Mosaics of natural forest and grassland tracts in sub-Saharan Africa provide differences in woody species biodiversity. These mosaics are of considerable interest as they are a major biodiversity bank. Their richness is felt to be threatened, for example by local burning. This study focuses on the impact of burning on biodiversity in the Budongo Forest Reserve in Uganda. Woody species at different development stages are compared between a forest stratum and the adjacent grassland stratum. Spatial variability of biodiversity indices is analysed within and between these strata, using statistical and geostatistical analysis methods. The forest stratum shows a higher woody species diversity on a per plot basis. With overall species diversity calculations, however, the grassland stratum has a higher woody species variability than the forest. For the long-term preservation of woody species diversity in this landscape, it is necessary to reconsider and adjust current management practices to maintain (fire) disturbances.