Red-ring Rot

Porodaedalea pini is a fungal 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. It is a rot of the heartwood. Signs of the fungus include shelf-shaped conks protruding from the trunks of trees. Spores produced on these conks are blown by the wind and go on to infect other trees.

Cap: Occasionally absent but usually present as a turned-over upper edge or, more commonly, as a well developed structure; up to about 25 cm across and 15 cm deep; vaguely kidney-shaped to semicircular or irregular; convex, becoming hoof-shaped; hairy toward the margin or overall; becoming furrowed and rough; usually zoned; reddish brown to gray-brown, dark brown, or black.

Pore Surface: Brownish yellow to yellow-brown; with 1-4 angular to nearly slot-like pores per mm; tube layers up to 6 mm deep.

Stem: Absent.

Flesh: Reddish brown to yellow-brown; corky to woody.