What mushrooms do in the winter

Last February saw a period of deep snowfall across Trust properties in the north east and beyond. Snow fell and blanketed Deeside, muffling the sounds of cars. The crossbills jip-jipped high in the Scots pines. For days there was no wind. The temperature plummeted to a record -23 degrees in Braemar. Then in a few weeks the weather changed: a tropical maritime flow from the Canaries. The snow didn’t melt but just sagged, and at one spot near Crathes Castle I saw a group of what looked like orange peels in the snow. I was curious to inspect them.

Autumn is the time we expect fungi. We can smell them coming. Autumn has its own aroma, of decomposition and dampening, cooling, photosynthesis grinding to a halt. Some find it a melancholy smell. If you are a mycophile, a lover of mushrooms, it smells like the beginning of mystery.

In a year at Trust properties in the north east I can see a fantastic array of mushrooms. It starts in springtime. Quite often, crowded on stumps, you will see glistening inkcaps. Their caps are micaceous, truly sparkling in the low light of April. There is a plantation woodland at Crathes, near the main drive, in which I once saw the cauliflower fungus in midsummer, Sparassis crispa, a huge, bleached and convoluted coral-like fungus. I still return to see if I can find it again. I imagine it re-appearing, like a ghost.

Read more by Roddy: The strange case of the Powdercap Strangler

Conditions being right, autumn is a cornucopia. The aroma of decomposition is partly fungi beginning to break down the plant material. Beneath the soil the mycelium – those threads that are one-fifth the width of a human hair – are growing, spreading, consuming plant matter, tendrils with the uncanny ability to coordinate themselves around objects. Fungi are in the ascendency. Before long, their fruiting bodies are thrust up, those caps and tongues visible indicators of the greater body below. They drop their spores to the wind and, job done, recede again.

As the months roll forward, the mycelium weakens. For every 10 degree drop in temperature, its ability to effect the chemical processes it needs is halved. In the record-breaking freeze it should be all but dead.

I trudge through the snow to the orange peels I have seen, and of course find they are not orange peels. They are, on a field of pure white, the caps of velvet shank. Completely frozen, though somehow appearing to relish that. So why, then, do some fungi buck the trend? In colder temperatures they should be inert, dormant.

There are quite a few who seem to have specialised in surviving winter. Maybe this shouldn’t be a surprise. After all, fungi are known to do well in the polar regions.

And for some, the name is a clue. Take winter chanterelle (as some do for the cooking pot), duller than its more usually picked autumn cousin. The herald of winter is rightly named and sometimes seen at Drum. At Haddo, the snowy and meadow waxcaps can easily persist into winter. Last year though, when that snow had all but melted, it seemed like the fungi left the best for last.

Like tufts of Santa’s beard, fine white blooms appeared on branches on the forest floor. Visitors were drawn to them in curiosity. You could see them ask themselves, ‘Why is this frozen so weirdly here and nowhere else?’.

The answer is fungi. A particular one called hair ice, Exidiopsis effusa. It prefers to grow in old woodland, in times of high humidity with the air just below freezing.

The mechanics of this fungi’s trick are poorly known, but by the magic of chemistry it ‘cultures’ ice, to keep it growing, in long hair-like strands, until the ice looks like a fine-combed silken beard, cascading from the branch. So, in winter, far from doing nothing, mushrooms do some very weird things!