One hundred and seventy poles of plantation-grown Kusia (Nauclea diderrichii Merill) of lengths 7 to 15m were extracted from the Pra-Anum Forest Reserve in Ghana. The cross-wise top and butt outer diameters and sapwood widths of the poles were measured, and their circumference taper and sapwood proportions determined. Small 'clear' defect-free specimens (obtained from 4 trees of length 14-15 m) were used in determining the basic density of the species as well as the modulus of rupture (MOR) and modulus of elasticity (MOE) of the wood species by the 3-point loading 5ystem on an 'Instron' Test Machine. The circumference taper averaged 31. 7 mm/m. The minimum sapwood width (23.6-55.2 mm) increases with pole length. The mean sapwood width and percentage volume averaged 37.5 mm and 31.1% respectively. Basic density averaged 607 kg/m3 'Green' MOR averaged 93.3 N/mm2, the 5th percentile 'characteristic' MOR was 73.50 N/mm2, and the derived designated fibre stress was 82.9 N/mm2 Using the fibre stress and the taper derived, the required dimension table for Kusia utility poles were determined. The dimensions and taper of Kusia render it particularly suitable for use as 10-15 m long poles for high voltage electric transmission and distribution support lines.
| Attachment | Size |
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| plant_grown_species.pdf | 6.2 MB |