A study on the diversity and distribution of plant abundances was conducted in the Bururi Forest Nature Reserve (RNFB) in Burundi in order to strengthen the conservation of plant species. The RNFB is a forest ecosystem located in an anthropized matrix, near the city of Bururi and agricultural villages. It is a forest stain resulting from the fragmentation of a large forest that once occupied the entire Congo-Nile Ridge. This study aims to test the hypothesis that the distribution of plant species abundances in conserved forests is consistent with the normal log distribution, thus indicating that the species are fairly distributed in this ecosystem. This distribution pattern is generally observed in stable ecosystems where interspecific competition is less important. The observed abundance distribution was compared to normal log, log serial, and broken stick models. Among the plant species inventoried, six of them are threatened with extinction in Burundi. The observed abundance distribution is consistent with the log series model, which shows the existence of disturbances that would influence the abundance distribution of species in the RNFB although this ecosystem is protected.