Understanding the distribution patterns of plant species and the underlying factors is crucial to the conservation and management of plant communities in savannah-woodland
ecosystems. This article describes the species composition, structure and diversity of woody species at four sites along a latitudinal gradient in the North Sahelian, South Sahelian, North Sudanian and South Sudanian sectors in western Burkina Faso. All woody species were systematically identified and measured in 82 sample plots measuring 50 × 20 m2. Density, dominance, frequency and species and family importance values were computed to characterize the species composition. A range of diversity measures were calculated to analyze the heterogeneity of each site. A total of 74 species representing 26 families and 53 genera were found. The predominant families were Combretaceae,
Mimosaceae and Caesalpiniaceae. Significant differences were found between the structural characteristics (p < 0.001) of sites and species. At some sites, the tree size class
distributions formed a reverse Jshaped curve, indicating vegetation dominated by juvenile individuals. Similarity in tree species composition between sites was found to be low,
which indicates high beta diversity and reflects differences in habitat conditions, topography and between site distances. These site-specific differences highlight the importance of landscape-scale approaches in understanding species distribution patterns, composition, structure and diversity, as well as in applying restoration and conservation measures
geared to total basal area and diversity in these ecosystems.

Biodiversity, Species richness, Environmental relation, Fragmented landscape, Conservation, Sudanian zone.