The forest is blooming with fungus in Lake Chelan National Recreation Area. Mushrooms are easy to find on the forest floor, but the mere presence of a few mushrooms does not reflect the abundance of fungus working under the soil, nor their importance.

On most of my recent hikes I’ve stumbled upon small excavations in the soil. Typically, the depressions are a few inches across and deep. Even though I haven’t witnessed the excavation in progress, just the end result, I suspect these are made by rodents searching for fungus in the soil. On the Lake Shore Trail, south of Stehekin, I found clue to support my hypothesis.

The small depression next to the tip of my shoe contains a truffle.

Inside the hole was a truffle. Truffles are mychhorizal fungi. They do not photosynthesize, but these fungi are not parasites. They live in a symbiotic relationship with tree roots. Trees provide the fungi with sugar and the fungi provide trees with water and nutrients like phosphorus and nitrogen.

This is the truffle at the end of the excavation. Over 350 truffle species in 50 genera inhabit the Pacific Northwest.

Truffles are highly sought after by fungal connoisseurs, human and rodent alike. They are especially important to flying squirrels, but rodents like flying squirrels are equally important to truffles. Unlike your typical toadstool, these underground fungus have no spore dispersal mechanism. They need animals to dig them up to spread their spores.

Northern Flying Squirrel (Glaucomys sabrinus), USFWS photo.

Flying squirrels, in particular, love truffles. Under the cover of darkness, flying squirrels find truffles by their odor, unearth them, and greedily devour them. Truffle spores are then distributed randomly and effectively in squirrel scat. For reasons unknown, my truffle was not harvested. Small rodents that eat truffles are preferred prey of owls and weasels. Was the excavator of this truffle snatched up by a unseen predator?

I don’t know the end to this particular story, but this is evidence of more than a rodent and hole. It symbolizes how predators need rodents; how rodents need fungi for food and trees for shelter; how trees need fungi for nutrients; how fungi need trees for sugars and rodents for dispersal. The tiny hole I found is more than superficial. It leads to a world of interdependence.

——

For more info on flying squirrels and truffles, check out Squirrels Cannot Live by Truffles Alone and Ties that Bind: Pacific Northwest Truffles, Trees, and Animals in Symbiosis.