Biomass and carbon stock in restored mangrove forests: Evidence from Indonesia

Mangrove restoration is widely recognized as a nature-based solution for enhancing blue carbon storage and mitigating climate change. However, quantitative assessments of biomass and carbon recovery in restored mangrove systems remain limited, particularly in Indonesia's ecotourism landscapes. This study evaluated aboveground and belowground biomass and associated carbon stocks in rehabilitated mangrove stands in the Balang Baru Ecotourism Area, Jeneponto Regency, South Sulawesi. Field measurements were conducted in April 2025 across five sampling stations, with 15 nested plots. Tree diameter at breast height (DBH) and height were recorded for all individuals with DBH ≥ 5 cm. Aboveground biomass (AGB) and belowground biomass (BGB) were estimated using allometric equations, and carbon stocks were derived using standard biomass-to-carbon conversion factors. The results indicated substantial biomass accumulation in the restored mangrove stands. Mean AGB and BGB were estimated at 95.20 Mg ha⁻¹ and 41.23 Mg ha⁻¹, respectively. Corresponding carbon stocks averaged 45.70 Mg C ha⁻¹ for aboveground carbon (AGC) and 16.08 Mg C ha⁻¹ for belowground carbon (BGC). Biomass and carbon stocks varied spatially among stations, with the highest values recorded at Station 5 (AGB: 126.19 Mg ha⁻¹) and the lowest at Station 4 (AGB: 67.30 Mg ha⁻¹). However, one-way ANOVA showed no statistically significant differences among stations (p > 0.05), indicating relatively comparable biomass recovery across the rehabilitated area. These findings suggest that restored mangrove stands in Balang Baru have developed substantial biomass and carbon storage capacity despite their relatively young age. The results highlight the potential contribution of community-based mangrove restoration to blue carbon initiatives and coastal ecosystem recovery. Continued long-term monitoring, along with the inclusion of soil organic carbon assessments, is recommended to obtain more comprehensive estimates of total carbon storage in restored mangrove ecosystems. Highlights

Restored mangroves in Balang Baru demonstrate significant biomass recovery. AGB reached 20 ± 10.56 Mg ha⁻¹ and BGB 41.23 ± 3.83 Mg ha⁻¹. Carbon stocks averaged 70 ± 5.07 Mg C ha⁻¹ (AGC) and 16.08 ± 1.49 Mg C ha⁻¹ (BGC). Biomass distribution among stations showed no significant differences. Restored mangroves contribute to blue carbon and climate mitigation.