Wood biomass availability for smallholder charcoal production in dry forest and savannah ecosystems of south-western Madagascar

Abstract

Deforestation has accelerated over the last decades in south-western Madagascar due to overutilization of natural resources, slash and burn agriculture and charcoal production. To provide information for sustainable forest management, we assessed the biomass availability of woody species frequently used for charcoal production. Semi-structured household interviews (N = 63) were conducted to collect information on charcoal production activities and identify the species used for this activity. A cluster sampling approach was applied to inventory woody species and measure DBH, total height and crown diameter. Allometric equations for wood biomass and wood volume estimation were established for Acacia bellula (N = 20), Acacia rovumae (N = 18), Albizia polyphylla (N = 17), Cedrelopsis spp. (N = 13) and mixed species (N = 43).Altogether, 68 species were found to be used for charcoal production. High correlations between DBH, total height and wood biomass were observed (R2 varied between 0.78 and 0.99). Wood biomass increased with distance to settlements and significantly differed between land cover types with highest values in the dry forest. Overall, tree biomass near villages was lower than biomass inside the National Park and in other semi-arid regions, mainly due to anthropogenic activities such as charcoal production.