applications. Despite this, it is not common on the local timber market due to a lack of basic and technological properties about the species [15]. Gmelina arborea is among the ten species that the Forestry Commission has selected for plantation establishment in Ghana.…”

Section: Introductionmentioning

confidence: 99%

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Sanding and Shaping Characteristics of Gmelina arborea Grown in Two Ecological Zones in Ghana

Mitchual

Owusu

Minkah

2019

JERR

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Poor machining of wood generates more residues which leads to low recovery in wood processing. Therefore, the availability of appropriate wood machining techniques would promote efficient utilization of logs. This study looked at the shaping and sanding properties of Gmelina arborea - a lesser-known species in Ghana - in order to promote its efficient utilization. Six trees from plantations at the Wet Evergreen and Dry Semi-Deciduous Forest Zones were extracted and processed into lumber using LT 15 horizontal wood-mizer. The average moisture content of samples just before the test was 14.57%. Specimens were prepared in accordance with ASTM D 143-83 and ASTM D 1666-87 (2004) for the sanding and shaping tests. The effects of tree location, grit size and spindle speed on sanding and shaping properties of Gmelina arborea wood were assessed using the visual approach. For the sanding test, grit size P80 was the best sandpaper to remove chipped and torn grain defects from the surfaces of Gmelina arborea lumber after planing. Spindle speed 10,000 rpm gave the best shaping output so it was recommended for shaping Gmelina arborea timber grown in Ghana. For the shaping operation, wood samples obtained from the Dry Semi-Deciduous Forest Zone had better surface quality than those obtained from the Wet Evergreen Forest Zone. A similar trend was obtained for the sanding test. The most common defects observed during grading of the shaped specimens were raised, chipped and fuzzy grains and those observed for the sanded specimen were fuzzy and scratchy defects. At 5% level of significance, tree location and spindle speed had significant effect on the surface quality of the shaped specimen.

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Section: Gmelina Arboreamentioning

confidence: 73%

Section: Sanding Quality Testmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sanding and Shaping Characteristics of Gmelina arborea Grown in Two Ecological Zones in Ghana

Mitchual

Owusu

Minkah

2019

JERR

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Biological resistance of thermally modified Gmelina arborea wood

Minkah,

Afrifah,

Antwi-Boasiako

et al. 2024

Maderas-Cienc Tecnol

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Thermal modification of wood is an environmentally friendly method to improve wood durability, mainly against microorganisms. By employing a process similar to the ThermoWood®, various Gmelina arborea (gamhar) wood specimens were thermally modified at 180 °C, 200 °C, and 220 °C for 3 hours. The effects of the thermal modification process on the resistance to decay by rot-fungi, and attack by subterranean, arboreal, and dry-wood termites were determined. Generally, the thermal modification improved the resistance of Gmelina arborea (gamhar) to decay by Trametes versicolor with increasing process temperature. However, the effect of the process was null on the resistance to biodeterioration by the brown-rot fungus Coniophora puteana and the dry-wood termites Cryptotermes brevis. Even so, the visual damage caused by Cryptotermes brevis was slight. Untreated and thermally modified woods recorded higher resistance to Coniophora puteana than Trametes versicolor. Mass loss caused by Nasutitermes corniger also decreased with increasing thermal modification temperature. According to the visual damage rating values, the attack by Nasutitermes corniger was slight. However, the thermal modification inversely impacted Gmelina arborea (gamhar) attack by Macrotermes sp., as its resistance in the field to the termites decreased with increasing modification temperature. Thus, the thermal modification process contributed to improving the decay resistance of the modified wood to white-rot fungus Trametes versicolor and attack by the arboreal termites Nasutitermes corniger exposed indoors. On the other hand, thermally modified Gmelina arborea (gamhar) wood was very susceptible to Macrotermes sp. in the field. This work would provide a reliable reference document to guide wood industry stakeholders in assessing the performance of untreated and thermally modified Gmelina arborea (gamhar) wood in situations exposed to fungi and termite species adopted.

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Chemical and Mechanical Characterization of Thermally Modified Gmelina arborea Wood

Minkah¹,

Afrifah²,

Batista³

et al. 2021

les-wood

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Gmelina arborea (Roxb. ex. Sm.) wood samples were thermally modified at 180 °C, 200 °C and 220 °C for 3 h, by employing a process similar to ThermoWood®. The resulting effects on the basic chemical composition and mechanical properties were determined. The results were analyzed statistically with ANOVA, and Least Square Deviation was used to compare means. Generally, after the thermal modification (TM) process, the cellulose, hemicelluloses and extractives content decreased significantly. By contrast, lignin proportions increased significantly. Untreated wood and samples modified at 180 °C indicated comparable modulus of elasticity (MOE), modulus of rupture (MOR), degree of integrity (I), fine fraction (F) and resistance to impact milling (RIM). Noteworthy reductions however occurred at 200 °C and 220 °C. Significant increases in Brinell hardness (BH) took place at 180 °C, recording a high decrease at 220 °C. Gmelina arborea could be modified suitably at 180 °C for structural and other purposes. To take advantage of other improved properties, modification at 200 °C could be employed for non-structural uses.

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Planing and Turning Characteristics of Gmelina arborea Grown in Two Ecological Zones in Ghana

Cited by 3 publications

References 3 publications

Sanding and Shaping Characteristics of Gmelina arborea Grown in Two Ecological Zones in Ghana

Sanding and Shaping Characteristics of Gmelina arborea Grown in Two Ecological Zones in Ghana

Biological resistance of thermally modified Gmelina arborea wood

Chemical and Mechanical Characterization of Thermally Modified Gmelina arborea Wood

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