Climate Change Altered Disturbance Regimes in
High Elevation Pine Ecosystems
Jesse A. Logan, USDA Forest Service, Logan, Utah
Ecological Amenities and Services
The forest area impacted by insects and pathogens is approximately 45 times that of fire, with an economic impact that is
almost 5 times as great. Dale VH, Joyce LA, McNulty S, et al. 2001. Climate change and forest disturbance. BioScience 51: 723-34.
Elevation - Voltinism
Whitebark Pine
Spruce/Fir
Lodgepole Pine
RRR – Study Site
> 1270 yr. old
Dana Perkins
Model for Adaptive Seasonality
(1) G-curve has an intersection (Synchrony)
(2) Winding Number =1 (Univoltione)
(3) G-curve Intersection is at an appropriate
time of year (Seasonality)
If any one of these conditions are violated,
Then it is not an adaptive seasonality
Railroad Ridge S. site 1996
Logan, J. A., P. V. Bolstad, B. J. Bentz, & D. L. Perkins.
1995. Assessing the effects of changing climate on
mountain pine beetle dynamics. pp. 86-108 In Hain, F. P., S.
M. Salom, W. F. Ravlin T. L. Payne, K. F. Raffa (eds.)
Proceedings, IUFRO Conference, Scolytid bark beetles:
behavior, population dynamics, and control of forest insects,
Maui, Hawaii, Feb., 1994.
Logan, J. A., and B. J. Bentz. 1999. Model analysis of
mountain pine beetle seasonality. Environ. Entomol. 28:
924-934
JA Logan and JA Powell. 2001. Ghost forests, global
Warming and the mountain pine beetle. Environ. Entoml.
47: 160-173.
MPB in High Elevation Ecosystems
2003
2001
Snowbank Mt.
8,000 ft.
2004
2003
Railroad Ridge
10,000 ft.
2004
2004 – Photo: Jeff Hicke
Sylvan Pass
YNP
1993
Change in Mean Ann. T ºC
BRADLEY ET AL. 2004. AMERICAN
CORDILLERA TEMPERATURE
CHANGES. GEOPHYSICAL RESEARCH
LETTERS, VOL. 31, L16210 – Average of
Seven coupled atmospheric-ocean GCMs. The
plots show the difference between the control
Simulations and simulations with a CO2
doubling scenario
Change in Mean Winter T ºC
Change in Mean Summer. T ºC
MONTANA
WYOMING
IDAHO
Basic Issues/Key Questions For Native Insects
in Historical Host Association
How unusual are the events we are seeing?
IUFRO – Maui, Hawaii - February, 1994
Something Outside Our Experience Appears
To be Going On
CONCLUSIONS
1. Physiologically based model predicted shift from
hostile to benign thermal habitat
2. Unprecedented outbreaks accompanied series of
warm years
3. Outbreak characteristic of invasive native species
4. Coupled GCM predict exceptionally sever
warming at high elevation and at biologically
sensitive time of year
5. Potential loss of ecological services and
biodiversity
6. Time to begin formulation of effective
management response