Feedback-driven response to multidecadal climatic variability at an alpine treeline

Physical Geography
By: , and 



The Pacific Decadal Oscillation (PDO) has significant climatological and ecological effects in northwestern North America. Its possible effects and their modification by feedbacks are examined in the forest-tundra ecotone in Glacier National Park, Montana, USA. Tree ring samples were collected to estimate establishment dates in 10 quadrats. Age-diameter regressions were used to estimate the ages of uncored trees. The temporal pattern of establishment and survival was compared to the pattern of the PDO. A wave of establishment began in the mid-1940s, rose to a peak rate in the mid-1970s, and dropped precipitously beginning ca. 1980 to near zero for the 1990s. The period of establishment primarily coincided with the negative phase of the PDO, but the establishment and survival pattern is not correlated with the PDO index. The pattern indicates a period during which establishment was possible and was augmented by positive feedback from surviving trees. Snow may be the most important factor in the feedback, but studies indicate that its effects vary locally. Spatially differentiated analyses of decadal or longer periodicity may elucidate responses to climatic variation.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Feedback-driven response to multidecadal climatic variability at an alpine treeline
Series title Physical Geography
DOI 10.2747/0272-3646.24.6.520
Volume 24
Issue 6
Year Published 2003
Language English
Publisher Taylor & Francis
Contributing office(s) Northern Rocky Mountain Science Center
Description 16 p.
First page 520
Last page 535
Country United States
State Montana
Other Geospatial Glacier National Park
Online Only (Y/N) N
Additional Online Files (Y/N) N
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