Research at The University of Arizona Ray Turner takes a compass reading before laying out a new study plot.
Bowers wraps a tape measure around the base of a palo verde.
The relationship between circumference and age will help her and Turner learn more about the palo verde population s age structure. Answers Monitoring changes on Tumamoc Hill that affect the saguaro population can be physically tough on researchers. Ask Janice E. Bowers of the Desert Lab. She added a self-imposed challenge to finish this field work before the hill s resident rattlesnakes got too lively later in the spring. Early in the 1990s, Ray Turner, Bowers and other Desert Lab scientists noticed that palo verde trees were dying in greater than usual numbers on Tumamoc Hill.