In this talk we will look at some of the simple physical and chemical methods used to understand how and when saguaro grow, how old they are, how much water they take up and how they respond to the local climate. Measuring height and plant diameter tells us about saguaro health and water usage. Measuring spine chemistry gives a non-invasive way to look back through the life history of the plant.

David Dettman served as the research scientist in charge of the Environmental Isotope Laboratory at the University of Arizona for more than 20 years, up to his retirement in 2023. His research focuses on how isotope ratios of the most common elements (carbon, oxygen, hydrogen, nitrogen) can be used to understand how animals and plants interact with their environments. Among many other topics, he has worked on ancient river systems, the post ice-age Great Lakes, the uplift of the Tibetan plateau, bird migration, cactus physiology / water use, and land snail shell chemistry as climate indicators. He continues to work closely with researchers in the Geosciences Department at the 

University of Arizona.

Everyone is welcome to come and join us for this special in person presentation. This meeting will also be a Zoom program and will be an important educational and informational event you must see. Excellent plant give aways will take place at the in person meeting but that portion of the program, because of the recording, will not appear on Zoom. When leaving the live in person meeting, please enjoy excellent refreshments provided by our member volunteers and also, everyone can get a special free plant when leaving, offered to you by the Tucson Cactus and Succulent Society.