The paper titled: Tritium analysis shows apple trees may be transpiring water several decades old, was accepted by HP and can be found Here.

Three current lab members Zhi (visiting faculty from Northwest A&F University, China), Jaivime Evaristo, and Jeffrey McDonnell, along with colleauges Bing Si (University of Saskatchewan) and Zhi Qiang Zhang (Nothwest A&F University, China) have had a paper accepted, that used Tritium values found in the apple juice of trees grown on the Loess Plateau in China. This paper builds on the ecohydrological separation theory, diving deaper into the question "how old might mobile water use by plants be"?