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Author(s):
Elizabeth M. Campbell, Robert E. Keane, Evan R. Larson, Michael P. Murray, Anna W. Schoettle, Carmen Wong
Year Published:

Cataloging Information

Topic(s):
Fire Ecology
Insects & Disease
Fire & Bark Beetles
Fire History
Frequency
Fire & Climate
Management Approaches
Recovery after fire
Resilience
Ecosystem(s):
Alpine forest/krummholz, Subalpine wet spruce-fir forest, Subalpine dry spruce-fir forest

NRFSN number: 11896
FRAMES RCS number: 13771
Record updated:

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.). Patterns of fire disturbance and post-fire regeneration in high-elevation five-needle pine ecosystems are highly variable over space and time. While stand-replacing fires predominate in some regions, mixed severity fire regimes that include low intensity surface fires and crown fire components, appear most common. Fire disturbance provides critical regeneration opportunities for most high-elevation five-needle pines but fire exclusion over the last century is having some impacts-such as major declines of white-bark pine (Pinus albicaulis Englem). Historic mountain pine beetle outbreaks caused episodes of mature high-elevation five-needle pine death over large regions. While these pines have adapted to this historic pattern of disturbance, global climate change is causing the geographic expansion of beetle outbreaks that are killing high-elevation pines in places with no history of major impacts. Expanding beetle outbreaks and exotic blister rust infections, which continue to intensify and spread into the southernmost geographic range of high-elevation five-needle pines, reduce the density of seed bearing trees and hasten succession. Global climate change may also generate more frequent severe fires. This may pose a threat to some pines and generate regeneration opportunities for others, provided beetle outbreaks and blister rust have not reduced the density of seed-bearing trees below critical thresholds. High-elevation five-needle pine ecosystem responses to disturbance are complex and while there is still much to learn, management efforts are moving forward to conserve and restore these critical components of mountain landscapes. Given the complexity and uncertainty of ecosystem response to disturbance, a cautious yet proactive approach to management will be necessary to build ecosystem resilience to future disturbances, whether natural or human-caused.

Citation

Campbell, Elizabeth M.; Keane, Robert E.; Larson, Evan R.; Murray, Michael P.; Schoettle, Anna W.; Wong, Carmen. 2011. Disturbance ecology of high-elevation five-needle pine ecosystems in western North America. In: Keane, Robert E.; Tomback, Diana F.; Murray, Michael P.; and Smith, Cyndi M., eds. 2011. The future of high-elevation, five-needle white pines in western North America: Proceedings of the High Five Symposium; 2010 June 28-30; Missoula, MT. Proceedings RMRS-P-63. Fort Collins, CO: USDA Forest Service, Rocky Mountain Research Station. p. 154-163.

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