September 2020
Vol 6, Issue 40

About The Cover

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ONLINE COVER Tropical forests, which store more than half of the planet's aboveground carbon, declined by 10% between 1990 and 2015 due to human activities. In addition to shrinking, these forests are becoming more fragmented, leaving trees at their edges vulnerable to turbulent winds and heightened fire risk. While some early research has found significant carbon loss at Amazon forest edges, its magnitude has remained poorly understood. To measure how fragmentation contributes to carbon losses from deforestation, Silva Junior et al. processed airborne LiDAR data, which measures distances using a laser, to model carbon loss as a function of forest edge age. Next, they applied this model across forest edge age maps from remote sensing data gathered between 2000 and 2015 to visualize edge-induced carbon loss in the region. The researchers found that Amazon forests lost 947 million tons of carbon along deforested edges between 2001 and 2015—one-third the quantity of carbon lost due to deforestation itself over the same time period. The findings point to fragile deforested edges as a significant, previously unmeasured source of carbon loss. [CREDIT: JACQUES JANGOUX/SCIENCE SOURCE]