Section 17 Saguaro Census

On December 8th, a group of four Summit Hut volunteers joined two community volunteers and two Park Services employees on a Saguaro Census. We met at the Saguaro East visitors center and made our way to the Mica View Picnic Area. Our fearless leader, Irene, gave a brief overview of the history of Saguaros in the park, and of Section 17, a section within the park that was first inventoried back in 1941. Just after the establishment of Saguaro National Monument, there was a tremendous decline in Saguaro population that could not be explained. There were many theories and attempted remedies but none proved successful. Because Section 17 was well established and has been counted previously, it makes for a great study in the current population and how it compared to that of 1941. To learn more about the plot’s history check out Irene’s webpage.

After the history lesson, we made our way to the plot we would be measuring, Plot D5. We were given a quick clinometer lesson and paired up with a Saguaro measuring veteran.

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Summit Hut Assistant Manager, Meaghan, setting up the clinometer.

We split into two groups that would work along the plot side by side. Once we reached the end of the plot, we swapped sides and double checked the other group’s inventory to ensure no Saguaro went unmeasured. We then swept back a third time retrieving the flags marking which saguaros had been measured.

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The largest saguaro our team measured.

We worked for about four hours and measured a total of 139 saguaros ranging in size from .4 meters up to 9.4 meters! The largest saguaro we measured also had 24 arms!

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Summit Hut Merchandiser, Carolyn, measuring a saguaro.

The next day, a group of 8th graders from Paulo Freire Freedom School completed the second half of plot D5. The results of our inventory can be seen here.

The general trend is the number of tall saguaros has diminished tremendously but there are far more small saguaros than there were during the 1941 census. Irene explained that much of this is due to the fact that there are far more trees in the park than there were in 1941 which provide shelter and protection to the young saguaros.

This census is an ongoing project and just about anyone can volunteer simply by emailing Irene. We had a great time and truly felt that we were participating in historic research. Who knows, maybe 70 years from now a group of volunteers will be counting the same plot and comparing their results to ours!

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