Date of Award


Degree Type


Degree Name

Master of Science (MS)



First Advisor

Dr. Luke Pangle

Second Advisor

Dr. Rebekah Chapman

Third Advisor

Dr. Brian Meyer


Traditional methodologies for measuring ratios of stable isotopes within the xylem water of trees involves destructive coring of the stem. A recent approach involves permanently installed probes within the stem, and an on-site assembly of pumps, switching valves, gas lines, and climate-controlled structure for field deployment of a laser spectrometer. The former method limits the possible temporal resolution of sampling, and sample size, while the latter may not be feasible for many research groups. Researchers have used direct liquid-vapor equilibration as a method to measure isotope ratios of the water in soil pores. Typically, this is done by placing soil samples in a fixed container, and allowing the liquid water within the soil to come into isotopic equilibrium with the headspace of the container. We present a novel approach to measuring xylem water that relies on liquid-vapor equilibration, built from the principals applied to soil samples.