Wood is a material of organic origin and as such it can be affected by the action of degrading agents such as insects or fungi. Sometimes the consequences of these interactions are very damaging, as is the case with example with termites. In others, these consequences are much less, so much so that we could even say that the effects remain in the visual.

In this article, we will talk about what is commonly known as the bluish wood fungus. It is a type of fungus that, as its name suggests, changes the color of the wood.

There are other types of fungi, which can have far more damaging effects, but that is the subject of another article.

What is the blue of the wood?

The blue of the wood is due to the action of a chromogenic fungus, usually ascomycetes, which feed on the contents of the wood cells, but do not alter the cell wall. The result is a change in the color of the wood, which acquires shades between blue and black.

Often the appearance is immediate, 5 or 6 days after sawing the wood and especially when it is cut.

Does this affect all woods equally?

Not all wood is affected in the same way.

On the one hand the wood must have a high degree of moisture, usually above 25%. These levels are not common in installed and properly preserved wood.

Coniferous woods are mainly affected after cutting, for example pine.

Consequences of the blue wood stain

Loss of wood value. Obviously, bluish wood cannot be sold at the same price as wood not affected by the fungus. The price can be reduced by up to 50%. Hence the logging companies

Feeding only on cellular content and not on the cell wall, the consequences of the action of this fungus are limited. The color is changed, but not the mechanical and physical properties wood, unless the attack is very severe.

How to treat or avoid bluish wood

The best and fastest way to prevent the appearance of this fungus is to reduce wood moisture at values ​​below 20-25% humidity immediately after cutting. This requires the use of industrial or artificial drying processes.

When the aim is to dry the wood naturally, it must be protected for the first 2-3 months, during which time the humidity level will be above the mentioned values.

Until a few years ago, to protect the wood during drying, chemical compounds that were highly effective against the fungus, but potentially toxic, such as pentachlorophenol sodium (NaPCP), were used. After the logical prohibition of some of these compounds, we found slightly less aggressive solutions, but effective if the recommendations and good practices are followed.