Treesearch

Successional whitebark pine (Pinus albicaulis) communities are dependent on fire and other disturbances for renewal (Arno 2001). Where whitebark pine regenerates results from cache site selection by Clark's nutcrackers (Nucifraga columbiana) in relation to the environmental tolerances of seeds and seedlings (Tomback 2001). After the 1988 Yellowstone fires, we studied the development of upper subalpine forest communities with particular focus on the regeneration of whitebark pine in two study areas - Mt. Washburn in Yellowstone National Park, and Henderson Mtn. in Gallatin National Forest....

According to the geographic mosaic theory of coevolution (Thompson 2005), the potential for coevolutionary relationships between interacting species varies with the presence of other species within a community. This implies that the strength of coevolution between two species may vary geographically. In this study, we ask whether there is a shift in vertebrate seed dispersers between core range and peripheral populations in two related five-needle white pines, limber (Pinus flexilis) and southwestern white (P. strobiformis). In the Rocky Mountains, limber pine ranges from southern British...

Clark's nutcrackers (Nucifraga columbiana) are well known for using conifer seeds as their principal nutriment source. Seeds are primarily harvested from whitebark (Pinus albicaulis), piñon (P. edulis), limber (P. flexilis), southwestern white (P. strobiformis), Jeffrey (P. jeffreyi), and ponderosa (P. ponderosa) pine as well as Douglas-fir (Pseudotsuga menziesii) (Tomback 1998). However, prior to our studies, sugar pine (Pinus lambertiana) seed harvest by Clark's nutcrackers was not documented. Sugar pine seeds, which bear long seed wings, are among the largest of pine seeds (average of...

Limber pine (Pinus flexilis) is listed provincially as endangered in the northern part of its geographic range (Alberta) due to the high mortality caused by white pine blister rust (WPBR) (Cronartium ribicola) and mountain pine beetle (Dendroctonus ponderosae), and limited regeneration opportunities due to fire exclusion. In the case of an endangered species, seed predators may accelerate this decline, particularly when their populations are regulated by more factors than the abundance of the declining species. Red squirrels (Tamiasciurus hudsonicus) are a major cause of pre-dispersal seed...

The population status of and habitat use by Clark's nutcrackers (Nucifraga columbiana) has rarely been studied and remains poorly understood, in part due to the previous lack of a reliable method of surveying nutcracker populations. Anecdotal evidence suggests that Clark's nutcrackers have recently declined precipitously throughout large parts of their range. A likely factor causing these declines is their mutualism with whitebark pine (Pinus albicaulis), which has suffered massive die-offs due to the recent mountain pine beetle (Dendroctonus ponderosae) epidemic and white pine blister...

The High Five symposium is devoted to exchanging information about a small group of pines with little commercial value but great importance to the ecology of high-mountain ecosystems of the West. These High Five pines include the subalpine and treeline species - whitebark (Pinus albicaulis), Rocky Mountain bristlecone (P. aristata), Great Basin bristlecone (P. longaeva), and foxtail (P. balfouriana) - the montane to subalpine pine, southwestern white (P. strobiformis), and the lower treeline to upper treeline pine, limber (P. flexilis). Here, we discuss the taxonomy, distribution, ecology,...

Lower treeline limber pine woodlands have received little attention in peer-reviewed literature and in management strategies. These ecologically distinct systems are thought to be seed repositories between discontinuous populations in the northern and central Rocky Mountains, serving as seed sources for bird dispersal between distinct mountain ranges. Their position on the lower treeline and foothills in semi-arid climate systems is predicted to be particularly vulnerable to climate change. The genetic variation within these stands is viewed as important to conservation geneticists in...

Ectomycorrhizal fungi are an important component of northern coniferous forests, including those of Pinus flexilis (limber pine) and P. albicaulis (whitebark pine) which are being decimated by white pine blister rust and mountain pine beetles. Ectomycorrhizal fungi are known to promote seedling establishment, tree health, and may play a role in forest sustainability. The goal of this research is to discover the native ectomycorrhizal fungi associated with these two pines in the Rocky Mountain region. Here we report 32 species of ectomycorrhizal fungi associated with whitebark pine, 26 with...

Whitebark pine (Pinus albicaulis) is declining in the central and northern Rocky Mountains from infection by the exotic pathogen Cronartium ribicola, which causes white pine blister rust, and from outbreaks of mountain pine beetle (Dendroctonus ponderosae). White pine blister rust has been present in Glacier and Waterton Lakes National Parks (NP) about two decades longer than in the Greater Yellowstone Area, but both Grand Teton and Yellowstone NP are currently experiencing major outbreaks of mountain pine beetle. McKinney and Tomback (2007) and McKinney and others (2009) demonstrated that...

Ecological impacts are occurring as white pine blister rust spreads and intensifies through ecologically and culturally important limber pine ecosystems of the Rocky Mountains and surrounding areas. The imminent threat of mountain pine beetle has heightened concerns. Therefore, information on the health status of limber pine is needed to facilitate management and restoration efforts. The objectives of this study were to: (1) evaluate the health of limber pine in Colorado, Wyoming, Montana, and North Dakota, (2) establish monitoring plots to assess cumulative ecological impacts of blister...