Many tropical forests around the world have been severely fragmented as human disturbance split once-contiguous forests into pieces. Previous research indicates trees on the edges of these fragments have higher mortality rates than trees growing in the interiors of forests. Researchers used satellite data and analysis software they developed to figure out how many forest fragments there are, and the extent of their edges. They discovered that there are around 50 million tropical forest fragments in the world today. When they calculated how much carbon is being released from tree death at these edges, they found a 31% increase from current tropical deforestation estimates.