Saguaro-Juniper Riparian Trees
Sources: Zimmerman, Robert, 1969, Plant Ecology of an Arid Basin Tres Alamos-Redington Area Southeastern Arizona, Geological Survey Professional Paper 485-D, Washington, D.C.; Kricher, John & Gordon Morrison, 1993, Ecology of Western Forests, NY: Houghton Mifflin Co.; USDA Forest Service Database.
The riparian trees to be found on the bottomlands of the San Pedro River and its tributaries, where groundwater is sufficiently close to the surface to support them, are members of genera having their ancient affiliations toward Eurasia -- ash, alder, cottonwood, hackberry, mulberry, sycamore, sumac, walnut, and willow. In contrast, the vegetation types found outside our valley floors mostly come from Mexico and the Sonoran Desert [Zimmerman p. D11].
Our Saguaro Juniper riparian stands occur in locations that approximate what Kricher & Morrison (cited above, pp.243-50) call "Arizona Canyon Riparian Forest", though that typology was constructed with reference to mountain canyons well further south, and we lack some of the plants and animals associated with this category, finding instead a more intensive mix with Arizona Uplands vegetation. In our area as elsewhere, these trees are very valuable for controlling stream-bank erosion.
