8. SOME AGROFORESTRY PRACTICES IN KENYA                   

8.15 Trees in gullies

Spatial arrangement

Trees or bananas can be used together with other vegetation to reduce erosion in gullies. By planting trees in gullies, land can be brought back into productive use.

Figure 8.18 Gully control

Areas where the practice is relevant

Generally in most gullies where efforts are made to stop the gully formation.

Establishment and spacing

Trees or bananas should not be planted on the floor of narrow gullies since the stems will decrease the cross-section of the gully thus increasing the velocity of any water flowing down its sides. The stems can also divert the stream to the sides of the gully, causing undermining erosion of the gully sides.

When the sides of a gully are not steeper than 1:1, or if there are steps on the sides, trees can be planted to stabilize the gully walls.

Management aspects

Management will depend on the species and purpose.

Benefits

Reclamation of land, tree production and reduced siltation downstream.

Examples of species

The best choices are easily propagated species with quick initial growth. Use of cuttings is recommended. Bananas and Morus alba are recommended. Euphorbia tirucalli, E. candelabrum, Croton spp., and Commiphora spp. are also very useful in gully reclamation.