Documenting Saguaro Mortality and Regeneration Project materials

The Saguaro Mortality and Regeneration Project was started in 1941 by employees of the U.S. Department of Agriculture Bureau of Plant Industry in partnership with the University of Arizona and National Park Service. Funding for the project was originally set up by Sen. Carl Hayden who wanted to find a way to preserve the saguaros.

The concern was the mortality rate and visible rot of saguaro cacti in Saguaro National Monument, so 64 ten-acre plot of Section 17 of the Monument were staked out by University of Arizona students who surveyed and staked out 13,304 saguaros. The field notebooks in this collection were used to record the observations of researchers who studied the condition of all the staked-out saguaros. The researchers divided Section 17 into a control and experiment group by removing and burring the saguaros with stem rot in the south half of the section while leaving those in the north half alone to be monitored as the control group. The results of this test can be found in the field notebooks dated 1941-1945. In 1946, the removal of saguaros was ended because researchers decided that the stem rot was not very contagious. Six ten-acre plots became the focus of this project for more than 80 years continuing on today. The remaining field notebooks dated 1946-2020 cover this part of the project.

Tom Orum, a plant pathologist originally from California, and his wife Nancy Ferguson, an ecosystems ecologist originally from Tennessee, moved to Tucson in the mid 1970's and married in 1980. They spent over four decades studying the saguaros in these six ten-acre plots in Saguaro National Monument beginning in 1979. Dr. Stanley Alcorn, who had begun his work on the project in 1955 and whose records are included in this collection, introduced Tom to the project. Soon after, Nancy joined in the effort. Tom and Nancy retired from their jobs at the University of Arizona in 2000 to devote their time to the project. Tom and Nancy are the third generation to continue this project which includes monitoring approximately six hundred saguaros throughout the Monument. Some of the plots the couple studied have been named Orum plots in their honor.

Tom and Nancy used specific tools for the project including a PVC pipe they used to measure the height of the saguaros and eventually nicknamed Charlotte. They also preferred a compass to GPS coordinates for their notes. Nancy took over the field notebooks which contain measurements of the cacti and observations about their condition. The couple searches for and celebrates finding new saguaros and keeps tabs on the older saguaros to monitor the effects climate change is having on the cacti. It has been found over the decades that climate change, especially droughts, and human activity are mainly responsible for the declining number of new saguaros in the Monument. With a lifespan occasionally reaching 200 years, it is not of major concern that saguaros are dying out, but it is difficult for the young saguaros to survive in the increasingly dry climate.

Tom and Nancy handed in their final survey of their beloved saguaros in 2022 and have retired from the project. The project continues in the capable hands of Don Swann, biologist of the Saguaro National Monument, and Kara O'Brien. Swann nominated Tom and Nancy for the Ray Turner award for their work on the project only a few years ago. Today, the project continues to hold the title of the longest running scientific survey in Saguaro National Monument and may perhaps hold the title of the longest running annual censuses of a perennial plant population.