Subject
Some physical and mechanical properties together with the natural decay resistance of the lesser known and lesser utilized timbers of Diospyros mespiliformis, Tyrachylobium verrucosum and Newtonia paucijuga, species from Tanzania were determined. The physical and strength properties of the timber species were determined following the methods of BS 373 (1957), Lavers (1969) and Ishengoma and Nagoda (1991). Natural decay resistance was determined using the brown-rot fungi (Coniophora puteana and Goeophyllum trabeum) and the white rot fungus (Coriolus versicolor) for both heartwood and sapwood in accordance with EN 113 (1993).
Results show that, D. mespiliformis and T. verrucosum are high density timbers with basic densities of 719 and 745 kg/m3, respectively, while N. paucijuga is a medium density timber with a basic density of density 607 kg/m3. With the exception of radial cleavage strength, which were comparable for all the timbers tested, T.verrucosum had higher strength properties than D. mespiliformis. Newtonia. paucijuga showed lowest strength value specifically in modulus of rupture (MOR), modulus of elasticity (MOE) and compressive strength than the other timbers tested. The work to maximum load, shear and radial cleavage strength of D. mespiliformis and N. paucijuga were comparable. If these timber species are promoted, D. mespiliformis and T. verrucosum can substitute Cassiporea malosana and Newtonia paucijuga can substitute Populus canescens.
Natural durability ratings according to EN 350-1 (1993) were as follows; N. paucijuga—1 (durable), D. mespiliformis—5 (not durable) and T. verrucosum—5 (not durable).
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Ishengoma, R.C., Gillah, P.R., Amartey, S.A. et al. Physical, mechanical and natural decay resistance properties of lesser known and lesser utilized Diospyros mespiliformis, Tyrachylobium verrucosum and Newtonia paucijuga timber species from Tanzania. Holz Roh Werkst 62, 387–389 (2004). https://doi.org/10.1007/s00107-003-0452-z
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DOI: https://doi.org/10.1007/s00107-003-0452-z