Reserves of Forest Carbon May Be Widely Overestimated, Study Says

The amount of carbon stored in the world’s tropical forests varies widely according to underlying geology and other factors, and current estimates of forest carbon reserves may be too high, according to a new study. A research team from the Carnegie Institution for Science used satellite mapping, laser probing of forest undergrowth from aircraft, and local ground surveys to estimate how much carbon was stored in the 17,000-square-mile lowland forest in the Madre de Dios region of Peru. The team’s surveys showed that the forest stored roughly 395 million tons of carbon — far less than the 587-million-ton estimate of the Intergovernmental Panel on Climate Change. The researchers, reporting in the journal Proceedings of the National Academy of Sciences, said that the earlier estimate was off because different tropical forests store varying amounts of carbon, and that forests where the underlying rocks are younger contain more carbon in soils and trees. In another study, researchers said that the number of insect species in tropical forests also varies widely according to topography, and that montane tropical forests in the Ecuadorean Andes and highlands of Costa Rica contained six times more insect species than predicted.