Browsing by Author "Pederson, Gregory Thomas"

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Long-term perspectives on northern Rockies climatic variability from tree rings in Glacier National Park, Montana
(Montana State University - Bozeman, College of Agriculture, 2004) Pederson, Gregory Thomas; Chairperson, Graduate Committee: Lisa J. Graumlich.
Instrumental climate records reveal fluctuations in summer moisture anomalies and winter snowpack in Glacier National Park, Montana, on decadal and multidecadal timescales. However, because climate records for the region are limited to the 20th century, studies on the impacts of long-duration variations in climate on physical and ecosystem processes were limited. Therefore, a reconstruction of summer moisture variability (June - August) spanning A.D. 1540-2000 was created from a multi-species network of tree-ring chronologies sampled in Glacier National Park. The reconstruction shows decadal-scale shifts between drought and pluvial events with a pronounced cool/wet period spanning the end of the Little Ice Age (A.D. 1770-1840). The single most exceptional drought event occurred over the 20th century (A.D. 1917-1941) and was associated with the most spatially consistent drought regime throughout the northern Rockies and Pacific Northwest over the past ~500 yrs. Among a wider spatial network of hydroclimatic reconstructions arrayed along a north-south Rocky Mountain transect, trends at Glacier National Park were found to be most similar to those in the Canadian Rockies and the Pacific Northwest.