Long-Term Monitoring of Coastal Afforestation Dynamics and Fire-Induced Biomass and Carbon Loss Using Landsat Time Series in Northwestern Tunisia

Coastal dune ecosystems play an essential role in shoreline stabilization, biodiversity conservation, and carbon storage, but they are increasingly threatened by human activities and climate-related disturbances. This study assessed long-term forest vegetation dynamics in restored coastal dune ecosystems in northwestern Tunisia, integrating a 30-year Landsat dataset (1994–2024) with Random Forest classification. We quantified changes in forest and shrubland cover, evaluated the effectiveness of dune stabilization reforestation (Pinus pinea and Acacia spp.), and assessed the impact of the 2023 wildfire on forest biomass and carbon stocks. The findings demonstrate that reforestation efforts reduced mobile sand areas by 42.9% over three decades, with 78% of the sand loss attributable to vegetation stabilization. When infrastructure-affected areas were excluded, sand decreased by 64.7%, confirming genuine reforestation effectiveness. The 2023 wildfire caused substantial forest biomass losses in the reforested pine stands (264.19 t·ha−1) and carbon reductions (124.17 t·ha−1). These losses reflect the high vulnerability of Mediterranean coastal forests to wildfire disturbances under recurrent summer drought and increasing temperatures. The study emphasizes the importance of long-term remote sensing time-series for coastal forest management and restoration planning in Mediterranean ecosystems.