On a birch tree in northern Ontario, a black, charred lump bulges from the flaky white bark. This lump is a chaga mushroom, and there’s a bounty on its life.

Chaga doesn’t look like a mushroom at all: it has no cap, no stem. It’s just a smoky, crusted ball, hardly distinguishable from a blackened burl or charred branch stub. A few strikes with an axe, a couple of back-and-forths with a hacksaw, or even a good whack with a stick can dislodge the main body of a chaga — also known as the conk — from its host tree. Breaking the conk open reveals an umber interior reminiscent of ’70s corduroy. It gives off a faint scent of sap and earth, and, when boiled, produces a tea that tastes like vanilla and wet dog.

The fungus grows mainly across Russia, Canada, and northern parts of the US, Europe, and Asia, and foragers in these regions comb forests for chaga every winter. Someone harvesting for themselves might pry off a nugget, leaving the rest of the conk to continue growing, while foragers looking for profits can hack whole masses off the tree, tossing them into the backs of pickup trucks to sell to retailers.

Chaga gives off a faint scent of sap and earth, and produces a tea that tastes like vanilla and wet dog.

Chaga is big business. The mushroom is powdered into pills, boiled for tea, distilled in alcohols, and blended in lotions and soaps for its purported health benefits. Proponents believe chaga’s cocktail of betulinic acid, phytosterols, polysaccharides, and beta-D-glucans can aid those suffering from cancer, high blood pressure, high cholesterol, immune deficiencies, viral infections, and even the aging process.

Nikki Standinghorn — owner of NeepSee Herbs, an Indigenous traditional medicine business in Saskatchewan — has sold and harvested chaga for years after learning about it from family members and acquaintances. Her customers purchase chaga tea: “Number one, for cancer. Number two, for diabetes. Number three, for arthritis.” Standinghorn uses chaga herself, and insists she hasn’t been sick once since she started. “I cannot brag enough about this stuff.”

Kevin McAuslan, former president of the Toronto Mycological Society, has made chaga “coffee” for years by boiling a nugget, running the softened chunk through a Vitamix, and then boiling the resulting mixture again.

“Anecdotally, in my family, we believe it helps in immune function,” McAuslan says. “If I have chaga before I go on a plane, I don’t get sick.”

It’s easy to dismiss chaga-hype as marketing buzz, but the fungus is medically interesting. While no large-scale studies have looked at chaga’s effects on humans, animal studies suggest benefits including immunity boosting, improved blood sugar and cholesterol, and reduced chronic inflammation.

Residents of Siberia and Indigenous people in North America have foraged chaga for centuries. The name “chaga” is derived from Russian, but the fungus has many names, including posahkan (Cree), shkitaagan (Anishinaabemowin), and mii’hlw and tiiuxw (Gitskan). Indigenous medicinal traditions have used the tea to relieve viral infections, and chaga smoke to treat aches and pains. In a Facebook Live video, Wikiwemikong herbal medicine expert Joseph Pitawanakwat recommends burning the inner part of the conk for migraine relief.

The fungus caught the wider world’s attention after the publication of health food writer David Wolfe’s 2012 book Chaga: King of the Medicinal Mushrooms. Wolfe’s book promoted chaga as an anti-cancer, anti-inflammatory, cardio-protective, liver-purifying superfood. As interest has grown, a cottage industry quickly developed to forage for, process, and sell the fungus — some would say too quickly.

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Wild-harvesting mushrooms is nothing new; professional foragers around the world supply restaurants and herbalists with the freshest and rarest fungi the forest has to offer. But when some of these foragers transitioned to chaga, they hit a snag: unlike most quick-growing culinary and medicinal fungi, chaga can take 15 years to reach harvestable size. And because it grows only on living trees, it can’t be farmed like conventional mushrooms.

Most fungi, including chaga, begin life as a spore. The chaga spore latches onto a wound on a birch tree, such as the site of a torn-off branch. The growing conk feeds off the heartwood inside the trunk, and extrudes out of the bark as a crusted fungal mass. Like a highly selective vampire, the chaga feeds on the living tree, and only completes its life cycle after its host dies, by forming a fruiting body that disperses spores. The tree’s death also triggers the decay of the conk.

