Ironwood Forest National Monument
Ironwood Forest National Monument protects a prime example of the Sonoran Desert, with 128,917 acres of mountains and hills scattered amongst broad, species-rich valleys. Five desert mountain ranges define the monument: the Roskruge and Waterman Mountains, the Silverbell, West Silverbell, and, on the fringe, the Sawtooth Mountains.
AWC is proposing that the Bureau of Land Management create four Wilderness Study Area (WSA) units in the Ironwood Forest NM. These units include Ragged Top (6,161 acres), Sawtooth Mountains (11,169 acres), Silver Bell Mountains (7,489 acres), and the West Silver Bell Mountains (8,598 acres), totaling 33,417 acres. This acreage represents only 25% of the entire monument, which is a reasonable compromise for the monument’s multiple uses. Protecting these areas as wilderness will assist the Bureau of Land Management in its responsibility to protect the objects of the Ironwood Forest National Monument and help ensure the longterm survival of the last bighorn sheep herd in the Tucson Basin.
Within the borders of Ironwood Forest National Monument, 474 species and subspecies of plants thrive, 8% of which do not occur in the nearest protected desert areas, the Tucson Mountains, or Organ Pipe National Park. A preliminary assessment of wildlife found up to 177 vertebrate species and 821 invertebrates. This includes a variety of sensitive species such as desert bighorn sheep, desert tortoise, California leaf-nosed bat, Mexican long-tongued bat, Lesser long-nosed bat, Western red bat, Merriam’s mesquite mouse, Rufous-winged sparrow, Tucson shovel-nosed snake, Ground snake, Pima pineapple cactus, Nichol’s turk’s head cactus, and 3 species of talus snail. The Monument also includes historic and potential habitat for the endangered cactus ferruginous pygmy owl.
The Monument supports the highest densities of ironwood trees in the Sonoran Desert, especially in upper parts of north and west facing bajadas. While ironwoods are associated with a great many species throughout their range, those found in the Monument support more plant species than anywhere else in the country. Ironwoods and other desert legumes are so important as nurse trees that many cacti, including saguaros, might not survive in our climate without them. Unfortunately, ironwoods are becoming threatened as the demand increases for their hard wood, which is used for ornamental carving and other human uses.
Open valleys between ranges contain vegetation of the hotter, flatter Lower Colorado subregion, primarily Creosote bush and White bursage. Trees in the valleys are mostly restricted to washes. Plants and animals that prefer these more open areas include many species at the eastern edge of their range: Banded sand snake, Desert horned lizard, Desert iguana, Leaf-nosed snakes, Long-tailed brush lizard, and Sidewinders.
In addition to the biological and geological resources, the area holds abundant rock art sites and other archeological objects of scientific interest. Humans have inhabited the area for more than 5,000 years. More than 200 sites from the prehistoric Hohokam period (600 A.D. to 1450 A.D.) have been recorded in the area. Two areas within the monument have been listed on the National Register of Historic Places, the Los Robles Archeological District, and the Cocoraque Butte Archeological District. The archeological artifacts include rhyolite and brown chert chipped stone, plain and decorated ceramics, and worked shell from the Gulf of California. The area also contains the remnants of the Mission Santa Ana, the last mission constructed in Pimeria Alta.
Within the monument, the Sawtooth range rises up as rugged, volcanic mountains with many jagged peaks, giving a saw-toothed appearance. A variety of small and large arches can be found on the numerous sharp ridgelines. This part of the monument varies from rocky peaks and ridges to bajadas and plains. Ragged Top Mountain abruptly rises 1,600 feet from the desert floor with spires and crags piercing the skyline that stand in marked contrast to the smooth silhouette of the nearby Silver Bell Mountain Range. Accumulations of fallen rocks and sand fan out from the bases and support an impressive forest of green ironwood, foothill palo verde, and mesquite trees.