Tree beards

Usnea lichen

Not far from the tree with the beetle engravings I discovered one with a tiny poof of lichen. Just the one, on a small tree that could even have been a long-dead sapling; there were no others near it, or even in the immediate area, that I could spot. I found this curious. At first I thought it was perhaps a reindeer lichen that had been picked up and dropped there by some animal, but when I picked it up it seemed to have grown around the twig, with a distinct groove down the centre. I ran off several shots, but lichens are a tough bunch to decipher, and I didn’t really know for sure what I was looking at.

Usnea lichen

I carried on up the trail, and a short distance later came upon some thick fruit-bearing trees, perhaps crabapples. I’d walked by these trees dozens of times before, and never noticed anything remarkable. But for whatever reason, that day something caught my eye: fuzzy patches of green lichen growing from their trunks. Whereas there’d just been the one on that first little tree, here there were dozens. None of them were very big, even the largest was not much larger than a tennis ball. Most were only half that size. They were very delicate and fine, almost hairlike. I had more of a suspicion as to the identity of these, but it would require returning home to ask the internet (my god is named Google; Google will provide).

Usnea lichen

I am fairly certain that these are Usnea sp., also known as Old Man’s Beard (which may refer to one of many species of Usnea lichen), or at the very least the latter bunch on the crabapples are. I’m not completely sure about the first one, I would probably need to go back to check out additional characteristics. Usnea lichens typically grow from the branches or trunks of trees, and are always fruticose – that is, highly branching. Some species grow more thickly than others, and some have broad flat bits that remind me a bit of opened venus fly trap jaws. There are a number of species that grow in Ontario, but I think this one might be Usnea subfloridana, a particularly filamentous species but one that doesn’t typically grow very large or long. Some species can grow very long, a foot or more, and completely cloak the branches of a tree.

Usnea lichen

All lichens are susceptible to air pollution, but Usnea lichens are especially so. They’re one of the first types of lichen to disappear with air pollution. Even when they persist, they may not grow more than a few millimeters. Their presence here is likely an indication of reasonably clear air quality.

When I think of Usnea, I typically think of Northern Parula warblers. Parulas are almost entirely dependent on long, draping species of Usnea for their nests. They don’t just use the lichen in the nest, the lichen is the nest. They’ll find a nice thick clump of the stuff and hollow out the inside. They don’t even always line it. Because the sort of Usnea the parula prefers mostly occurs in the coniferous forests of the Canadian Sheild, the bird is rare in southern Ontario. We’re right at the edge of the Shield here, but I don’t think these little puffs are going to cut it.

Usnea lichen

Most Usnea lichens, along with a few others such as reindeer lichen, contain usnic acid, a bitter-tasting molecule believed to be used to deter animals that might browse on the lichen (apparently it doesn’t deter the reindeer). It also happens to be a very potent antibiotic and antifungal agent, and is high in vitamin C. These latter properties resulted in it being a common medicinal agent used by Native Americans to treat infections – both internally, as a tea, and externally, as a compress on wounds. The fine, branching nature of the lichen also made it a good substitute for gauze. In modern day herbal medicine it is often used in teas or other products intended to treat respiratory and urinary tract infections.

All good things to know if I find myself lost and sick in the northern woods…

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13 responses to “Tree beards

  1. This is one big difference I’ve noticed between New Brunswick and Ontario, the abundance of Beard Lichen here. Googling “northern parula distribution”, I turned up a BBS map showing a much higher number of Northern Parula sightings here in the Maritimes.

    Unfortunately, an accompanying paragraph stated: “In Nova Scotia… prefers 40-year-old stands of trees…density positively correlated with tree density, basal area, canopy cover, and canopy height…” To me, that means that there may be more Northern Parula in my new home, but my chances of seeing one aren’t much better . ;)

    Reference: http://www.uwgb.edu/birds/greatlakes/species/nopa.htm

    • It does seem that beard lichen is much more abundant along both coasts, Lavenderbay, I guess due to the higher humidity from being next to the ocean. Probably the greatest trouble you’ll have with parulas is just spotting them as they flit about in the dense tree canopy! True of any warbler, really. They’ve got a pretty distinctive song, though – if you memorize that and then go out hiking in May and June, you should at least be able to hear them.

  2. My adventures with lichen are mostly from Nantucket Island, off Cape Cod. The island is richly loaded with the stuff; some trees in winter looking like they could be tropical. A similarity with the Maritimes: the rich humidity of the ocean, along with its warming influence, probably has a lot to do with the lichen richness.

    • I expect you’re right, Matthew. I’ve only been to the east coast a couple of times, both short visits, one when I was quite young. I’ve spent a lot of time on the west coast, though, and it’s amazing how much the coastal humidity really affects lichen growth.

  3. Thank you so much! I see a lot of lichen here, but never knew their names.

    • Same here, Suziam. It’s a bit of an overwhelming group. The stuff is everywhere but it’s often so similar to others, and there’s no really good guide, so it’s hard to learn.

  4. This is a great post, as always! I hardly saw any Treebeards in London, but I’m going to try harder! I was wondering if you could shed some light on the mysterious “leaf litter” gathered on some trees – on tallest as well as small trees, is it made by insects? I never tried to destroy one thinking it’s made by some wasps for protection! Or is it just a bunch of dead leaves?

    • Good luck, Ani! I don’t know if they’ll be as prevalent down there, but it may just be a matter of looking closely. I think most of them will be associated with coniferous trees.

      I’m not quite sure what you’re referring to when you say “leaf litter” – do you mean something like the image below? If so, these are probably squirrel nests, they collect leaves and twigs into a ball and hollow out the centre to sleep/nest in.

  5. I love this title..
    Your blog posts are always full of knowledge…great photos..
    Thanks!

  6. Eileen Blanchard

    Enjoyed reading your post…i was cross country skiing in the park yesterday and saw many Tree Beards…it was interesting to note…having worked many years in nunavut where there are no trees it was refreshing to learn more about them…I love your interesting and informative posts….Thanks

  7. I would like to know how to get rid of it. It is killing my tree. It is covering it top to bottom. It has killed other trees in the neighborhood. I would hate for the tree to die. Help, Karen

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