Visually comparing photos of a tree fungus with photos of common fungi is a good way to identify the fungus. Other tips include noting the fungus color, shape and size; weighting it against common fungi; identifying the effects of the fungus to research those against the effects of other fungi and researching the fungi that are commonly found in the same region as the tree.
Identifying the type of tree affected is a good way to narrow down some possible fungi, since some fungi more commonly affect certain trees. The canker rot fungus, for example, is known for attacking hardwood trees, while the fungus Nectria coccinea var. faginata attacks the American beech tree. Where the fungus is affecting the tree is also important. Some fungi, such as the Cronartium comandrae Pk., affect the inner bark of a tree rather than the exterior.
Once the type of fungus is identified, it is easier to treat the tree. Some trees will only need a spray treatment of an anti-fungal mixture, such as hydrated lime mixed with copper sulphate, while others may require limb removal. Limbs that are removed should not be used on the property or composted to avoid the spread of the fungus.