Caractérisation des peuplements ligneux sur le tracé de la Grande Muraille Verte au Tchad

La connaissance des caracteristiques du peuplement ligneux du trace de la Grande Muraille Verte (GMV) du Tchad permet de comprendre leur structure et fonctionnement afin de proposer des strategies de gestion durable. C’est dans ce cadre que ce travail vise a caracteriser la flore et la vegetation ligneuses sur le trace de la GMV du Tchad. La methodologie utilisee consiste a determiner la composition floristique et la structure du peuplement ligneux dans les trois sites retenus (Lac, Kanem et Bahr El Ghazal). Les inventaires floristiques ont permis de recenser 18 especes reparties en 15 genres et 9 familles. La flore ligneuse est dominee par la famille des Mimosaseae. La densite des ligneux (34,67 ind.ha -1 ) et le recouvrement (1604,30 m².ha -1 ) sont plus importants au Lac et faible au Bahr El Ghazal (densite de 21,39 ind.ha -1 et recouvrement de 465,66 m².ha -1 ), quant a la surface terriere, elle est plus elevee au Kanem (3,39 m².ha -1 ). La distribution par classes de hauteur et de circonference des ligneux revele une predominance des individus de la strate arbustive dans les trois sites. L’etude de la regeneration naturelle montre que Acacia raddiana et Balanites aegyptiaca  presentent le potentiel de regeneration le plus eleve dans les trois sites. Globalement, les resultats obtenus montrent que les especes les plus adaptees aux conditions ecologiques de la GMV au Tchad sont Acacia raddiana et Balanites aegyptiaca et par consequent, doivent etre choisies pour la restauration de ces ecosystemes. © 2015 International Formulae Group. All rights reserved. Mots cles: Tchad, GMV, vegetation, peuplement, structure, regeneration English Title:  Characterization of the ligneous populatings on the route of the Great Green Wall in Chad English Abstract The knowledge of ligneous populating characteristics of the route of the Great Green Wall (GGW) of Chad helps to understand their structure and function in order to propose strategies for sustainable management. This study was carried out to characterize the flora and the tree vegetation present on the Chad  Great Green Wall (GGW) line. The methodology consisted in determining the floristic composition and the structure of the tree population in three sites: Lac, Kanem, and Bahr El Ghazal. The floristic inventories have identified 18 species distributed into 15 genera and 9 families. Trees are dominated by the Mimosaseae family. Their density (34.67 individuals ha -1 ) and their recovery (1604.3 m 2 ha -1 ) are more important at Lac and lower at Bahr El Ghazal with 21.39 individuals ha  -1 and 465.66 m 2 ha -1 , respectively. However, the basal area of the vegetation was more important at Kanem with 3.39 m 2 ha -1 . The distribution by classes of height and circumference of the trees indicates a predominance of the shrub layer in all the three sites. The study of the natural regeneration reveals that Acacia raddiana and Balanites aegyptiaca present the highest regeneration potential in the three sites. Globally, the results obtained in this study show that the most adapted species to the ecological conditions of the Chad’s GGW are Acacia raddiana and Balanites aegyptiaca . Consequently, these species must be considered during the restoration of the given ecosystems. © 2015 International Formulae Group. All rights reserved. Keywords: Chad, GGW, vegetation, population, structure, regeneration