Giant polypore (Meripilus giganteus)

Common host(s)                    Most often on Beech, but occasionally on other broadleaved trees.

Colonisation strategy            Gains entry via injuries to large roots.

Symptoms                              Annual large, clustered layers of pale brown, tan or pink/orange/brown growths up to 1m across. Form at root/trunk interface or on large roots radiating out from the trunk. Sometimes appear to be growing in the soil, but are in fact attached to roots. Fruiting bodies are short lived and turn to black jelly-like mass after a few weeks or after frost.

Type of rot                             White rot. Sometimes soft rot also. Heartwood of major roots is rotted, but sapwood remains unharmed and still functions. So crown may look healthy as conducting tissue in sapwood is okay.

Part(s) of tree affected          Lower stem base, roots.

Significance                            Quickly compromises structural strength. Very hazardous because crown remains vigorous but roots weakened, sudden wind-throw can occur.

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