Title

Holocene Fire History of the Area Surrounding Lemanasky Lake, Eastern Cascades, Washington

Presenter Information

Grant Clifton
Megan Walsh

Document Type

Oral Presentation

Location

SURC Ballroom B/C/D

Start Date

21-5-2015

End Date

21-5-2015

Keywords

Fire, Charcoal, Paleoecology

Abstract

Macroscopic charcoal analysis of lake sediments has been successfully used to reconstruct past fire patterns throughout the Pacific Northwest; however, there has been little research done on the forests of the eastern Cascades of Washington State. This research reconstructs the fire history of Lemanasky Lake, Washington (48.7°N, -119.6°W; elevation: 1088 m), located in the Cascade foothills near the Sinlahekin Wildlife Area, roughly five miles northwest of Tonasket, Washington. The analysis of macroscopic charcoal from a five-meter long sediment core provides a record of Holocene fire activity in the forest surrounding the lake. The primary research question addressed in this study is: “How has fire activity changed at the study site during the Holocene, and what has been the cause of those changes?” In order to reconstruct the local fire history of the site, we counted all macroscopic charcoal particles >125 microns from contiguous 2 cm3 samples taken at 1 cm intervals. Our results suggest intentional fire suppression during the last ~100 years, which was preceded by frequent, low severity ground fires, with less fire activity prior to that. This reconstruction not only facilitates our understanding of changes in fire frequency and severity at the site as a result a past climatic variability, but more importantly shows how 20th century fire suppression has affected the forest. Additionally, the results may assist landowners within the wildlife-urban interface of Washington in implementing safe fire management practices.

Poster Number

26

Faculty Mentor(s)

Megan Walsh

Department/Program

Anthropology & Museum Studies

Additional Mentoring Department

Geography

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May 21st, 8:30 AM May 21st, 11:00 AM

Holocene Fire History of the Area Surrounding Lemanasky Lake, Eastern Cascades, Washington

SURC Ballroom B/C/D

Macroscopic charcoal analysis of lake sediments has been successfully used to reconstruct past fire patterns throughout the Pacific Northwest; however, there has been little research done on the forests of the eastern Cascades of Washington State. This research reconstructs the fire history of Lemanasky Lake, Washington (48.7°N, -119.6°W; elevation: 1088 m), located in the Cascade foothills near the Sinlahekin Wildlife Area, roughly five miles northwest of Tonasket, Washington. The analysis of macroscopic charcoal from a five-meter long sediment core provides a record of Holocene fire activity in the forest surrounding the lake. The primary research question addressed in this study is: “How has fire activity changed at the study site during the Holocene, and what has been the cause of those changes?” In order to reconstruct the local fire history of the site, we counted all macroscopic charcoal particles >125 microns from contiguous 2 cm3 samples taken at 1 cm intervals. Our results suggest intentional fire suppression during the last ~100 years, which was preceded by frequent, low severity ground fires, with less fire activity prior to that. This reconstruction not only facilitates our understanding of changes in fire frequency and severity at the site as a result a past climatic variability, but more importantly shows how 20th century fire suppression has affected the forest. Additionally, the results may assist landowners within the wildlife-urban interface of Washington in implementing safe fire management practices.