Importance de Coula edulis Baill. pour les populations du Sud-Est du Gabon: niveaux de prélèvement et potentiel économique de l'espèce

Importance of Coula edulis Baill. for the People of South-East Gabon: Harvest Levels and Economic Potential. Coula edulis is a non-timber forest tree species that provides edible fruits for local people. However, its economical importance has never been quantified. The present study aimed to identify the fate of stocks of harvested C. edulis fruits in Gabonese villages, emphasizing the social impact and economic income generated by this activity. Our investigations revealed that C. edulis fruits are predominantly utilized for own subsistence, since trading proportion concerned less than 20% of collected fruits. The average income from trade during the harvest period (two months) varied from € 1.7 to € 3.3 per household, depending on the proximity of the market (local or urban). The economical potential of C. edulis fruits could be improved if a sustainable production strategy through domestication processes and agroforestry practices was developed. Such a strategy may also contribute to the increase of the local demand of C. edulis fruits, assuming that a better diffusion was also carried out

Identité et écologie des espèces forestières commerciales d'Afrique centrale : le cas de Milicia spp. (synthèse bibliographique)

Identity and ecology of Central African timber tree species: the case of Milicia spp., a review. Iroko designates the two African tree species Milicia excelsa (Welw.) C.C.Berg and Milicia regia (A.Chev.) C.C.Berg known as highly valuable in the timber trade. Despite its economical importance and a decrease in population densities due to exploitation, there is a significant lack of ecological and sylvicultural knowledge required for a sustainable management of iroko. In West Africa, M. excelsa has received more attention from scientists than M. regia, but several topics clearly need further investigations or outcomes cannot be transferred in the context of Central African rainforests. A first thing to verify is whether speciation really occurred in the genus Milicia: morphological differences between the two species are very low, and a revision in this genus may lead to some rearrangements of conservatory and management policies related to this taxonomic group. Furthermore, (i) patterns related to the reproductive phenology and its controlling factors, (ii) gene flow among and between populations and individuals regarding life history traits, influence of human activities and paleoecological perturbations, and (iii) dynamics of seedling populations are among aspects that require emphasis in order to propose efficient tools for forest managers. Unless scientists provide these crucial data, the abundance of iroko in tropical rainforests will only depend on expensive plantations activities

Le noisetier d'Afrique (Coula edulis Baill.). Un produit forestier non ligneux méconnu

African walnut (Coula edulis Baill.). An unknown non-timber forest product. Non-timber forest products (NTFPs) are of significant nutritional, economic and cultural importance for the people of central Africa. However, many products have not yet been the subject of scientific studies; such is the case of Coula edulis. Although very little is known about this species, it has many uses and its fruits are regularly eaten and marketed by various communities. Cultivation of this tree species remains however very limited, mainly because of the low germination potential of its seeds. Its wood, renowned for its termite resistance, is used locally for construction. Mechanical tests conducted on the timber have put its technological aptitudes to the fore; it has indeed the potential to become one of the most sought-after commercial species. As in the future, Coula edulis could be managed for its wood as well as its non timber products, in-depth studies aiming at the sustainable development of this natural resource need to be implemented

Définition du profil écologique de l'azobé, Lophira alata, une espèce ligneuse africaine de grande importance : synthèse bibliographique et perspectives pour des recherches futures

Definition of the ecological profile of Lophira alata (ekki), a major important African timber species: literature review and perspectives for future studies. Over two decades, labors made in order to promote sustainable management of African tropical forests are tackled to the lack of knowledge about this complex ecosystem. Ecological parameters of timber species are no more studied, this complicates long-term sustainable forest management. This literature review related to the ecology and silviculture of ekki, Lophira alata Banks ex C.F.Gaertn. (Ochnaceae), a main African timber species recorded as "vulnerable" in the IUCN Red List, will serve as a study's case. The planned literature review reveals the doubt about its taxonomy, as well as the lack of understanding concerning its reproductive biology, growth conditions, population dynamics parameters, and the spatial distribution of its genetic diversity. The deficiency of knowledge about its ecological needs and the factors which have historically influenced its population dynamics explain why most silvicultural trails provide hazardous and uncertain results. Remedying these gaps in order to improve its ecological characterization and innovative silvicultural trails, would be a significant contribution to the sustainable management of its populations

Le genre Guibourtia Benn., un taxon à haute valeur commerciale et sociétale (synthèse bibliographique)

Guibourtia Benn.: a high conservation value genus. A review. Introduction. Known as a genus of great socio-cultural and economical importance, Guibourtia Benn. includes morphologically very similar multipurpose sister species, found in various habitats with different climate and soil conditions. In many places, Guibourtia is subject to local overexploitation by forest companies and local communities. As the population density of Guibourtia species is generally very low, it may be necessary to conduct scientific investigations that will provide valuable information for the management of the populations concerned. Literature. This paper is based on an extensive literature review and summarizes the available information on the genus Guibourtia, in terms of botany, ecology, genetics, forestry and ethnobotany. Our review provided evidence that, to date, ecological and silvicultural knowledge regarding Guibourtia species is lacking and that it is very difficult to morphologically differentiate very similar sister species. In addition, we provide a new determination key for the genus Guibourtia. Conclusion. Based on the available information, it is difficult to assess the conservation status of these taxa. Further investigations are needed to suggest appropriate management strategies for Guibourtia. Moreover, species diversity within this genus and its distribution in various tropical biomes make it an excellent biological model for understanding the historical, biological and environmental mechanisms that explain the diversity of tropical moist forests

Ploidy level of the cultivated yams (Dioscorea cayenensis/D. rotundata complex) from Benin Republic as determined by chromosome counting and flow cytometry

The ploidy level of ninety Guinea yam (Dioscorea Cayenesis/D. rotundata complex) cultivars identified within Benin were determined by both chromosome counting from root tip cells and flow cytometry. Three different ploidy levels (4x,6x,8x,) were detected among the samples. Eighty cultivars were tetraploid, five were hexaploid, three were octoploidy and two 4x and 8x ploidy levels. Chromosome counts were in agreement with data from flow cytometry that provides an easier assay for ploidy analysis. Flow cytometry was found to be a reliable tool for rapid determination of ploidy level in yam

Ploidy level of the cultivated yams (Dioscorea cayenensis/D. rotundata complex) from Benin Republic as determined by chromosome counting and flow cytometry

The ploidy levels of ninety Guinea yam (Dioscorea cayenensis/D. rotundata complex) cultivars identified within Benin were determined by both chromosome counting from root tip cells and flow cytometry. Three different ploidy levels (4x, 6x, 8x) were detected among the samples. Eighty cultivars were tetraploid, five were hexaploid, three were octoploid and two cultivars, 'Tam-Sam' and 'Youbé' were mixoploid with both 4x and 8x ploidy levels. Chromosome counts were in agreement with data from flow cytometry that provides an easier assay for ploidy analysis. Flow cytometry was found to be a reliable tool for rapid determination of ploidy level in yam. (African Crop Science Journal 8(4) 2000: 355-364

Development of nuclear SNP markers for genetic tracking of Iroko, Milicia excelsa and Milicia regia

Restriction associated DNA sequencing was conducted on two genetically independent individuals of Iroko, Milicia excelsa, for the discovery of nuclear SNPs. Ninety-four samples, well-distributed over the natural range and including timber DNA, were screened at 138 loci on a MassARRAY iPLEX system. Amplification success was high and 77 loci were selected to design a set of markers for genetic timber tracking purposes