Preliminary results from trials of exotic acacias

Acacias (Acacia spp.) are found in Australia, Asia, Africa and the Americas. Many of the Australian species are notable for having phyllodes instead of true leaves, while most of the other species are notably thorny. Many acacias have the sort of attributes that characterize successful exotics, including the ability to fix nitrogen. Acacia catechu is the most important indigenous acacia in Nepal and is grown in plantations for its multiple products, but particularly for katha (used for mastication) and cutch (used for tanning, lubrication etc.). More then fifty exotic acacias have been introduced and tested on sites ranging from the terai to the high middle mountains. Preliminary trial results suggest that the following species are suitable for planting more widely in Nepal: A. auriculiformis, A. crassicarpa and A. holosericea in the terai/bhabar terai; and A. dealbata, A. mearnsii, A. podalyriifolia, A. holosericea and A. decurrens in the middle and high mountains. The next phase of this work is to establish operational-size plantings of these species to test them further. No additional research has yet been planned for A. catechu, but provenance testing is suggested to determine the most suitable provenances for the production of katha and cutch. This will help to optimize the production of such products from plantations and reduce pressure on the declining natural stands.