We studied wet and dry savanna woodland in Benin, West Africa, to describe tree-community structure as an important natural resource. Twelve plots of 1-ha each were set up in sub-sahelian central and north areas of Benin. Our objectives were: (i) to describe floristic composition and structure of savanna communities, (ii) to elucidate physiognomic characteristics and diversity of the existing woody vegetation, and (iii) to assess how climate (rainfall) as environmental variable affects community composition and structure in savanna woodlands.

Multivariate analyses were performed to characterize savanna vegetation, and the skewness of trunk-diameter distribution and allometry analysis between tree-size dimensions were used to quantify site-scale and population-level structure.

We recorded 3,781 trees consisted of 70 species and 34 families where Caesalpiniaceae was dominant. In savanna areas, species composition and population structure varied from plot to plot suggesting that species show site preference. Skewness of population structure was negatively correlated with maximum height of species, suggesting poor regeneration capacity for canopy species. We found that rainfall pattern strongly affected the composition and structure of woodlands in sub-sahelian savanna in Benin.