North American Warm Desert Riparian

Photo point 751
Cottonwood and ash are abundant in the Four Mile Canyon at the northern end of the study area. This view is south, upcanyon, at about 4500 feet, on 26 September 2011. The riparian trees are festooned with canyon grape (Vitis arizonica) and poison ivy, with some vines as thick as a man's wrist.
The view up Redfield Canyon near its confluence with Jackson Canyon, at 4000 feet, on 23 September 2010, 4000 feet. Although long stretches of Redfield hold no surface water for much of the year, the canyon supports a distinctly riparian assemblage of sycamore (Platanus wrightii), alder (Alnus oblongifolia), willow (Salix bonplandiana), walnut (Juglans major), and hackberry (Celtis reticulata). Photo by Lon and Queta.

Photo point 794
Sycamore and walnut lining Willow Creek, about one mile east of Cake Mountain, where several small springs dot the northern study area. 4900 feet, 27 September 2011.
The presence of cottonwood, willow, walnut and sycamore are the surest indicators of the North American Warm Desert Riparian ecosystem, for they cannot persist outside the riparian corridor. As mapped in this study, the ecosystem ranges from 3900 feet, where Rattlesnake Canyon exits the National Forest, up to 5000 feet, at Mitchell Spring.
For this study, the North American Warm Desert Riparian ecosystem is distinguished from the cooler Rocky Mountain Montane Riparian by the lack of big pines (meaning, all pines but pinyon) and cypress. The transition from one to the other occurred in two places: near the confluence of Rattlesnake and Pipestem Canyons and near the confluence of Redfield Canyon and Gold Gulch (just south of Hooker Cabin). Elsewhere, the Warm Desert Riparian usually graded upsteam into Madrean Lower Montane Pine-Oak, as obligate riparian species were replaced with big pines and cypress that were capable of living both in the canyon bottom and on the slopes.
This ecosystem, while called riparian, has dry stretches at a scale too fine to map for this study. Yet although long stretches may be dry for much of the year, subsurface water supports unusually large trees. For instance, in Redfield, there are hackberries (Celtis reticulata) up to 50 feet tall.
Finally, short stretches of outstanding riparian habitat were mapped, sometimes only a quarter mile long, such as Norton Spring in Scanlon Wash, and Mitchell Spring in its namesake canyon. The latter holds willow, ash, cottonwood, sycamore, walnut, willow, cattails and, in September of 2001, thousands of blooming cardinal flower, Lobelia cardinalis.
Canyons mapped in this ecosystem include:
Four Mile Canyon
Sycamore Canyon
Redfield Canyon
Oak Creek
Rattlesnake Creek
Paddy's River
Norton Spring, in upper Scanlon Wash (west side, near Sombrero Butte)
Pipeline Canyon (a west side tributary of Copper Creek)
Kielberg Canyon
Sunset Canyon
Negro Canyon
South Negro Canyon
Jackson Canyon
Mitchell Canyon
Bear Canyon
Other Vegetation Classifications
The North American Warm Desert Riparian ecosystem includes elements of several vegetation types mapped or described in other classification schemes. In each of the six schemes referred to below, the * symbol marks the vegetation type most similar to the Warm Desert Riparian.
And what is meant by ‘most similar’? For the USFS Plant “Habitat Type” (Potential Association) and the Brown, Lowe, and Pase “Biome”, the * symbol denotes the best fit based on the description of the Habitat Type or Biome. For the Landfire, ReGap, and USFS PNVT and mid-scale dominance classifications, which are presently mapped as 30 meter pixels, the * symbol denotes the classification that was most commonly attributed within the Warm Desert Riparian, as mapped in this effort. The actual percentage attributed is given in parenthesis (%).
For example, the grassland polygons created by this study were used as a 'cookie-cutter' on the Landfire Existing Vegetation Type (EVT) layer (see methods). Within this study’s Warm Desert Riparian ecosystem, 27% of the EVT pixels were attributed as Warm Desert Riparian, while 24% were Mogollon Chaparral, and 20% were Madrean Mixed Juniper.
NOTE: There is a poor correspondence between this map and remotely-sensed maps based on analysis of 30 meter square pixels. This is at least in part due to the narrow corridor that is typical of riparian systems, which is often only one pixel (30 meters) wide. The skinny band of riparian vegetation, while easy for a human to spot, is apparently not so easy for a computer to figure out. Because of the high vegetation cover, riparian vegetation is often misattributed as chaparral.
Landfire Existing Vegetation Type (EVT, version 1.0.5)
North American Warm Desert Riparian* (27%)
Mogollon Chaparral (24%)
Madrean Pinyon-juniper (20%)
Landfire Biophysical Setting (BpS, version 1.0.0, which is older but judged by the author as locally more accurate)
North American Warm Desert Riparian Systems - Stringers * (37%)
Mogollon Chaparral (28%)
Madrean Pinyon-Juniper (11%)
Rocky Mountain Montane Riparian (9%)
North American Warm Desert Riparian (7%)
USFS Mid-scale Dominance Type
Upper Pine-Oak (14%) (PINUS_QUERC)
(Note: the Coronado Mid-scale map did not map riparian habitat, and hence had no riparian vegetation type)
USFS Plant Habitat Type (Potential Association)
Arizona sycamore series (PLWR2 series) *
USFS Potential Natural Vegetation Type (PNVT, based on 24 Oct 2011 draft map)
Interior chaparral * (66%)
Semi-desert grassland (18%)
Madrean pine-oak woodland (9%)
Madrean encinal (6%)
Note: Although there is a 'cottonwood/willow riparian forest' vegetation type, it was not mapped by the PNVT map within the Galiuros.
Brown, Lowe, and Pase Biome
Interior Southwestern Riparian Deciduous Forest and Woodland
Southwest Regional GAP Ecological System
Mogollon chaparral * (63%)
Mesquite upland shrub (18%)
Madrean pine-oak (11%)
Madrean pinyon-juniper (6%)
188 ha
Area in acres: 
464 acres