Mushroom

A fallen log remains part of woodland life. Fungi break down its wood, which also supports other organisms, including insect larvae. Researcher Susana Gonçalves explains that some tree cavities result from fungal activity and can later shelter animals. A standing tree with cavities and a log on the ground offer different things to observe. In green spaces, retaining veteran trees requires assessment and monitoring of the risk of falling. This ecological explanation does not confirm a connection between the beetle photographed in Cabeceiras and a particular tree.

But wood does not always decay in the same way. In white rot, fungi break down lignin and cellulose; the wood may become pale, fibrous or spongy. In brown rot, decay mainly affects cellulose and hemicellulose, leaving a brownish residue rich in lignin. Wood may become brittle and break into small blocks. The University of California distinguishes these processes by their effects on wood components.

White and brown describe the decay, not the colour of a mushroom cap. They are not species names either. A visible reproductive structure on a trunk reveals only part of the story: decay may extend upwards or downwards and remain hidden. A photograph cannot measure that extent or assess a tree’s stability.

In Laetiporus sulphureus, Kew describes yellow reproductive structures arranged like shelves on trees. The fungus acts on dead wood inside trunks and larger branches, contributing to its decomposition. This description explains a growth form; it does not confirm the species in Cabeceiras or allow other fungi to be identified by colour alone.

The yellow belongs to the structure visible outside; the fungus’s activity extends into the wood. Kew describes decay that turns it brown and can leave cavities inside. Looking only at the shelves therefore shows just part of the process. Its presence on a tree does not mean every part of the tree is dead: the text refers to dead wood inside trunks and branches. This description does not assess the stability of individual trees.