Allometric models for estimating above- and below ground biomass of individual trees in Cameroonian submontane forest

Abstract

This study is the first to develop allometric models for estimating above-ground biomass (AGB) and below-ground biomass (BGB) of individual trees based on destructive sampling procedures in the montane tropical forests of Central Africa. As Cameroon is committed to Reducing Emissions from Deforestation and Forest Degradation (REDD) initiatives, it is particularly important for the country to develop such models. The data used for the modeling covered a wide range of tree species (34) and diameters at breast height (dbh) from 6 to 117 cm. The AGB and BGB models were developed from 60 and 30 tree samples, respectively. The developed AGB models explained a large part of the biomass variation (Pseudo-R2 0.80-0.87) and performed well when tested over different size classes. A model with dbh, basic wood density and total tree height (h) as independent variables is generally recommended for application if appropriate information on h is available. Tests of previously developed AGB models with modeling data, where large mean prediction errors occurred, generally demonstrated the importance of developing local models. BGB models performed reasonably well over different size classes, and biomass per unit area will probably be appropriately estimated when applying them. Some of the challenges related to the estimation BGB for small trees mean, however, imply that, the models may need to be recalibrated if more data becomes available.