Afforestation/Reforestation Based on Gmelina Arborea (Verbenaceae) in Tropical Africa: Floristic and Structural Analysis, Carbon Storage and Economic Value (Cameroon)

The study was carried out in three selected plantations. Sampling was made infive 100x20 m2 plots per site. Overall, 32 species, 36 genera and 17 families were surveyed. Hymenocardia acida, Combretum adenogonium, Daniellia oliveri, Entada africana, Terminalia macroptera, T. laxiflora, Lannea schimperi, Lophira lanceolata, Maytenus senegalensis, Ochna schweinfurthiana, Protea madiensis, Psorospermum senegalense, Piliostigma thonningii, Sarcocephalus latifolius and Securidaca longepedunculata were the most important species. The richness index ranged from 2.53±0.05-7.74±0.03. Shannon index was 3 in all sites. Density ranged from 98±2.01-253±10.23 stems/ha. Basal area was statistically significant among the sites (p70 %). The vertical structure showed three types of figures; L shape, symmetrical bell shape and unsymmetrical bell shape. These structures confirmed a good regeneration of timbers in the sites. There was a positive correlation of the species dispersal in the sites (p<0.001). The amount of AGB was 23.50±0.38 t C/ha. The amount of C sequestration was 86.28±16.57 t CO2eq/ha. The ecosystem service payments ranged between 258.87±24.88-8629.25±248.16 €/ha with the lowest values for CDM price and the highest for REDD+price. A financing of such projects is required in the frame of creating adaptation and attenuation measures to global warming effects

Correlation between Associated Trees, Cocoa Trees and Carbon Stocks Potential in Cocoa Agroforests of Southern Cameroon

This study was conducted in the Cocoa Agro-Forests (CAF) of Mengomo’s locality. The aim was to evaluate the influence of some factors on carbon stocks. The sampling was done in 30 plots of 25 x 25 m 2 in which all trees with a dbh?10 cm were inventoried. The Shannon, Simpson and Evernnessindexes were calculated to characterize the diversity of trees associated with cocoa. 62 species belonging to 48 genera and 27 families were identified, the Anacardiaceae, Moraceae, Caesalpiniaceae,  Mimosaceae and Rutaceae, were revealed the most diverse families, with 5 species each. Shannon’s (3.66), Evernness’s (0.76) and Simpson’s (0.96) indexes have reflected a low diversity, dominated by some fewspecies. The average density of cocoa trees is 1028 trees/ha. They store about 22.51±5.86 Mg C/ha. Associated trees stored 124.20±60.05Mg C/ha for tree density of 113 trees/ha. These CAF sequestered about 146.71Mg C/ha. The multiple correspondence analyses showed that carbon stocks in the CAF are positively correlated with the associated trees and the age of the CAF and negatively correlated with the abundance of cocoa trees. The biomass of cocoa is independent of the associated trees, but is inversely related to the density of the associated trees