Because it requires a living host, chaga can’t be farmed on dead logs as is common with culinary mushrooms like oyster and shitake. As chaga-enthusiasm grew, the industry was left with two options to meet demand. One option was to cultivate lab-grown chaga (likely by sprinkling spores on cooked grains like rye, wheat, or rice, and harvesting the resulting fungal tissue). While lab-grown chaga is highly scalable, the health food world alleges it contains fewer beneficial compounds. That left option two: scale up foraging.

Like a highly selective vampire, the chaga feeds on the living tree, and only completes its life cycle after its host dies.

A resource industry conducted without regulation on public land — like most Canadian chaga foraging — is not a recipe for sustainability. Foragers pick all the fungus they can find to sell to anyone who will buy. This approach can clear large areas of commercially viable chaga stocks.

Sustainability concerns for forest products in general — and chaga in particular — have been discussed for years in the press. However, with more chaga experts claiming that accessible chaga stocks are starting to fall, the industry is now at a crossroads: buyers can either rework their supply chains and foraging practises to retain a continuous stream of chaga, or opt for larger short-term profits, hastening an end to the wild-foraged chaga industry.

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This is the picture painted by Dwight Thornton. Thornton is a chaga consumer, forager, and seller based in New Brunswick. To his knowledge, he was the first North American to sell chaga online; after taking it for his own health, and sharing it with family and friends, Thornton started selling chaga in 2007.

“When I put chaga on the first website, it wasn’t for resellers and marketers. It was for people like myself who needed it,” Thornton says. He believes his chaga tea habit — around 1.5 litres a day — cured him of a debilitating liver illness, and that others can benefit from the mushroom.

Thornton now buys chaga from other harvesters to sell on his website. According to Thornton, “If sustainability is going to happen, it has to happen with us buyers.”

Professional foragers are naturally inclined to sell whatever they can. That’s why Thornton requires his suppliers to adhere to a code of conduct aimed at maximizing sustainability and medicinal value.

Some especially reckless harvesters even cut down trees to access high-growing chaga infections.

Unsustainable harvesting comes from short-term thinking; because chaga grows inside the tree as well as outside, a harvester can net extra income by chiselling out the whole fungus from the tree. This provides a short-term profit boost for that individual forager. But it ultimately harms the chaga population of the forest: removing a whole chaga from a tree prevents it from one day completing its life cycle and dispersing more spores. It also damages the inside of the tree, leaving it vulnerable to infection and eventually death. According to both Thornton and Standinghorn, some especially reckless harvesters even cut down trees to access high-growing chaga infections, further impacting the forest.

If a forager only takes part of the conk, not only will the remainder form a fruiting body when the tree eventually dies, but the conk will also continue to grow as long as its host tree lives, producing extra fungus for the harvester in coming years.

Thornton asks his foragers to only bring him whole, mature mushrooms, with a clean cut to show they did not cut inside the tree. He insists that the chaga he buys be harvested in winter, when the host tree’s sap stops running and the chaga’s store of nutrients should be highest. While buyer policies like Thornton’s could ensure a sustainable supply, he’s aware they only currently apply to his harvesters. “Other buyers, they’re not so picky,” he says. “They don’t care.”

Standinghorn also realized the importance of buyer responsibility early on in her chaga-selling career. “When I realized how much I could sell to the public, I was worried about the sustainability,” she says. So she released a series of videos explaining chaga’s benefits and how to sustainably harvest it.

Standinghorn’s method is to only take half the external conk, rather than the whole thing. She believes that this harvesting ratio optimizes the mushroom’s ability to regenerate. She has harvested chaga from the same three spots, year after year, without any dip in supply.

“This is an amazing medicine.” Standinghorn says. “It’ll be there forever for us if we sustain it properly.”

