Urban Commonality Rating

This rating reflects the likelihood of encountering any individual species on an urban tree. Several species can be found in most areas of the country and are extremely common on urban trees. Other species may be more common in some geographic areas are relatively rare in others, reflecting host distribution and/or climatic ranges. Some species seem to be relatively rare in urban environments but are relatively common in forest habitats.

Very Common

Very common species that those that are encountered almost every year and typically have a wide host range and can be found on hosts that are common in urban environments (for example Norway maple and honeylocust) (Photograph 1). They are mostly annual species but also include a couple of perennial species that are likely to be found fruiting when the host is encountered.

Photograph 1. Ganoderma lucidum is very common on urban trees because of its wide host range and common development on Norway maple, honeylocust and other common urban tree species.
Photograph 1. Ganoderma lucidum is very common on urban trees because of its wide host range and common development on Norway maple, honeylocust and other common urban tree species.

Common

These are the annual fungi that are often found on urban trees but may have more restricted host ranges or fruit less commonly on an annual basis. Several perennial species fall into this category because of their perennial nature, relatively wide host range, and frequent appearance on urban tree species.

Photograph 2. Common species are mostly annual wood decay fungi that have more restricted host ranges such as Grifola frondosa shown here that prefers oaks.
Photograph 2. Common species are mostly annual wood decay fungi that have more restricted host ranges such as Grifola frondosa shown here that prefers oaks.

Uncommon

This category is for species that are less common on urban trees because of host restrictions or an apparent preference for forested habitats. Some are relatively common in woodlands are seldom found on urban trees.

Photograph 3. Some wood decay species are common in forested habitats but are uncommon on urban species such as Oxyporus populinus shown here on sugar maple, or are less common on urban trees because of host range preferences.
Photograph 3. Some wood decay species are common in forested habitats but are uncommon on urban species such as Oxyporus populinus shown here on sugar maple, or are less common on urban trees because of host range preferences.

Rare

Some wood decay species are rare on urban trees and are relatively rare even in forested habitats. It would be unusual to find the species in this category on an urban tree.

Photograph 4. Some wood decay fungi are rare on urban trees and also relatively rare in forest habitats. Fistulina hepatica is easy to identify given the appearance of its fruiting structure, but is rarely found on urban trees.
Photograph 4. Some wood decay fungi are rare on urban trees and also relatively rare in forest habitats. Fistulina hepatica is easy to identify given the appearance of its fruiting structure, but is rarely found on urban trees.