Evaluation of Selected Mechanical Properties of Blighia sapida K. Koenig Wood

Abstract

Over exploitation of economic tree species in the forest due to their high demand has made wood loggers shift their attention to Lesser Used Species such as Blighia sapida as alternative source of wood in Nigeria. The knowledge on the quality of the wood would to a long extent enhance the utilization of the wood. However, little information is provided on the mechanical properties of the wood species and the general belief among most wood users is that it is not a good timber species and that it cannot be utilized for any wood-based products that require strength. Therefore, investigating the mechanical properties of the timber species for better acceptability in the timber market becomes necessary. Three standing trees of Blighia sapida were purposively felled in the University of Ibadan community, Ibadan, Nigeria. 500 mm billets were gotten from wood dics at the top, middle, and base of the tree and each partitioned into three, the outerrwood, middlewood and the innerwood, in line with specified standard for each selected mechanical property test (Modulus of Elasticity, Modulus of Rupture, Impact bending strength, and Compressive strength parallel to grain) were all evaluated. Modulus of rupture with mean value 118.47 ± 1.96 N/mm2, ranged from 103.67 ± 3.42 to 144.26 ± 3.68 N/mm2. Modulus of Elasticity with mean value 10649.99 ± 167.51 N/mm2, ranged from 9237.14 ± 399.22 to 12877.35 ± 284.61 N/mm2. Compressive strength parallel to grain with the average value 52.86 ± 0.81 N/mm2, ranged from 42.88 ± 1.32 to 62.62 ± 1.65 N/mm2. Mean impact bending strength was 28.05 ± 0.58 N/mm2, ranged from 24.56 ± 0.86 to 35.09 ± 1.71 N/mm2. The average Modulus of Rupture and Modulus of Elasticity of Blighia sapida wood indicated that the wood falls within the category of medium construction strength timbers. The maximum compressive strength value for Blighia sapida wood revealed that it compared well with other economic tree species that are widely known for various structural applications. Therefore, the general belief among wood users that it is not a good timber species and that it cannot be utilized for any wood-based product that requires strength is far from the truth. It can therefore be concluded that the timber can be used for some building constructions, sheeting and lining, furniture, carpentry, veneer wood production, cabinet work, and so on.