Haploporus odorus is rare and typical taiga species with circum-boreal distribution, more common in Sweden, Finland and Russia and more rare in Norway, Canada and China. Its is a wood-inhabiting polypore (shelf) fungus forming large white perennial sporocarps on the trunks of old living willow (Salix) in mainly old natural forest. The sporocarps are easily identified by its strikingly strong sweet smell of anise that is evident many meters from their characteristic fruiting body. The mycelia in the wood may live on in the trunk wood as long as the willow is alive. The population of H. odorus is assessed to have declined during the last 30 years by almost 30%, and the decline is continuing, mainly due to felling of old willows during forest harvest and in combination with few willows develop to old trees with habitat for the fungus in managed forests. The decline has decreased in Fennoscandia as old willows largely nowadays are maintained as retention trees at clear-cutting. It is red listed in Red Data books for regions of Russia, as VU (Vulnerable) in Norway and Sweden, as NT (Near Threatened) in Finland and considered rare in Canada and China. Haploporus odorus is assessed as NT (Near Threatened) based on criteria A2c+3c+4c.
Haploporus odorus has relatively large (up to 15 cm broad) grey to white polypore fruiting bodies on the trunks of living Salix. It causes a white rot of the wood. Fruiting bodies have a strong vanilla-anise odor that can be detected from distances up to 10 m away. They remain strongly fragrant years after drying. In the field, the somewhat similar Trametes suaveolens can be distinguished by having only a fleeting anise odor that disappears after drying. Micromorphologically, H. odorus is distinctive because of its asperulate (tiny warts) dextrinoid (staining reddish-brown in Melzer’s reagent) basidiospores.
Haploporus odorus is a boreal is a saprotrophic fungus large white boreal wood decay polypore (shelf) fungus that is found on the trunks of a single tree host species (Salix) with very few exceptions. It causes wood decay (white rot), and is easily identified by its strikingly strong sweet smell of anise that is evident many meters from the fruiting body. The population of H. odorus is estimated to be in decline due to ungulate grazing, natural disturbances (forest fires), intensive forest management, drainage to produce agricultural land and melting permafrost. It is listed in red data books for regions of Russia, listed as vulnerable (A2C) in Sweden, near threatened in Norway, and considered rare in China.
Haploporus odorus is circumboreal with its main distribution in Fennoscandia and Russia. In Europe, present in southeast Norway, northeastern Sweden, Finland (Fraiture and Otto 2015) and Russia, where it is documented in 18 administrative regions. In Poland, only two records before 1970. Considered rare in China [not mapped], collected in Changbaishan Nature Reserve of northeastern China (Dai, 2003). Also present in North America [not mapped], known from scattered sites in western Canada (Southeastern Manitoba to north central Saskatchewan, northwestern Alberta, south central Saskatchewan, Northwest Territories, and northern British Columbia). All collections in Canada have been recorded north of 52 degrees N, except for two sites in central Manitoba, near its eastern range in this country. Two questionable records have been documented from the United States (Indiana, 1892, Montana, 1907). It might be expected to occur in Alaska. Earlier published record of occurrence in England (Ing 1992) was based on a misidentification. There is a questionable record from Armenia, on Acer, from Ijevan floristic region.
The distribution is almost exclusively boreal in Europe, with many records from Sweden (>4,000 records 1985-2017) and Finland and a few in Norway. In Russia, is widespread in old forests of taiga-zone where Salix caprea is present. It is considered rare in China (one published record from Northeast China; Dai 2003).
In Sweden, it is listed as Vulnerable (VU A2c, 2015) as the total population in the country is estimated to have declined between 50 and 30% during the past 30 years (1985-2015), due to forest management (clear-cutting) and the large population of Moose (Alces alces) holding back the rejuvenation of Salix trees, as well as the loss of natural disturbances like wildfires. For similar reasons, it is assessed as Near Threatened (NT A2c; C2ai) in Finland (2010). In Norway it is Vulnerable (VU D1) due to less than 300 localities. It is included in seven regional Red Data Books of Russian Federation (Arkhangelsk Oblast 2009, Karelia Republic 2007, Komi Republic 2009, Lenigrad Oblast 2000, Sverdlovsk Oblast 2009, Tumen
Oblast 2004, Khanty-Mansi Okrug 2013), but it is not included in the national Red Data Book of Russia (2008), and it is not suggested for the next edition of the RDB of Russia.
