Forests have long been seen as important sinks, or storage sites, for greenhouse gases. But scientists recently discovered that tree trunks emit methane, a powerful greenhouse gas at least 25 times more potent than carbon dioxide in the short-term.
The discovery comes from researchers at the University of Delaware, who measured methane output from soils, individual trees, and decomposing woody biomass lying on a forest floor in northeast Maryland over a 10-month period.
Using a mobile greenhouse gas analyzer, the University of Delaware researchers found that while forest soils suck up and store methane, tree trunks actually release the gas. They also found that different tree species release it at different rates. One theory they posed was that internal rotting or infection inside the tree trunk could cause the methane leaks. The findings were published recently in the journal Ecosystems.
“When people develop ecosystem to global-scale methane budgets, there’s always a chunk in which it is uncertain from where that methane is coming,” said University of Delaware doctoral student Daniel Warner, lead author of the study, in a statement. “Methane emissions by vegetation and tree trunks are seen as a newly considered source that might bring that budget closer to our estimates.”