Ring widths from whitebark pine (Pinus albicaulis Englem.) and subalpine larch (Larix lyallii Parl.) collected at three high-elevation sites were used to develop tree-growth chronologies to reconstruct summer temperature anomalies. A step-wise multiple regression procedure was used to screen potential predictor variables to generate a transfer function capable of skillfully reconstructing summer temperature. The resulting regression model explained approximately 38% of the adjusted variance in the instrumental temperature record. The fidelity of the reconstruction was verified using product mean and sign tests, both of which suggested significant predictive power in the reconstructions (p < 0.05). Reduction of error (RE) and coefficient of efficiency (CE) measures were both positive, indicating the reconstruction contained useful climate information. Cool periods often coincided with reduced solar activity and/or periods of increased volcanic activity. Differences between this reconstruction and others encompassing a broader geographic scale highlight the importance of developing local reconstructions of climate variability, particularly when used in conjunction with ecological data sets that describe the occurrence of fires or insect epidemics. Mixed and divergent climate-response relationships were evident in the whitebark pine chronologies and suggest subalpine larch may be a more useful species than whitebark pine to target for the development of temperature reconstructions in this region.
Bibliographical noteFunding Information:
This research is based on work supported by the National Science Foundation under Grant No. SBR-9619411 and a Research Joint Venture agreement form the USDA Forest Service, No. RMRS-99611-RJVA. I am grateful for assistance in the field from Kiyomi Morino, Mark Betancourt, John Braman, Sharon Horn, Tom Harlan, Tom Swetnam, and Matt Rollins. Peter Brown and Connie Woodhouse graciously provided additional subalpine larch samples from Baker Lake, Montana which substantially improved the tree-ring chronology sample depth in its earliest periods. Tom Swetnam, Malcolm Hughes, Patrick Bartlein, Grant Elliott, Evan Larson, and two anonymous reviewers offered valuable comments on earlier drafts of this research.
Copyright 2011 Elsevier B.V., All rights reserved.
- Northern Rocky Mountains
- Selway-Bitterroot wilderness area
- Subalpine larch
- Whitebark pine