Miombo woodlands play a crucial role for biodiversity conservation, the carbon cycle and the livelihood of millions of people in sub-Saharan Africa (SSA) and cover about 2.7-3.5 million km2. They are under intense pressure from direct and indirect human disturbances. The demand for wood energy, especially for charcoal, is becoming a major driver of anthropogenic forest disturbance in SSA. Charcoal production is also an important source of income for rural farmers involved in this activity and is the only affordable source of energy for most urban residents. Yet, there are challenges in detecting production sites with remote sensing and quantifying the large-scale impacts of this activity. This research assesses the landscape impacts of charcoal production in Zambia, a country dominated by miombo woodlands. We address the following questions: 1) Can we detect charcoal production sites using remote sensing? 2) What are the direct and indirect impacts of charcoal production? We combined remote sensing data (planetScope and Sentinel 2A) and field observations including vegetation survey, spatial delimitation of charcoal production sites, and survey to producers in a hotspot production region to characterize the impacts on carbon stocks and tree diversity, as well as to study its link to permanent land conversion.
Results/Conclusions
We found that the aboveground biomass declines on average by fifty percent at charcoal production sites, which vary in size between 0.05 and 2 hectares. The wood harvesting is done by selectively cutting dominant tree species of the genus Brachystegia and Julbernardia. The generation of fine and coarse woody debris from tree harvesting for charcoal making renders the sites more susceptible to intense fires. The latter can affect the regeneration potential of the sites by killing the stumps that would otherwise be re-sprouting. Agricultural expansion is the main driver of forest conversion on customary land where charcoal is produced as a by-product. Charcoal production is however the driving force of forest disturbance in Forest Reserves where agriculture is prohibited. Very high-resolution imagery with high temporal frequency allowed detecting charcoal production sites. Greenhouse gas emissions from forest disturbance due to charcoal making are important and additional to emissions from deforestation in Forest Reserves. Monitoring forest disturbance caused by charcoal production is now crucial due to large-scale pervasive direct and indirect impacts on this woody ecosystem and to the intensification of the practice in Zambia and elsewhere in SSA.