Pterocarpus erinaceus is a native tree species of the Guineo-Sudanian and Sudano-Sahelian zones where natural stands are under constant pressure and heavily exploited for timber, animal feeding and others uses. A part from the overexploitation, climate change could also become a serious threat to the species natural distribution. For that purposes, this study aims to assess the vulnerability of P. erinaceus potential niche to climate change within its natural distribution area in West Africa. Niche predictions are based on 6,981 natural occurrence of the species and 19 global bioclimatic variables available through WorldClim. The future niche of the species is predicted according to three concentration pathways (RCPs 2.6, 4.5 and 8.5) of BC model for 2050 and 2070, thanks to Maxent software. P. erinaceus is currently reported from Senegal to Cameroon. Its potential niche covers the Sudano-Sahelian zone and the Dahomey gap on approximately 17.42% of the total area of these countries. In general, the niche of the species is not sensitive to climate change, regardless of the climate scenario and the year. Compared to its initial niche, the niche of the species will increase from 22.33% to 43.61% in 2050 and from 27.12% to 53.61% in 2070. However, this ecological expansion observed mainly in the Gulf of Guinea, will be associated with a considerable decrease in the Sahel and central Nigeria. This study shows the importance of promoting the development of innovative silvicultural strategies for the extension and restoration of natural stands of P. erinaceus in order to meet sustainably the timber needs of the West African region. It helps also to strengthening the roles of natural forests in providing ecosystem services and mitigating climate change effects.

Bien que plusieurs fruitiers sauvages aient été étudiés au Bénin, d’autres, dont Cola millenii K. Schum., y demeurent peu documentés. Cette étude avait pour objectif d’inventorier les connaissances ethnobotaniques de C. millenii par les groupes socioculturels béninois. Des entretiens individuels structurés ont été menés auprès de 1 009 personnes. La fréquence relative de citation et l’indice d’efficacité ont été utilisés pour apprécier respectivement l’importance relative de chaque utilisation et le niveau d’efficacité de la plante dans le traitement d’une maladie donnée. C. millenii relève de huit catégories d’usage. L’usage alimentaire de la pulpe du fruit est le plus pratiqué. Le paludisme est la maladie la plus citée. Globalement, l’espèce serait très efficace dans le traitement du paludisme, de l’ictère, des maux de ventre, de l’hypertension, des courbatures, de la fatigue, de la fièvre et du vertige ; moyennement efficace dans le traitement de l’asthme, des troubles liés à la grossesse et de l’enflure des pieds ; mais peu efficace contre l’oligospermie. La feuille est la partie la plus utilisée et la décoction est le mode de préparation le plus employé dans le traitement des maladies. Les Anii et Chabè préfèrent l’usage alimentaire de l’espèce tandis que son usage à des fins magiques et comme brosse végétale ou bois de service est privilégié par les Adja et Kotafon. Par contre, les Aïzo l’utilisent plus à des fins médicinales, et son usage comme bois d’œuvre est plus important pour les Mahi. Les feuilles et les fruits sont les parties les plus commercialisées. Malgré son importance, l’espèce subit diverses pressions et bénéficie très peu de mesures de conservation. Des recherches futures devraient se pencher sur sa sylviculture pour assurer sa domestication.

The structural characterization of Prosopis africana of Benin was studied on the basis of forest inventory conducted in three different vegetation types (savannah, fallow, and field) and three climate zones. The data collected in 139 plots of 1000 m 2 each related to the diameter at breast (1.3 m above ground), total height, identification, and measurement of DBH related P. africana species height. Tree-ring parameters such as Blackman and Green indices, basal area, average diameter, height of Lorey, and density were calculated and interpreted. Dendrometric settings of vegetation type and climate zone (Guinea, Sudan-Guinea, and Sudan) were compared through analysis of variance (ANOVA). There is a significant difference in dendrometric settings according to the type of vegetation and climate zone. Basal area, density, and average diameter are, respectively, 4.47 m 2 /ha, 34.95 stems/ha, and 37.02 cm in the fields; 3.01 m 2 /ha, 34.74 stems/ha, and 33.66 cm in fallows; 3.31 m 2 /ha, 52.39 stems/ha, and 29.61 cm in the savannahs. The diameter distribution and height observed at the theoretical Weibull distribution show that the diameter and height of the populations of the species are present in all positively skewed distributions or asymmetric left, a characteristic of single-species stands with predominance of young individuals or small diameters or heights.

