The Mogollon Chaparral ecosystem ranged from 4700 feet near the confluence of Rattlesnake and Pipestem Canyons, to 6500 feet near Grassy Peak. As mapped in this study, chaparral is actually a type of Madrean encinal with short oaks (under 15 feet) and associated species that combine for over 60% cover. It is chaparral only in the broadest sense of the word, as an ecosystem dominated by fire-adapted evergreen shrubs, typically with small leaves. In the Galiuros, this is primarily Quercus emoryi, a putative Q. grisea, Q. arizonica, Q. rugosa, Q. hypoleucoides, and manzanita. Alligator juniper (Juniperus deppeana) and pinyon pine were common associates, occasionally in the company of Rhus choriopylla, Cercocarpus montanus, and Garrya wrightii.

 

Places with similar cover values for combined pinyon pine and manzanita were not mapped as chaparral. As can be seen in the description of the Madrean Pinyon –Juniper ecosystem (e.g., Photo Point 382), such places typically have a taller canopy and a more open understory. However, there are other places within the pinyon-juniper (e.g., Photo Points 505 and 566) that could just as well be described as 'chaparral'.

 

Quercus chyrsolepis (canyon live oak), an oak often associated with chaparral, was not common in the those areas visited during the study. Quercus turbinella, another chaparral species, was common in the northern study area, but only as part of Great Basin Pinyon-Juniper ecosystem, with a taller canopy and a more open understory; the oak did not form dense thickets.

 

It should be mentioned that Landfire mapped over 17,000 acres of chaparral in the Galiuros, far more than the 2600 acres mapped in this study. It’s hard to say why 'Landfire chaparral' is abundant - there is no clear rule set. But is does appear that within the Galiuros, every pixel that Landfire attributes as an Existing Vegetation Height (EVT) of ‘1 to 3 meter shrub’ is subsequently mapped as either Madrean Oriental Chaparral or Mogollon Chaparral (which includes the Quercus turbinella and Cercocarpus montanus Alliances). Oddly, ‘Existing Vegetation Cover’, or EVC, does not play a role in the Landfire attribution scheme for chaparral. Presumably, this is because fire can reduce cover, and hence low cover might indicate recently burned chaparral. In any case, Landfire's 'chaparral' includes vast areas of scrubby south-facing slopes in lower Redfield and Rattlesnake watersheds, but much of this is actually thickets of catclaw and mesquite.

 

Finally, this study probably underestimates chaparral on the east side of the Galiuros, where watercourses form a system of distributaries at the toe of the mountain. The resulting broad fans of vegetation usually mapped as encinal or juniper savanna, but in truth it was impossible to use the current imagery to determine the dominant species, which varied dramatically between oaks, junipers, and manzanita. In some cases, the fans are likely composed of dense manzanita, and would behave as such in a fire.

 

 

The view south from a slope above Rattlesnake Canyon (see Photo Point 454 above), through a thicket of manzanita (Arctostaphylos pungens) averaging 4 feet tall (1.3 m) and 40% cover. A pair of oaks, Emory and a species similar to Q. grisea, provides similar cover, but are typically 10 to 14 feet tall (4 m). Alligator juniper (Juniperus deppeana) was the most common associate 3 m tall, 5-9% cover), followed by border pinyon (Pinus discolor, 3 m, 1-4%), silktassel (Garrya wrightii, 1.3 m, 1-4%), and beargrass (Nolina microcarpa, 1.2 m, 1-4%). There was no evidence of a single cohort of any species, but instead the opposite: all size classes were represented, giving the effect of no distinct canopy or understory. The only grass to reach 1-4% cover was a species of Muhlenbergia. 16 May 2011, at 5130 feet (1560 m).

 

 

 

 

 

On a steep north-facing slope of loose colluvium above Pipestem Canyon, netleaf and silverleaf oak (Q. rugosa and Q. hypoleucoides) combine for 40-60% cover, while New Mexico locust (Robinia neomexicana) adds another 20%. On similarly steep slopes (70% grade) among outcrops of more competent rhyolite, there is usually pinyon-juniper woodland. 5260 ft (1600 m), 14 May 2011.

 

 

The view south of Madrean Encinal, not chaparral, along a west-facing slope above Rattlesnake Canyon, about one mile (1.6 km) south of Powers Garden. This photo illustrates the similarity of encinal and chaparral - many oaks – as well as the differences. This encinal site lacks manzanita, and has more beargrass and perennial bunch grasses than places mapped as chaparral. 16 May 2011, at 5130 feet (1560 m).

 

 

The Mogollon Chaparral ecosystem includes elements of several vegetation types mapped or described in other classification schemes. In each of the seven schemes referred to below, the * symbol marks the vegetation type most similar to the Mogollon Chaparral ecological system.

 

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 Mogollon Chaparral, as mapped in this effort. The actual percentage attributed is given in parenthesis (%).

 

For example, the Mogollon Chaparral 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 Mogollon Chaparral, 46% of the EVT pixels were attributed as Madrean Pinyon-Juniper, 38% as Madrean Encinal, 11% as Madrean Pine-Oak, and 10% as Mogollon Chaparral.

 

Landfire Existing Vegetation Type (EVT, version 1.0.5)

Madrean Pinyon-Juniper Woodland * (46%)

Madrean Encinal (38%)

Madrean Lower Montane Pine-Oak Forest and Woodland (11%)

Mogollon Chaparral (includes Q. turbinella and Cercocarpus montanus alliances) (10%)

Note: Landfire mapped 17,067 acres of chaparral, or 6907 ha, compared to the 2612 acres (1057 ha ) mapped in this study.

 

Landfire Biophysical Setting (BpS, version 1.0.0, which is older but judged by the author as locally more accurate)

Madrean Pinyon-Juniper Woodland * (54%)

Madrean Encinal (28%)

Madrean Lower Montane Pine-Oak Forest and Woodland (11%)

Mogollon Chaparral (4%)

Rocky Mountain Montane Riparian Systems (3%)

 

Upper Pine-Oak * (52%) (PINUS_QUERC)

Oak-Juniper-Pinyon Mix (45%) (JUDE2, JUDE2_QUAR, JUDE2_QUEM, JUDE2_QUERC, JUMO, JUNIP_QUERC, PICEB, PIMO, QUAR, QUAR_QUEM, QUEM, QUEM_QUOB, QUERC, QUOB)

Quercus emoryi/Arctostaphylos pungens * QUEM/ARPU5

(Note: as stated in the USFS handbook, Plant Associations of New Mexico and Arizona: Woodlands, “Recent or frequent past fires could reduce the conifers and increase shrub components. Vegetation would resemble chaparral.”

 

USFS Potential Natural Vegetation Type (PNVT) based on 24 Oct 2011 draft map

Madrean Pine-oak Woodland * (61%)

Interior Chaparral (18%)

Madrean Encinal (13%)

Mixed conifer – Frequent Fire (7%)

Brown, Lowe, and Pase Biome

Interior Chaparral (Manzanita series)

 

Southwest Regional GAP Ecological System

Madrean Pine-oak * (61%)

Mogollon Chaparral (19%)

Madrean Pinyon–Juniper (13%)

Rocky Mountain Ponderosa Pine (7%)