Digital measurements of millions of trees indicate that previous studies likely overestimate the amount of carbon stored by temperate U.S. forests, according to a new NASA study.
The findings could help scientists better understand the impact that trees have on the amount of carbon in the atmosphere. Although it is a well-established fact that trees absorb carbon and store it long-term, researchers are unsure how much is stored in global forests.
"Estimates of the carbon content of living trees typically rely on a method that is based on cutting down trees," said Laura Duncanson, a postdoctoral fellow at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "It takes a lot of effort to cut down trees, particularly the biggest ones, so this just isn't practical to do in large numbers."
Because of this limitation, field studies aim to strategically sample trees. When looking at U.S. forests, for example, on average about 30 trees of each species would be cut down and measured. Researchers would then use basic mathematical models to scale up those measurements to many thousands, or even millions, of trees, resulting in an estimate of the biomass - the amount of carbon stored - for an entire forest.