The Alexis Nakota Sioux Nation in Canada (2015), whose traditional territory encompasses 121,000 square miles of central Alberta, in 20 years of searching for this particular fungus, noted that “very few (estimated as less than 1%) “stands of diamond willow actually have the fungus”. Several Salix species have distinctive diamond-shaped cankers thought to be caused by other fungi, and Haploporus odorus frequently fruits on these cankers. Herbarium specimens are sparse: 17 from BC, 12 from Alberta, and 2 each from Manitoba, Saskatchewan and Northwest Territories, for a total number of 35 collections.
The European part of the population is considered to have declined of by up to 20-30%. The population decline is mainly caused by felling of old willows at forest harvest. Ungulate grazing, natural disturbances (forest fires) and historically also drainage to produce agricultural land have all contributed to and will continue to contribute to declining populations. Climate change also has a potential to cause decrease in habitat for the fungus, due to increased herbivory by mammals on young growth as willow host populations migrate further north, potentially restricting the number of trees that achieve mature growth (Winder et al. 2011). Likewise increased melting of permafrost will cause initial flooding and inundation of sloughs and bogs that host willow trees encircle, before transitioning to drier conditions (Smith 2010).
Population Trend: Decreasing
Haploporus odorus is a specialized saprotrophic wood-inhabiting fungus growing almost exclusively on Salix caprea (Goat Willow). It causes wood decay (white rot). Although the sporocarps are perennial and may become several years old, the wood mycelia live in the trunks as long as the willow is alive. The species is restricted to more or less wet habitats with old willows. Suitable habitats in northern Europe and Russia are described as moist depressions in spruce dominated old-growth forests and undisturbed old stands along brooks. In Canada, it is typically found in sunken areas (diamonds) on trunks of old Salix trees, in low-lying areas near bogs. The majority of the collections have been made in latitudes north of 52 degrees. In Europe, H. odorus is used as an indicator species for Goat Willows and forest sites with high conservation value (Nitare 2010). A few collections have been made on other tree species: Populus (aspen) in Alberta, Canada (DAOM 94373, Fraxinus (ash) in Manitoba, Canada (Jorgensen, 1961); Alnus (alder) in Northwest Territories, Canada, (DAOM 94371); Prunus cerasis (Sour Cherry) in Fennoscandia. A single record from Armenia is questionable based on photograph and host (Prunus).
The main threat and cause for the decline of Haploporus odorus is felling of old willows during forest harvesting. Few willows develop in to old appropriate habitat in managed forest of today. Nowadays, old willows are generally kept as retention trees at forest harvesting in Fennoscandia, hence the decline of H. odorus and is appropriate habitat is being reduced. Ungulate grazing, forest fires, earlier also drainage of forests, is contributing to declining populations via habitat reduction. Harvesting by First Nations for traditional uses (medical and spiritual uses) are unlikely to interfere with sustainable population levels. Climate change also has a potential to cause future decrease in habitat for the fungus, due to increased
herbivory by mammals on young growth as willow host populations migrate further north, potentially restricting the number of trees that achieve mature growth (Winder et al. 2011). Likewise increased melting of permafrost will cause initial flooding and inundation of sloughs and bogs that host willow trees encircle, before transitioning to drier conditions (Smith 2010).
In Canada, the traditional uses of the dried fruiting bodies by First Nations is acknowledged, and habitat of “diamond willow trees” is preserved and designated as sensitive. Most recently, sensitive diamond willow habitats identified by First Nations communities during consultation processes resulted in rerouting of a TransCanada natural gas pipeline near Chetwynd, BC, by use of a road bore, running it underneath the stand rather than cutting it down. A description of this process is available at: http://blog.transcanada.com/pipeline-project-protects-diamond-willow-fungus/. At this time the fungus is not being commercially exploited for its medicinal or traditional uses, but as it is easily cultured, it could be potentially produced via artificial inoculation of suitable host substrate, thus avoiding the need for wild harvesting.
