Portland State University. Department of Environmental Science and Management
Kelly E. Gleason
Term of Graduation
Date of Publication
Master of Science (M.S.) in Environmental Science and Management
Environmental Science and Management
Cascades, Forest Disturbance, Forest Fire, Hydrology, Snow Hydrology, Water Resources
1 online resource (xiii, 114 pages)
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.
© 2023 Megan Nicole Guinn
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Guinn, Megan Nicole, "Forest Fire Effects on Snow Storage and Melt Across Scales of Forest Recovery in the Western Oregon Cascades" (2023). Dissertations and Theses. Paper 6539.