Changes in intensity of white pine blister rust on western white pine across time and changing climate in the interior northwestern USA
| Authors: | Mee-Sook Kim, Jane E. Stewart, Marcus V. Warwell, John W. Hanna, Paul J. Zambino, Geral McDonald, Bryce A. Richardson, Ned B. Klopfenstein |
| Year: | 2025 |
| Type: | Paper |
| Station: | Rocky Mountain Research Station |
| Source: | Corvallis, OR: Oregon State University, Engineering Resources and Management, Swiss Needle Cast Cooperative |
Abstract
Western white pine (WWP; Pinus monticola) is a keystone species in temperate, moist forests of western North America, where it displays adaptation to a range of climates and resilience to native root diseases (e.g., Harvey et al. 2008). Since Cronartium ribicola, the cause of white pine blister rust (WPBR), was introduced to North America in the early 1900s, WPBR has become well established and caused a dramatic reduction of WWP across its range (e.g., Neuenschwander et al. 1999; Harvey et al. 2008). Over recent decades, casual observations have indicated that WPBR incidence rates may be lower in some naturally regenerated WWP stands than was historically reported in the decades following the introduction of C. ribicola into WWP stands of northern Idaho, USA and adjacent regions (G.I. McDonald and others, person observations). In general, WPBR incidence historically increased on average by ca. 3% per year on WWP between the ages of 2-40 years (e.g., Carlson and Toko, 1968; Ketcham et al. 1968). Analyses of recent WPBR incidence rates in regenerated WWP sites may be useful to identify sites with reduced WPBR intensity where natural regeneration of WWP should be encouraged by forest managers to foster forest resilience. Although WWP is considered a generalist with populations that exhibit relatively broad climatic adaptation, ongoing climate change will likely alter its geographic range (e.g., Rehfeldt et al. 2020). For future forests, increased reliance on WWP might offer some resilience to climate change, provided that the concomitant WPBR intensity allows for sufficient WWP growth and survival to maturity.