Survival and early growth of Australian tree species planted at a termite-infested site in Zimbabwe.

Abstract

Substantial differences were found in the survival and height of 47 seedlots of 36 Australian tree species in an introduction trial on a site at Kadoma, Zimbabwe, infested with the termite Odontotermes transvaalensis. The site had moderately deep soil (red-brown clay loam) and a mean annual rainfall of 730 mm. Seedlings from each seedlot were planted at 2.5×2.5 m spacing in plots of 25 trees in Dec. 1985. Preliminary results, 6 months after planting, showed that survival ranged from 6 to 98% and height from 0.16 to 1.29 m. Species showing the best survival were: Acacia melanoxylon, A. leptocarpa, A. auriculiformis, A. cowleana, A. polystachya, A. crassicarpa and Eucalyptus gibsonensis. The survival of the Petford provenance of E. camaldulensis, the most commonly planted species in rural woodlots, was significantly less than 12 of the Acacia seedlots tested. Only amongst Acacia species was there a relation between survival and height. It is considered that most of the mortality in the trial was caused by termites.