8. SOME AGROFORESTRY PRACTICES IN KENYA                   

8.4 Live fences and hedges

Spatial arrangement

Live fences may be established all around the farm, but it is most common to establish such a fence around the homestead.

Figure 8.3 Markhamia lutea used as boundary markers in a living fence

Areas where the practice is relevant

This practice is relevant for most farming systems except on irrigation schemes and in the most arid areas. Fences are more important where livestock graze and hedges elsewhere.

Establishment and spacing

Very many individual shrubs are required to make a fence or a hedge. Thus the propagation method must be simple and cheap. Direct seed sowing or use of cuttings (depending on species) is primarily recommended, but for Dovyalis caffra and cypress it may be better to raise seedlings in an on-farm nursery since they have small seeds and are relatively slow starters.

It is best to plant seeds, seedlings or cuttings in two staggered rows so that an impenetrable fence or hedge is formed. The distance between the rows can be 15-30 cm with the same space within the rows. Directly sown fences must be well looked after and protected initially.

Management aspects

Fences and hedges need regular trimming so as not to overgrow (see Case Reports No. 15 and 16 for details). Some species which are very thorny, e.g. Caesalpinia decapetala, are sometimes regarded as too difficult to manage and should be avoided if the thorniness is not really needed as a deterrent to cattle. Live fences are often combined with trees for the production of wood. Either some stems of the fence species can be allowed to grow large, e.g. cypress, or trees of another species can be planted in the fence and allowed to grow well protected by the fence.

If live fences are to be introduced it is essential to consider the land-use pattern throughout the year. Fires are a hazard for many species, and livestock may be a threat in the initial stages.

Benefits

Fences and hedges are often multipurpose. Some of their uses are to:

• Provide shade and a windbreak for the compound

• Control movement of cattle

• Be ornamental

• Provide protection for chickens against birds of prey

• Provide privacy

• Production of mulch, fruit, bee forage or wood

• Help in soil conservation.

There are few risks. Live fences require labour for maintenance, and if they are not maintained they lose their intended function and begin to compete with crops. Caesalpinia decapetala may be too thorny to have near houses as children may suffer. The latex of Euphorbia tirucalli is very poisonous and dangerous for the eyes. Fences and hedges may harbour snakes, and some shrub species may turn into weeds, e.g. Lantana camara. Thevetia peruviana is also very poisonous.

Examples of species

Acacia brevispica, Acacia nilotica, Acacia tortilis, Agave sisalana, Albizia amara, Balanites spp., Caesalpinia decapetala, Calliandra calothyrsus, Carissa edulis, Croton dichogamus, Croton megalocarpus, Cupressus lusitanica, Casuarina spp., Dovyalis caffra, Euphorbia tirucalli, Gliricidia sepiunt, Morus alba, Lantana camara, Parkinsonia aculeata, Pithecellobium dulce, Prosopis spp., Psidium guajava, Thevetia peruviana, Ziziphus spp.

Figure 8.4 A cattle-proof sisal hedge also provides material for basket making