& Key message Mansonia altissima A. Chev. has an aggregated distribution at the juvenile life stage that becomes random at the mature life stage. Ceiba pentandra (L.) Gaertn could play the role of nurse plant in the management of M. altissima populations providing them a moderate forest shade in large gaps for early growth. M. altissima and Triplochiton scleroxylon K. Schum. displayed independent distribution patterns. & Context M. altissima is a species with economic value found in moist semi-deciduous forests of tropical Africa. The analysis of spatial distribution patterns can help to understand the ecology of this species in forest stands dominated by emergent pioneer tree species like C. pentandra and T. scleroxylon. & Aims To assess the spatial distribution patterns of M. altissima and spatial relationships with C. pentandra and T. scleroxylon in their natural habitat. & Methods We investigated the spatial patterns of the three species during three life stages; juvenile (immature trees), premature (trees with minimum flowering diameter) and mature (trees with minimum fruiting diameter). Diameter at breast height (DBH) was measured and geographical coordinates of trees were recorded within ten one-ha plots, divided into sixteen subplots (625 m 2 ). We computed the L(r) function, normalized from Ripley's K(r) function to detect aggregated, random or regular distribution patterns. & Results Aggregations were detected in juvenile and premature M. altissima. Size and scales of spatial aggregation were inversely proportional to the DBH size. M. altissima and C. pentandra displayed interspecific association patterns at the similar life stages. Both species were positively associated within a radius ≥ 3 m. No positive association was detected between M. altissima and T. scleroxylon. & Conclusion Interspecific association patterns between M. altissima and C. pentandra suggest that C. pentandra could be used as a nurse tree in reforestation and management practices of M. altissima populations.

Background Pterocarpus erinaceus Poir. is a spontaneous species from the three ecological zones of Benin. It is multipurpose species integrated to the socio-economic and cultural livelihood of populations, especially in rural areas. This study examined the different uses made of the organs of Pterocarpus erinaceus in Benin in relation to sociolinguistic diversity with a view to highlighting the knowledge of local populations on Pterocarpus erinaceus and the threats to the species. Methods A total of 355 respondents, spread over 18 townships in Benin, were interviewed using a questionnaire. About 57 uses shared into 7 categories of use have been identified from the different sociolinguistic and socio-professional groups. Relative citation frequencies (FRC) of each habitat were then calculated for the description of habitat variation according to Ecological zones (EZ). In order to describe the diversification of the categories of uses and the organs / part of the tree, Principal component analyzes are carried out on the matrices comprising relative citation frequencies (FRC) grouping together the socio-demographic factors and the categories of use under the packages FactoMineR and factoextra Results This study revelated that the wood of Pterocarpus erinaceus is used (25.43%) in crafts, as charcoal, and service wood, while the leaves are mainly used (23.14%) as fodder and by traditional medecine. Concerning the roots and bark, they are used (27.14%) not only for evil spirits and bewitchment but also in animal medecine in cattle. About 60 diseases and symptoms are cured by the various organs of Pterocarpus erinaceus. These different uses of Pterocarpus erinaceus varied from one sociolinguistic group to another. Conclusion The study showed that all organs of Pterocarpus erinaceus are used in various forms of use for various purposes and make it an important species for rural communities. This result suggests the need to define conservation strategies for natural stands of Pterocarpus erinaceus for the sustainable management of the species.