Interagency Whitebark Pine Health Monitoring Program for the Greater Yellowstone Ecosystem, 2004 Annual Report

Greater Yellowstone Whitebark Pine Monitoring Working Group

The 2004 annual report regarding the monitoring of whitebark pine in the Greater Yellowstone Ecosystem. Included details about questions asked, methods, results, and the status of monitored trees. Whitebark pine (Pinus albicaulis) is a keystone species throughout the Greater Yellowstone Ecosystem (GYE), the cones of which serve as a major food source for grizzly bears (Ursus arctos) and other wildlife species. Whitebark pine stands have been decimated in areas of the northern Rocky Mountains due to the introduction of an exotic fungus-white pine blister rust (Cronartium ribicola)as well as mountain pine beetles (Dendroctonus ponderosae). Resource managers from eight federal land management units have worked together as the Greater Yellowstone Whitebark Pine Subcommittee of the Greater Yellowstone Coordinating Committee (GYCC) to ensure the viability and function of whitebark pine in this ecosystem. In 2003 an additional working group was established to focus on an integrated monitoring effort throughout the GYE. The objectives of our monitoring were aimed at assessing the current status of white pine blister rust, whether or not blister rust is increasing within the GYE, and whether the resulting mortality of whitebark pine is sufficient to warrant consideration of management intervention (e.g., active restoration). Our study area is the entire GYE, comprised of 6 National Forests and 2 National Parks, although during 2004 our sample was restricted to within the Grizzly Bear Primary Conservation Area (PCA) because of limitations in the mapped distribution of whitebark pine (WbP) for the entire study area. We will extend beyond the PCA beginning in 2005. In 2004, transects were established and permanently marked for long-term trend monitoring in 45 stands of whitebark pine. In six of these stands, one additional transect was surveyed to assess within stand variation in blister rust. In total, 51 transects were sampled and 1,012 live trees surveyed. The number of whitebark pine trees sampled within these transects ranged from 1 to 141. Our data indicated that blister rust was relatively widespread throughout the PCA. Thirty six of the 51 (71%) transects had some indication of blister rust. Although blister rust was widespread, the infection severity was relatively low. We estimated that the proportion of trees infected with blister rust within the PCA to be 0.189 +/-0.05 SE, and most infected trees had less than or equal to 2 cankers. Further, most of the cankers also occurred on branches, which pose considerably less risk to the tree than cankers located on the trunks. Our data also indicated a high degree of observer variability in detecting indicators of blister rust and characteristics of trees used to indicate health. The concern over observer variability from our results extend well beyond the GYE effort and suggests a general need for better training and possible refinement of the methods used to assess blister rust. (Abstract as submitted by authors).

Interagency Whitebark Pine Health Monitoring Program for the Greater Yellowstone Ecosystem, 2004 Annual Report

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