Secondary Miombo woodlands and forest plan-tations occupy increasing areas in Mozambique, the former due to anthropogenic activities. Plantations, mainly spe-cies of Eucalyptus and Pinus , are being established on sites previously covered by secondary Miombo woodlands. This affects the evolution, cycle and spatiotemporal patterns of carbon (C) storage and stocks in forest ecosystems. The esti-mation of C storage, which is indispensable for formulating climate change policies on sequestrating CO 2 , requires tools such as biomass models and biomass conversion and expan-sion factors (BCEF). In Mozambique, these tools are needed for both indigenous forests and plantations. The objective of this study is to fit species-specific allometric biomass models and BCEF for exotic and indigenous tree species. To incor-porate efficient inter-species variability, biomass equations were fitted using nonlinear mixed-effects models. All tree component biomass models had good predictability; how-ever, better predictive accuracy and ability was observed for the 2-predictors biomass model with tree height as a second predictor. The majority of the variability in BCEF was explained by the variation in tree species. Miombo spe-cies had larger crown biomass per unit of stem diameter and stored larger amounts of biomass per stem volume. How-ever, due to relatively rapid growth, larger stem diameters, heights, and stand density, the plantations stored more bio-mass per tree and per unit area.