Allometric Equation for Aerial Carbon Estimation (AGC) of Rhizophora racemosa and Avicennia germinans Mangroves of Olende and Ozouri in the Ogooué Delta in Gabon

Abstract

The global carbon is determined by forests at 45%. Mangroves sequester more carbon per area unit than the dry land forest. The carbon sequestration capacities of mangroves in the Ogooue Delta are still unknown. Thus, this study aims to set up a carbon estimation equation for the species Rhizophora racemosa and Avicennia germinans of the Ogooué Delta mangroves in Gabon. Data was collected in 25 m * 25 m square plots in four sites. The dendrometry parameters collected were mainly diameter at breast height (DBH) with a forest meter and height from the laser rangefinder. The individual basal area and volume of each tree was determined using the Husch et al. (2003) method. This resulted in a fractal-shaped equation of the type: y=αxβ, i.e., AGC = 0.000112*DBH2.466 with a determination rate of 96%, a relative bias of 0.007 and an RMSE of 1.2. This model was developed with a dataset of 47 individuals and validated with 41 individuals, i.e., 53% versus 47%. This study also allowed us to understand that the DBH structure of Ozouri and Olendé mangroves is stable without external disturbance