Truffles In the Forest

In the mid twentieth century young foresters were informed by their professors that there were mysterious growths in the forest, called mycorrhizal fungi, which grew in association with tree roots and had a fairly significant effect on the health and performance of the trees. Beyond that, not much was known. Since then, we have learned that there is a symbiotic, interdependent relationship between trees, mycological fungi, and forest rodents. Mycorrhizal fungi have been around for nearly half a billion years. Thus it is hardly surprising that most are now so specialized that they cannot survive unless they are in contact with their host plants. Many plants have also become equally dependent on mycorrhizal fungi and without them become stunted and yellow, often due to a lack of mineral elements such as nitrogen or phosphorus. Fungal fruiting bodies such as mushrooms, conks, and coral fungi distribute their spores by means of wind. But the fruiting bodies of truffle species are located underground and are not released into the air. So rodents and other small mammals perform the role of spore dispersal. In Europe, female pigs were traditionally used to find and harvest ripe truffles; in the wild it was the wild boars that found ripe truffles, ate them and dispersed their spores. In North America, flying squirrels glide down from the trees at night to forage on the ground for food. Ripe truffles, a primary part of their diet, are dug up and consumed. When the squirrels defecate elsewhere, they spread the spores of the truffles to new locations. In this way, trees gain packets of spores from beneficial fungi deposited near their roots. In addition, owls feed on flying squirrels. The owls then also deposit packets of squirrel and spore remains even further afield, benefiting trees elsewhere. To complete the cycle, the forest trees provide habitat for the owls and the squirrels. So, how do the animals find truffles? By smell - mature mushrooms emit a distinctive aroma, often pungent or fragrant. Various kinds of truffles have various smells: some of them are pleasant for humans, others are not (for example, the smell of rotten onions, freshly laid road asphalt). But obviously, the animals find the aromas attractive. So, truffles are not only a gastronomic product but also an important link in the network of interacting components of the forest.

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