The independent microorganisms of our planet earth Part three

Penicillium green mould and Aspergillus black mould, for example, can grow just as well on strawberry jam as on the leather sole of a shoe; all they need is a little moisture. Fungi are very fond of feeding on rotten wood; the net of their filaments can make its way into the trunk of a decaying tree or into a fallen branch in a way that is impractical for bacteria, smaller and less complicated. The filaments penetrate the woody tissue of the dry trunk passing from one cell to another as they digest the substance that forms the cell wall. When a tree is felled, the fungi begin to settle immediately on the surface of the cut stump and each type of tree is colonized by a certain variety of fungus.  

Beech stumps, for example, are then populated by several species, some orange, others purple and finally black with a tar-like appearance, while, on the other hand, there are much fewer that invade oak wood, perhaps because of its high tannic acid content. The coniferous forests also have their own particular flora, of which the orange Calocera viscose gelatinous fungus is a part.  

Sometimes, fungi able to live indistinctly on the basis of a tree felled as a base of operations to launch their offensive against the roots of nearby trees, with such disastrous results that forest rangers sometimes favor the implantation in the stumps of harmless fungi that prevent dangerous species from settling.