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Eleven Acacia species native to Australia's tropical dry zone and a local control, Cassia siamea, were tested in a species trial at Tuy Phong in coastal southeastern Vietnam. The aim of the trial was to find species suitable for site rehabilitation and wood production under dry tropical conditions (mean annual rainfall 700 mm, mean annual temperature 27 degrees C) on infertile white sands where other tree species had performed poorly.

Assessments of height and diameter growth and survival were made 6, 10, 26 and 41 months after planting. Initial establishment was successful with survival at 6 months good (over 60%) to excellent (over 90%). Significant differences between species in growth traits were evident at 6 months and in subsequent measures. By age 41 months, Acacia difficilis was clearly the fastest-growing species with mean height of 5.6 in, mean dbh of largest stem of 6.5 cm and survival of 60%. Acacia tumida (height 4.6 m, dbh 5.1 cm, survival at 41 months 68%) and A. torulosa (height 3.6 m, dbh 3.9 m and survival 84%) also performed well. A. auriculiformis, A. elachantha, A. longispicata, and Cassia siamea were poorly adapted to the site conditions, with less than 30% survival at 41 months. Inoculation in the nursery with selected strains of Bradyrhizobium produced an improvement in nursery growth for some Acacia species but this effect was not sustained in the field. The trial results suggest that successful plantations for fuelwood production, dune stabilisation and site amelioration could be established under semi-arid conditions on the white sands by planting A. difficilis, A. tumida and A. torulosa.