DOMESTICATION OF TROPICAL TREES: AN APPROACH SECURING FUTURE PRODUCTIVITY AND DIVERSITY IN MANAGED ECOSYSTEMS

SUMMARY In recent years, progress has been made with domestication of Triplochiton scleroxylon, an important timber tree of the moist West African forests. Seed viability has been extended from a few weeks to many months by appropriate drying and cold storage. Seed supply is irregular, but the successful development of vegetative propagation methods has provided an alternative, regular supply of planting stock. Rooted cuttings have the further advantage that they can readily be tested to identify promising clones of good form. To this end, experiments on the physiology of branching have allowed the development of a screening technique which can predict later branching habit from tests on small plants. The occurrence of precocious flowering in glasshouse conditions has allowed progress towards control over reproduction, and cross-pollinations with deep frozen pollen have produced viable seeds from clones only 2-5 years old. The possibility of similarly domesticating many other tree species is discussed in relation to the need for improved selections for use in diverse managed eco­ systems. Obtaining sustained yields of food and wood products on land formerly under moist tropical forest clearly depends on learning how to combine increased output from currently under-utilized species with soil improvement and ex situ conservation.