Charcoal production and its implication for woodland degradation and climate change in the Forest-Savannah Transition Zone of Ghana: the case of Kintampo Municipality

Abstract

Charcoal production plays an important role in global socio-economic development as a source of income, energy and rural poverty alleviation. However, increasing commercial charcoal production has raised concerns about its effects on woodland and climate change mitigation. This thesis assessed the effects of commercial charcoal production in 23 charcoal production sites in Asantekwa and Kunsu communities of the Kintampo Municipality of Ghana. The effects of charcoal production on woodland were assessed in terms of the general land cover dynamics, extent of harvested sites, basal area, changes carbon dioxide equivalent (CO2e) emission based on allometric models. The influence of tenure arrangements for charcoal production on woodland was also assessed. The general land cover changes were analyzed using Landsat satellite images for 1986, 2001 and 2014. The extent of each harvested site was mapped and the median compared with 0.05 ha, the Intergovernmental Panel on Climate Change (IPCC) area threshold for degraded woodlands using Wilcoxon test. Inventory of all tree species of diameters at breast height (dbh) of 5 cm or more was carried out prior to the harvest. The basal area of the harvested trees were compared with the remnant trees using Mann Whitney test. Seven allometric models were developed based on the mass of the harvested trees and a combination of wood density, dbh and height of harvested trees, the best of which was selected based on the corrected Akaike Information Criterion. The CO2e from the harvested trees were computed from the harvested biomass while CO2e in the remnant trees was estimated using the best allometric model developed. The two were compared using the Mann Whitney test. Binary logistic regression was used to identify significant factors that influence the likelihood of woodland being degraded based on the views of 103 charcoal producers. The results of the study show that the annual rates of gain and loss in woodland for 2001 – 2014 were 0.88 % and 2.10 %, respectively signifying that woodland cover is losing faster than it is gaining for the period 2001– 2014. The median of the harvested sites (n = 23, M = 0.23 ha, P = 1.00) was significantly greater than 0.05 ha, the IPCC area threshold for degraded woodlands at 95 % confidence level while median basal area of the harvested trees (5.2 m2 ha-1) was also significantly greater than that of the remnant trees (n = 23, 2.6m2 ha-1, P < 0.001) at 95 % confidence level. The best allometric model for estimating AGB in the Forest-Savannah Transition zone is AGB = 0.0580ρ(dbh2H) 0.999. The median CO2e from the harvested trees (74.82 t ha-1) was significantly (P < 0.001) greater than that in the remnant trees (24.71 t ha-1). Procedure of access to woodland and attitude of charcoal producers were factors that significantly influence the likelihood of woodland being degraded in the study area. The results suggest that intensive large scale charcoal production could initiate woodland degradation and could be a source of CO2e emission, which could have negative implications for climate change mitigation in the study area. Stump-shoot pruning at the harvested sites should be rigorously implemented to enable the sites regain their pre-harvested state and climate change mitigation potential of woodland in the study area.