Assessing carbon fluxes and aspen mortality in Colorado mountain forests

Project Background

Although tree mortality has the potential to alter ecosystem carbon cycles, how mortality scales up to ecosystem flux and functions remains uncertain; however, with climate change leading to more frequent and severe drought events across the western US, large-scale tree mortality has become an increasingly large issue. In particular, quaking aspen is the most widespread tree species in North America but has faced significant large-scale drought-induced mortality events (dubbed Sudden Aspen Decline, or SAD) across much of the western regions of its range.

In order to explore the interface between mortality attributes, ecosystem properties, and how they scale up to ecosystem fluxes in quaking aspen forests threatened by SAD, we will be using eddy covariance flux tower techniques to measure both Gross Primary Productivity (GPP), a measure of the influx of carbon into an ecosystem through photosynthesis, and Net Ecosystem Exchange (NEE), a measure of the exchange of CO2 between the atmosphere and the biosphere. We will also be conducting field surveys to measure mortality, stand density, basal area, and species composition within the flux tower footprint. The combination of direct ground-based measurements with ecosystem fluxes in this study will improve our ability to model the impacts of mortality on forest function and carbon sequestration.

Student Role

Students selected to work on this project will be participating in fieldwork in Southwestern Colorado, in the San Juan National Forest. Responsibilities will include conducting mortality surveys, measuring species composition and basal area. This can include multiple days camping in the forest, full days outdoors assessing trees and vegetation, as well as potentially processing any samples that are brought back to the lab at the University of Utah. Students should be comfortable camping for multiple days and working full days outdoors. Students may also assist graduate and postdoctoral researchers with other research projects in the Anderegg Lab as needed, on things such as massing dry samples, scanning leaves for leaf area measurements, entering data, and other lab work. Students are not expected to be familiar with any lab or field techniques, but should bring with them instead a desire to learn and conduct research in both the field and the lab.

Student Learning Outcomes and Benefits

Working in the Anderegg Lab will give the student the chance to gain a variety of field and lab skills and research experience in a large, supportive lab group. Whether or not they eventually choose to pursue an academic or other research-based career, the student will gain many skills working in our lab that are broadly applicable: experience reading and discussing a scientific paper, designing an experiment with feasibly testable hypotheses, planning and troubleshooting experiments, general experience working in research lab and field environments, a general understanding of drought impacts on trees and carbon fluxes, basic data analysis techniques, and presentation skills. The student will have the chance to work with other highly motivated undergraduate students, graduate students, and postdoctoral researchers with widely varied research interests and study areas. The Anderegg Lab has an excellent track record for assisting undergraduates with their own projects and interests, as well as applying for other grant opportunities in the future. Many of our past summer undergraduate researchers have continued doing research in our lab in following summers or even during the academic year.

APPLY NOW

William Anderegg

Associate Professor

Science

School of Biological Sciences

Our research focuses around a central question:

What is the future of Earth’s forests in a changing climate? Massive forest mortality events of many tree species in the last two decades prompt concerns that drought, insects, and wildfire may devastate forests in the coming decades. We study how drought and climate change affect forest ecosystems, including tree physiology, species interactions, carbon cycling, and biosphere-atmosphere feedbacks. This research spans a broad array of spatial scales from xylem cells to ecosystems and seeks to gain a better mechanistic understanding of how climate change will affect forests around the world.

Mentor Philosophy

We will meet regularly with the student to help them with their independent project design, learn new techniques, to help prepare them for SPUR meetings, and to answer any questions that they may have. In these meetings, we will guide the student and help them learn at their own pace in a supportive environment. We want the student to feel comfortable asking questions while learning new methods and concepts. In addition, students will be able to meet with members of the lab whenever needed or desired so they can participate in our lab’s collaborative environment and possibly work on other projects that may interest them. Near the end of the 10-week program, we will help the student with data analysis, poster creation and formatting, and presentation practice. If the student is eligible and choses to continue work into Fall 2022, we will provide assistance and support for submitting a follow-up (e.g. UROP) proposal.