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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/5238

Title: Assessing Depreciation for Valuation Purposes - A Decompositional Approach
Authors: Gyamfi-Yeboah, F.
Ayitey, J.
Keywords: Cell type
durability class
vessel- fibre ratio
Issue Date: Aug-2009
Publisher: Journal of Science and Technology
Citation: Journal of Science and Technology, Vol. 29 No. 2, 2009 pp 46-53
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.) C. C. 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 (V-F) ratios, specific gravities (SGs) and durabilities. Vessels, fibres and their proportions were examined from macerates and T.S. of prepared slides. While the timbers ex¬hibit major hardwood cell-types (e.g. vessels, fibres and parenchyma), intra-stem variability ex¬ists with more vessels and greater V-F 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. V-F 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 V-F ratios and SGs are R2 = 34%, 84%, 32% and 1% respectively. Timbers with greatest vessels and V-F 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 V-F ratio and SG relationship (R2 = 84%), is very durable.
Description: Article published in the Journal of Science and Technology, Vol. 29 No. 2, 2009 pp 46-53
URI: http://hdl.handle.net/123456789/5238
Appears in Collections:Journal of Science and Technology 2000-

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