Vessel-fibre ratio, specific gravity and durability of four Ghanaian hardwoods

C Antwi-Boasiako, E Atta-Obeng - Journal of Science and Technology …, 2009 - ajol.info
Journal of Science and Technology (Ghana), 2009ajol.info
Several factors affect wood durability but the influence of anatomy is scarcely studied.
Vessels and fibres sampled across and along stems of Milicia excelsa (Welw.) CC
Berg)(odum), En-tandrophragma cylindricum (Sprague) Sprague (sapele), Terminalia
ivorensis A. Chev.(emire) and Antiaris toxicaria Lesch.(kyenkyen) were studied to
understand the relationship between their vessel-fibre (VF) ratios, specific gravities (SGs)
and durabilities. Vessels, fibres and their proportions were examined from macerates and …
Abstract
Several factors affect wood durability but the influence of anatomy is scarcely studied. Vessels and fibres sampled across and along stems of Milicia excelsa (Welw.) CC Berg)(odum), En-tandrophragma cylindricum (Sprague) Sprague (sapele), Terminalia ivorensis A. Chev.(emire) and Antiaris toxicaria Lesch.(kyenkyen) were studied to understand the relationship between their vessel-fibre (VF) ratios, specific gravities (SGs) and durabilities. Vessels, fibres and their proportions were examined from macerates and TS of prepared slides. While the timbers ex-hibit major hardwood cell-types (eg vessels, fibres and parenchyma), intra-stem variability ex-ists with more vessels and greater VF ratios at the crowns and in sapwoods than at the butts and in heartwoods, unlike for fibres. Inter-specific variation also shows A. toxicaria has the greatest vessel content then T. ivorensis, E. cylindricum and M. excelsa, a contrary pattern for fibre con-tents. VF ratio ranks as: A. toxicaria> E. cylindricum> T. ivorensis> M. excelsa, while SGs are higher in E. cylindricum (667) and M. excelsa (635) than in T. ivorensis (507) and A. toxi-caria (505), which hardly differ from published data. Except for E. cylindricum, butts have the greatest SGs. Correlations between their VF ratios and SGs are R2= 34%, 84%, 32% and 1% respectively. Timbers with greatest vessels and VF ratios but least fibres and SGs have weak relationship and very low durabilities, as in A. toxicaria (R2= 1%). However, M. excelsa, which has the strongest VF ratio and SG relationship (R2= 84%), is very durable.
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