Woody species diversity and aboveground carbon stocks in agroforestry systems in Burkina Faso

In the semi-arid areas of West Africa, agroforestry systems (AFS) play a crucial role in livelihood support and climate change mitigation. Yet, in Burkina Faso, these ecosystems are insufficiently accounted for in national efforts to sequester atmospheric carbon dioxide due to the scarcity of data about their carbon storage potential. This study aimed to assess woody species diversity and aboveground carbon stocks in AFS across three climatic zones of Burkina Faso. Dendrometric measurements of 4733 individuals were carried out using a systematic sampling design in 180 farmlands sampled across the Sahel, Sudan-Sahel, and Sudan climatic zones of Burkina Faso, with 60 farmlands per climatic zone. Diversity indices were used to assess woody species diversity, dendrometric measurements were used to estimate aboveground carbon stocks of woody species using allometric equation. The findings showed a γ-diversity of 71 woody species belonging to 53 genera and 25 families across the three climatic zones. Species richness (S = 6.53), Shannon’s index and Simpson’s index (H = 1.26; D = 0.59) were highest in the Sudan-Sahel zone. However, the mean aboveground carbon stocks increased from the Sahel zone (2.3 to 3.4 Mg C ha−1) to the Sudan zone (6.1 to 8.1 Mg C ha−1). Carbon stock was positively correlated with stand density (0.56 < r < 0.61) and diversity (S, H, D) (0.3 < r < 0.41), highlighting the positive relationships between biodiversity and ecosystem functioning. This study highlights the co-benefits associated with policies maintaining stand diversity and carbon storage in AFS as a mean to increase the resilience of these systems to changing environmental conditions.