Cashew expansion holds potential for carbon stocks enhancement in the forest-savannah transitional zone of Ghana

Abstract

Despite the scientific contributions of earlier studies to the understanding of shifts in land-use to cashew in the forest-savannah transition zone, some questions remain unanswered: (1) what is the extent of landscape-level conversions associated with cashew? (2) could the expansion of cashew in the forest-savannah transitional zone potentially serve as a carbon mitigation strategy relative to other land uses at the landscape level? and (3) how does the land use dynamics associated with cashew development hold implications for Ghana’s climate change mitigation strategies? The Wenchi Municipality was used as a case study. Landsat images for 2000, 2015 and 2020 were classified to produce land cover maps using the random forest algorithm to overall accuracies of 72.6 %, 86.9 % and 91.2 %, respectively. The InVEST software was used to estimate the carbon sequestered by each land cover class in the landscape. Finally, 150 cashew farmers, four focus group discussions and key experts were interviewed. The results show that cashew plantations had increased in the Municipality by 31103.05 ha between 2000 and 2020. The shift in land use towards cashew increased the Above Ground Carbon from 599956.73 tons to 1039402.32 tons between 2000 and 2020, representing 696219.15 tons (883.5 %) increase in the Municipality. According to the farmers, the shift in land use to cashew was mainly due to the available ready market and relative higher income. This suggests that, there is great potential for mitigating climate change in the forest-savannah transitional zone using cashew. Hence, Ghana needs to explore the gains associated with cashew plantations, particularly as it transforms low-income crops with challenging post-harvest and marketing constraints into relatively lucrative income generation cashew, which has major implications for improvements in livelihood and co-benefits for carbon stocks enhancement. Ultimately, as Ghana rolls out its Nationally Determined Contributions implementation among other forestry sector climate change mitigation interventions, it is important to consider the role of cashew as a major contributor to carbon stocks enhancement within the Forest–Savannah transitional zone. This study provides major decision support for formulating policies, interventions, and measures to promote climate change and livelihood improvement opportunities while rolling out safeguard measures to prevent further conversion of relatively high carbon stocks landscapes, such as the savannah woodlands within the forest-savannah transitional zone.