Fungi are one of the world’s least explored biological phenomena, yet they are a very ancient group of living organisms. They are neither a plant, nor an animal. At current, only about 40,000 – 100,000 species have been described, with estimates that there could be upwards of 5.1 million total species (Blackwell, 2011). Fungi are important to our own well-being; without Fungi, our planet would look vastly different.

The Importance of Tree Fungus

Fungi are of critical importance because they are saprobic organisms—meaning that they decay organic matter. They do this through a process known as endocytosis, whereby they undergo extracellular digestion through the secretion of enzymes which aid in the breakdown of organic matter in the environment. The degredation of this organic matter is then followed by absorption of those solubilized, broken-down products. Endocytosis occurs primarily at the apical tip (i.e., the end) of the hyphae that extend out well beyond the body of the fungus. By extending their hyphae throughout the environment, Fungi can explore and capitalize on extremely dilute nutrient concentrations (which is commonly the case in nutrient-poor soils).

Types of Tree Fungi

The wide array (and various reproductive structures) of Fungi never cease to amaze me (see photo)! They are ubiquitous in our everyday life. Fungi are a taxonomic kingdom (i.e., Eumycota) with wide-spread, global distributions. Fungi (and their spores) can be found most everywhere—in the soil, on trees, on fallen wood debris, in the air, on an old fence post in the yard, and even in our foods. Their wide-spread distribution is largely due to the organism’s ability to produce (literally) billions of spores per fruiting body. The spores produced, can be the result of either sexual or asexual reproduction, and these spores have many mechanisms that allow them to lie dormant for many years until the time to germinate is just right. These spores are then carried to new locations via wind, water, insects, and even us.

Fungi Damage and Treatment

Fungi on trees can certainly be a cause for concern. Fungal fruiting bodies often appear at the site of an injury (or wound) that exposes the internal wood of the tree. Therefore, proper pruning techniques become extremely important for the well-being of a tree and its long-term survival. Making proper arborist cuts allows the tree to compartmentalize (i.e., close) the wound quicker, and this, in turn, reduces the chance of later infection by a fungus. But, this is also true for trunk wounds, which can lead to structural defects along the main trunk. Protecting the main stem of your tree from such injuries will greatly prolong the life of any tree. Should you see a fungus appear on your tree, it is best to have the tree inspected by a Certified Arborist. The arrival of a fungus on your tree should be taken seriously, especially if the tree is large, in a high-traffic area, or near valuable structures.


Blackwell, M., 2011. The Fungi: 1, 2, 3… 5.1 million species?. American journal of botany, 98(3), pp.426-438.