Performance of four-year-old Australian and Papua New Guinean <i>Acacia</i> species/provenances at Kongowe, Kibaha, Tanzania

Abstract

This study to compare performance of three Australian–Papua New Guinean Acacia species/provenances (A. mangium, A. auriculiformis, A. crassicarpa) and A. julifera was conducted at Kongowe, Kibaha, Tanzania. Species/provenances were evaluated for survival, growth (diameter, height and volume), wood basic density and wood biomass. The trial was laid out using a randomised complete block design with three replications of 22 treatments (species/provenances). Data for survival, diameter at breast height and height was collected at ages 2 and 4 years from the nine inner-plot trees. Six defect-free trees from each treatment were selected at random for volume, wood basic density and biomass measurements. Results showed significant differences in survival, height and diameter growth among species/provenances at all assessment occasions. Average untransformed survival at 4 years ranged from 16.0% to 93.3%. Acacia crassicarpa from Bensbach, Papua New Guinea (PNG), had the largest diameter (13.9 cm) and A. crassicarpa from Bimadebum, PNG, had the largest height (12.6 m). Volume production and wood biomass differed significantly (p < 0.001) among species/provenances. Acacia crassicarpa from Bensbach, PNG, had the highest volume (58.7 m³ ha^–1) and wood biomass (53.4 t ha^–1) while A. mangium from Kongowe, Tanzania, had the lowest height (4.6 m), volume (1.92 m³ ha^–1) and wood biomass (2.7 t ha^–1). Acacia mangium from Claudie River, Queensland, had the highest basic density (610.6 kg m^–3) while the accession from Bituri, PNG, had the lowest (375.2 kg  m^–3). Ordinal ranking indicated that the three best-performing Australian–PNG Acacia species/provenances were A. crassicarpa from  Bimadebum, PNG; A. crassicarpa from Bensbach, PNG; and A. auriculiformis from south of Coen, Cape York. The three poorest  species/provenances were A. mangium from Kongowe, Kibaha, Tanzania; A. julifera subsp. julifera from Ipswich, Queensland; and A. mangium from Balimo, PNG. The best-performing species/provenances  are recommended for planting in Kongowe and other areas with similar ecological conditions.

Keywords: Australian–Papua New Guinean acacias; biomass; performance; Tanzania

Southern Forests 2010, 72(1): 13–22