Root-rotting fungi associated with mortality of conifer saplings in northern Ontario

Abstract

The roots of 435 dead or dying saplings, averaging 10 years of age, of seven conifer species from the Boreal Forest of northern Ontario were examined for root rot. Only trees with no obvious cause of death or decline, other than root rot, were selected. Eighty-three percent of the trees had root rot. Cultures revealed that Armillariamellea (Vahl ex Fr.) Kummer was associated with root rot in 68% of all trees examined, including more than 45% of the trees in each species. Ten other root-rotting fungi were isolated from 1% or fewer of the trees, 7 of them from balsam fir (Abiesbalsamea [L.] Mill.) and 3 from black spruce (Piceamariana [Mill.] B.S.P.). Scytinostromagalactinum (Fr.) Donk was isolated from sapwood of roots and lower stems of red pine (Pinusresinosa Ait.), balsam fir, white pine (P. strobes L.), and black spruce and appeared to be parasitic on these species. Coniophoraputeana (Schum. ex Fr.) Karst. was apparently associated with the death of one balsam fir.