Participating Students - April Chiriboga

April Chiriboga
University of Arizona
Tree Ring Lab
BART Enrollment Year: 2006
Email Address: aprilc at
Atmospheric Mentor: Malcolm Hughes & Xubin Zeng, University of Arizona
Biospheric Mentor: Scott Saleska, University of Arizona

April received her B.S. in Evolution and Ecology from Ohio State University in 2003. While at Ohio State, April worked as a research assistant in the labs of Dr. Lonnie Thompson, Geosciences Department, and Peter Curtis, Evolution, Ecology, and Organismal Biology Department. Her projects included using data taken from ice cores to correlate the frequency of the El Nino Southern Oscillation with monsoon failures in Asia and computer modeling to predict how northern forests will respond to global climate change. April also spent summers studying CO2 fertilization in plants at the Smithsonian Environmental Research Center in Edgewater, Maryland and weather prediction models at the NASA Goddard Space Flight Center in Greenbelt Maryland.

April is currently enrolled at the University of Arizona in the Geosciences PhD program, working in the Laboratory of Tree Ring Research. The goal of her research, conducted at the University of Michigan Biological Station as part of the BART IGERT Program, is to explore how climate change will affect northern hardwood forest ability to sequester atmospheric carbon dioxide.

Using the flux data available from the UMBS forest, the total amount of carbon taken up by the stand can be compared to remote sensing estimates of foliage production, and ground based biometric estimates of woody tissue production. This will illuminate where trees allocate carbon drawn down from the atmosphere. Mechanistic models can then be used to predict how climate drives carbon storage changes in woody tissues and foliage, from year to year.

Research Topics:

From the ground up: Integrating carbon monitoring approaches for a northern hardwood forest

Carbon trapped in woody tissues serves as a sink for atmospheric carbon dioxide. Because of the role that carbon dioxide plays in climate change, mechanisms controlling atmospheric concentration are of particular interest.

Remote sensing has recently been used to monitor changes in the biosphere, especially those related to plant productivity. The assumption made by these studies is that remotely sensed changes in productivity are representative of changes in carbon storage. This may not be the cae; partitioning of carbon within a plant may not remain the same over time within an individual tree. The goal of this study is to establish a causal link between remotely sensed productivity and carbon accumulation, in recalcitrant tissues such as wood, through carbon flux data. Once this link is made, further investigations into the spatial and temporal variability of carbon storage can be undertaken.

Measures of carbon flux will be used to link tree ring records of carbon storage to remote sensing vegetation indices at the University of Michigan Biological Station.  This will allow ground-truthing of remote sensing measures of plant productivity at this and other Ameriflux tower sites.  Tree ring records and a mechanistic tree ring model using local meteorological data can then be used to produce a spatial and temporal map of climate-sensitive carbon allocation in woody tissues across the continental United States of America .