What does the term 'sap stain fungi' refer to?

The term 'sap stain fungi' specifically refers to fungi that cause discoloration in wood, primarily affecting the sapwood portion of the tree. These fungi do not decompose the wood in the way that decay fungi do; instead, they penetrate the wood and form dark stains, which can be unsightly and detrimental to the wood's market value. While sap stain fungi can affect the appearance of the wood, they do not necessarily compromise its structural integrity significantly. This ability to discolor wood while not causing major structural decay makes the understanding of sap stain fungi crucial for those involved in the timber and lumber industries. The focus here is on the staining effect rather than the decay or other impacts on the trees or wood.