Question
My Daughter is doing a report on Arizona for school. We would like to add a segment on Saguaro Cacti & we have not been able to locate a source pertaining age. We would like to know how long they live and how to determine age. Would you help? Could you point us to literature to answer these questions?

Answer
Dave,

Unfortunately there is no definitive way to determine the age of a saguaro cactus. They don't produce rings like a tree. They also grow at different rates at different times during their life span. For example, they are estimated to take roughly 60 years to attain the height of the average man.

After they produce arms, their growth rate accelerates. Here is a good website that may help: http://jan.ucc.nau.edu/~plants-c/bio414/species%20pages/Carnegia%20gigantea.htm

Good luck!

Sincerely,

Greg