Distribution and severity of white pine blister rust and mountain pine beetle on whitebark pine in British Columbia

• Published in: Canadian journal of forest research Vol. 30; no. 7; pp. 1051 - 1059
• Main Authors: Campbell, E.M, Antos, J.A
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.07.2000; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: alternative hosts; Biological and medical sciences; cankers; climatic factors; Cronartium ribicola; Dendroctonus ponderosae; disease transmission; Diseases & pests; forest decline; forest inventory; Fundamental and applied biological sciences. Psychology; fungal diseases of plants; Fungal plant pathogens; incidence; mortality; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; Phytopathology. Animal pests. Plant and forest protection; Pines; Pinus albicaulis; Ribes; site factors; stand structure; virulence; British Columbia; Canada; North America; America; Climate; Plant pathogen; Coleoptera; Insecta; Basidiomycetes; Environmental factor; Pinus albicaulis; Epidemiology; Fungi; Cronartium ribicola; Pest; Understory; Softwood forest tree; Gymnospermae; Dendroctonus ponderosae; Damage; Thallophyta; Forest stand; Mortality; Infection; Population survey; Spatial distribution; Arthropoda; Coniferales; Spermatophyta; Severity score; Invertebrata; Scolytidae
• ISSN: 0045-5067; 1208-6037
• DOI: 10.1139/x00-020

A major decline in the abundance of whitebark pine (Pinus albicaulis Engelm.) has recently occurred in the United States, primarily as a result of white pine blister rust (Cronartium ribicola J.C. Fisch. Ex Raben.). However, no information on the status of whitebark pine in British Columbia, Canada, was available. We sampled 54 subalpine stands in British Columbia, examining all whitebark pine trees within plots for evidence of blister rust and mountain pine beetle (Dendroctonus ponderosae Hopk.) damage. About 21% of all whitebark pine stems were dead, and blister rust was the most important agent of mortality. Of all living trees sampled, 27% had obvious blister rust infection (cankers), but actual incidence was suspected of being as high as 44% (using all evidence of blister rust). Blister rust incidence and whitebark pine mortality were significantly related to differences in stand structure and the presence of Ribes spp., but relationships with local climate and site variables were absent or weak. The lack of strong relationships with climate suggests favourable conditions for the spread of the disease throughout most of British Columbia. Very little evidence of mountain pine beetle was found. Overall, the prospects for whitebark pine in British Columbia do not appear good; a large reduction in population levels seems imminent.