DECAY OF LODGEPOLE PINE IN TWO FOOTHILLS SECTIONS OF THE BOREAL FOREST IN ALBERTA

Cull in lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) is highly variable in the B19a and B19c Sections of the Boreal Forest in Alberta, depending upon whether the wood is used for pulp or sawed products. Sixty-nine per cent of 2,436 sample trees were suspected of containing volumes of red heartwood stain and advanced decay on the basis of the presence of external defects. Fifty-three per cent of the suspects were sound, 36 per cent had red heartwood stain and 11 per cent were partly or entirely decayed. Sixty per cent of the trees without external defects were sound, and 40 per cent had red heartwood stain. In cubic-foot measure decay was unimportant in stands less than 100 years old. In older stands a few infested trees accounted for most of the decay. In foot-board measure 62 of 2,746 sample trees were totally culled and 122 were partially culled. Considerable loss occured in 90-year old and older stands near Whitecourt and in 170-year old stands in the other sample areas. Fomes pini (Thore) Lloyd and Polyporus tomentosus Fr. were the principal fungi isolated from white pitted trunk rots. P. tomentosus and Flammula alnicola (Fr.) Kummer were isolated most frequently from white pitted root and butt rots, and Coniophora puteana (Schum. ex Fr.) Karst. from brown cubical root and butt rots. Peniophora pseudo-pini Weres. and Gibson was the most frequently isolated fungus but was always associated with red heartwood stain. Scars of all kinds were the most important points of entry for decay fungi.