African forests suffer from severe fragmentation that further causes forest degradation near forest edges. The impact of fires used for slash-and-burn on forest edge effects remains unclear. Here, using high-resolution satellite-based forest-cover and biomass datasets, we find that edge effects extend a median distance and an interquartile range of \(0.11_{ - 0.04}^{ + 0.06}\,{\mathrm{km}}\) and \(0.15_{ - 0.05}^{ + 0.09}\,{\mathrm{km}}\) into moist and dry forests, and biomass within the forest edge zones has a carbon deficit of 4.1 PgC. Fires occurred in 52% of the forest edges and increased the carbon deficit by \(5.5_{ - 2.9}^{ + 4.3}\,{\mathrm{MgC}}\,{\mathrm{ha}^{{-1}}}\), compared with non-fire edges, through both the direct impact of fires intruding into forests and the indirect impact of changes in the local atmospheric circulations increasing canopy dryness. If small-scale slash-and-burn practices continue, increased fragmentation during 2010–2100 will result in a carbon loss from edge effects of 0.54–4.6 PgC. Fragmentation-caused forest degradation could be avoided by implementing dedicated forest protection policies supported by satellite monitoring of forest edges.

非洲森林遭受严重的破碎化，进一步导致森林边缘附近的森林退化。用于刀耕火种的火灾对森林边缘效应的影响仍不清楚。在这里，使用基于卫星的高分辨率森林覆盖和生物量数据集，我们发现边缘效应扩展了中位距离和四分位数范围\(0.11_{ - 0.04}^{ + 0.06}\,{\mathrm{km }}\)和\(0.15_{ - 0.05}^{ + 0.09}\,{\mathrm{km}}\)进入潮湿和干燥的森林，森林边缘区域内的生物量碳赤字为 4.1 PgC。52% 的森林边缘发生火灾，碳赤字增加了\(5.5_{ - 2.9}^{ + 4.3}\,{\mathrm{MgC}}\,{\mathrm{ha}^{{-1 }}}\)，与非火灾边缘相比，火灾侵入森林的直接影响和局部大气环流变化的间接影响增加了树冠干燥度。如果继续小规模刀耕火种做法，2010-2100 年期间增加的碎片化将导致 0.54-4.6 PgC 的边缘效应造成的碳损失。通过实施由森林边缘卫星监测支持的专门森林保护政策，可以避免碎片化导致的森林退化。