It is a plant pathogen that causes tree disease commonly known as "red ring rot" or "white speck".

This disease, extremely common in the conifers of North America, decays tree trunks, rendering them useless for lumber.

In advanced stages of decay, small, spindle-shaped white pockets are formed due to the degradation of lignin by P.

[5] P. pini is the most common pathogen to Engelmann spruce (Picea engelmannii) and causes the largest decay columns.

[6] Once they land on a suitable small wound or twig stub, the spores may germinate and the mycelia grow into the inner wood and cause infection.

[10] Spores blown by the wind land and germinate on wounds, so in managed forests, care should be taken to prevent any injury to trees during harvest or other activities.

[6] This disease is most common in the Pacific Northwest, where cool wet weather greatly facilitates the pathogen.

In most cases, complete elimination of red ring rot is not an objective, and some control is achieved by cultural practices.

[5] During harvest, treating tree wounds and stumps with antagonistic fungi has led to considerable success in controlling decays and rot.

[5] It has been estimated that over three-fourths of the total 17% of decayed, overmature Douglas-fir in the Pacific Northwest were in decline due to red ring rot.

[11] Apart from the economic impacts of this disease, red ring rot decay may lead to mechanical failure of live trees, which may cause a potential hazard in recreational or public areas.

[13] Additionally, decayed trees, rotting from the inside-out, serve as important habitat to cavity-nesting birds and mammals.