Mechanical properties and natural durability along the stem of Cleistopholis patens (Ngo ne Nkyene) wood and its feasibility for structural use and furniture construction

Abstract

The over-dependence on the primary timber species has resulted in increased focus on research in the Lesser Used Species (LUS). Cleistopholis patens is an LUS commonly found in Sierra Leone and Ghana, yet it is commercially underutilized. This study assessed some physical, mechanical, and natural durability of C. patens against termites in comparison with other known commercial species. Three C. patens trees, collected from Assin Akropong Forest Reserve near Assin Fosu in the Central Region of Ghana were used for the study. Moisture content along the stem ranged from 12.38 - 13.81 % from butt to top. The basic density Values showed that C. patens is a low-density species with a range of 198.7 – 273.2 Kg/m3 from top to butt along the stem. The mean Modulus of Rupture, Modulus of Elasticity, Compression parallel to grain and shear parallel to the grain along the stem (from top to butt) were, 44.58 - 53.92 Nmm-2, 7268 - 8200 Nmm-2, 22.76 - 28.87 Nmm-2 and 5.508 - 7.678 Nmm-2, respectively. The mechanical strength properties values suggest that C. patens generally has a low strength for the butt portion and very low strength for the top and middle portions. The mean natural durability (i.e. mass loss) for the various sections along the stem ranged from 87.75 to 100 % (from butt to top) suggesting that C. patens is a nondurable timber. Generally, the mean values for the butt portion was significantly different (P < 0.05) from the other portions (middle and top) in all the parameters that were studied. The butt portion of C. patens thus have better usability potentials than the top and the middle and must be exploited for various applications such ceiling joist, interior joinery and wall partitioning. However, additional protection with preservative treatment would be required where outdoor applications are necessary. The use of the middle and top portions should be accompanied by preservative treatment in all possible applications (indoor and outdoor purposes).