Treesearch

I examined the regeneration of whitebark pine (Pinus albicaulis) and four other high elevation conifers in young subalpine forest following two stand replacing fires in the Canadian Rockies. These were the Vermilion Pass fire of 1968, located in Kootenay and Banff national parks, and the Rock Canyon Creek fire of 1960, located approximately 125 km further southeast in the Invermere Forest District of British Columbia. I surveyed 103 100-m2 plots in total, with roughly equal sampling intensity across the environmental gradients of altitude, aspect, and distance to the mature forest edge. I...

Cronartium ribicola is a fungal pathogen that causes a blister rust disease of white pines, Ribes, and other hosts in the genera Castilleja and Pedicularis. Although blister rust can damage white pine trees and stands, the severity and significance of these impacts vary with time, place, and management. We use a natural history approach to describe the history, biology, and management of C. ribicola. We review its status as a non-native pathogen, likely ecological and evolutionary behavior, and implications for management.

There is a critical need for information on the status and trend of whitebark pine (Pinus albicaulis) in the Greater Yellowstone Ecosystem (GYE). Concerns over the combined effects of white pine blister rust (WPBR, Cronartium ribicola), mountain pine beetle (MPB, Dendroctonus ponderosae), and climate change prompted an interagency working group to design and implement a long-term monitoring program in the GYE. Our primary objective was to determine the status and trends in the proportion of trees >1.4 m tall infected with WPBR and to provide information to federal managers, at a regional...

The combined threats of the current mountain pine beetle (Dendroctonus ponderosae, MPB) epidemic with the imminent invasion of white pine blister rust (caused by the non-native fungus Cronartium ribicola, WPBR) in limber pine (Pinus flexilis) forests in northern Colorado threatens the limber pine's regeneration cycle and ecosystem function. Over one million hectares of Colorado forests have been infested by MPB between 1996 and 2008 (U.S. Department of Agriculture 2010). Limber pine makes up only approximately 3 percent of this infested area (U.S. Department of Agriculture, unpublished...

The nearly two million acres of high elevation forests in the Western United States are not an important source of timber or any other market products. However, that does not mean that the forests are not highly valuable. Visitors and nonvisitors alike value the unique five-needle pine trees found in these high elevation ecosystems. In this study, we estimate the nonmarket benefits of preserving high elevation forests in the Western United States from the threat of white pine blister rust (WPBR), a non-native pathogen. A contingent valuation survey collected information about attitudes,...

Whitebark pine's (Pinus albicaulis) notable ecological values, combined with its precarious state, underscore the need for monitoring its health and dynamics. Populations of whitebark pine are in decline throughout most of its range. White pine blister rust, caused by the fungus Cronartium ribicola, has denuded stands since introduction during the early 1900s (Tomback and Achuff 2010). The exclusion of fire, which historically promoted whitebark pine over its competitors, has further lessened its proportional abundance with competitors (Murray 2007; Murray and others 2000). Mountain pine...

Whitebark pine (Pinus albicaulis) populations are under threat across the species' range from white pine blister rust (Cronartium ribicola), mountain pine beetle (Dendroctonus ponderosae), fire exclusion and climate change (Tomback and Achuff 2010). Loss of whitebark pine is predicted to have cascading effects on the following ecological services: provision of high-energy food for wildlife (Tomback and Kendall 2001), facilitation of succession (Callaway 1998) and retention of snowpack (Tomback and others 2001).

White pine blister rust occurs when there are compatible interactions between susceptible hosts (white pines and Ribes spp.), inoculum (Cronartium ribicola spores), and local weather conditions during infection. The five spore stages of the white pine blister rust (WPBR) fungus have specific temperature and moisture conditions necessary for production, germination, and dissemination of spores. Local meteorological conditions may be important factors in infection success, infection periodicity and disease intensification over time.

Pinus aristata Engelm., Rocky Mountain bristlecone pine, has a narrow geographic and elevational distribution and occurs in disjunct mountain-top populations throughout Colorado and New Mexico in its core range. The species' unique aesthetic and ecological traits combined with the threats of the exotic disease white pine blister rust (WPBR), climate change in high elevation systems, and an outbreak of a native bark beetle make P. aristata of conservation interest, however, little is known about the species genetic structure or adaptive capabilities. Genetic diversity is the foundation for...

This paper synthesizes existing information about the disturbance ecology of high-elevation five-needle pine ecosystems, describing disturbances regimes, how they are changing or are expected to change, and the implications for ecosystem persistence. As it provides the context for ecosystem conservation/restoration programs, we devote particular attention to wildfire and its interactions with mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreaks and white pine blister rust (Cronartium ribicola J.C. Fisch.).