First Advisor

Kelly E. Gleason

Term of Graduation

Summer 2023

Date of Publication

9-29-2023

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Environmental Science and Management

Department

Environmental Science and Management

Language

English

Subjects

Cascades, Forest Disturbance, Forest Fire, Hydrology, Snow Hydrology, Water Resources

DOI

10.15760/etd.3674

Physical Description

1 online resource (xiii, 114 pages)

Abstract

Snow is the largest component of water storage in the western United States, it serves as a key moisture source for forested ecosystems and is fundamentally linked to streamflow and nutrient cycling. Snow is vulnerable to climatic warming, and a key consequence of declining mountain snowpack is the escalation in wildfire frequency, extent, intensity, and duration across the seasonal snow zone. Fire modifies the spatial extent of snow in watersheds, reducing snow water storage and timing of melt across burned forests. Forested mountain ecosystems and water supplies are facing shifts in their structure, function, and succession. Previous research has focused on short-term forest fire effects on snow hydrology. However, no previous study has empirically investigated the recovery of forest fire effects on snow-storage and melt over decades following fire. With the intensity and frequency of forest fires increasing and snowpack declining in the western United States, a common question is how to reduce forest fire risk while increasing watersheds efficiency at generating water supplies? Here we present a potential answer to such a question, where snowpack observations taken from the western Oregon Cascades illustrate that over decades following fire, snow in burned forests store more snow volume and delay melt timing for similar to an open area. We evaluate the long-term recovery of forest fire effects on snow accumulation and melt. We combined in-situ point based measurements, continuous time-lapse photography within three burned forests, and a remote sensing and multivariate analysis of basin scale forest fire effects on snow cover in the western Oregon Cascades. We found that forest fires increase snow accumulation and eventually delay snowmelt around 10 days later 10 years following fire compared to immediately following fire Decades following forest fire, burned forests may retain more snow longer in spring and result in long term benefits for water resources. Allowing forest fire to burn in snow dominated headwaters may increase snow storage for water resources management.

Rights

© 2023 Megan Nicole Guinn

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

Comments

Financial support for all of these research efforts that was provided by the National Science Foundation Rapid Award #2102762, NASA award #80NSSC19K0002, and the US Army Corps of Engineers Award #W912HZ2220004.

Persistent Identifier

https://archives.pdx.edu/ds/psu/40916

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