Phenological interactions between tree and understory herbaceous vegetation of a sahelian semi-arid savanna

This study was conducted during the 1990 planting cycle and focused on interactions between trees and the herbaceous layer caused by their phenological behaviour in a Sahelian semi-arid savanna. The results show that (1) the plant phenological development (tree and grassy group) was synchronous; (2) the tree phenological behaviours were most clearly differentiated because reproduction, flowering and fructification phases were spread out throughout the year and (3) the herbaceous species cycle was then essentially determined by the short biologically damp period? 60 days in 1990. The foliage stage of the ligneous species spread on the considered period, with a reduced realization rate (30 to 40%) due to an invasion of locusts. At the grassy group level, the considerable growth rate in every development stage indicated that there was apparently no competition for soil water. Both trees and grass used the available soil water with grass only exploiting the upper soil layer.