THE DETERIORATION BY FUNGI OF JACK, RED, AND WHITE PINE KILLED BY FIRE IN ONTARIO

Abstract

The nature, causes, and rate of pathological deterioration of jack, red, and white pine killed by fire in the Mississagi region of Ontario in 1948 were studied to determine the practicability and probable duration of profitable salvage operations in such stands. Blue and brown sapwood stains appeared in all species 1 year after the fire, and became extensive during the succeeding 3 years. Sap rot was first noted 2 years after the fire; 5 years after the fire most of the sapwood was affected, and in some cases this rot extended into the heartwood. Three fungi, Peniophora gigantea (Fries) Massee, Polyporus anceps Peck, and Polyporus abietinus Dicks. ex Fries, were isolated consistently from white sap rots, while Fomes pinicola (Sw.) Cooke and Fomes subroseus (Weir) Overh. were recovered from many of the brown sap rots. The increase in the volume of heart rot encountered during the course of the study, chiefly associated with Fomes pini (Thore) Lloyd, was much greater than that observed in living pine over a similar period, and for this reason the excess was considered as a form of deterioration. The average rate of radial penetration of visible deterioration was significantly faster in trees with widely spaced annual rings in the outer portion of the bole than in slow-growing trees. Variations in the severity of burn in individual trees or stands apparently had little effect on the rate of pathological deterioration.