Treesearch

Limber pine ( Pinus flexilis James) and Rocky Mountain bristlecone pine (P. aristata Engelm.; hereafter referred to as bristlecone pine) are the dominant pines that occupy high elevation habitats of the southern Rockies. Bristlecone pine is primarily a subalpine and tree-line species while limber pine in the southern Rocky Mountains grows from 1600 m in the short grass steppe to over 3300 m elevation near the continental divide (see Schoettle 2004). These trees provide many ecosystem services including food for corvids, bears and squirrels, watershed protection, and picturesque gnarled...

White pine blister rust (caused by the non-native pathogen Cronartium ribicola) reached northern California about 80 years ago. Over the years its spread southward had been primarily recorded on sugar pine. However, observations on its occurrence had also been reported in several of the higher elevation five-needled white pine species in California. Since the late 1990s, field surveys have substantiated that rust is present in several of these higher elevation species. The combined results of three local surveys in the Sierra Nevada and Warner mountains documented the occurrence of rust in...

A goal of breeding programs for resistance to white pine blister rust is the development of multigenic resistance, even if the genetics and mechanisms of resistance may be imperfectly understood. The goal of multigenic resistance has prompted efforts to categorize host resistance reactions at increasingly finer scales, to identify heritable traits that may confer quantitative resistance. PCR amplification of Cronartium ribicola DNA presents a sensitive and highly specific method for detection of C. ribicola in host tissues, and is well suited to screening of large numbers of samples for...

Pinus monticola (Dougl. ex D. Don.) maintains a complex defence system that detects white pine blister rust pathogen (Cronartium ribicola J.C.Fisch.) and activates resistance responses. A thorough understanding of how it functions at the molecular level would provide us new strategies for creating forest trees with durable disease resistance. Our research focuses on molecular dissection of P. monticola major gene (Cr2) resistance and quantitative partial resistance. To characterize the Cr2 gene, resistance gene family encoding proteins with nucleotide-binding-site and leucine- rich- repeat...

Infection and mortality levels from Cronartium ribicola, the fungus causing white pine blister rust, are very high in parts of the geographic range of Pinus albicaulis (whitebark pine) and P. strobiformis (Southwestern white pine). Genetic resistance to this non-native fungus will be one of the key factors in maintaining or restoring populations of these species in areas of high blister rust incidence. Trials at Dorena Genetic Resource Center (Dorena GRC), OR, for blister rust resistance evaluation of seedling progenies of P. albicaulis from Oregon and Washington populations began in 2001;...

Many ecologically important, five-needle white pine forests that historically dominated the high elevation landscapes of western North America are now being heavily impacted by mountain pine beetle (Dendroctonus spp.) outbreaks, the exotic disease white pine blister rust (WPBR), and altered high elevation fire regimes. Management intervention using specially designed strategic treatments will be needed to conserve these keystone species. The goal of this intervention is to promote self-sustaining five-needle white pine ecosystems that have both resilience to disturbances and genetic...

This paper offers a preliminary investigation into the conditions under which it might be optimal to engage in proactive management of a non-timber forest resource in the presence of an invasive species whose spread is unaffected by management action. Proactive management is defined as treating an uninfected area to encourage healthy ecosystem function, given that the arrival of the invasive is inevitable. Inspired by the problem of white pine blister rust in the Rocky Mountain west of the United States, the model was solved under varying assumptions concerning the scale of management...

The 35 papers in this proceedings are divided into four sections; the first includes an introduction to the symposium theme of Shrublands as wildlands and wildlife habitat, along with keynote addresses discussing geographic affiliations of eastern Montana's "great Plains Flora" and methodology for surveying mule deer winter range habitat use and condition. The next two sections cluster papers on wildlife habitat and ecological relationships. These sections provide a diverse sampling of topics examining the nature and impacts of intra- and inter-trophic relationships among plants and...

Assisted migration - the translocation of a species into a climatically-suitable location outside of its current range - has been proposed as a means of saving vulnerable species from extinction as temperatures rise due to climate change. We explore this controversial technique using the keystone wildlife symbiote and ecosystem engineer, whitebark pine (Pinus albicaulis). Species distribution models (SDMs) predict that whitebark pine will be extirpated from most of its current range over the next 70 years. However, the same models indicate that a large quadrant of northwestern British...

Species distribution models (SDMs) predict that whitebark pine (Pinus albicaulis) will lose much of its current climatic range in Cascadia (the Pacific Northwest in the United States plus British Columbia, Canada) by the 2080s as the climate warms. However, the same models indicate that the species will simultaneously gain a large, climatically-favorable habitat expanse northwest of its current northern range limit. While SDMs are one of the best tools available for predicting range shifts under climate change, their shortcomings, particularly for threatened species like whitebark pine,...