Shiitake - Lentinula edodes

Good evening, friends,

This week’s mushroom is one I imagine most of us are familiar with - the Shiitake (Lentinula edodes). I found a few of these mushrooms after the recent rain on a dead Norway maple tree (Acer platanoides) that I felled and inoculated with Shiitake mycelium last spring. A lot of my job is invasive species removal so it was a “two birds one stone” situation to not only remove a couple invasive trees to free up resources for nearby sugar maples, but also to be able to turn the undesirable trees into edible mushrooms. I also tried this with Lion’s Mane mushrooms (Hericium) and the invasive Tree of Heaven (Ailanthus) but I won’t have an idea if that works until the fall.

A slug got to the mushroom on the left before I did. The black in the photo is beeswax that I heated up and used to seal the holes where I injected the shiitake mycelium.

Fun Facts

Shiitake has been cultivated for almost a millennium with recorded cultivation dating back to roughly ~1100AD . Some people say they’ve been cultivated for over 1000, some say it dates back to specifically the year 1209 during the Song dynasty in China - I don’t know, I wasn’t there. What we do know is that shiitake cultivation in the US is still in its infancy since spawn - the mycelium used for growing mushrooms - was only permitted into the US in 1972. Prior to then the USDA allegedly wouldn’t allow shiitake spawn into the country due to a confusion with the similarly named species Lentinus lepidius (now Neolentinus lepidius) that will rot rail ties.¹

Shiitake have been revered in Asia for their purported medicinal properties - antioxidant, anticarcinogenic, and anti-inflammatory to name a few - and there’s some science to corroborate these claims. A double-blind randomized clinical trial involving fifty-two healthy, young people (aged 21-49) looked at whether the consumption of dried shiitake everyday for four weeks benefited their immune system. Let’s decipher the science speak just a bit: “double-blind” means neither the participants nor the researches know who receives the placebo, “randomized” means the placebo group and the shiitake group were assigned randomly, and “clinical trial” just means it was tested in humans. The results of the study showed that after the four weeks NK cells (natural-killer cells, specialized cells in your immune system) increased two-fold and inflammatory markers in the body were also reduced.²

A small mushroom popping out of an inoculation point. I didn’t cut the felled tree into logs because the powers that be (my boss) wanted it to look natural in the landscape. Instead, I used a lot of inoculation points to help the shiitake get an advantage over other hungry fungi in the tree.

Lentinan is a compound found only in Shiitake and it has been used in China and Japan to help treat cancer since the 1980s. A comprehensive review of 135 clinical trials that took place from 2004 to 2016 showed that, in conjunction with chemotherapy, Lentinan both improved patients’ quality of life and increased the efficacy of chemotherapy and radiation.³ We touched on just a few, but no matter how you’re consuming these mushrooms - dried, cooked, in broth, or via an extract - there seem to be myriad beneficial compounds and nutrients for your body to absorb.

Here are some from the fall fruiting out of an oak log I inoculated in 2021. Some were too dry to cook by the time I checked so we just used them as a broth for soups and cooking rice.

Ecology

You’re not going to run into shiitake in your local park. L. edodes is endemic to eastern Asia where it digests and fruits out of the dead wood of Shii trees (Castanopsis cuspidata) - this tree is also where the Shiitake gets its name. The Shii tree is an evergreen that is related to oaks and beech, and subsequently a lot of shiitake inoculation is done with oak logs. The mushrooms will typically grow in the spring and fall in the northeast - usually after rain when temps are between 50 to 70 degrees. Just like with plants, growers have developed strains of Shiitake that are cold weather specific, warm weather specific, or generalists.

The fungus is hardy and can digest a variety of different wood and organic material which allows the species to be widely and easily cultivated. It is apparently the second most cultivated mushroom in the world after Agaricus bisporus which is the white button mushroom/crimini/portabello (they’re all the same 😱). A fun fact sneaking into the ecology section :)

Many commercial growers cultivate Shiitake in bags on a mixed substrate containing grain and other non-wood organic matter. I ordered one to see what it was like and this was what it looked like earlier today.

Shiitakes have your typical toadstool shape with cap and stipe (stem). They pop out of a universal veil (the white, shaggy membrane seen above left which the little brown cap is erupting through) and also a partial veil which protects the gills until they mature. They have closely crowded white gills, which I failed to take a picture of, and white spores to boot. Even when cultivated outdoors the spores are not viable to grow on other dead wood, so while it is an exotic species not native to the continent, it is not considered invasive.

There’s a lot more to research here, this email is just a little white fleck - a remnant of the universal veil - on the cap of this magnificent mushroom (we’re going for a fungal “tip of the iceberg” analogy). Maybe I’ll dig a little deeper and present about it at the For the Love of Fungi Festival in the Catskills the weekend of 9/30-10/1, or at the recently announced second annual New York Mycological Society Fungus Festival on 10/15. Or maybe I’ll do a part two next week, I mean I didn’t even touch on the inoculation process. Who the heck knows?

I did, however, forget to alert everyone last week about the full moon this past Friday and that bothered me all week. I’ll work to see this doesn’t happen again,

Aubrey

PS. In my online research I came across this fun article from the myco-author and writer Doug Bierend about creating a local supply chain for shiitake logs. This involved the logs being inoculated in Kingston, NY and sailed down the Hudson River to Brooklyn.

General References (footnotes even further down):

1) https://www.uvm.edu/sites/default/files/media/ShiitakeGuide.pdf

2) https://www.inaturalist.org/taxa/123351-Lentinula-edodes

3) Dai X, Stanilka JM, Rowe CA, Esteves EA, Nieves C Jr, Spaiser SJ, Christman MC, Langkamp-Henken B, Percival SS. Consuming Lentinula edodes (Shiitake) Mushrooms Daily Improves Human Immunity: A Randomized Dietary Intervention in Healthy Young Adults. J Am Coll Nutr. 2015;34(6):478-87. doi: 10.1080/07315724.2014.950391. Epub 2015 Apr 11. PMID: 25866155.

4) https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/lentinula-edodes

1 - Bone, Eugenia. Mycophilia: Revelations From the Weird World of Mushrooms. Rodale Books, 2013. Page 133. 2 - Dai X, et al. (Reference 3 above) 3 - Rogers, Robert Dale. Medicinal Mushrooms: The Human Clinical Trials.Prairie Deva Press, 2020. Page 61.