Local Ecological Knowledge and forest inventories reveal Afzelia africana Sm. decline in Benin, West Africa

• A. africana in Benin is dominated by small trees with few large ones. • Local ecological knowledge confirms population decline and main threats. • Communities apply assisted regeneration and sacred protection. • Integrating local ecological knowledge with inventories strengthens species assessments. • Green Index is a monitoring tool for IUCN and CITES threatened species. Afzelia africana is a key forest species in West Africa, particularly in Benin, where it supports both ecological stability and local livelihoods. However, the species has been listed as Vulnerable on the IUCN Red List since 2019 due to increasing human pressure. This study combines Local Ecological Knowledge (LEK) with forest inventory data to provide a comprehensive assessment of its conservation status in Benin. LEK revealed that the species is declining mainly due to logging, with additional pressures from branch pruning, agricultural expansion, vegetation fires, and drought. Forest inventories confirmed these perceptions, showing populations dominated by small-diameter trees (5–30 cm) and very few large individuals (>60 cm). Adults were present in about 74.55 % of plots, while regenerating and subadult trees occurred in fewer plots (<38.79 % and 23.03 %, respectively), indicating an overall imbalance in life stages and limited successful recruitment. Communities reported several traditional conservation measures, including assisted natural regeneration, targeted reforestation, planting A. africana as a shade tree in house courtyards, and preserving it as a sacred species. Integrating LEK with quantitative data yields a nuanced understanding of threats to A. afri cana. It not only confirms its population decline but also reveals regeneration bottlenecks and highlights community-led strategies that support its persistence. It provides critical added value by uncovering the complex social-ecological drivers behind observed trends. This biocultural approach represents the first assessment of A. africana in Benin that explicitly links population structure with local conservation practices, offering a transferable framework for managing threatened tree species in tropical regions.