Trial 1: Species and provenance trial of Acacia aneura, A. farnesiana, A. nilotica, A. senegal and A. tortilis
This trial was made up of 12 provenances of Acacia. The species included A. aneura (Australia, one provenance), A. farnesiana (Mexico, one provenance), A. nilotica (India, Senegal and Sudan, six provenances), A. senegal (Senegal, one provenance) and A. tortilis (Senegal and Sudan, three provenances). The trial was established with a spacing of 3 x 4 metres in 1988 and assessed after 5 years in 1992.
The fastest growing provenances had an increment rate of 0.75 m2 ha-1 y-1, corresponding to a dry weight production of approximately 2 t ha-1 y-1. The provenances with the fastest growth in basal area were of A. nilotica, A. senegal and A. tortilis, while A. aneura and A. farnesiana showed poor performance, partly because of a low survival.
Differences between species were not significant, but there was a large variation between provenances, and several significant differences within A. nilotica and A. tortilis were found. In A. nilotica, the African provenances had the highest survival, and the two best performers were provenances from Senegal and Sudan. Indian provenances were intermediate to poor. In A. tortilis, the provenance of the subspecies spirocarpa behaved clearly differently from the two provenances of subspecies raddiana