Tree growth and inferred temperature variability at the North American Arctic treeline

Publication Status is "Submitted" Or "In Press: 
LDEO Publication: 
Publication Type: 
Year of Publication: 
2009
Editor: 
Journal Title: 
Global and Planetary Change
Journal Date: 
Jan
Place Published: 
Tertiary Title: 
Volume: 
65
Issue: 
1-2
Pages: 
71-82
Section / Start page: 
Publisher: 
ISBN Number: 
0921-8181
ISSN Number: 
Edition: 
Short Title: 
Accession Number: 
ISI:000263630800006
LDEO Publication Number: 
Call Number: 
Abstract: 

We present white spruce (Picea glauca) tree-ring width and maximum latewood density chronologies for two latitudinal treeline sites in northern interior Canada: along the Coppermine River in the Northwest Territories (NWT); and in the Thelon River Sanctuary, Nunavut. These chronologies provide climate and tree growth information for these two remote locations, filling a sizeable gap in spatial coverage of proxy records used to reconstruct temperature variability for the Northern Hemisphere. They represent some of the longest high-resolution proxies available for northern North America, dating as far back as AD 1046 for Coppermine ring widths. These chronologies correlate significantly with hemispheric-scale annual temperature reconstructions for the past millennium. Density records from both sites show a positive relationship with warm-season temperature data since similar to the mid-20th century, although this link is somewhat weaker in recent decades (since similar to 1980). Both ring-width chronologies demonstrate even greater loss of temperature sensitivity, and in the Thelon ring-width series a sustained reduction in growth appears linked to increased drought stress in this recent period. Diminishing correlations with temperature are also found when the Thelon ring-width and climate data are prewhitened, indicating that any low frequency uncertainties in the instrumental or tree-ring data (e.g., artifacts from the standardization process) cannot entirely account for this result. Our findings therefore suggest a recent loss of temperature sensitivity at these northern treeline locations that varies with the parameter and site studied. These and other uncertainties in the tree-ring as well as instrumental data will need to be resolved in future efforts to relate northern tree-ring records to temperature variability on a range of spatial scales. (C) 2008 Elsevier B.V. All rights reserved.

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411EKTimes Cited:0Cited References Count:52

DOI: 
DOI 10.1016/j.gloplacha.2008.10.011