Mushrooms are not only fascinating to look at; they are the main recyclers in nature. They break down wood and humus into their original components and provide food for living plants by returning dead trees and forest litter to simple organic materials in a form suitable for plants to use.

Some mushrooms have a symbiotic relationship with other plants. This beneficial association may be expressed by a tree giving up some of its glucose to the fungus while the fungus gives some of its minerals to the tree. This is why some mushrooms are always associated with certain trees. One group of symbiotic mushrooms grows underground and can only be found by digging for them, but to even find them requires specially trained dogs or pigs. An example of these would be truffles, which are very expensive and sought after by chefs the world over.