Post-Glacial Fire and Vegetation History of Horsetail Lake in the Teanaway Area of the Central Eastern Cascades, Washington

Presenter Information

Serafina Ferri
Megan Walsh

Document Type

Oral Presentation

Campus where you would like to present

SURC Ballroom B/C/D

Start Date

21-5-2015

End Date

21-5-2015

Keywords

Biogeography, Environment, Reconstruction

Abstract

Landscapes of the Pacific Northwest have been shaped by dramatic shifts in climate since the last glacial maximum, and more recently, by human activity. However, it is unclear how past relationships between people, fire, and climate played out on the landscape. The purpose of this research is to reconstruct the post-glacial paleoenvironmental history of a wetland known as Horsetail Lake, located in the Teanaway area of the eastern Cascades. The goal is to evaluate how fire activity and vegetation patterns have varied under different climatic scenarios during the last ~13,000 years and in relation to human land-use actions. This lake was selected because it is one of only a few natural wetlands that exist in the Teanaway area below an elevation of 4,000 feet, and because the archaeological record supports the idea that people utilized mountain environments in the eastern Cascades similar to that around the site. In 2011, a nine-meter long sediment core was extracted from Horsetail Lake using a modified Livingstone corer. High-resolution macroscopic charcoal and pollen analysis is being used to reconstruct the fire and vegetation history of the Horsetail Lake watershed. The chronology of the sediment will be determined using radiocarbon (14C) dating and tephra layer identification. Preliminary results of this study show that fire frequency and severity has varied widely at Horsetail Lake during the post-glacial period. The early Holocene shows high fire activity with a drop in fire activity during the middle Holocene. Fire activity then becomes more frequent during the late Holocene. Completion of the pollen analysis will show how the forest around Horsetail Lake has changed both in terms of composition and structure in relation to the fire history. My results will hopefully be incorporated in future management plans of forest environments in the eastern Cascades as climate continues to change.

Poster Number

34

Faculty Mentor(s)

Megan Walsh

Department/Program

Resource Management

Additional Mentoring Department

Resource Management

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May 21st, 11:30 AM May 21st, 2:00 PM

Post-Glacial Fire and Vegetation History of Horsetail Lake in the Teanaway Area of the Central Eastern Cascades, Washington

SURC Ballroom B/C/D

Landscapes of the Pacific Northwest have been shaped by dramatic shifts in climate since the last glacial maximum, and more recently, by human activity. However, it is unclear how past relationships between people, fire, and climate played out on the landscape. The purpose of this research is to reconstruct the post-glacial paleoenvironmental history of a wetland known as Horsetail Lake, located in the Teanaway area of the eastern Cascades. The goal is to evaluate how fire activity and vegetation patterns have varied under different climatic scenarios during the last ~13,000 years and in relation to human land-use actions. This lake was selected because it is one of only a few natural wetlands that exist in the Teanaway area below an elevation of 4,000 feet, and because the archaeological record supports the idea that people utilized mountain environments in the eastern Cascades similar to that around the site. In 2011, a nine-meter long sediment core was extracted from Horsetail Lake using a modified Livingstone corer. High-resolution macroscopic charcoal and pollen analysis is being used to reconstruct the fire and vegetation history of the Horsetail Lake watershed. The chronology of the sediment will be determined using radiocarbon (14C) dating and tephra layer identification. Preliminary results of this study show that fire frequency and severity has varied widely at Horsetail Lake during the post-glacial period. The early Holocene shows high fire activity with a drop in fire activity during the middle Holocene. Fire activity then becomes more frequent during the late Holocene. Completion of the pollen analysis will show how the forest around Horsetail Lake has changed both in terms of composition and structure in relation to the fire history. My results will hopefully be incorporated in future management plans of forest environments in the eastern Cascades as climate continues to change.