Assessing forest cover and tree density dynamics in the Congo–Nile Divide region, Western Rwanda

The loss of forest cover across landscapes poses significant environmental challenges, particularly within biodiversity hotspots. In Rwanda, the Congo–Nile Crest is one such critical hotspot, rich in biodiversity and situated between the two largest basins in Africa, the Congo and Nile basins. However, limited knowledge is currently available on the dynamics of forest cover and tree density within this region, hindering informed decision-making for sustainable forest and tree management. Therefore, this study aims to assess forest cover and tree density changes between 2009 and 2019 using high-resolution aerial imagery and advanced geospatial analysis. The findings reveal a 7% increase in overall forest cover within the studied period, with 43% of the forest remaining stable, and a minimal loss of about 2.1% primarily from plantations. Tree density outside natural forest showed a positive trend, with an average increase of about 23 trees per hectare, and a strong positive correlation (r = 0.74) between 2009 and 2019, indicating a consistent spatial distribution. Areas with higher tree density in 2009 gained additional trees, as indicated by a regression slope of 1.05, suggesting continued restoration efforts. However, nearly 18% of sites experienced a decline in tree density, indicating uneven recovery and localized degradation. These findings highlight the success of Rwanda’s ambitions toward increasing forest cover, but also stress the need for targeted interventions in areas that faced decline and those with less tree cover. This study provides valuable insights for future forest management initiatives and emphasizes the importance of forest cover and tree density in biodiversity conservation.