Natural Resources
Conservation Service
Ecological site F041XA130AZ
Mountains
23-25" p.z.
(QUHY, QUAR)
Last updated: 4/09/2021
Accessed: 09/06/2026
-
Search
Major Land Resource Area or ecological site by name and/or ID.
PreviousSectionsNextGeneral information
Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
MLRA notes
Major Land Resource Area (MLRA): 041X–Madrean Archipelago
AZ 41.1 – Mexican Oak-Pine Forest and Oak Savannah
Elevations range from 4500 to 10,700 feet and precipitation ranges from 16 to 30 inches. Vegetation includes Emory oak, Mexican blue oak, Arizona white oak, one-seed juniper, alligator juniper, sacahuista, California bricklebush, skunkbush sumac, Arizona rosewood, wait-a-bit mimosa, sideoats grama, blue grama, purple grama, wooly bunchgrass, plains lovegrass, squirreltail, and pinyon ricegrass. The soil temperature regime ranges from thermic to mesic and the soil moisture regime ranges from aridic ustic to typic ustic. This unit occurs within the Basin and Range Physiographic Province and is characterized by numerous mountain ranges that rise abruptly from broad, plain-like valleys and basins. Igneous and metamorphic rock classes dominate the mountain ranges and sediments filling the basins represent combinations of fluvial, lacustrine, colluvial and alluvial deposits.Table 1. Dominant plant species
Tree (1) Quercus hypoleucoides
(2) Quercus arizonicaShrub (1) Garrya wrightii
Herbaceous Not specified
Physiographic features
This site occurs on hillslopes and ridgetops. Slope aspect is site differentiatiing at elevations near land resource subarea boundaries.
Table 2. Representative physiographic features
Landforms (1) Hill
(2) Ridge
Ponding frequency None Elevation 6000 – 7400 ft Slope 15 – 70 % Climatic features
Precipitation in this zone of the common resource area ranges from 16-20 inches per year with elevations from 4700-5500 feet. Approximately 40% of this moisture comes as gentle rain or snow during the winter-spring (Oct-Apr) season; originates in the north Pacific and Gulf of California and comes as frontal storms with long duration and low intensity. The remaining 60% falls in the summer season (May-Sep); originates in the Gulf of Mexico and are convective, usually brief, intense thunderstorms. Snow is common Dec-Mar, averaging 5-15 inches per year, but rarely lasts more than a week. May and June are the driest months. Humidity is low.
Temperatures are mild. Freezing temperatures are common at night from Oct-May, but daytime temperatures are almost always over 40 F. Below 0 F temperatures can occur Dec-Feb. Daytime summer highs rarely exceed 95 F.
Species like plains lovegrass, bottlebrush squirreltail, Arizona white oak and Emory oak begin growth in late March to April. Warm season grasses begin growth in July or August with receipt of the first summer rains.Table 3 Representative climatic features
Frost-free period (average) 200 days Freeze-free period (average) Precipitation total (average) 20 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
Soil features
These are shallow to moderately deep soils formed on a variety of parent materials. Bedrock types include a variety of acidic and neutral igneous rocks; metamorphics like schist, gneiss and quartzite; & non-calcareous sedimentary rocks like sandstone, arkose and conglomerate. These soils are dark colored in the upper part with an organic layer 1-2 inches thick of oak leaves and duff on the surface. Bedrock is slightly weathered at the soil juncture (5-10 inches). Surfaces are well protected by covers of rock, cobbles, and gravels. Plant-soil moisture relationships are good. Numerous areas of rock outcrop occur intermingled with soil areas.
Soils mapped on this unit include: SSA-667 Santa Cruz area MU HtF Hogris very steep and Telephone very steep; SSA-669 Pima county E part MU 75 Boriana and Spudrock.Table 4. Representative soil features
Parent material (1) Alluvium – gneiss
Surface texture (1) Very flaggy sandy loam
Family particle size (1) Loamy
Permeability class Rapid to very rapid Soil depth 20 – 40 in Available water capacity
(0-40in)0 – 2.5 in Ecological dynamics
The plant communities found on an ecological site are naturally variable. Composition and production will vary with yearly conditions, location, aspect, and the natural variability of the soils. The Historical Climax Plant Community represents the natural potential plant communities found on relict or relatively undisturbed sites. Other plant communities described here represent plant communities that are known to occur when the site is disturbed by factors such as fire, grazing, or drought.
Production data provided in this site description is standardized to air dry weight at the end of the summer growing season. The plant communities described in this site description are based on near normal rainfall years.
NRCS uses a Similarity Index to compare existing plant communities to the plant communities described here. Similarity index is determined by comparing the production and composition of a plant community to the production and composition of a plant community described in this site description. To determine Similarity index, compare the production (air dry weight) of each species to that shown in the plant community description. For each species, count no more than the maximum amount shown for the species, and for each group, count no more than the maximum amount shown for each group. Divide the resulting total by the total normal year production shown in the plant community description. If the rainfall has ben significantly above or below normal, use the total production shown for above or below normal years. If field data is not collected at the end of the summer growing season, then the field data must be corrected to the end of the year production before comparing it to the site description. The growth curve can be used as a guide for estimating production at the end of the summer growing season.
