Local management and propagation techniques range from retaining certain trees in the shamba and around the home compound, to propagating and actively managing and tending selected trees or groups of trees. (Table 5.3 lists identified indigenous species that have been propagated in Tanzania by farmers.)
Preliminary findings from a study undertaken by Kajembe (1992) indicate that the most complex spatial arrangements were found in home gardens and that simpler planting patterns were found away from the homestead and on farmland. Further, exotic tree species tend to be more prominent in zonal arrangements, whereas indigenous trees often grow naturally among crops or fallows. Findings from the formal survey show that indigenous trees tend to be planted around the home compound or, in areas where farmers are concerned about soil improvement or water retention, and where retained or protected trees have been cut.
A variety of propagation methods is used depending on the species and the techniques known by the farmer. Those identified during the survey include:
· direct sowing, for example, guava (Psidium guajava), mango (Mangifera indica), and Pterocarpus angolensis;· vegetative propagation by cuttings, for example, Acacia tortilis, Commiphora africana, Commiphora ugogoensis, Euphorbia tirucalli, Ficus sycomorus, Ficus thonningii, and Grewia platyclada;
· vegetative propagation by suckers, for example, Albizia schimperana, Juniperus procera, Ocotea usambarensis, Olea capensis, Podocarpus latifolius, Vangueria infausta;
· transplanting wildlings, for example, Acacia tortilis, Albizia schimperana, Commiphora africana, Commiphora ugogoensis, Ficus thonningii, Ocotea usambarensis;
· coppicing in order to produce new shoots from stumps that have been cut, for example Acacia spp..
Weeding, protection and watering were the most frequent management techniques identified by survey respondents. However, many farmers indicated that once planted, the tree received no after care until pruning or harvesting. Management practices seen in the field included putting ripe, fresh melons at the base of new seedlings (in this case pawpaw) to provide water and nutrients to young plants, placing thorny Acacia branches around young seedlings to protect them from cattle grazing, weeding around the plant, and in a few cases watering individual trees.
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TABLE 5.3 Acacia albida (F. albida) |
Pruning was also mentioned as a silvicultural technique by a few respondents, but they stated that they did not undertake it to specifically improve productivity.
