Date of Award:

5-2017

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Wildland Resources

Committee Chair(s)

Michael Jenkins

Committee

Michael Jenkins

Committee

Thomas C. Edwards, Jr.

Committee

Peter Howe

Committee

R. Douglas Ramsey

Committee

Justin Runyon

Abstract

Many high elevation conifer species, including high elevation five needle pines, are declining throughout western North America. Warming temperatures, mountain pine beetle, white pine blister rust and alteration of naturally occurring fire regimes represent an interactive set of circumstances leading to greater risk. The loss of these treeline pines can detrimentally impact biodiversity and valuable ecosystem services including wildlife habitat, watershed and soil protection, aesthetics and recreation. Great Basin bristlecone pine ecosystems are naturally highly fragmented because of their elevational requirements. However, they may become even more fragmented due to combined impacts of warming temperature, insects and diseases listed above. This study increased the knowledge of Great Basin bristlecone pine ecology by examining response to climate change with respect to fire, fuels and tree chemistry. The first study examined alteration of the fire regime and showed that fuels in Great Basin bristlecone pine decreased with elevation. Yet, canopy fuels that are more susceptible to fire, suggested fire potential may increase at higher elevations with warming air temperatures, which could threaten the oldest individuals of this iconic species. Examination of tree chemistry to environmental gradients (like elevation and temperature) demonstrated a clear response to climate induced environmental stress. This has the potential to alter flammability and the effectiveness of tree defenses to mountain pine beetle. Lastly, this research determined that volatile organic compounds emitted from Great Basin bristlecone pine foliage influence host selection for mountain pine beetle. All three of these studies will aid in developing unique forest management practices to increase forest resilience of treeline species and could provide insight into the mechanisms underlying the incredible longevity of Great Basin bristlecone pine.

Checksum

9daecbbe57357f6e394a7e2078a537ed

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 .