Mist is rising from the Water of Ae, turning gold as the dawn light slips across the valley through the forest of birch and pine. Fieldfares clatter down the path at our presence and a goldcrest calls sibilantly through the still air. Under the mist, a dipper stands up to its shins in the flow of clear water, bobbing with the ripples running over the rocks. I want to clamber down the bank and stick my finger in the river but by the bank I stop. A white branch catches my eye. I reach out a fingertip to feel that instead, and it crumbles to my touch like the powdery flakes of fresh snowfall.
Hair ice. Uncommon but a speciality here. It is one of nature’s finest magic tricks: the freezing temperature revealing invisible processes. It needs damp air and a fungus, Exidiopsis effusa, to form. The fungus expels moisture along the radial rays of the wood and when this moisture meets the freezing air, it turns to ice. The wood keeps expelling water that freezes into thin wispy filaments, strands of ice that are almost invisible individually, that form a thick fur together.
I hold one branch up to the sun: I see tiny water droplets suspended on the hair-like strings of ice. They burn white in the light, a cold blue in the shade. Best of all is how the name fits perfectly. The ice is coiffed. It has a parting. Either side of the branch its strands head off in different directions, neither crossing the parting but both curling around, ending up facing the same direction, almost as if it has been styled by the night’s air.
Perhaps the greatest trick of all is in its disappearance. When we return down the path an hour later, the golden morning sunlight has crept across the river, warming our side of the bank. The ice has vanished, leaving only wood, damp from the thaw, clear of bark and moss. And I realise then something I’ve wanted to know all year. The clarity of ice is this: that nothing lasts for ever. The real trick is how to make the most of it.