Carbon stocks and biodiversity of coastal lowland forests in South Africa: implications for aligning sustainable development and carbon mitigation initiatives

Indigenous forests represent South Africa’s smallest biome, yet they are critical spaces for aligning sustainable development goals with carbon mitigation activities and conservation. The objectives of this study were to quantify the productivity and biodiversity of coastal lowland forests in the Dwesa Cwebe nature reserve in the Eastern Cape Province and characterize how estimates differed among alternative allometric equations. Using a complete tree census across six plots in the reserve, a total of 1489 trees were inventoried in 2011 and again in 2016. Aboveground tree carbon averaged 99.8 Mg C ha⁻¹ (range 77.2–126.9 Mg C ha⁻¹) using locally derived equations and 214.6 Mg C ha⁻¹ using generalized equations. Tree aboveground net primary productivity averaged 1041.8 g C m⁻² y⁻¹. Forty-eight tree species were identified, including many species important to the livelihoods of local communities for medicinal, ceremonial, and other provisioning services. Overall, this study shows that current conservation activities are concomitant with high tree productivity and high levels of C stocks and biodiversity, including species of local and regional significance. Sustaining forest productivity and biodiversity in the future will be critical for maintaining ecosystem services and enhancing stewardship of forest resources in the region.