The potential of plantations of terminalia superba engl. & diels for wood and biomass production (Mayombe Forest, Democratic Republic of Congo)

Abstract

In the 1940s-1950s, large limba (Terminalia superba Engl. and Diels) plantations were established in the Democratic Republic of Congo to reduce the pressure on the natural forests. The objective of this study was to evaluate the potential of these long-rotation plantations as production forests (timber) and carbon sinks. Five different plantations, between 50 and 58 years old, were sampled. Over a sample surface of more than 73 ha, the diameter above buttresses of 2 680 trees, bole height of 265 trees and tree height of 128 trees was measured. To estimate the commercial volume, a nonlinear power law regression was used (R2 = 0.95). A power law variance function was applied to counter heteroscedasticity of the residual plot. Estimates of commercial tree and stand volume at 50 to 58 y were 5.6 ± 4.1 m3 and 183.9 ± 135.0 m3 ha-1.Stand volumes appear low but are explained by a large decrease in tree density. However, the mean volume increment of 3.2-3.7 m3 ha-1 y-1 corresponds well with teak plantations of a similar age. For limba, aboveground biomass and carbon estimates of this study (resp. 108.4 and 54.2 Mg ha-1) differ significantly from those of existing aboveground biomass models (resp. 135.7-143.9 Mg ha-1 biomass and 67.9-72.0 Mg ha-1 C). All aboveground biomass and carbon estimates for T. superba stands were lower than for the estimates of young fast-growing plantations like Tectona grandis L. f., Eucalyptus spp. and Acacia spp. (≤ 30 y). © 2010 INRA, EDP Sciences.