Missoula Current

A forest ecology professor at the University of Montana has turned to the post-fire landscape in an effort to estimate the abundance of morel mushrooms that appeared after a 2014 blaze in California's Sierra Nevada.

Professor Andrew Larson, who studied more than 1,100 sample plots within the burn area, recently published his finding in the June addition of Forest Ecology and Management.

“So many people love to harvest and eat morel mushrooms, but there is very little research that measures the abundance of morels after a forest has burned,” Larson said. “We wanted to give forest managers concrete data on morel abundance.”

Larson and his co-authors conducted their study in the Yosemite Forest Dynamics Plot, a long-term research site located in Yosemite National Park. A fire burned the research site in September 2013, killing more than 70 percent of the trees. Researchers sought out the morels the following spring.

Where morels were found, most of the ground surface was 100 percent burned by fire. Morels typically are found close together, Larson said, yet unevenly distributed across the landscape.

Larson said white fir forests in Yosemite alone could produce an average crop of more than 1 million morels per year, a sustainable amount for recreational picking.

“The magnitude of post-fire morel production, especially the first year after fire, clearly supports the park’s current rule allowing people to pick one pint per day for personal use,” he said.

At the start of their study, Larson’s team was surprised by how little research has been conducted on morel mushroom productivity. With so many questions unanswered, Larson and his co-authors also propose a conceptual model to guide future research that could help explain the mushroom’s spatial distribution in burned areas.

“We reviewed every published paper on post-fire morel mushroom productivity we could find,” Larson said. “Amazingly, only three earlier studies – in Alaska, Oregon and British Columbia – provide statistically sound estimates of morel abundance after forest fires.”