Annual or Perennial

Annual and perennial identify whether the fruiting of a decay fungus produces spores for a single growing season or part of a growing season (annual), or whether the fungus continues to produce a new pore layer and spores from the same fruiting structure over several or more years (perennial). The terms do not refer to the progression of decay of wood in the tree which continues whether the fungus is producing a fruiting structure or not on the tree.

Annual

Annual wood decay fungi develop fruiting bodies that only produce spores for one growing season or a small portion of a growing season. These fungi generally either produce mushrooms (Photographs 1 and 2), or conks that are tough and leathery (Photographs 3 ) but not woody. The mushrooms may have gills, pores or a smooth spore producing layer, while the tough and leathery fungi usually have a poroid spore producing layer (see hymenium for these descriptions).

Some annual fungi may linger on infected trees from fruiting earlier in the season or the fruiting can be found the growing season the year after they initially produced spores (Photograph 3 and 4) . In some cases they may be found still attached to the tree, or at the base of the tree after they have fallen off. Annual fruiting fungi may only fruit in certain years and therefore may or may not fruit in consecutive years on the same tree.

A small number of the wood decay fungi with annual fruiting structures produce black, crusty, fungal material on the bark or decayed wood of infected trees (Photo 5). These fungi may also produce a secondary spore stage on their surface early in the season that covers the surface with a white or gray colored spore layer (Photograph 6).

Indications the mushroom or conk is an annual fruiting structure are:

  • Mushroom, or soft and fleshy fruiting, on wood or attached to roots on the soil next to or near the tree
  • Dried mushrooms that have discolored brown, black or are discolored and moldy
  • Presence of similar sized and off-color conks adjacent to fresh fruiting during the growing season
  • Absence of more than a single pore layer when the conk is cut in half
Photograph 1. Mushroom of an annual wood decay fungus on a beech .
Photograph 1. Mushroom of an annual wood decay fungus on a beech.
Photograph 2. Group of mushrooms of a root decay fungus on a maple.
Photograph 2. Group of mushrooms of a root decay fungus on a maple.
Photograph 3. Tough or leathery conks of an annual fungus showing fresh fruiting and older conks from the previous year in the background.
Photograph 3. Tough or leathery conks of an annual fungus showing fresh fruiting and older conks from the previous year in the background. Photographs were taken in September, and older conks are from the last year.
Photograph 4. Fruiting of an annual fungus showing the dried and drying mushrooms from two flushes of fruiting.
Photograph 4. Fruiting of an annual fungus showing the dried and drying mushrooms from two flushes of fruiting.
Photograph 5. Black, crusty fruiting of an annual fruiting fungus that does not produce a conspicuous conk or mushroom. Some of the fungi with black crusty fruiting produce round or finger like fruiting structures.
Photograph 5. Black, crusty fruiting of an annual fruiting fungus that does not produce a conspicuous conk or mushroom. Some of the fungi with black crusty fruiting produce round or finger like fruiting structures.
Photograph 6. White and gray fungal growth on the surface of an annual decay fungus. The growth is covering the black crusty fungal fruiting beneath it.
Photograph 6. White and gray fungal growth on the surface of an annual decay fungus. The growth is covering the black crusty fungal fruiting beneath it.

Perennial

Wood decay fungi with perennial fruiting bodies produce spores in more than one season from the same conk. The conks of these fungi are woody and are usually difficult to remove from the wood they are attached to. Virtually all are attached to the trunk of the main trunk of the tree or larger diameter scaffold branches. On rarer occasion they may be found attached to large diameter buttress roots. They seldom if ever are found fruiting from buried roots next to or at distances away from the base of the tree.

Indications the conk is a perennial fruiting structure are:

  • Woody, hoof-shaped or flattened conks attached to the trunk or large scaffold branches (Photographs 7 and 8).
  • Difficult to remove from the tree without a mallet or considerable effort
  • Typically thick (2-5+ inches) and increasing in thickness and size with age as evidenced by
  • Evidence of multiple pore layers when the conk is broken in half (Photograph 9).
Photograph 7. Hoof-shaped conk of a perennial wood decay fungus. These conks are difficult to remove by hand without substantial downward force being applied.
Photograph 7. Hoof-shaped conk of a perennial wood decay fungus. These conks are difficult to remove by hand without substantial downward force being applied.
Photograph 8. Flattened or applanate conk of a perennial wood decay fungus. Note the ridges or rings on the conk indicating each year’s growth of a new pore layer.
Photograph 8. Flattened or applanate conk of a perennial wood decay fungus. Note the ridges or rings on the conk indicating each year’s growth of a new pore layer.
Photograph 9. Splitting a perennial conk to show the previous year’s pore layers that have been covered over by growth of a new pore layer. This conk is several years old. Red arrow points to current year’s pore layer and the green and yellow arrows previous year’s pore layers that are now filled with fungal growth.
Photograph 9. Splitting a perennial conk to show the previous year’s pore layers that have been covered over by growth of a new pore layer. This conk is several years old. Red arrow points to current year’s pore layer and the green and yellow arrows previous year’s pore layers that are now filled with fungal growth.