This entry is in response to a conversation that I had about the life history and habits of “Chicken of the Woods” or Laetiporus conifericola. When I was first introduced to this polypore, it was called Polyporus sulfurous, then Laetiporus sulfurous, now L. conifericola. What next? The species conifericola is defined as occurring in western North America on conifers. L. huronensis is similar to L. conifericola in utilizing conifers as hosts, but occurs in the east and has slightly smaller spores. Genetic and mating compatibility studies support its’ separation from L. huronensis and other species. The application of L. sulfurous to our local fungi was not appropriate as L. sulfurous is now a more narrowly defined species that occurs in the east forests on hardwoods. Mea culpa for all of the taxonomically incorrect lists that I’ve generated.
I did enjoy this Latin description from the publication with the original formal description of L. conifericola: Habitat ad substrato arbores coniferas, in parte Americae Borealis occidenti extrema
Tom Volk has a thorough history of the changes in nomenclature associated with this taxon. http://botit.botany.wisc.edu/toms_fungi/jul2001.html
Back to the prompting conversation, it wasn’t the usual one that I have with people about where to find this fungus and how to cook it, but concerned its’ classification as a parasite or a decomposer. The idea expressed was that it couldn’t be both. I couldn’t really think of a good reason why not, since the enzymes responsible for degrading the cellulose & hemi-cellulose would provide food for the fungus and result in wood decomposition. I believe that the question really concerned whether or not the tree has to be dead for the fungus to infect it I didn’t think so; since I was fairly certain that I’ve seen fruiting bodies on live trees.
A little research answered the question; spores invade the living tree through wounds, (caused by tree fall, animals, etc). The fungus infects the sap wood then moves into the heartwood of living trees. Apparently the fungus leaves the active xylem and phloem intact, so the tree is capable of living until decomposition reduces the structural integrity of the heartwood. Wind is usually the ultimate cause of tree death, bole snap probably being more common than tipping in infected trees. L. conifericola is also capable of decomposing the wood of the dead tree and continues to grow vegetatively for an undetermined amount of time before fruiting. Since the fungus infected a living tree, I’d call it a parasite. A legitimate point could be that although the tree itself is alive, the heartwood isn’t. This seems like quibbling, so I’ll stick with calling the fungus a parasite.
Laetiporus causes a brown rot (ie; only decomposes the cellulose which leaves the brown colored lignin behind. Cellulose forms the primary cell wall, so after this carbohydrate is decomposed what is left is the secondary material (lignin) without the subtending structure. That is the wood falls apart in characteristic cubical shapes with thin sheets of white mycelium between the brown remains of the wood.
I haven’t found any information yet on how long it takes from infection to fruiting, but I suspect a rather long time. One bit of research on decay after wounding suggests that it takes a rather long time, but didn’t discuss fruiting directly.
I found a list of tree decay fungi occurring in southeastern Alaska by P. Hennon.
On Spruce:
White rot fungi include: Phellinus pini, Heterobasidium annosum, Armillaria, Meruliius sp. Phellinus nigrotimitatus.
Brown rot fungi include: Fomitopsis pinicola, Phaeolus schweinitzii, L. conifericola, Antrodia heteromorpha, Lentinus kauffmanii.
On Hemlock:
White rot: Armillaria sp. Heterobasidium annosum, Pholiota adiposa, Phellinus hartigii, Phellinus pini, and Ganoderma applanatum.
Brown rot fungi are Fomitopsis pinicola, L. conifericola, Phaeolus schweinitzii, and Hericium.
Since most of the polypores that I find in the woods are cellulose decomposers (P. Hennon concurred with this observation) this prompts another question, does anything make use of the lignin? So far, I’ve confirmed that lignin is an extremely stable chemical and makes up roughly 30% of the forest soils and that some Actinomycetes can apparently break lignin down as can some fungi (white rotting types). Is the majority of the lignin from these decomposed trees another carbon sink? It might be interesting to test the ability of local soil bacteria and fungi to utilize lignin as a carbon source. They certainly don’t like corn meal agar. There is probably a way to incorporate ground up decayed tree in growth media.
P. Hennon raised some interesting ideas about the importance of Heart rot fungi in our forests. If most of the bole snap in trees is caused by structural weakness due to fungal infection, then these fungi are quite important in maintenance of a structurally diverse forest. I’ll have to start counting tipped trees vs. bole snap (with decay) trees on my wanders.
Are Heart Rot Fungi Major Factors of Disturbance in Gap-Dynamic Forests?
http://www.vetmed.wsu.edu/org_NWS/NWSci%20journal%20articles/1995%20files/Issue%204/v69%20p284%20Hennon.PDF
By the way, Chicken of the woods is good sauted and added to pasta sauce or omlettes.
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