Hair Ice

Form follows fungus

One of my pleasures of getting outside is the joy of discovery. Perhaps it’s a terra cotta beast I have overlooked dozens of times or a bird I had long noticed but not really seen or simply something special that was completely new to me. When this happens, I am often sent down a delicious path seeking out more information in newspapers and scientific papers, 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. All of this work adds up to a community more enjoyable, more livable, and more sustaining to my spirit.

The most recent time this happened was on a very cold morning, when my wife, a pal of ours, and I were walking at Tolt River-John MacDonald Park. The air was brisk, the ground frosty, and the decaying tree limbs erupting in beauty. In particular, we were attracted by a curious phenomena 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. Known as a white root fungi (please feel free to use this as the name of your next rock band), E. effusa is a saprophyte capable of decomposing the lignin that gives wood its strength, something very few organisms can accomplish. In his wonderful 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.’” It’s probably less dangerous than it sounds.

But back to what E. effusa did along the river. The fungus helped create the tufts of hair ice—each strand is .0008 inch wide (human hair ranges from 0.002 to 0.005 inches) and up to 8 inches long—via a process called ice segregation. During ice formation inside the wood, after the initial formation of ice nuclei, 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 no E. effusa is present, the ice turns crusty but if E. effusa is present, it provides decomposed lignin and tannin that act as a combination curler and hair spray shaping and setting the fine strands of ice growing out of the wood.

Part of what makes the science so wonderful to me is that the first person to propose the fungus/hair ice connection was one of my heroes Alfred Wegener in 1918. A meteorologist, explorer, and hot air balloon experimenter (he was the one time holder of the endurance record, staying aloft for 52 hours with his brother), Wegener is best known for his theory of continental drift, which proposed that Earth’s land masses had once formed a single great continent. Like his theory on hair ice, decades would pass before later scientists proved he was correct.

We in the Puget lowland are lucky because hair ice grows only within a limited band between 45º and 55º north latitude on the downed limbs of broad-leafed trees, including two of our resident species, alder (Alnus ruby) and bigleaf maple (Acer macrophylum).

Wandering the trails we kept stopping to marvel over the strands of shimmering evanescence. When we touched them, we found that the hair ice had a curious density of texture that I now wonder may have been the product of the decomposed lignin, as if their structural strength had been transferred from the wood to ice, as if all were part of one amazing, interwoven community. As we walked along, I felt that each limb covered in hair ice was a beautiful gift, our reward for stopping to notice something new, our reward for being part of this community, too.


Upcoming Virtual Talks (Click for link to all talks, including ones for Homewaters)
March 4 - 6PM - Secrets of Seattle’s Ship Canal & Locks - Seattle Architecture Fdn.
March 11 - 7PM - Secrets of Seattle’s Historic Botany - Seattle Audubon


Where did this tidal change occur? This was one of my favorite days of discovery working on Homewaters: A Human and Natural History of Puget Sound.