What are Mycorrhizae. The term mycorrhiza (plural mycorrhizae) is rather like the term “marriage”. It describes an association, a relationship. If both parties to the relationship are compatible, and conditions suitable, they will both benefit. Otherwise, the relationship is of no benefit to either and it ceases. One party to this relationship is your tree; the other is a microscopic beneficial fungus. The fungus forms a sheath-like structure at the root tips through which it passes to the tree various nutrients it has gathered from the soil in exchange for food the tree has produced through photosynthesis (remember, fungi are not able to produce their own food in this way).…