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Variation of wood density and mechanical properties of blackwood (Acacia melanoxylon R. Br.)
Published Date April 2014, Vol.56:975–980,doi:10.1016/j.matdes.2013.12.016 Author
José Saporiti Machado a
José Luís Louzada b
António J.A. Santos c,d,e
Lina Nunes a
Ofélia Anjos c,f,,
José Rodrigues e
Rogério M.S. Simões d
Helena Pereira c
aLaboratório Nacional de Engenharia Civil, Departamento de Estruturas de Madeira, Avenida do Brasil, 101, 700-066 Lisboa, Portugal
bCentro de Investigação e de Tecnologias Agro-Ambientais e Biológicas (CITAB), Departamento Florestal, Universidade Trás-os-Montes e Alto Douro (UTAD), 5001-801 Vila Real, Portugal
cCentro de Estudos Florestais, Instituto Superior de Agronomia, Universidade Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal
dResearch Unit of Textile and Paper Materials, Universidade da Beira Interior, 6201-001 Covilhã, Portugal
eTropical Research Institute of Portugal (IICT), Forestry and Forest Products Centre, Tapada da Ajuda, 1349-017 Lisboa, Portugal
fInstituto Politécnico de Castelo Branco, Escola Superior Agrária, Apartado 119, Castelo Branco, Portugal
Received 12 August 2013. Accepted 7 December 2013. Available online 15 December 2013.
Potentiality of blackwood as an alternative species to the hardwood timber industry.
Variation of Acacia melanoxylon wood density.
Variability of mechanical properties of Acacia melanoxylon.
Increase the low knowledge of Acacia melanoxylon wood.
The variation of wood density and mechanical properties with site, tree and within tree (longitudinal and radial) were studied for blackwood (Acacia melanoxylonR. Br.) grown in four sites in Portugal. Twenty trees were randomly selected (40 cm dbh class, 33–51 years of age), sampled at three stem height levels (5%, 35% and 65% of tree height) and three radial positions (10%, 50% and 90% of radius). They were further tested for air-dry density at 12% moisture content, bending strength (MOR), modulus of elasticity (MOE) and compression strength parallel to grain (CS), using ISO standards.
The overall mean properties of blackwood were: 654 kg m−3density, 139 N mm−2MOR, 141 × 102N mm−2MOE and 61 N mm−2CS. Site was not a significant source of variation for all wood properties. The variation between individual trees was the most important. Within the tree, the radial variation was highly significant for all traits, while the longitudinal variation was only significant for density. The correlation of density with the mechanical properties was moderate.
Blackwood showed potential for being an alternative species to supply the industry with valuable hardwood timber. The significant differences found between the trees demonstrate the possibility of selection and improvement for increased wood quality.