Aging European forests full to the brim with carbon

Trees' capacity to sequester carbon dioxide from the atmosphere is dwindling

STORING CARBON  A mixture of conifers (greens), such as pine trees, and broadleaved trees (reds and browns), such as eucalyptuses and poplars, grow in forests throughout Europe. Old age, fires, insects and deforestation threaten the forests’ carbon storage capacity.

Map courtesy of Geerten Hengeveld

Europe’s forests are nearing their capacity to stockpile carbon, researchers warn August 18 in Nature Climate Change. Full forests mean more carbon dioxide — a greenhouse gas — in the atmosphere.

Centuries of deforestation shrunk Europe’s forests, but since the 1950s the continent’s woods have been steadily recovering. More than 60 years of growth have turned the forests into major carbon caches, or sinks: A hectare of mature forest can hold 65 metric tons of carbon.

Though scientists have estimated that the forests will continue to squirrel away carbon, Gert-Jan Nabuurs of Wageningen University in the Netherlands and colleagues disagree. Their new analysis of data from 29 European countries uncovers early warning signs that forests’ room for storage has nearly topped out.

The aging trees aren’t growing as fast as they once did, and they’re more susceptible to fires and insects, the researchers report. Urban sprawl is also curbing the spread of forested areas. European countries should consider changing forest management strategies to make the carbon sinks last, the authors suggest.

Meghan Rosen is a staff writer who reports on the life sciences for Science News. She earned a Ph.D. in biochemistry and molecular biology with an emphasis in biotechnology from the University of California, Davis, and later graduated from the science communication program at UC Santa Cruz.

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