Allometry and biomass distribution in replanted mangrove plantations at Gazi Bay, Kenya

Abstract

1. This study reports above-ground biomass of 5 and 8 years old mangrove plantations in Kenya. Trees with stem diameter greater than 5.0 cm inside 100m2 sample plots were harvested, and then separated into stems (trunks), branches, leaves and prop roots. 2. Mean above-ground biomass was calculated at 20.25 t dry matter ha 1 for Rhizophora mucronata Lam., 11.7 t dry matter ha 1 for Avicennia marina (Forsk.) Vierh., 6.7 t dry matter ha 1 for Sonneratia alba Sm. and 3.7 t dry matter ha 1 for Ceriops tagal (Perr.) C. B. Robinson. In A. marina and R. mucronata, stems (52.19%) and prop-roots (30.28%), respectively, accounted for the highest proportion of the above-ground dry weight. While in S. alba and C. tagal, branch biomass represented the highest percentage of biomass, 48.20% and 43.62%, respectively. 3. The total above-ground biomass of R. mucronata was best estimated from regression equations using a combination of height and diameter above stilt root as the independent variables. ForA.marina, C. tagal and S. alba there was no simple correlation found between the above-ground biomass and tree height or stem diameter. 4. Comparison of the regression models with those developed elsewhere gave different biomass values in these plots, further reinforcing the need for the use of site-specific allometric equations for biomass estimation.