Publication Date

Spring 2023

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Studies

Advisor

Will Russell

Subject Areas

Environmental studies

Abstract

Land managers need tools to mitigate wildfire proliferation in the western United States. Prescribed burning may be an effective tool to reduce wildfire severity and promote healthy landscapes. In 2020, a large-scale wildfire provided a rare opportunity to compare early postfire data between areas with and without a history of prescribed burning. Field data were collected approximately one year after a wildfire in fifty 20-meter plots from sites treated with prescribed fire in either 1999, 2007, or 2011 and fifty from sites without a history of prescribed fire. The influence of prescribed burning on forest resistance, resilience, and risk of repeated wildfire were assessed using generalized linear mixed effects models (GLMMs), in the coast redwood (Sequoia sempervirens) forests’ southern range, where tanoak (Notholithocarpus densiflorus), and Douglas-fir (Pseudotsuga menziesii) were the codominant tree species. Areas with a history of prescribed burning were found to have greater wildfire resistance, shown by higher percent canopy retention and percent of trees that were living. Increased wildfire resilience was indicated by higher counts of early post-fire coast redwood seedlings. In addition, reduced repeated wildfire risk was demonstrated by fewer total tanoaks, standing dead trees, and a lower stand density compared to sites without prescribed fire. Results indicate that prescribed fire may improve redwood forest stand resistance and resilience, and that these benefits may maintain after a wildfire event.

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