Alaska's Forest Shift Could Slash Wildfire Carbon Loss

Scientists just discovered that a quiet transformation happening across Alaska's forests could become one of nature's most powerful tools against climate change.

New research from Northern Arizona University shows that boreal forests dominated by birch and aspen trees release less than half the carbon of traditional spruce forests when they burn. The study, published in Nature Climate Change, examined nearly a dozen large fire scars across Alaska and Yukon to understand how different tree types affect wildfire emissions.

"This work shows that not all boreal forests burn the same way," said Betsy Black, who led the study. "As deciduous trees become more common after fire, they can fundamentally change how much carbon is lost to the atmosphere during future wildfires."

The difference comes down to where these trees store carbon. Deciduous forests pack more carbon into their fire-resistant trunks and less in the deep organic soils that burn easily during wildfires. When flames sweep through, the result is dramatically lower emissions.

This matters because boreal forests store a massive fraction of the world's land-based carbon, accumulated over centuries in thick soils. As wildfires grow larger and more frequent with warming temperatures, scientists have worried these forests could flip from carbon storage vaults to carbon emission sources.

The Bright Side

The research team found something unexpected when they dug into the data. Not only do deciduous forests release less carbon overall, but this forest shift is already happening naturally across northwestern North America after severe fires.

Professor Michelle Mack, senior author on the study, noted their earlier research showed deciduous forests accumulate much more carbon after fires than spruce forests. "But we were curious about what happens to that carbon when these forests burn," she said. "No one had measured that before."

The findings provide critical information for improving wildfire and climate models. By understanding exactly how much carbon different forest types release and what controls those losses, scientists can better predict future climate scenarios.

Even under extreme fire conditions, carbon losses in deciduous forests remained consistently lower than in conifer forests. This suggests that as more birch and aspen trees replace burned spruce stands, each acre that burns will send less carbon into the atmosphere.

Nature might be giving us an unexpected ally in the fight against climate change, one tree at a time.