Organ Pipe Cactus National Monument is the only place in the United States to see large stands of organ pipe cacti growing naturally, though their range extends far south into Mexico. The organ pipe cactus is a wonderful example of the adaptations that cacti need to flourish in the Sonoran Desert. Like its fellow cacti and other desert inhabitants, it is tuned to the rhythms of the sun and the infrequent rains.
This warmth-loving species can be found on south-facing rocky slopes in the monument. This location is critical during the winter months, when severe frosts can actually kill the entire cactus. Sub-freezing temperatures will kill young tissue at the end of the stems. When growth begins again, the results are indentations, or the appearance of circular waves on the organ pipes. Bumpy or wavy pipes are a record of previous battles with unusual cold. As a result, the range of the organ pipe cactus is limited by frost and freezing temperatures. In the summer it protects itself from heat and water loss by storing large quantities of water in its pulpy flesh, using a unique photosynthesis pathway, having a water proof skin, and shading itself with its sharp spines.
A Plant of Different Names
The O'odham people of southern Arizona are experts at living off the land. The organ pipe cactus, or chuhuis, was a survival tool that provided construction material and high calorie fruit that could easily be turned into preserves, syrup, and wine.
It's a time of great joy when the harvest season arrives. During the harvest festivities, all other ventures are temporarily halted, including farming and religious duties, to fully celebrate the harvest with song and dance. The fruit is so important that the O'odham calendar revolves around the lifecyle of the cacti in the desert.
As the first European pioneers ventured west in the 17th century, they encountered the chuhuis. When looking at its exposed skeleton, the pioneers were reminded of the large musical pipe organs that adorn the cathedrals of Europe, and so the name "organ pipe cactus" was given to them. These European explorers were eager to try the wine, jelly and dried fruit made from the organ pipe cactus fruit, and observed the festivals with curiosity.
Today, during the summer harvest season, you can see O'odham members harvesting the chuhuis fruit within the monument to continue their deep connections with this plant that has been here for thousands of years.
The organ pipe cactus originated in the warm, dry tropics. When the global climate warmed at the end of the last Ice Age, the cactus slowly began migrating further north and arrived in the Sonoran Desert only about 3500 years ago.
Here, the cacti were exposed to colder winter nights with sub-freezing temperatures, preventing its range from extending any further. Sub-freezing temperatures will kill young tissue at the top of the stems. If the freeze is short, the cacti will survive with only the sccar of a bumpy stem, while prolonged freezing temperatures will kill the entire plant. Within the monument, these cacti favor warm locations such as the dark, volcanic rock on southern facing hillsides. These rocks absorb solar heat and release the heat at night, wrapping the tropical cactus in blankets of warm air.
The organ pipe cactus can live to over 150 years in age, and produces their first flower near the age of 35. These cacti are slow-growing, only growing about 2.5 inches a year, with the greatest growth occuring during the summer monsoons. For the first 10 years, it will be no bigger than a few inches and is prone to being trampled by animals or being washed out by heavy monsoon storms. Very few organ pipe cacti will survive until they grow their first stem at around 30 years old. Once the first stem is grown, the plant is large enough that it can withstand colder temperatures, drought, and disturbance with greater ease. At this point, threats are limited to disease, infection, or lightning strikes.
Sweet Nectar of the Desert
The organ pipe cactus starts producing its first flowers around 35 years of age. These cacti bloom in May through June, depending on the timing of the winter rains. They open their creamy-white flowers only at night and close up again by mid-morning, leaving little time for daytime pollinators like birds and bees to feast on the sweet flower nectar. Lesser long-nosed bats are the primary nighttime pollinators of these cacti, and over the centuries have developed a unique relationship with them.
The fruit of the organ pipe ripens just before the summer rains and splits open to reveal a bright red seed-studded pulp. These seeds, with the aid of nurse plants or rocks, have the potential to grow from small seedlings into hundred-armed giants reaching ten to twenty feet into the air.
Across the monument, visitors may spot beautiful, unique cacti with unusual crowns. These are cristate, or "crested", cacti, It's estimated that one in 200,000 cacti have this unique mutation, and cristates have been noted in a variety of succulent plants from cholla to prickly pear.
These cacti have a genetic mutation that forms when the cells in the stem begin to divide outward instead of in its normal circular pattern. This results in the growth of a feathery, fan-shaped crest at the tip of the cactus' arm. The cause for this mutation is unknown, but one theory believes frost may play a role. One way or another, it's a delight to see these spectacular cristate cacti across the monument!
What Does The Future Hold?
Over the last 200 years, the temperature of the earth has increased at an umparalelled rate. Temperatures have increased faster than ever recorded, and humans are having a direct impact on the earth's climate.
Organ Pipe Cactus national Monument has observed changes in climate including altered monsoon seasons, less winter moisture, and longer periods of drought. The monument has tracked temperature in the area for over 100 years, and since 1950, the daily average temperature has increased by 3 degrees Fahrenheit.
Being a tropical plant, the organ pipe cactus relies on predicatble moisture to grow and produce flowers. If the rain patterns continue to shift and rainfall totals continue to drop, the organ pipe cacti might be in danger. The question remains: can the organ pipe ccti sucessfully adapt to the chagining conditions, or will the changes be too quick for the plant to survive?