Date of Award:

12-2026

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Wildland Resources

Committee Chair(s)

Larissa Yocom

Committee

Larissa Yocom

Committee

Brendan P. Murphy

Committee

Patrick Belmont

Committee

R. Justin DeRose

Committee

Doug Ramsey

Abstract

Wildfire is a natural part of many forest ecosystems, but in the western United States, wildfires have become larger, more frequent, and more severe in recent decades. There are serious problems after severe wildfire, including erosion, flooding, and debris flows that threaten water quality, roads, and communities. Because of this, land managers need better ways to decide where fuel treatments, such as prescribed burning or thinning, can most effectively reduce wildfire damage and post-fire risks.

In this dissertation, I studied how fuel treatments might reduce wildfire severity and lower the risk of post-fire debris flows in Utah. First, I built a model to predict how severely forests are likely to burn across the state. Next, I used simulated treatment scenarios to test how different fuel treatments changed wildfire severity in different forest types and under different weather conditions. Finally, I applied those results to real watersheds in Utah to estimate how treatments could reduce post-fire debris-flow risk.

The results showed that treatment effectiveness depends strongly on forest type. In some forests, especially ponderosa pine, spruce-fir, and lodgepole pine, reducing fuels had a strong effect on lowering fire severity. In other forest types, weather played a larger role, which made treatments less effective. Across most forests, treatments that reduced both canopy fuels and surface fuels produced the greatest reductions in wildfire severity.

At the watershed scale, treatment costs and benefits also varied. Prescribed burning was generally the most cost-effective treatment. In several watersheds, including Electric Lake, Big Cottonwood Canyon, Panguitch Lake, and Rockport, cost-effective treatments provided the greatest reduction in post-fire risk for the money invested, making them especially important areas for management. Other watersheds showed less cost-benefit tradeoffs in decision making, where intensive treatments can be prioritized for maximal benefit, where high risk exists. I also created map products to help managers identify where different treatments are likely to provide the greatest benefit.

Overall, this research provides a practical framework for helping land managers target fuel treatments where they are most likely to reduce both severe wildfire and the costly erosion risks that can follow.

Download

Share

COinS

Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .