5 takeaways:

➀ Forests provide a “massive” storehouse of carbon — about 50% of a tree’s mass, said Grant M. Domke of the U.S. Forest Service. And as trees grow, they continue absorbing some carbon from the atmosphere, becoming what’s known as a “carbon sink.” One of Domke’s jobs is to estimate the size of the U.S. carbon sink, which is one of the most important resources for keeping excess carbon out of the atmosphere. In 2019, that carbon sink totaled 775 million metric tons, “the equivalent of taking more than 168 million passenger vehicles off the road for a year or the emissions from 196 coal-fired power plants for one year,” Domke said. “A massive contribution to the overall carbon budget.”

➁ If the sink shrinks, that stinks. Since 1990, America’s forest land sink has declined, from about 860 million metric tons to 775 million metric tons in 2019. Carbon is released into the atmosphere when wood is burned — whether in a forest fire or as an energy source — as well as when trees are harvested. Over the last three decades, the contribution of forest land to emissions offsets in the U.S. has remained relatively stable at around 14%, despite a decline since 2005 in overall carbon dioxide emissions. “This suggests the carbon sink strength in the U.S. … is slowly diminishing,” Domke said.

➂ The federal government counts trees much as it counts people — and reporters can access its data. The Forest Inventory and Analysis Program — essentially the nation’s census of trees — finds roughly 1.38 trillion trees on approximately 310 million hectares of forest land in the United States, representing about one-third of the entire U.S. land base, Domke said. The census takers visit forested land plots around the country on a regular basis, collecting the kind of information that helps calculate the carbon sink. “How has that diameter changed? How is the height changed? Are there new trees on the plot?” Domke said. Reporters can use the Forest Inventory and Analysis Program to get down to the state and county level on the tree census and where carbon is being stored.

➃ About 60% of U.S. forests are privately owned. But the fraction held by individual landowners, corporations and real estate companies varies widely by region. The other 40% are owned by federal, state, local and tribal governments. (The feds have by far the biggest share, holding two-thirds of the government’s forested lands.) On the regional level, things look very different. In the West, the government is the biggest forest owner. In the Southeast, most forests are owned by private landowners, many with small plots of a few dozen acres. That becomes relevant as the wood-pellet industry in the Southeast continues to grow, generally sourcing its wood from private landowners.

➄ The wood-pellet industry is growing rapidly but is still a small share of wood consumption. Bob Abt, who researchers forest economics and management at North Carolina State University, said that the consumption of southern trees for the creation of pellets that are used in energy has shot from zero in 2005 to about 20 million tons by 2019. That helps prop up prices as other uses of southern trees, such as for paper, have declined. The country has not yet achieved “peak pellets” he said. “There’s still expansion of pellets and new mills coming in,” Abt said, noting plants set to open or expand in several southern states.

Speakers: 

Bob Abt, Carl Alwin Schenck Professor Emeritus, North Carolina State University

Grant M. Domke, Team Leader, Research Forester, U.S. Forest Service, U.S. Department of Agriculture

This program was funded by the David and Lucile Packard Foundation. NPF is solely responsible for the content.