A Dendroclimatic Record of Paleoclimate of the Last 10,000 Years, Glacier Bay National Park and Preserve: Progress Understanding Climate Change In Southeast Alaska
Our investigations in 2007 focused on continuing collection and analyses of tree rings from living trees and building a long ring-width series from interstadial wood. These interstadial forests were extensive and their preservation, although discontinuous and fragmented, is remarkable. In situ stump...
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| Format: | Text |
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DigitalCommons@University of Nebraska - Lincoln
2007
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| Online Access: | https://digitalcommons.unl.edu/usarmyresearch/22 https://digitalcommons.unl.edu/context/usarmyresearch/article/1029/viewcontent/Lawson_etal_2007_AnnualPaleoclimateReport.pdf |
| Summary: | Our investigations in 2007 focused on continuing collection and analyses of tree rings from living trees and building a long ring-width series from interstadial wood. These interstadial forests were extensive and their preservation, although discontinuous and fragmented, is remarkable. In situ stumps, still rooted in growth position, and logs held within sediments remain from forests that existed at various times between glaciations over approximately the last 10,000 years. We have analyzed previous and new collections of ring-width tree-ring series, including a multiple species collection from near Excursion Ridge in the southeast portion of the Park. These tree-ring series have a strong temperature signal and together with our other collections along the Gulf of Alaska are being used in three undergraduate theses. The trees show a divergence from expected growth within some sites and this decrease in growth is being investigated in Glacier Bay and along the Gulf of Alaska. We continue to share our tree-ring data with other researchers (Capps, Clague, Luckman) working on ice-dammed lakes of Brady Glacier who have been able to tree-ring date a significant lake damming event along the ice margin. Denny Capps, a PhD candidate from Simon Fraser University, worked at The College of Wooster Tree Ring Lab on tree cores from Brady Glacier during the fall of 2007, acquiring data that will be useful to both of our projects. Our further sampling and tree-ring dating of logs from the southern end of Glacier Bay suggests a remarkably rapid advance of the tidewater glacier as it reached near its Holocene maximum in the early 1700s. This is an interesting find in that it meshes with the relatively well-documented oral history compiled by others for the area and the recent work of Streveler, Connor, Howell and Montieth. We built on our work in the previous year that developed calendar-dated ice advances about AD 800 and a relative tree-ring sequence spanning several hundred years tied to radiocarbon dating that suggests ice ... |
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