Ganoderma applanatum
This fungi affects many broadleaf trees, its most common host is Fagus/Beech its fruiting body is perennial so can be found all year round. Ganoderma is a root and butt decay fungus and can lead to mechanical failure of the stem or base. However the partially decayed wood can retain much tensile strength so failure is most likly to occur whenless the 30-35% of sound wood is left. Trees with this fungi can live safely for many years if in good health as the tree can produce compensatory growth due to the flex caused by the decay, in simple terms the tree can adpat and reinforce intself.
Another note of importance, as with all decay fungi its host and host condition all play a role in the extent of decay, i recently felled a Horse Chesnut with Ganoderma after just 6 years of the fruiting bodies emerging this trees stem had severly decay to less than 25% sound wood, and what was left was like polysterene.
Inonotus hispidus
This can be found most commonly on Fraxinus/Ash, also affects Platanus x hispanica/London Plane, Juglans/Walnut, Malus/Apple Ulmus/Elm and Acer/Sycamore.
The fruiting bodies are annual and can appear from May to Feburary, if the fruiting bodies are not present on the tree they can leave behind a tell-tale small black mark or the fruiting bodies may be found on the floor in a blackend desiccated state. It is usually found on the main trunk or major branches sometimes emerging from pruning wounds or other defect in the bark. Causes a white rot in the area of wood where the fungi is found, degrades the lignin and cellulose at roughly equal rates and leads to brittle fracture although this varies depending at what stage the fungi invasion is at also dependent on the host.
Inonotus hispidus on Ash for example is considered a potentially serious pathageon, on London Plane its less of a concern due to the higher concentration of Lignin.
