Single-species allometric equations for above-ground biomass of most abundant long-lived pioneer species in semi-deciduous rain forests of the central region of Cameroon

Abstract

The implementation of REDD+ and AFR100 mechanisms require the availability of reliable allometric models, which are mathematical functions for estimating forest biomass from independent variables such as diameter at breast height (dbh), crown diameter, wood density and tree height. Although many equations have been developed to estimate tree biomass in undegraded forests, very few models have been developed for secondary forest species. The aim of this study was to establish single-species allometric models for estimating biomass of pioneer species in semi-deciduous forests in the central region of Cameroon and to evaluate their accuracy. Data of above-ground biomass were obtained from destructive sampling of 103 pioneer trees belonging to three species: Distemonanthus benthamianus, Musanga cecropioides and Trema orientalis. Model comparison were based on Akaike Information Criterion (AIC), average deviation and the coefficient R2adj. The different tests with combinations of dendrometric variables shows that whatever the species considered, the diameter at breast height appears as a good single predictor of biomass (Adjuted R²adj ˃ 0.97 in all three species). The use of the crown diameter in the model in Musanga cecropioides has considerably improved the quality of the fit. However, the consideration of these three variables in the model gave even better results (Adj.R² = 0.978-0.988). The comparison of these present models with the equations previously developed shows that the models in this article provide a better estimate of biomass. However, several important data from semi-deciduous forest remain essential for the adjustment of multi-specie models.