Hericium coralloides fruit bodies are fleshy and large (up to 400 mm in diameter), branched and covered with hanging spines up to 1 cm long, whitish at first to creamy-yellow when old, they are said to be one of the most beautiful fruit bodies. This wood inhabiting fungus occurs in (mostly) old-growth native forest or on ancient trees in urban parks, it is mainly related to Fagus sp., but has been found also on a variety of broadleaves, for instance on Betula sp., Populus sp., Fraxinus sp. in Scandinavia, on deciduous and evergreen oak species in Mediterranean areas. It grows mostly on fallen trunks and larger branches but also occurs on standing dead trunks.
As far as natural beech forests in Europe are concerned, the beech prefers sites favorable for agriculture and subsequently large areas of beech forest have been cleared for agricultural production. In some regions the reduction and fragmentation in beech populations has been dramatic. Most beech and broadleaved forests are managed forest, so the species is mainly threatened by logging, removal of death wood, deforestation and/or fragmentation and/or other changes of natural habitat.
In conclusion Hericium coralloides, even if broad leaved habitats have had dramatic changes in the last 100 years, has a worldwide distribution, and is both very common in some countries and rare in some others. At national level it is surely at a different threat category such as NT or VU.
Awaiting molecular analysis of this maybe cryptic species that seems to be different in different continents/nations, it is assessed as LC (Least Concern).
Some synonyms (as classified by Species Fungorum):
Hydnum coralloides Scop. (1772)
Hericium ramosum (Bull.) Letell. (1826)
Medusina coralloides (Scop.) Chevall. (1826)
Merisma coralloides (Scop.) Spreng. (1827)
Friesites coralloides (Scop.) P. Karst. (1879)
Dryodon coralloides (Scop.) P. Karst. (1881)
Manina coralloides (Scop.) Banker (1912)
Preliminary global red-list assessment: LC (Least Concern).
This mainly beech wood-inhabiting species is widely distributed and also occurring at more trivial conditions and not estimated to have a habitat that is or will be declining with more than 30% during 30 years (the recommended time for evaluation of wood-inhabiting species in beech recommended by Dahlberg & Mueller, 2011).
Original motivation: Infrequent establishment and low germination of basidiospores (ca. 1% in laboratory incubation) may be the causes of apparent rarity in Europe.
Reduced amount of appropriate habitats (natural beech forests). Beech prefers sites favorable for agriculture and subsequently large areas of beech forest have been cleared for agricultural production. As a result, a large proportion of beech genetic diversity has probably been destroyed. This land clearing has also fragmented the remaining stands. In some regions the reduction in beech populations has been dramatic.
Some beech stands may be at risk from climate change, particularly those in the lowlands where precipitation is expected to decrease and summer temperatures to increase.
Furthermore, most of the existing beech forests are managed forests, which characterizes with much lower level of death wood amount (below 10m3/ha) than natural beech forests (above 100m3/ha).
H. coralloides fruit bodies are large (up to 400mm in diameter), easy to notice and recognize, they are said to be one of the most beautiful fruit bodies. Therefore it is potentially an umbrella species (for a range of species, smaller and overlooked, but also connected to natural beech forests with supplies of large diameter death wood).
Considering the species in its wider concept (Hericium coralloides s.l.) it seems present more or less everywhere in the northern hemisphere, seldom found in the southern one with some collections in Perù, Chile, Argentina, South Africa, India, and again widespread in New Sealand.
The population and current trends varies from zone to zone, in India it’s considered a rare species, while in Japan and new Zealand it is widespread and frequent. In various countries the sites of occurence are confirmed, so for instance in Poland (Kujawa 2020). On the other hand in other countries there is a decline of the presence of this wood inhabiting species due to logging or other human activities. The beatyful species is more frequently detected than many inconspicuous mushroom species, and there are more recent records than older ones.
Anyway in general increases of recorded localities probably do not reflect increases in population size. Instead, they serve to highlight the tremendous increases in local recording group activity, database usage, networking and publicity.
Their fruit bodies are hard to miss, so fruit bodies are probably not under recorded.
Population Trend: Decreasing
Hericium coralloides is mainly found in old, mature forests with a long history of continuous tree cover, retained dead wood and a range of tree age classes. Growing up on fallen trunks, larger branches and also on standing dead trunks and sometimes on leaving trees, it can be found also on old single trees in city parks. The common host of this wood inhabiting fungus causing white rot, are deciduous trees, mainly Fagus sylvatica, Quercus sp.pl., Fraxinus sp.pl.
H. coralloides seems to fruit quite regularly on a tree but for few seasons (ca. 5 years) and the fruit bodies usually signify a relatively advanced state of underlying decay.
Reduction and fragmentation of appropriate habitats (old growth natural forests).
Simplification of the structure of potential habitats (e.g. reduction of the amount of large diameter death wood).
Edibility and hence harvesting of the fruit bodies.
Management of the species must largely depend on conservation of trees and sites currently known to harbor fruiting individuals and, in the longer term, ensuring continuity of tree species and conditions which favor fruiting, spore production and subsequent colonization.
It is essential to leave as much large diameter dead wood in situ as possible.
The fungus is also cultivated and therefor the conservation ex-situ and its reintroduction could be proposed.
Determining numbers of genets per tree. This is the highest priority, as this will improve the species status assessments (Red List category).
H. coralloides frequently fruit in axenic culture, perhaps indicating that lack of fruit bodies in the field truly indicates lack of mycelial individuals, although it may be that natural fruiting is impeded by encapsulation within central woody tissues.
The duration of the homokaryotic phase is unknown but may be prolonged due to low frequency of contact between mating compatible partners in natural substrata.
Confirmation the mating system of H. coralloides (propably bifactorial). This will indicate the potential for inbreeding.
Mode of establishment within trees. The species is probably latently present within functional sapwood, but more sparsely than other primary colonizers of angiosperm wood. This may be a reason for rarity. Determining how the species enter functional sapwood is therefore crucial to understanding rarity and might also assist beech forestry managers in their choice of trees to leave standing to ensure continuity of H. coralloides fruiting populations.
Understanding spore production, dispersal and germination is crucial to understanding a species’ population dynamics, genetics and distribution patterns.
H. coralloides is widespread in New Zealand, though molecular studies likely needed to confirm conspecificity of Southern Hemisphere populations with those from Europe. The species is not considered threatened in New Zealand; it occurs in (mostly) old-growth native forest.
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