Carbon storage, biodiversity and species composition of Miombo woodlands in recovery trajectory after charcoal production and slash and burn agriculture in Zambia’s Copperbelt
Abstract of Working Paper 119
There is increasing awareness of the United Nations Reduction of Emissions from Deforestation and Forest Degradation (UN-REDD) programme in tropical woodland
This programme aims to increase Carbon (C) storage and conserve biodiversity, linking them to livelihood improvement. The objective of this study was to
provide an integrated understanding of aboveground (AG) C storage, structural and floristic composition in charcoal and agriculture fallows in Miombo woodland of
We conducted ecological surveys; measuring tree diameters and assessing species composition on twenty-four 0.25 ha plots in undisturbed woodlands, and fifty-eight plots re-growing after agriculture (5-58 years) and charcoal production (5- 44 years).
Undisturbed Miombo stored 39.6 t C ha-1 AG, while after clearance, C stocks accumulated at 0.98 and 1.42 t C ha-1 yr-1 in agriculture and charcoal fallows respectively. There were no significant differences in C stocks between woodlands and ≥ 20 year old fallows, implying that in terms of AG C storage, woodlands sufficiently recover after 20 years.
Stem densities were significantly higher in charcoal than agriculture fallows but the difference reduced with fallow age. Importance values (IVI) show low presence of less fire resistant tree species such as Uapaca kirkiana Müll. Arg. in the initial regrowth of post agriculture fallows, while higher dominance was observed in charcoal fallows. Shannon diversity indices showed high diversity in both woodlands and fallows though the Jaccard similarity coefficient indicated low species similarities, suggesting that though Miombo recover relatively fast in terms of forest structure and C storage, species composition takes longer to recuperate.
Findings show that agriculture and charcoal fallows hold an enormous management potential for emerging C-based payments for ecosystem services. Forest management should consider managing fallows for C sequestration and biodiversity restoration through natural succession in Miombo systems. In view of the uncertainty of species recovery, mature Miombo woodlands should be conserved for continued ecosystem functioning and supply of ecosystem services.