Phellinus (Fomes) pini decay associated with sweetfern rust in sapwood of jack pine

Abstract

Phellinus (Fomes) pini (Thore ex Fr.) A. Ames was associated with cankers and discolored wood caused by the rust fungus Cronartiumcomptoniae Arth. in sapwood of young jack pines (Pinusbanksiana Lamb.). Patterns of decay throughout the tree were influenced by the severity of rust-induced cankers. Fifteen trees 17 to 42 years old and 3 trees 78 to 81 years old with basal cankers of C. comptoniae and sporophores of P. pini were examined macroscopically with a video processor image analyzer and microscopically with scanning electron microscopy. The average length of the discoloration and decay columns was 5.19 m. The twisted and shortened tracheids of cankered sapwood restricted the growth of P. pini. The greatest volume of defect was located above the canker. Scanning electron microscopy demonstrated a localized delignification of the altered sapwood. Degraded areas were separated from unaltered wood by resin-filled tracheids. The youngest jack pine with sporophores of P. pini was a 17-year-old tree.