UBC Theses and Dissertations
Tomentosus root rot of white spruce in central British Columbia Merler, Hadrian
Root disease in 50-70 year-old fully stocked white spruce stands in central British Columbia was investigated in two fashions. The first method was done by root excavation; to establish the identity of the causal organism, to investigate the etiology, and assess the damage caused by the disease. The second method involved, a survey of six 1.2 ha stands in order to estimate the incidence of the disease. Polyporus tomentosus Fr. was the only pathogen involved. Infection of spruce trees resulted when roots contacted previously existing inoculum. Although tree species other than spruce were in contact with infected roots, only spruce was infected by the root rot. No consistent crown symptoms were apparent. A complex with the root weevil Hylobius warreni Wood was evident. Results from the survey estimated that 28.4% of the area investigated was occupied by diseased trees. Of these 22.6% had butt rot, and for whole stands, 1% of the standing trees were windthrown in one season as a result of disease. Diseased trees suffered a 20% reduction of basal area increment. It was not possible to measure the mortality caused by the fungus.