Saguaro

I spent this past holiday weekend in Arizona and took hundreds of pics of the beautiful ecosystems there.  Our home base was in Sedona, but we spent time in the Grand Canyon and Phoenix as well.  Phoenix is in the northern limit of the Sonoran desert - known perhaps best for its most famous inhabitant, the Saguaro cactus, Carnegiea gigantea.
 

 

The saguaro is endemic to the Sonoran Desert, which stretches from Phoenix to northern Mexico.  Some occur near the lower Colorado River in California as well.  It's a massively tall tree, reaching heights up to fifty feet.  When you encounter one that tall, you can speculate that it's lived for as long as two hundred years. 

 

The tree's structure is not like a typical woody tree - instead the interior is comprised of wooden rods.  This allows the plant to expand and contract based on the amount of water it is storing.  Roots are shallow and stretch as far as fifty feet away from the trunk - this maximizes the amount of water the plant can capture during the rare rainfall.

 

The saguaro provides habitat to many desert birds, including gila woodpeckers and flickers, as well as desert raptors like elf and screech owls.  In addition to the many bird species found in the Sonoran Desert (350), there are 60 mammals, 20 amphibians, 30 fish and 100 reptiles.  In this little roadside park, I saw dozens of desert cottontails and greater roadrunners.

 

Here a younger saguaro is in the foreground to the right.  Saguaros must reach fourteen to sixteen feet in height (age 75, approximately) before it begins to branch.  

Saguaros are by far, one of the most iconographic American plants.  It's easy to overlook how big they get.  For precisely that reason, here's a shot illustrating its massive size.  For the record, I'm about 5'-3"!!