One of my joys of discovery is heading down an absorbing path of seeking out more information in newspapers and scientific journals, reaching out to friends and colleagues, or delving into the books waiting to be probed on my bookshelf. No matter where these paths lead me, I feel I am rewarded by the knowledge I gain and the connections I make.
I have had this happen many times in my writing life, including this encounter on a very cold winter day. My wife and I were walking with a pal of ours at Tolt River-John MacDonald Park (about 20 miles east of Seattle). The air was brisk, the ground frosty, and the decaying tree limbs erupting in beauty. In particular, we were attracted by a curious phenomenon none of us had ever seen. Sprouting out of the downed wood were what looked like tufts of fine hair, brilliantly white and curled like Albert Einstein’s mane but better kempt.
Known appropriately as hair ice, this fragile and ephemeral feature owes its origin to the winter-active fungus Exidiopsis effusa. It is a white root fungus (please feel free to use this as the name of your next rock band) capable of decomposing the lignin—a complex organic polymer—that gives wood its strength, something very few organisms can accomplish. In his thoughtful book Entangled Life, Merlin Sheldrake writes that the decomposition is accomplished by “highly reactive molecules, known as ‘free radicals,’ which crack open lignin . . . [via] ‘enzymatic combustion.’” I suspect it’s probably less dangerous than it sounds.
But back to what E. effusa does in the Pacific Northwest. The fungus helps create the tufts of hair ice via a process called ice segregation. After the initial formation of ice nuclei in the limb, new ice extracts additional water from the wood, which leads to more ice growth that eventually extrudes out through holes in the limb’s surface. If E. effusa isn’t present, the ice turns crusty, but if E. effusa is present, it provides decomposed lignin and tannin, which act as a combination curler and hair spray, shaping and setting the fine strands of ice growing out of the wood. They are so fine that they are between 2.5 and 6.5 times narrower than a human hair. Some strands can grow up to 8 inches long, or about the size of an average banana. Sadly, I have yet to encounter such cascading locks of hair ice; all of the hair ice I have seen has been less than two inches long.
Part of what makes the science so splendid to me is that the first person to propose (in 1918) the fungus and hair ice connection was one of my heroes, Alfred Wegener. A meteorologist, explorer, and hot-air balloon experimenter, Wegener is best known for his theory of continental drift. Like his theory on hair ice, decades would pass before scientists proved he was correct about how the Earth’s land masses once formed a single great continent.
On-going research has found that hair ice growth requires rotten hardwoods, including two of our resident species, red alder and bigleaf maple, and high humidity, such as after snow melt or heavy rain. The temperature should be just below freezing in windless conditions. Curiously, climate change may lead to more hair ice in temperate latitudes, such as the PNW, because there will be more snow free periods, and if the temperature subsequently does drop below freezing, hair ice can form.
If you touch the gossamer strands, you will find that the hair ice has a curious density of texture that is most likely the product of the decomposed lignin, as if its structural strength had been transferred from the wood to ice, as if all were part of one amazing, interwoven community. Despite this tenacity, hair ice will melt quickly if held too long and tends to last for only a few hours to days. Fortunately, hair ice can regrow year after year on the same branch, as long as E. effusa is present, so it’s a gift that keeps on giving.
I have been fortunate to encounter hair ice many times over the past few years. I usually stop to marvel over the shimmering evanescence and to rejoice in the amazing surprises of the natural world. As usual, I am glad I followed that path of research to understand this beautiful winter feature.
On one of the recent times I saw hair ice in the past week, I was also excited to locate a woodpecker in a tree, which may not sound cool or unusual but it was. I was hiking with pals on the Poo Poo Point trail at Tiger Mountain when we saw abundant, fresh looking wood bits and chips around a snag. I suspected that the wood was from the poundings of a Pileated Woodpecker but we couldn’t locate a hole so continued on our way. When we walked back by an hour or two later, however, the light had changed and I noticed a couple inch hole about 30 feet up the snag. As I gawked I heard a sound from within the dead tree. Clearly someone was pecking away. Being the busybody I am, I lightly tapped the base of the tree with my hiking pole, the sound stopped, and a Hairy Woodpecker flew out of the hole.
I didn’t mean to disturb the bird and felt bad that I had driven away the industrious homemaker. A birding friend, however, told me later that “woodpeckers are quite hearty” (perhaps she meant hardy but she is a writer so who knows) and that I was sort of a meanie but the bird would return soon to continue feeding or broadening out the cavity for winter roosting. I sincerely hope so.
This is a repeat of one of my first newsletters, from February 2001. I decided to repost it (though slightly modified), primarily because I have encountered hair ice several times during this recent cold spell. I suspect I will continue to see it throughout winter and hope you do, too. Here’s a link to more information about hair ice formation.
I recently heard this quote and found it thoughtful. “When we repeat the same words and phrases that appear in the daily media, we accept the absence of a larger framework. To have such a framework requires more concepts, and having more concepts requires reading. So get the screens out of your room and surround yourself with books.”
Timothy Snyder in his book On Tyranny
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