March 31, 2017
Thanks to Alissa Simon, HMU Tutor, for today's post.
“The word saguaro originated in Ópata, a language spoken by peoples of the Sonoran Desert region of Mexico. It came into English by way of the Spanish spoken by the Mexican settlers of the American West. The very saguaros we see today may well have been around when the word was first noted, some 150 years ago - this amazing cactus can live for up to 200 years.” - Merriam-Webster
Sometimes, it is important to dwell upon something small. The saguaro, say, which is undoubtedly the tallest desert creature, but in the greater perspective of the world, is remarkably small. It can only survive in the narrowest of conditions, and yet somehow, the tall, human-like structure has become synonymous with desert lifestyles. The saguaro cactus (pronounced suh-WAH-roh) offers a prime example of the complexity of desert habitats. After a recent visit to the Sonoran Desert, I felt it would be interesting to take a closer look at a place which conceals so much life.
Descending from the Mogollon Rim (pronounced Mug-EE-yawn) into the Sonoran Desert, saguaros appear quickly, suddenly, and in great numbers as if a sea of life exploded on the desert floor. The metaphor of sea indicates depth or breadth, but this desert is the opposite of a literal sea. It is, actually, the sea's remains. As this patch of earth moved northward over millions of years, it also drained and dried out. Saguaros choose to live in a basin or valley that was once a shoreline, but is now nearly deprived of all water.
Saguaros grow slowly, but can live up to two hundred years. In fact, a twenty year old saguaro would be easy to miss, having grown up to about 2 inches tall. As they age, most begin to add arms, giving them the iconic look of a distant, dry and hot vista from a western movie. Also as they age, they begin to bloom in the spring. White flowers cluster in spots and each bud opens only for about twenty-four hours. The dense, red, bulbous fruit pod produced from the blossoms can carry up to two thousand seeds. These seeds need to be deposited by birds and then they require rain to develop into a seedling. The seedlings require shade and moisture in order to continue to grow. Unfortunately, all of those conditions are rarely met in the desert, and so the survival of saguaros becomes a masterful study in patience and adaptation.
It is the largest cactus in the United States. Though the saguaro can grow to be 60 feet tall, they leave very shallow roots. The saguaro uses a single, center root that grows down 2 feet or more, while the rest spread just under the surface for the best chance at grabbing water. Like other plants, the roots soak up water. Unlike other plants, the saguaro can store up to two hundred gallons of water in skin that stretches to contain it all. This is a useful technique in areas which see little water, but when it does rain, the desert floor runs thick with muddy floods. This, obviously, greatly increases the weight of the cactus, and its danger of falling over. The waxy skin prevents water loss, while also allowing for the growth of thick spines. Few animals can penetrate the skin, and even fewer dare due to the dangerous thorns. In this way, the saguaro collects, stores and protects its immense water supply in a place that rarely sees water.
Another mystery of the saguaro is their ability to produce arms. The cactus must reach about sixty years of age before it can grow the first arm. And yet, some never grow any, preferring to remain a single column. It is unclear what factors affect the growth of a branch. Like all desert beings, the saguaro is a master of survival.
Deserts provide little water, hot days, cold nights and minimal shade. Shelter is imperative. Birds have figured out that the saguaro offers a brilliant hiding spot. Woodpeckers are able to dig into the skin of a saguaro, building a well-hidden and well-fortified nest. In addition, they are able to stay cool in summer and keep the nests at a relatively stable temperature. After they leave the nest, it is likely that another inhabitant will find the open space useful. In this way, the saguaro becomes a housing complex. The communities are free to come and go. Once the hole exists, the saguaro continues to grow, exposing the scar for future residents, but maintaining internal moisture, temperature and structure for a long time. This is due to the dense, hard fibers hidden just under the surface of the skin. Once a saguaro dies, this fiber dries into a very hard wood, which can be used for many additional purposes.
Desert survival depends upon community. Without these massive structures, many other plants and animals would suffer. They grow from a dry seabed, impressively towering above the earth, and yet, for all that height, they are limited to a fairly small, specific geographical location. Learn more about this impressive species on the Saguaro National Park Service's website: https://www.nps.gov/sagu/learn/photosmultimedia/videos.htm
If you would like to read literature about the desert, or are interested in these landscapes, the following authors/works include often include cactus, desert and drought as main characters:
Desert Solitaire by Edward Abbey
Travels with Charley by John Steinbeck
Animal Dreams or The Bean Trees by Barbara Kingsolver
Bless Me, Última by Rudolpho Anaya
House Made of Dawn, N. Scott Momaday
The Milagro Beanfield War, by John Nichols
Leslie Marmon Silko
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