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 data sets, we find that edge effects extend a median distance and an interquartile range of 0.11-0.04+0.06 km and 0.15-0.05+0.09 km into moist and dry forests, and biomass within the forest edge zones has a carbon deficit of 4.1 Pg C. Fires occurred in 52% of the forest edges and increased the carbon deficit by 5.5-2.9+4.3 Mg C ha^-1, compared to 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 Pg C. Fragmentation caused forest degradation could be avoided by implementing dedicated forest protection policies, supported by satellite monitoring of forest edges.
 

森林退化,火灾,生物量,遥感观测