Quantification Des Stocks De Carbone De Trois Pools Clés De Carbone En Afrique Centrale : Cas De La Forêt Marécageuse De La Likouala (Nord Congo)

The data of carbon stock of central African swamps forests are very few. This study carried out an assessment of the carbon stock of living biomass and coarse woody debris of three biotopes (flooded forest, seasonal flooded forest, and terra firm forest) of Likouala swamp forest (North of Congo). The average of the carbon stock are 190.72±98.7 tC/ha, 39.69±21.24 tC/ha, and 9.45±6.6 tC/ha respectively for above ground, billow ground, and coarse woody debris. The carbon stock of our swamp forest tends to increase generally from the flooded forest to the terra firm forest. In addition, the average of the coarse woody debris carbon stock increases with the increasing of the above ground carbon stock

Banque de graines du sol et déterminants de la germination du tali, Erythrophleum suaveolens (Guill. & Perr.) Brenan

peer reviewedCette étude évalue l’abondance des graines d’Erythrophleum suaveolens dans la banque du sol des forêts denses humides d’Afrique centrale. Les travaux ont été menés au Nord-Congo dans deux types forestiers : la forêt à Celtis sur des sols argilo-sableux à sablo-argileux et la forêt à Manilkara sur des sols sableux. Les tiges d’E. suaveolens (dhp ≥ 10 cm) ont été inventoriées dans deux parcelles de 400 ha, et les structures diamétriques de leurs populations ont été comparées. En outre, 80 fosses (2 x 40 fosses par type de forêt) ont été creusées aux pieds de 20 arbres (10 par forêt), sur trois couches contiguës de 10 cm chacune, soit à une profondeur totale de 30 cm, et l’abondance des graines dans la banque du sol a été évaluée. La dormance des graines récoltées a été testée par des essais de germination après traitement au H2SO4 et cinq graines prélevées jusqu’à une profondeur de 20 cm dans la forêt à Celtis ont été utilisées pour estimer leur âge par Spectroscopie de Masse par Accélérateur (SMA). La comparaison des structures diamétriques indique une plus grande proportion de tiges de faible diamètre dans la forêt à Celtis. Alors que les densités de tiges (dhp ≥ 10 cm) sont proches, avec 0,85 et 1,05 tige/ha respectivement, dans la forêt à Celtis et la forêt à Manilkara, les densités de graines sont significativement plus élevées dans la forêt à Celtis (8,55 graines/m2) que dans la forêt à Manilkara (0,15 graine/m2). Le pourcentage maximum de germination obtenu était de 19,1 % pour des graines n’ayant subi aucun traitement. Les lots traités à l’acide ont présenté de moindres taux de germination. Ces graines pourraient se conserver une dizaine d’années dans la banque du sol. Les facteurs pouvant influencer les variations de densité des graines sont discutés et des recommandations sylvicoles sont formulées

Guide pratique des plantations d'arbres des forêts denses humides d'Afrique

In Africa, tree plantations are likely to be developed for several reasons: restoration of production capacities and services provided by natural forests, enhancement of agroforestry lands, easier harvesting of wood and non-wood forest products, etc. As exotic species only provide specific services, it is important to revitalize the planting of local species. This is the purpose of this guide, which focuses on species of dense rainforests, capitalizing on the results of past and recent trials in six African countries, and on the This is the purpose of this guide, which focuses on species of dense rainforests, capitalizing on the results of past and recent trials in six African countries, and mobilizing individual skills and knowledge. The book provides a practical approach to the various stages of a silvicultural program: seed collection and management, nursery construction and management, and plantation installation and management. An estimate of the costs and profitability of such plantations is also provided. Finally, the book describes in detail the silvicultural itinerary of 50 tree species of the African rainforests. This guide is intended for a wide audience: managers, forestry technicians and engineers, students and scientists interested in tropical silviculture

Pantropical variability in tree crown allometry

Aim Tree crowns determine light interception, carbon and water exchange. Thus, understanding the factors causing tree crown allometry to vary at the tree and stand level matters greatly for the development of future vegetation modelling and for the calibration of remote sensing products. Nevertheless, we know little about large‐scale variation and determinants in tropical tree crown allometry. In this study, we explored the continental variation in scaling exponents of site‐specific crown allometry and assessed their relationships with environmental and stand‐level variables in the tropics. Location Global tropics. Time period Early 21st century. Major taxa studied Woody plants. Methods Using a dataset of 87,737 trees distributed among 245 forest and savanna sites across the tropics, we fitted site‐specific allometric relationships between crown dimensions (crown depth, diameter and volume) and stem diameter using power‐law models. Stand‐level and environmental drivers of crown allometric relationships were assessed at pantropical and continental scales. Results The scaling exponents of allometric relationships between stem diameter and crown dimensions were higher in savannas than in forests. We identified that continental crown models were better than pantropical crown models and that continental differences in crown allometric relationships were driven by both stand‐level (wood density) and environmental (precipitation, cation exchange capacity and soil texture) variables for both tropical biomes. For a given diameter, forest trees from Asia and savanna trees from Australia had smaller crown dimensions than trees in Africa and America, with crown volumes for some Asian forest trees being smaller than those of trees in African forests. Main conclusions Our results provide new insight into geographical variability, with large continental differences in tropical tree crown allometry that were driven by stand‐level and environmental variables. They have implications for the assessment of ecosystem function and for the monitoring of woody biomass by remote sensing techniques in the global tropics