Treesearch

The nonnative pathogen Cronartium ribicola, the cause of the lethal white pine blister rust (WPBR) disease, is spreading through limber pine (Pinus flexilis) and Rocky Mountain bristlecone pine (P. aristata) forests of the southern Rocky Mountains (USA). An integrated regional program - the Proactive Strategy - is characterizing the infestation and gaining ecological and genetic knowledge of these less well studied ecosystems. This knowledge will provide the science foundation for early interventions to mitigate the development of ecological impacts to the high mountain headwater ecosystems...

Drippy blight is an emergent disease of red oaks, caused by the interaction between a kermes scale insect (Allokermes galliformis) and a bacterium (Lonsdalea quercina subsp. quercina). Multi-locus sequence analysis was used to confirm the bacterial pathogen’s identity and its relationship to other phylogenetically related Enterobacteriaceae species. Further, Koch’s postulates were performed on sapling red oaks. Prior to the discovery of drippy blight disease in Colorado, in the United States, the bacterium was reported on oak trees in California but was limited to acorn infections. The...

Wilderness and other protected natural areas like national forests, parks and refuges are managed to provide high quality recreational opportunities while preserving natural resource conditions. In managing recreation visitation, land managers could allow visitors to create their own infrastructure of trails and campsites, or they could choose to apply an impact management strategy to provide an infrastructure that includes sustainably designed trails and campsites. Recreation ecology studies have repeatedly demonstrated that informal “visitor-created” trails and campsites are generally...

Allokermes galliformis (Riley) (Hemiptera: Kermesidae), sometimes referred to as the ‘pin oak kermes’, has emerged as a significant pest of red oaks grown in the Front Range area of eastern Colorado. Although kermes scales infrequently cause significant tree damage, a novel association exists between the pin oak kermes and the pathogenic bacterium Lonsdalea quercina subsp. quercina. Together, they produce drippy blight disease of red oaks which is characterized by significant branch dieback. Field studies were conducted in Boulder, CO during 2015–2016 to better understand the life history...

Whitebark pine (Pinus albicaulis) is very susceptible to white pine blister rust, caused by the fungal pathogen Cronartium ribicola. Operational programs to develop resistant populations of whitebark pine are underway. These programs rely on artificial inoculation of young seedlings and can evaluate hundreds of parent trees using seedling progeny in a relatively short time. The trial reported here was undertaken at Dorena Genetic Resource Center (Cottage Grove, Oregon, USA). Inoculation was very effective and produced a high incidence and severity of disease in the seedlings with 99.9...

Controlled inoculations of whitebark pine (Pinus albicaulis) families in British Columbia (BC), Canada, took place in 2013 and 2014 at the Kalamalka Forestry Centre in Vernon. This effort has focused on 40 families from the Kootenay region with results (identification of disease-resistant families) expected over the next 5 years. Meanwhile, demand continues for further screening of whitebark pine from other regions in Canada. New funding from the BC Forest Genetics Council will permit work to continue. Our plan is to inoculate 40 additional families per year (2016-2018). Seedlings will be...

Southwestern white pine (SWWP, Pinus strobiformis), a long-lived conifer in Mexico and the southwestern United States, is very susceptible to the nonnative pathogen Cronartium ribicola, the cause of white pine blister rust. Due to the recent introduction of C. ribicola to the Southwest, the future viability of many populations of SWWP is in jeopardy. Fortunately, some early studies showed that there is at least a low frequency of genetic resistance in SWWP. In partnership with the U.S. Department of Agriculture, Forest Service (USDA FS), Southwestern Region Forest Health Protection and...

White pine blister rust, a devastating disease caused by the rust pathogen Cronartium ribicola, has been attacking and killing western white pines (Pinus monticola) for more than 100 years since its introduction to the Canadian province of British Columbia (BC) (Hunt 2009). There is a single dominant (major) gene for resistance (MGR) that produces a hypersensitive infection spot similar to that observed in resistant reactions in other plants attacked by rust pathogens. It was first found in a limited geographic area of southern Oregon, USA, known as the Champion Mines (Kinloch et al....

The Lick Creek Demonstration/Research Forest is one of those places in the West that many foresters may not be familiar with by name but by photographs. Posters depicting forest change over the years circulated widely from the 1980s to 2000s, following Forest Service General Technical Reports from Gruell et al. (1982) and Smith and Arno (1999).

Whitebark pine (Pinus albicaulis Engelm.) has recently experienced high mortality due to multiple stressors, and future population viability may rely on natural regeneration. We assessed whitebark pine seedling densities throughout the US Rocky Mountains and identified stand, site, and climatic variables related to seedling presence based on data from 1,217 USDA Forest Service Forest Inventory and Analysis plots. Although mean densities were highest in the whitebark pine forest type, 83% of sites with seedlings present occurred in non-whitebark pine forest types, and the highest densities...