Dried mushrooms slow climate warming in Northern forests

Irvine, Calif. — The fight against climate warming has an unexpected ally in mushrooms growing in dry spruce forests covering Alaska, Canada, Scandinavia and other northern regions, a new UC Irvine study finds.

When soil in these forests is warmed, fungi that feed on dead plant material dry out and produce significantly less climate-warming carbon dioxide than fungi in cooler, wetter soil. This came as a surprise to scientists, who expected warmer soil to emit larger amounts of carbon dioxide because extreme cold is believed to slow down the process by which fungi convert soil carbon into carbon dioxide.

Knowing how forests cycle carbon is crucial to accurately predicting global climate warming, which in turn guides public policy to curb greenhouse gas emissions. This is especially important in northern forests, which contain an estimated 30 percent of the Earth's soil carbon, equivalent to the amount of atmospheric carbon.

"We don't get a vicious cycle of warming in dry, boreal forests. Instead, we get the reverse, where warming actually prevents further warming from occurring," said Steven Allison, ecology and evolutionary biology assistant professor and lead author of the study. "The Earth's natural processes could give us some time to implement responsible policies to counteract warming globally."