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

Abstract

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 (p<0.001). All sites were floristically similar (k>70 %). 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 CO_2eq/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.