Whitebark pine is an ecologically important high-elevation tree species distributed across much of the western United States and Canada. Unfortunately, this species is now undergoing rapid decline in many portions of its range due to an exotic disease, white pine blister rust. The objective of this research was to develop a practical, time efficient, yet accurate, method for rating white pine blister rust disease severity in whitebark pine. The system provides estimates of disease severity at the single tree or stand level, and of the within-tree distribution of infection. It can also be used to provide an overall estimate of disease incidence in a stand. Results of our rapid rating system were compared with a more time-consuming canker counting method. Overall estimates of disease severity using the rapid rating system and the canker-counting system were comparable. Both mean total canker counts and % incidence were highly correlated with mean total disease severity rating scores.
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|Published - Mar 2005