State and transition model
Custom diagramStandard diagram
More interactive model formats are also available. View Interactive Models
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
Historic Climax Plant CommunityCommunity 1.1
Historic Climax Plant CommunityThe potential plant community on this site is a closed canopy of evergreen liveoak species, juniper, and pinyon. Canopy cover is over 50%. A sparse understory of cool and warm season grasses and forbs persist uner the tree canopy. The aspect is evergreen woodland. Mature tree heights average 20 feet.
Naturally occuring wildfires in Jun-Aug are an important factor shaping these plant communities. The major live oak species are very fire tolerant. Plants have a multi-stem lifeform on this site as a result of sprouting after periodic wildfires. Due to the lack of herbaceous understory, surface fires did not carry into these plant communities. They probably burned in very droughty years in large severe fires. They take from 20-30 years to recover fully from a severe burn. Soil erosion can be greater after a fire. This acts to lengthen the time needed for vegetation to recover as new soil slowly weathers from parent materials. The presence of Mexican pinyon on this site (not fire tolerant) further suggests fire-free intervals may be quite long (20-40 years). There appears to be a connection geomorphically, with large-scale erosion and sediment events called debris flows, and past severe wildfires. Tree stems run from 400-700 per acre. Average height is 20 feet. Average stem diameter is 7 inches. Canopy cover ranges from 50-70%. Above ground annual growth of trees is 2% of net live volume in mature stands.
Periodic severe drought can occur in this region. A severe drought in the 1950s caysed wudespread forest fires in this site and associated pine sites. Less severe droughts in 1988-89 and 1993-94 also caused large scale wildfires to occur in these woodlands.
Forest understory. Understory vegetation is very sparse in this plant community. Even after severe fire, sprouts from trees and large shrubs preclude any significant development of herbaceous growth on the site.
Additional community tables
Table 5. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
This site produces very little herbaceous forage for livestock. It is suitable for year-round use by horses, but only winter-spring use by cattle as cool weather and free water permit more even use of the rugged terrain. Cattle diets will contain from 10-30% oak browse in the spring and fall. Mountain lion predation can be severe on calves and colts. Animals should be moved from this site as they calve or foal to avoid losses to lion predation.
This site usually forms the basis for home ranges of black bear and mountain lions in southern Ariozna. Due to dense stands of trees and very steep slopes the density of Coues whitetail deer is less than on lower elevation sites. This site is important habitat for bandtail pigeons, thick-billed parrots, elegant trogon, Mearns quail, and turkey species. Free water occurs infrequently as springs or seeps on hillsides or in canyons. Small water catchments (over tank aprons) usually provide year-round water at these elevations during average precipitation.Wood products
Net annual growth of evergreen tree species on this site is about 2% of total volume. These species take a long time to reach sexual maturity. Oak species do not produce acorns until they reach 60-80 years of age. Silverleaf oak sprouts vigorously after fire and usually recovers to preburn volume within 30 years. The lifespan of these species is 200-300 years. In mature stands, dead wood averages 10-15% of total volume.
Equipment use is limited due to severe, very steep slopes, severe stonyness, cobbly soils, rock outcrops, hard bedrock and shallow soils (washouts common). Flooding potential is slight.
Erosion potential is severe in all cleared areas, roads & trails due to shallow erodible soils, steep slopes and high R factors. Compaction potential is slight to moderate. Rutting potential is severe.
Fuelwood harvest should be limited to areas with slopes less than 20%. A 20-30 year rotation on coppice sprouts will maximize wood products. Prescriptions should be designed to preserve and/or enhance other values like wildlife, scenic and hydrologic. Lop and scatter trash from wood harvest.
Prescribed burning in the cool season can reduce woody fuels and open tree canopies. Fire breaks need to be designed to keep grades belop 20% and water control features need to be installed as needed to prevent roadway erosion.
Use fuelwood harvest and prescribed burning to control mistletoe and heart rot fungus.
Natural regeneration is excellent for silverleaf oak. Plant competition is slight for sprouting species; severe for seedlings.
Windthrow hazard is slight.Other information
T&E Species
New Mexican ridgenose rattlesnake (Crotalus willardi obscurus); American peregrin falcon (Falco peregrinus anatum); Mexican spotted owl (Strix occidentalis lucida); Mexican gray wolf (Canis lupus baileyi); Lesser long-nose bat (Leptonycteris curasoae yerbabuena); and Ocelot (Felis pardalis)Supporting information
Type locality
Location 1: Cochise County, AZ Township/Range/Section T23S R19E S2 General legal description Fort Huachuca - Upper Garden Canyon Location 2: Pima County, AZ Township/Range/Section T14S R17E S24 General legal description Saguaro National Monument Location 3: Cochise County, AZ Township/Range/Section T22S R24E S29 General legal description Mule Mountains - Dixie Canyon Location 4: Pima County, AZ General legal description Catalina Mountains - Samaniego Ridge Contributors
Karlynn Huling
Larry D. EllicottApproval
Curtis Talbot, 4/09/2021
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
Author(s)/participant(s) Contact for lead author Date 09/06/2026 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
-
Number and height of erosional pedestals or terracettes:
-
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
-
Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
-
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
-
Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
-
Perennial plant reproductive capability:
Print Options
Sections
Font
AAAAOther
PrintThe Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
Accessibility statement
