Year of Award

2018

Document Type

Dissertation

Degree Type

Doctor of Philosophy (PhD)

Degree Name

Systems Ecology

Department or School/College

College of Forestry and Conservation

Committee Chair

Ashley P. Ballantyne

Commitee Members

Solomon Z. Dobrowski, Zachary A. Holden, Erin L. Landguth, Andrew J. Larson

Keywords

climate, dendrochronology, disturbance, forest, north america, remote sensing

Abstract

Forest disturbances result in numerous impacts on ecosystem services. In the western United States, disturbances such as wildfires and bark beetle outbreaks have resulted in millions of hectares of dead trees. Despite the potential for these events to have significant climatic impacts, it remains a challenge both to effectively locate and characterize disturbance events across landscapes, and to identify the disturbance biophysical and biochemical impacts. The objective of my dissertation research was to improve the ways in which we locate and classify forest disturbances over large areas, as well as to increase our understanding of disturbance biophysical and biochemical impacts and how those impacts vary according to ecosystem properties.

In chapter 1, I researched how a severe mountain pine beetle outbreak in western Montana influenced the future characteristics of lodgepole pine forests through the use of dendrochronological and climate station data. I investigated whether the outbreak had differentially impacted differing growth phenotypes, resulting in changes in forest productivity, and how growth phenotype related to patterns of growth-climate sensitivity. In chapter 2, I moved up in scale to investigate the biophysical and biochemical impacts of multiple forest disturbance classes, as well as how impacts of forest disturbances differed across varying ecoregions around the western United States. For chapter 3, I sought to improve our ability to understand the climatic impacts of forest disturbances by developing a logical framework to more accurately and efficiently detect and attribute forest disturbances using satellite imagery.

The results of my work demonstrate the potential for large-scale impacts of forest disturbances on climate, and also suggest that current disturbances may alter the future forest-climate interactions. Additionally, the results from chapters 1 and 2 suggest that there is significant variability in the impacts of forest disturbances on climate, both within and among ecoregions and among disturbance types. This variability is mostly ignored in large-scale simulations of disturbance, despite its potential to significantly alter model and simulation results. The framework developed for my 3rd chapter will enable a better understanding of the variability of forest disturbances and allow for better prediction of their impacts on climate and other ecosystem properties.

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© Copyright 2018 Leila Ann Cooper