Whitebark Pine ( Pinus albicaulis) in Mt. Rainier National Park, Washington, USA: Response to Blister Rust Infection

• Main Authors: Ettl, Gregory J, Cottone, Nicholas
• Format: Book Part
• Language: English
• Published: Oxford University PressNew York, NY 2004
• Subjects: Ursus arctos
• Online Access: http://dx.doi.org/10.1093/oso/9780195166460.003.0004; https://academic.oup.com/book/chapter-pdf/52323740/isbn-9780195166460-book-part-4.pdf

Abstract The decline of whitebark pine (Pinus albicaulis Engelm.) across North America is well documented (Tomback et al. 2001) and is attributed to fire exclusion, insect outbreaks, and various fungal blights and rusts (Arno and Hoff 1990, Hoff and Hagle 1990, Keane and Arno 1993, Keane et al. 1994). White pine blister rust is a major source of whitebark pine mortality throughout western North America, with the heaviest mortality rates in Washington, Idaho, and northwestern Montana (Kendall and Keane 2001). In early 1995, blister rust was present on all sampled sites in Mt. Rainier National Park (Rochefort 1995) and was a likely cause of mortality in many trees (DelPrato 1999). Whitebark pine is in danger of becoming locally extinct. Whitebark pine is a member of the stone pines (family Pinaceae, genus Pinus, subgenus Strobus, section Strobus, subsection Cembrae) that contain species with indehiscent cones and require birds for dispersal (McCaughey and Schmidt 2001). Whitebark pine is almost completely dependent on Clark’s nutcracker (Nucifraga columbiana Wilson) for seed dispersal and successful germination (Tomback and Linhart 1990) through their extensive caching of seeds. Because squirrels cache whitebark pine seeds and bears often raid these caches, the decline of whitebark pine has important implicaions for many wildlife species. In Yellowstone National Park, whitebark pine cone crops have been linked to grizzly bear (Ursus arctos L.) sightings at lower elevations; when seeds are abundant, bears feed on seeds in the high country and avoid encounters with humans (Mattson et al. 1992). There is almost a doubling in mortality rates of grizzly bears in non-mast seed years than in mast years as grizzly bear–human conflicts increase, resulting in declining bear populations (Pease and Mattson 1999).