Gerry Tietje
Ironwood Forest National Monument is located west of the Avra Valley, Marana, and I-10. It was established on June 9, 2000, so this year will be its 25th anniversary. The 190,000-acre preserve contains portions of four mountain ranges, including the Silver Bell Mountain range. Its most prominent peak is Ragged Top Mountain, with a 3,907-foot elevation. The preserve surrounds the active Silver Bell Mine, which produces 50 tons of copper a day. The Ironwood Forest National Monument is habitat for many species of plants and animals, including the endangered ferruginous pygmy owl, which is only 6 inches tall and nests in cavities of saguaros and trees. The only remaining indigenous population of desert bighorn sheep resides in the preserve. There is also an 80-armed saguaro, and of course, the ironwood trees, for which the national monument is named.
Ironwood trees are only found in the Sonoran Desert. Their wood is one of the hardest and most dense of any tree in the world, much harder than hickory. Ironwood trees are also one of the most rot-resistant trees, which enables them to live many, many years, four to five times longer than mesquite and palo verde trees which are also common in Ironwood Forest National Monument. Their wood is prized by woodworkers, and is used for tool handles, mallets, and carvings. The bark is used for medicinal purposes. Ironwood trees are deciduous and grow slowly up to 25 feet high and 25 feet wide. Small, elliptical leaflets appear in spring. Lavender and white blossoms appear later at the ends of short shoots along the branches. The flowering season is the end of May into early June, and the blossoms last from 10 to 18 days.
Ironwood trees are important to the Sonoran Desert ecosystem because they, along with mesquite and palo verde trees, serve as “nurse trees.” Nurse trees provide safe sites for seed dispersal and protect seedlings, like saguaro seedlings, from the harsh winter cold and intense summer heat, giving them a chance to get a good start. They also protect young plants from predators. You will often see saguaros growing amid nurse trees. The saguaros are long-lived, so mesquite and palo verde trees often die around them, but the long-lived ironwood trees do not.
If you would like to see ironwood trees in bloom this year, you can drive to Ironwood Forest National Monument late this month, or early June. There is a dirt road (Ragged Top Road) off W Silverbell Road that leads to a small parking lot near Ragged Top Mountain where there are several ironwood trees. The roads in other parts of the preserve are not maintained and difficult to drive on, even for high-clearance SUVs. Closer to SaddleBrooke Ranch, there are ironwood trees along E Park Link Drive, especially as you travel west after mile marker 10. There are even a couple of small ironwood trees along our Nature Trail.