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Meripilus Giganteus


Meripilus Giganteus

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Caused By:-     The Bracket fungus Meripilus giganteus


Meripilus giganteus is a bracket fungus also known as the Giant polypore, Polyporus gigantea or Grifola giganteus. It is often found in large clumps at the base of trees, although fruiting bodies are sometimes found some distance away from the trunk. It causes a white rot in the roots and eventually death, often by being blown over, in various types of broadleaved trees, particularly beech (Fagus), but also Abies, Picea, Pinus, Quercus and Ulmus species. It is considered very serious and dangerous when it is found in an urban environment. When the fruiting body appears in late Summer or Autumn it is a sign that the fungus is very well established in the deep roots leaving the shallow roots until last and the tree could become unstable if it is not so already. The more numerous the clumps of fruiting bodies generally the greater the risk. Often the beech tree will look in good health right until the end, however if the crown is also thin and dying back, the risk is greater. The reason for this is that the fungus destroys the deeper-going roots, leaving the shallower roots healthy and intact until the very last.
However it should be said that this diagnosis is not clear cut and each tree must be considered on its own individual merits. There are certain techniques that can be employed to accurately ascertain the extent of the fungal decay and the likely chance of failure.
Fruiting body is 50-80cm across, rosette-like, consisting of numerous flattened fan-shaped caps around a common base. The individual tan or light brown caps range from 10 to 30 cm across and 1 to 3cm thick, The tubes and polypores are 4 to 6 mm deep and terminate in tiny round white pores between 3 and 5 per mm. When bruised, the pores turn black.
If cooked very slowly, young specimens are reported to have a slight sour taste and fibrous texture; however, they have been known to cause stomach upsets so are probably best avoided altogether. Picture from Wikimedia Commons


As this fungus only seem to attack mature trees an arborist or tree surgeon should be called to examine the individual tree as each tree must be considered individually.

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