Abstract Biome conservatism is prevalent during the evolution of plant lineages. However, studies assessing biome lability, i.e. the capacity to shift biomes and its impact on tropical tree species diversification is currently limited. To address this, we analysed an endemic lineage of African tropical trees to investigate phylogenetic patterns of biome conservatism and lability and their impact on speciation and extinction rates. We reconstructed a time-calibrated phylogeny of the Berlinia clad