Known to hold the greatest amount of carbon of all the world’s forests, the dense forests of the tropics have a significant impact on climate and were a topic of great interest at the recent climate conference in Paris (COP21). Indeed, the preservation of these forests and the Reduction of Emissions from Deforestation and forest Degradation (REDD+) are key ingredients of the Paris Agreement.
A new study, “Degradation in carbon stocks near tropical forest edges,” published today in Nature Communications, points out that the amount of carbon stored at forest edges has until now been overestimated by nearly 10 percent. Because tropical deforestation is an important contributor to global greenhouse gas emissions, proper accounting is necessary to inform management policies and assess national carbon stocks, and correct estimates will be required by the Paris Agreement.
Total annual global deforestation, one third of which is in the tropics, amounts to an area about the size of Uruguay. When the forest edge is taken into account, forest fragmentation could amount to as much as 24 percent of global carbon losses from deforestation. “Because of the spatial variability in carbon density, the common approach derived from field data and multiplied by the forest area extent tends to overestimate the total carbon stock,” said Alessandro Baccini, a WHRC scientist who took part in the study. “This is due to the limitation of existing field plots,” he added “but, as the study shows, improved remote sensing derived products will be of great help in better quantifying total carbon density.” Understanding the exact amount of loss is of utmost importance for forest policy and management.
Employing remote sensing, the team of scientists discovered that fragmentation at the edges of forests far exceeded previous estimates of forest biomass. They concluded that “forest configuration can be as important to assigning values for carbon storage as differences among regions or ecosystems.” As remote sensing products improve, there will be better accounting for “edge effects,” enabling effective restoration and forest management strategies. The scientists note that a burgeoning population will create further expansion into forested areas and underscores “the urgency of understanding the full ramifications of forest fragmentation and degradation.”
WHRC is an independent research institute where scientists investigate the causes and effects of climate change to identify and implement opportunities for conservation, restoration and economic development around the globe.