Establishment and management of seed production areas of tropical tree species in northern Australia.

Abstract

Of the 29 seed production areas (SPAs) established in northern Australia during 1988-91, 3 failed. The SPAs covered 34 ha in total and comprised Acacia aulacocarpa, A. auriculiformis, A. crassicarpa, A. mangium, Eucalyptus pellita, E. urophylla and Casuarina junghuhniana. Tree survival up to the first thinning in the acacia SPAs was in excess of 90%, whereas survival in the eucalypt SPAs was around 70-80%. Queensland provenances had the best form (long, straight boles) and Papua New Guinea provenances were the most vigorous. Northern Territory provenances were inferior in terms of growth and had a tendency to form multistems. An initial spacing of 5 m between rows and 2 m between plants was satisfactory for A. aulacocarpa, A. crassicarpa and A. mangium. Spacings of 3 m × 1.5 m, 3 m × 1.8 m or 5 m × 2 m were satisfactory for A. auriculiformis, the eucalypts and C. junghuhniana. Individuals of A. auriculiformis from Queensland were propagated by cuttings to establish clonal seed orchards. All families were retained in the SPAs with selective thinning being carried out only within families. Phenological observations on flowering and seeding of different provenance regions have commenced.