Every winter, David Koubek, a farmer from Bremen, would be leveled by bronchitis or pneumonia, rendering the 40-year-old useless for days. But last winter he started drinking copious amounts of chaga tea, and his chronic respiratory problems were “stopped in its tracks,” according to his wife, Jessica Koubek.

Chaga, a medicinal mushroom that grows on decaying birch trees, is being celebrated as a preventative for ailments that include lyme disease, cancer, tumors and the flu. From Bremen to Limington to Portland, farmers and herbalists are finding a market for this tree mushroom, which has been used as a superfood in Russia for centuries. In Maine, it is sold in health food stores and farmers markets in the form of teas and tinctures and is just starting to hit the mainstream.

In books like “Chaga: King of the Medicinal Mushrooms,” author David Wolfe states the fungus is rich in antioxidant power and can induce apoptosis, the spontaneous breakdown of cancer cells. It also can “squelch the strong oxidative damage to healthy tissue caused by radioactive chemotherapy.”

Jessica Koubek, who has researched chaga with her “chagaholic” husband, David, said it can alleviate myriad symptoms.

“It works as a general immune-boosting tonic and doesn’t give you a high and a crash like coffee; it’s a mellow energy booster,” the 39-year-old Maine native said.

Though this dietary supplement is not yet recognized by the Food and Drug Administration, it is starting to enter the medical mainstream. Greg Marley, a mushroom expert from Rockland, has led the charge for chaga in Maine for more than a decade. Lately, he is encouraged.

“I’ve seen a fairly significant change. When I started talking about chaga 10 or 12 years ago, there was a fair amount of pushback. As doctors are becoming more comfortable that they don’t have all the answers, that’s changing incrementally,” said Marley, who has poured over studies from abroad on chaga and dedicates a chapter in his book, “Mushrooms for Health: Medicinal Secrets of Northeastern Fungi,” to its benefits.

Though the list of claims is long, above all, chaga supports a better functioning immune system.

“The areas where it is most clearly supported are immune stimulation,” Marley said, calling chaga “a great anti-inflammatory, which helps protect the body from opportunistic infection.”

It has assisted people with gastrointestinal problems, and “a number of people with joint pain report better mobility,” Marley said.

The longest history of chaga use is for treating gastrointestinal disorders and malignancy in Siberia for three centuries, Marley said. Ongoing research being conducted in South Korea and Russia are specifically addressing inflammation.

His own anecdotal research on joint relief is not backed by hard numbers; it’s based on people.

“I’m absolutely hearing from people who report back to me saying, ‘I’ve been much more mobile. I’m not walking with a cane and am without pain,’” after taking chaga, Marley said.

The mushroomer makes his own double-extraction chaga tincture, which he dilutes with water, to fend off bronchitis attacks during long Maine winters. Though Marley considers chaga to be effective, he cautions consumption should be part of an overall health regime.

“Chaga is wonderful mushroom, but it is not a panacea. I urge people to become critical thinkers and cautious consumers,” he said.

Chaga has not been tested for its anti-cancer properties in clinical studies, but there is “good support for it. It is certainly being used as an herbal supplement to fight cancer,” Marley said.

The climate in Maine — cold winters and not too hot summers — makes the state ripe for birch trees and chaga growth. As a result, more farmers are walking through the woods on chaga hunts.

Lauren Pignatello, a traditional herbalist with 20 years experience, forages for chaga in the forests near her home in Whitefield.

Pignatello, who runs Swallowtail Farm and Creamery, adds ground chaga to kefir and cocoa for a smoothie or in her coffee or hot chocolate. During a recent pregnancy, she incorporated chaga into her fermented and raw dairy diet.

“It gave my immune system a gentle boost. I hardly felt sick,” said the 43-year-old, who also runs a cottage apothecary in Portland, where she sells chaga. “I use it as an immune tonic. It is also used for keeping one young.”

In Maine, such experiences keep harvested chaga sales chugging along.

Michelle Hopkins, who launched Mainelychaga.com two year ago, sells chaga in chunks for $45 a pound or ground for $60 for 16 ounces. Her online business has picked up this year as news of chaga’s health properties spreads. A mention on “The Dr. Oz Show” didn’t hurt.

“People are starting to talk about it more. … It hasn’t slowed down,” said Hopkins, who fills orders for customers from Vermont, California and Washington state eager for her chaga harvested in St. Albans and in the North Maine Woods.

Many do-it-yourselfers are rolling up their selves and finding it themselves.

David Koubek didn’t look to the shelves of his local co-op for chaga, but to his 55-acre property, and found it plentiful. This summer The Good Shepherd’s Farm added chaga, sold in chunks or ground, in containers and brewed by the cup or chilled over ice, next to organic vegetables and fresh-baked bread, at the Portland Farmers’ Market. Often the brewed tea is sold out by midday.

“People are wondering what those big, black humps are at the table,” said Jessica Koubek, who will continue to sell chaga at Monument Square on Wednesdays through November.

“They are medically rich,” she said. “People are intrigued.”

Chaga purveyors, such as Vicki Marion of Fresh Pickins Farm in Limington, extol the virtues of this medicinal mushroom. But Marion is quick to point out “we are not doctors.” She knows anecdotally it works, because she takes it herself.

“It’s incredible. I feel cleaner and brighter, and I don’t have any ailments,” said Marion, who at 60 years old is an active gardener and sells fresh-cut flowers. She notices that those who buy her chaga, foraged by her son and sold as a tincture or tea, come back for more.

“It is growing. A lot of people are asking about it. I get return customers. It is not a one-time hit,” she said. “We are very keen on it.”

Kathleen Pierce

A lifelong journalist with a deep curiosity for what's next. Interested in food, culture, trends and the thrill of a good scoop. BDN features reporter based in Portland since 2013.