Girth growth of trees was monitored monthly with band-dendrometers during two years on two stands of sudanian savannah vegetation in Western Burkina Faso. The growth rates of individuals as well as the relative growth rates of the basal area were assessed. Seasonal increment of basal area occurs from July up to September during the rainiest period of the year. Stem shrinkage begins in October or November when the soil becomes dry. From March up to May, leafing, which occurs when soil water availability is low, induces important trunks shrinkage. This reflects the high water stress undergone by the trees. The inter-season from March to May appears therefore critical for the hydric balance of savannah trees.