One of the most challenging aspects of studying the natural history of bracket fungi is to define exactly what one includes in this grouping. Bracket fungi is a commonly known classification, but since it is based upon the fungi’s pattern of growth as opposed to genetics and evolutionary history, there is a lot of gray area as to what is and is not considered bracket fungi. Generally, bracket fungi are identified as fungi that form fruiting bodies on living or dead trees in horizontal rows that look like shelves or brackets; these fruiting bodies are known as conks. They can be found in small, separate fruiting bodies as well as massive aggregates with many rows of conks. They tend to be woody, leathery, or fleshy in texture (Fogel & Rogers 2006). Because this blog post is meant to share information on the subject of our group’s natural history project, bracket fungi, we find it imperative to define what exactly we include in our scope of research. Our natural history project is centered on the effect of the decay class of trees and wood on the species diversity of fungi. Thus, our research on bracket fungi will focus on all species of wood decomposing fungi found in the Morgan Arboretum in St. Anne de Bellevue, Quebec.
Polypores are a more scientific grouping closely related to bracket fungi. The two classifications contain much of the same species, though some bracket fungi are not polypores, and vice versa. Polyporous fungi are defined by the multitude of pores that mark them, differentiating them from most other fungi that contain gills instead. These pores contain the spore-producing cells of the fungus, known as basidia. Interestingly, these pores are all perfectly vertical, as the spores must be able to fall out of the pores without sticking to the sides. Another distinguishing factor of polypores and bracket fungi is the lack of a stem; only a few polypores have a short stem. Otherwise, they grow directly from the wood on which they live (Fogel & Rogers 2006).
Many people may not be aware of the importance of fungal growth in forests, but they are actually of high ecological significance. Polypores and other wood-decaying fungi are vital for forest ecosystems to function properly (Lonsdale et al. 2008). Many species of bracket fungi provide microhabitats for a number of organisms. In a study by Thunes et al (2000), it was discovered that a species of bracket fungus called Fomitopsis pinicola provides habitats to over 60 species of beetles living in a Norwegian spruce forest. The fruiting body of bracket fungus F. pinicola and other polypore species represent a unique niche within forest ecosystems. They not only provide habitats but are also food sources for a large variety of insects. Of the 778 beetle species in the proposed Norwegian Red List, around 100 of them are associated with bracket fungi.
Not only do bracket fungi provide microhabitats, they also help in the regeneration of forests. They have active roles in wood decomposition, which in turn contribute to nutrient recycling, soil formation and the carbon budget of forest ecosystems (Lonsdale et al. 2008). Recent studies have investigated the relationships between dead wood, insect populations and polypores. One of these studies discusses the importance of the conservation of dead wood. They have found that there are higher numbers of fungal species where there are higher quantities of dead wood; however, dead wood levels in a forest can be very unpredictable and could become dangerously low. Some species of polypores are being classified as threatened or near threatened in Finland, and they suspect that the main cause is the reduction of suitable habitats (Rajala et al. 2010). Their habitats have been largely reduced due to human activities such as deforestation and logging (Hattori et al. 2012). With more trees removed by human activities, there have been less dead logs on the ground and less available habitat for polypore species.
These threats to species diversity of bracket fungi are a huge concern today. The importance of these fungi is undeniable and multifaceted. In addition to polypores’ importance to ecosystems, they are also used as food or medicine in some parts of the world. For example, Lignosus rhinocerotis is popularly used to treat coughs and asthma (Hattori et al. 2012). The following is a description of two prominent polypore species found in the Morgan Arboretum adapted from Michael Kuo’s website and the field guides by Raymond McNeil (2006) and George Barron (1999):
The Red-banded Polypore (Fomitopsis pinicola) is a large and conspicuous perennial species distributed across the Northern Hemisphere in coniferous forests. The fruiting bodies of this fungus are thick and woody and have a distinctive red to grayish cap with a lacquered appearance. There is a yellow to red band at the leading edge of the cap, which gives the species its common name, ending in a white margin. The lower surface is white to light brown and covered in tiny round pores that produce spores, typical of species in the order Polyporales. The Red-banded Polypore is a saprophytic fungus, meaning that it feeds on dead woody material. It grows mainly on dead conifers and occasionally dead deciduous trees, but may also become parasitic on living trees.
The Turkey Tail (Trametes versicolor) is one of the more colourful species found in North American woods. The fruiting bodies of this fungus are heavily banded with thin concentric stripes of varying colours, including tones of brown, red, tan, blue, white, yellow, green, grey, ending in a white margin. These bands of colours resemble the tails of turkeys, hence its common name. The cap is also variably covered in fuzzy, velvet-like hairs. Like the Red-banded Polypore, Turkey Tails also produce spores in tiny pores which are white to yellow in colour. It is a small species ranging in size from 1-8cm, and its flesh is thin but tough. The Turkey Tail is saprophytic, and grows in dense clusters on deciduous trees, infrequently on conifers.
Recommended guidebooks for the fungi o the St-Lawrence Lowlands:
Barron, G. L. (1999) Mushrooms of Ontario and eastern Canada. Lone Pine Pub. Edmonton.
McNeil, R. (2006) Le grand livre des champignons du Québec et de l’est du Canada. Éditions M. Quintin, Waterloo, Québec.
McNeil, R. (2007) Champignons communs du Québec et de l’est du Canada. Éditions Michel Quintin, Waterloo, Québec.
Fogel, R. & Rogers, P. “Shelf fungi.” Fun Facts About Fungi. Utah State University Intermountain Herbarium. 14Nov. 2006. Web. 19 Oct. 2012. http://herbarium.usu.edu/fungi/funfacts/shelffungi.htm
Hattori, T; Yamashita, S; Lee, S. (2012) Diversity and conservation of wood-inhabiting polypores and other aphyllophoraceous fungi in Malaysia. Biodiversity and Conservation. 21, 2375-2396. DOI: 10.1007/s10531-012-0238-x
Lonsdale, D; Pautasso, M; Holdenrieder, O. (2008) Wood-decaying fungi in the forest: conservation needs and management options. European Journal of Forest Reseach. 127, 1-22. DOI: 10.1007/s10342-007-0182-6
Rajala, T; Peltoniemi, M; Pennanen, T; Makipaa, R. (2010) Relationship between wood-inhabiting fungi determined by molecular analysis (denaturing gradient gel electrophoresis) and quality of decaying logs. Canadian Journal of Forest Research. 40, 2384-2397. DOI: 10.1139/X10-176
Thunes, K.H.; Midtgaard, F; Gjerde, I. (2000) Diversity of coleoptera of the bracket fungus Fomitopsis pinicola in a Norwegian spruce forest. Biodiversity and Conservation. 9, 833-852. DOI: 10.1023/A:1008927410513