Tropical deforestation in Africa has profound effects on the global carbon (C) cycle, with major implications for climate change and sustainable development. In Sub-Saharan Africa, where over 66% of the population depends on forests for their livelihoods, deforestation driven by agricultural expansion leads to significant losses in carbon stock.
In the recent study by Grieco et al. “Impacts of deforestation and land use/land cover change on carbon stock dynamics in Jomoro District, Ghana” we provide crucial insights into how deforestation and conversion to tree plantations or secondary forests, impact carbon stocks in tropical ecosystems to elucidate how different land uses/cover and stand ages affect carbon storage across various carbon ecosystem pools.
Primary forests, despite their lesser direct economic benefit compared to tree plantations, are essential for carbon storage. The study found that primary forests hold a significantly higher total carbon stock, averaging 427.1 MgC ha−1, compared to secondary forests and tree plantations. Notably, mixed plantations have shown similar carbon storage potential, especially in above-ground carbon (AGC) and soil organic carbon (SOC) pools, aligning with other research highlighting the multiple benefits of mixed-species plantations.
In primary forests, AGC constitutes about 61.7% of the total carbon stock, with SOC contributing 20.4%. Although with different proportions, AGC and SOC are the pools contributing in a larger part to the total ecosystem C-stock. This proportion remains consistent across different land uses, though AGC is more significant in older plantations like coconut and rubber. Conversely, younger plantations, such as oil palm, show higher SOC contributions, likely due to residual carbon from former forest cover, which diminishes as the plantation matures.
Younger stands, including secondary forests and young rubber plantations, exhibit higher rates of carbon accumulation, particularly in AGC. However, as these stands age, the rate of carbon sequestration decreases. This pattern is evident across various plantation types, highlighting the dynamic role of younger ecosystems in carbon sequestration.
SOC is prone to depletion after deforestation and plantation establishment. Although older plantations experience a slower rate of SOC loss, significant depletion occurs over time, especially in monocultures like coconut and rubber. Mixed plantations, however, demonstrate more stable SOC levels, emphasizing their role in maintaining soil health and overall ecosystem carbon balance.
Primary and secondary forests confirm having a pivotal role in carbon sequestration but it is recognized the potential of mixed plantations to enhance carbon storage. Implementing effective land management strategies, such as promoting mixed-species plantations, can bolster carbon sequestration, support local livelihoods, and contribute to climate change mitigation. This could be further investigated and could have positive implications in long-term sustainable rural development.