United States Department of Agriculture, Forest Service
Pacific Southwest Research Station
Sierra Nevada Research Center
Medieval Forests, Volcanism, and Response to Climate: Clues to ecological effects of
future climate changes
The Research:
Whitewing Mountain, 3030 m, is a broad peak extending above
current treeline that lies east of the main Sierra Nevada crest
and adjacent to the Inyo Craters volcanic chain. The last eruptive
sequence of Glass Creek Vent occurred ~500-800 years ago and
covered the flanks and summit of Whitewing Mountain with
more than 4 m of tephra. Strewn on top of the tephra over the
otherwise barren summit plateau are hundreds of well-preserved
dead tree stems, many of which are large, straight, and exhibit
evidence of rapid growth from their tree-rings. The surprising
growth rate, form, and occurrence of trees in this ‘ghost forest’ at
this elevation suggest that they grew under climates very different
from the present. Regular orientation of the tree stems and
absence of stump bases suggest that the trees died in the Glass
Creek Vent eruption. A similar situation exists on adjacent San
Joaquin Mountain. We are using these natural events to unravel the
story of forest origin, the climate under which the forests grew,
and the exact year of the volcanic event.
Objectives:
• Identify species and determine dates of trees that grew in the
ghost forest on the summit of Whitewing Mountain.
• Accurately date the last eruption of Glass Creek vent.
• Model the climatic conditions under which the forest grew and
interpret the significance and implications for forest response to
future climate change.
Our Mission:
Sierra Nevada Ecosystems are
complex and our knowledge
of them is incomplete.
As a result, the long term
outcome of any given land
and resource management
strategy is uncertain. We
will provide assistance to
land managers and policy
makers by addressing this
management dilemma
through targeted research,
emphasizing an integrated,
ecoregional approach to
examine particular physical,
ecological, and socioeconomic issues, across a
range of appropriate spatial
and temporal scales specific
to each issue.
This unit will represent the
collective research expertise
and interests of scientists
located in Fresno, Davis
and Albany as well as other
scientists within the Pacific
Southwest Research Station.
With a full spectrum of
research, from long term,
fundamental research
to short-term, tactical
applications, this Center
is intended to support
conservation, restoration,
and sustainable utilization of
the lands within the Sierra
Nevada ecoregion.
Application of Research Results:
Using ecological niche theory and contemporary distributions of the species,
we modeled paleoclimate during the Medieval period of the ghost forest to be
significantly warmer (+3.2 degrees C annual minimum temperature) and slightly drier
(-24 mm annual precipitation) than present. These values resemble projections for
California in the next 70-100 years under conditions of global warming, and give
insight into the potential responses of forests in subalpine zones. Based on conditions
at Whitewing Mountain, forest managers and conservationists may expect much larger
movement of tree species in response to climate change than has been anticipated to
date. Non-equilibrium changes, with species moving individualistically, rather than in
equilibrium with their current ranges, may be expected. Regional extirpations, such
as happened to sugar pine in the eastern Sierra following climatic change at the end
of the Medieval period, should also be a potential outcome that managers evaluate as
they plan climate-informed policy.
Location:
Whitewing Mountain, 10,012’ (3030
m), eastern Sierra Nevada, between
Mammoth Lakes, and June Lake,
CA, Mono County, and similar
environmental locations nearby (San
Joaquin Mountain).
Publications:
PDFs available at: http://www.fs.fed.us/psw/programs/snrc/staff/millar
• Millar, C.I., J.C. King, R.D. Westfall, H.A. Alden, and D.L. Delany. 2006. Late
Holocene forest dynamics, volcanism, and climate change at Whitewing Mountain and
San Joaquin Ridge, Mono County, Sierra Nevada, CA, USA. Quaternary Research 66
(2006): 273-287.
• Poster: Millar, CI; Westfall, RD; Delany, DL; King, JC; and Alden, HA. 2004. HighElevation Response of Conifers to Climate Change in the Sierra Nevada and Western
Great Basin, USA: Treeline Elevation is Not the Primary Effect.
• Poster: Millar, CI; Westfall, RD; Delany, DL; King, JC; and Alden, HA. 2004.
Climate as an Ecosystem Architect; Responses of High-Elevation Conifers to Past
Climate Variability.
http://www.fs.fed.us/psw/programs/snrc
USDA Forest Service
Pacific Southwest Research Station
Sierra Nevada Research Center
Albany Location:
800 Buchanan Street
Albany, CA 94710
For further information contact:
Dr. Connie Millar
cmillar@fs.fed.us
Mailing Address:
P.O. Box 245
Berkeley, CA 94701
Dr. Peter Stine, Program Manager
Phone: 510-559-6300
Fax: 510-559-6440
Davis Location:
2121 Second Street
Suite A101
Davis, CA 95616
Phone: 530-759-1700
Fax: 530-747-0241
Fresno Location:
2081 E. Sierra Avenue
Fresno, CA 93710
Phone: 559-323-3200
Fax: 559-297-3355