Confirmation of host range. Bondartzev (1950) indicated a much broader host range, but some of these records might be attributed to Trametes suaveolens (Niemela, 1971).
At this time the fungus is not being commercially exploited for its medicinal or traditional uses, but as it is easily cultured, it could be potentially produced via artificial inoculation of suitable host substrate, thus avoiding the need for wild harvesting.
Alexis Nakota Sioux Nation, 2015. Research of the Tlous pertaining to TransCanada’s proposed McLeod River NGTL pipeline. Submitted by ANSN Consultation Office, October 2015, support provided by Barry A. Hochstein, Four Medicines Consulting Ltd. https://docs.neb-one.gc.ca/ll-eng/llisapi.dll/Open/2837190
Blanchette, R.A. 1997. Haploporus odorus: A sacred fungus in traditional Native American culture of the northern plains. Mycologia 89(2): 233-240.
Bondartsev, A., and R. Singer. 1950. Novye daddye o trutovike Trametes odora Fr. Bot. Zurnal 35: 73-77.
Callan, B. 2000. Two web-accessible fungus databases and their relationship to a preliminary list of rare macrofungi for British Columbia. pp. 109-112 in Darling, L. (ed.) Proceedings of a conference on the biology and management of species and habitats at risk, Kamloops, BC. 15-19 Feb, 1999. Volume One. BC Ministry of Environment, Lands and Parks, Victoria, BC, and University College of the Cariboo, Kamloops BC. 490 pp.
Dai, 2003. Rare and threatened polypores in the ecosystem of Changbaishan Nature Reserve of northeastern China. Ying Yong Sheng Tai Xue Bao Jun 14(6): 1015-1018 (in Chinese).
Dahlberg, A. & Cronenberg, H. 2003. 33 threatened fungi in Eurpoe. Complementary and revise information oncandidates for listing in Appendix 1 of the Bern Convention. Document T-PVS (2001) 34 rev.2. Swedish Environmental Protection Agency (EPA) and European Council for the Conservation of Fungi (ECCF). 82. pp.
Eriksson, J. 1958. Studies in the Heterobasidiomycetes and Homobasidiomycetes-Aphyllophorales of Muddus National Park in North Sweden.
Symbolae Botanicae Upsalienses 16:1-172.
Fraiture, A., and Otto, P. (eds.) 2015. Distribution, ecology and status of 51 macromycetes in Europe. Results of the ECCF Mapping Programme. Meise, Botanic Garden Meise. Scripta Botanica Belgica Vol. 53. 247 pp.
Ing, B. 1992. A provisional red data list of British Fungi. Mycologist 6: 124-128
Jorgensen, E. 1961. III Year forestry student collects wood-decaying fungus yet unreported from North America. The Annual Ring, Faculty of Forestry, University of Toronto.
Mirck, J. and Schroeder, W. 2013. Composition, stand structure, and biomass estimates of “willow rings” on the Canadian Prairies. Bioenergy Research 6: 864-876.
Nanagulian, S. 2002. Some dates about distribution and conservation of threatened mushrooms in Armenia. http://www.wsl.ch/eccf/Armenia.pdf
Niemela, T. 1971. On Fennoscandian Polypores. 1. Haploporus odorus (Sommerf.) Bond. & Sing. Ann. Bot. Fennici 8: 237-244.
Popov, in European Council for the Conservation of fungi. Newsletter 15-Summer 2010.
Ryvarden, L., and R.L. Gilbertson. 1993. European polypores. Part 1. Abortiporus - Lindtneria. Fungiflora, Oslo. 387 pp.
Smith, S. 2010. Trends in permafrost conditions and ecology in northern Canada. Canadian biodiversity: ecosystem status and trends 2010. Technical Thematic Report No. 9. Published by the Canadian Councils of Resource Ministers.
Winder, R., Nelson, E.A., and Beardmore, T. 2011. Ecological implications for assisted migration in Canadian forests. The Forestry Chronicle 87(6): 713-744.