Abstract:
This study was conducted to determine basic density, fibre length and some strength properties of Lonchocarpus capassa and Combretum zeyheri suitable for growing under agroforestry systems in Kilosa district. A total of three 13 year old trees from each species were sampled in Rudewa Gongoni village for the study. Diameter at Breast Height (DBH) and height of each tree were measured. The trees were then felled and cut into logs. Each log was cross cut into three 1.5 m billets representing the butt, middle and the top. The billets were sawn into small scantlings from which small specimens for determination of selected properties were taken. Standard methods were employed in determining the selected properties of the two species. Basic density was determined using water displacement method while fibre length was measured using a microprojector. Strength properties were determined using a Monsanto Tensiometer wood-testing machine. Results showed that basic density of L. capassa and C. zeyheri was 569.3 and 580 kgm-3 respectively. The basic density of the two species did not differ significantly (p<0.05). The mean fibre length of L. capassa was 1.38 mm and was significantly (p<0.0001) longer than that of C. zeyheri which was 1.2 mm. Results further showed that there was highly significant (p<0.0001) difference in modulus of elasticity (MOE), modulus rupture (MOR), shear, compressive and cleavage strength between the two species. MOE, MOR, compression and cleavage strength values of L. capassa are similar to those of Pterocarpus angolensis and Juniperus procera. Hence, L. capassa can be used in furniture especially in the place of the well known species whereas basing on its density, MOE and MOR, C. zeyheri can be used for construction purposes. Further research on hardness, impact bending strength, natural durability and treatability with preservatives, finishing and working properties of these two species is recommended.
