Survival of Inonotus tomentosus in Stumps and Subsequent Infection of Young Stands in North Central British Columbia

1991

S. 1049-1057

4 Abb., 7 Tab., 21 Lit. Ang.

Unselbständiges Werk

200089418

Distribution of tomentosus root disease in spruce (Picea glauca (Moench) Voss and P. glauca x engelmannii Engelm.) and pine (Pinus contorta var. latifolia Engelm.) stumps in 1- to 30-year-old harvest units, survival of Inonotus tomentosus (Fr.) Teng in stumps, and infection of regeneration trees were examined by transect surveys and root excavations. The number of diseased stumps ranged from 8 to 71 per hectare (2.1-27.5%); these were in patches, commonly two to three stumps each. Viable mycelium was found in 80 and 53% of the 30-year-old spruce and pine stumps, respectively. Distal growth by I. tomentosus in roots ceased shortly after harvest. Narrow decay and stain columns were observed in 1- and 2-year-old spruce stumps. In older stumps, the fungus had colonized the sapwood and bark. In pine, colonization of the bark and cambium was common at all stump ages. Spruce stumps, with longer, horizontally oriented roots and a greater percentage of colonized roots, caused more infections of regeneration than pine stumps (14 and 5%, respecitvely, of the five regeneration trees closest to each stump). Regeneration trees had a 25% chance of infection if planted within 2 m of decayed spruce stumps and 0.5 m of decayed pine stumps. The probability of infection decreased to 10% at 3.75 and 2.75 m from spruce and pine stumps, respectively. Both spruce and pine regeneration were infected, often at points of disruption in the bark, such as a feeder root or root branch.