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New Brunswick’s yellow birch forests are especially brittle, and therefore more susceptible to chaga infections, according to Thornton. In the fall of 2019, foragers he works with found a cube van sporting Québec plates in the woods, loaded with bags of chaga. The New Brunswickers asked the van’s owners to leave; for mushroom hunters, territory is sacrosanct.

Unfortunately, this territory-crossing is emblematic of the cut-and-run mentality that, according to Grant Lauzon, is putting commercial chaga supplies at risk. Lauzon runs Greenfoot.ca, a chaga sustainability website. He describes large health food companies buying all the chaga their harvesters can provide, while foragers moving from one area to another give the appearance of an unlimited supply. Meanwhile, in the background, whole forests are depleted of mature chaga.

To spark a new business model, Lauzon developed a scaled-down device for producing chaga extract. Using this device, an individual forager could create their own extract for sale, bypassing larger companies and giving them an economic incentive to keep the chaga populations in their area healthy. Next, Lauzon looked into protecting chaga populations from human overharvesting.

Taking only part of the conk is wise foraging, Lauzon says. However, in his view, it’s not enough for a forager to do no harm by harvesting properly. Instead, that harvester must also protect the chaga population from others’ unsustainable practices.

Managed well, chaga-seeding could form the foundation of a sustainable wildcraft industry.

Observing the life cycle of chaga, Lauzon discovered that it’s possible to “plant” freshly harvested chaga back onto a tree. Using a drill, a forager can bore into a tree, place a thumbnail-sized chunk of freshly harvested chaga inside, and seal the hole with wax to protect the fungus from the elements. In time, the chaga chunk infects the tree and, eventually, bursts out as a new conk.

On private land, this seeding method could lead to chaga farming: a harvester could work out an agreement with the landowner and seed the chaga for a reliable supply. This approach was developed simultaneously in Europe, where one Estonian company offers professional chaga seeding to land owners.

On public land, where intentionally spreading a tree fungus is ethically questionable, a forager could re-infect a tree after harvesting to counter unsustainable harvesting. If a second harvester digs out the remaining conk from the tree, the newly introduced infection still has a chance of growing and forming a conk in coming years. While not a great outcome for the perpetually infected tree, it’s good news for the forager who knows the chaga will have a chance to spore and produce more conks in the future.

Based on chaga’s growth requirements, Lauzon estimates that Ontario foragers could sustainably harvest 15 metric tonnes of chaga per year from easily accessible forests, while Québec harvesters could bring in as much as 25 tonnes. Managed well, this could form the foundation of a sustainable wildcrafted chaga industry, and generate jobs in rural communities.

This is key, because the demand for chaga is unlikely to go away. Approximately 71% of Canadians have consumed some form of natural health product. Demand for these products is generally driven by increased diet consciousness, rising health care costs, and an older population. These factors are unlikely to diminish anytime soon, and the marketing around chaga’s health benefits fits neatly with consumer desires.

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In Lauzon’s view, natural chaga production peaked years ago, and human interventions are the only viable path forward. A sustainable chaga future is not necessarily a given, though, and Lauzon foresees a few possible scenarios. Chaga harvesting could increase until demand is so high and supply so low that the fungus becomes a luxury good. Alternatively, companies may resort to vat-grown chaga, with a smaller amount of wild chaga mixed in, or to multi-mushroom blends that mask a shrinking chaga supply.

While pessimism is well-founded, there’s also reason for hope: managing forest resources is an ancient practice. The Canadian maple syrup industry is an example of disciplined forest resource management. Sugar maple tapping — which requires draining the right amount of sap from a specific type of tree — might offer a model for chaga sellers. Managed correctly, chaga in Canada could become as sustainable as this sweet national delicacy.

Lauzon believes — based on interest in the methods he’s developed — that sustainability isn’t far off. Over the last two years, he’s seen foragers embracing locally managed operations aimed at balancing chaga stocks with consumer demand. “It really has shifted into the care of the harvesters,” he says. “My pleasant surprise is: the tide is turning, and it’s all of us working together to make that happen.”