Mushroom

A fallen log is still part of the forest life. Fungus decomposes wood, which also sustains other organisms, including insect larvae. The researcher Susana Gonçalves explains that certain tree cavities result from fungal activity and can then serve as an animal shelter. A tree with cavities and a trunk on the ground offer different situations to observe. In green spaces, conserving old trees requires assessing and monitoring the risk of falling. This ecological explanation does not confirm an association between the beetle photographed in Cabeceiras and a specific tree.

But the wood does not always break down in the same way. In white rot, the fungi degrade lignin and cellulose; the wood can become clear, fibrous or spongy. In brown rot, the degradation reaches mainly cellulose and hemicellulose, becoming a brownish residue rich in lignin. The wood can become fragile and fragmented into small blocks. The University of California distinguishes these processes by the effect on the components of the wood.

White and chestnut describe decomposition, not the color of a mushroom hat. Nor are species names. A reproductive structure visible in the trunk shows only part of the story: decomposition can extend up or down and remain hidden. A photograph does not allow to measure this extension or evaluate the stability of the tree.

In Laetiporus sulphureus, Kew describes yellow reproductive structures that are available as shelves on trees. The fungus acts on the dead wood of the interior of larger trunks and branches, contributing to their decomposition. The description explains a form of growth; it does not confirm the presence of this species in Cabeceiras nor allows to recognize other fungi only by color.

Yellow belongs to the structure that is seen outside; the activity of the fungus extends to wood. Kew describes a decomposition that makes it brown and can leave cavities inside. Looking only at the shelves is therefore looking at a part of the process. The presence in a tree does not mean that all its parts are dead: the text refers to dead wood inside trunks and branches. This description does not evaluate the stability of concrete trees.