Natural Resources
Conservation Service
Ecological site F039XA135AZ
Basalt Hills
17-22" p.z.
(PIPO, QUGA)
Last updated: 9/05/2019
Accessed: 09/18/2026
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Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
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Figure 1. Mapped extent
Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.
MLRA notes
Major Land Resource Area (MLRA): 039X–Mogollon Transition North
AZ 39.1 Mogollon Plateau Coniferous Forests
Elevations range from 7000 to 12,500 feet and precipitation averages 20 to 35 inches per year. Vegetation includes ponderosa pine, Gambel oak, Arizona walnut, sycamore, Douglas fir, blue spruce, Arizona fescue, sheep fescue, mountain muhly, muttongrass, junegrass, pine dropseed, and dryland sedges. The soil temperature regime ranges from mesic to frigid and the soil moisture regime ranges from typic ustic to udic ustic. This unit occurs within the Colorado Plateau Physiographic Province and is characterized by a sequence of flat to gently dipping sedimentary rocks eroded into plateaus, valleys and deep canyons. Sedimentary rock classes dominate the plateau with volcanic fields occurring for the most part near its margin.Associated sites
F039XA132AZ Cinder Upland 17-22" p.z. (QUGA, PIPO)
F039XA133AZ Basalt Upland 17-22" p.z. (PIPO)
F039XA136AZ Cinder Hills 17-22" p.z. (PIPO, QUGA)
Table 1. Dominant plant species
Tree (1) Pinus ponderosa
(2) Quercus gambeliiShrub (1) Robinia neomexicana
Herbaceous (1) Muhlenbergia montana
(2) Blepharoneuron tricholepisPhysiographic features
This site occurs on basalt hills. It does not benefit from run-in moisture from adjacent areas.
Table 2. Representative physiographic features
Landforms (1) Hill
Elevation 6000 – 8000 ft Slope 8 – 30 % Aspect Aspect is not a significant factor Climatic features
About 40% of the moisture in this Common Resource Area (CRA), or Land Resource Unit (LRU) comes as rain from June to September. The remainder comes from October to May as snow or light rain. Extreme temperatures of 97 and -37 degrees Fahrenheit have been recorded. Some moisture is usually received every month.
Table 3 Representative climatic features
Frost-free period (average) 170 days Freeze-free period (average) 120 days Precipitation total (average) 20 in BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
Frequently found in scattered natural wetlands and springs.
Soil features
The soils characterizing this site are shallow to basalt bedrock and are non-effervescent. The surface soil has a minimum depth of 1 to 3 inches. The subsoil and underlying layers has a slow permeability and is well drained. This site cannot absorb and hold all the moisture the climate supplies. Coarse fragments average 15 to 35 percent.
Taxonomic units mapped on this site include: from SSA-637 Yavapai County Western Part MU's DaF & MdF-Dandrea; SSA-675 San Carlos IR area MU 32-Ess; SSA-695 Kaibab NF area MU 2-Cabezon.Table 4. Representative soil features
Parent material (1) Colluvium – basalt
Surface texture (1) Very stony loam
(2) Very cobbly loam
Family particle size (1) Clayey
Drainage class Well drained Permeability class Slow Soil depth 40 – 60 in Surface fragment cover <=3" 15 – 35 % Surface fragment cover >3" 10 – 22 % Available water capacity
(0-40in)5 – 7 in Soil reaction (1:1 water)
(0-40in)5.6 – 7.8 Subsurface fragment volume <=3"
(Depth not specified)15 – 35 % Subsurface fragment volume >3"
(Depth not specified)10 – 17 % 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 grazing, fire, 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 shown for the group. Divide the resulting total by the total normal year production shown in the plant community description. If rainfall has been 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
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
Ponderosa Pine Dominant. Ponderosa Pine dominates this site with and understory of herbaceous species. There are a few, isolated mature stands of gambel oak.Community 1.1
Historic Climax Plant CommunityThe understory plant community on this site is dominated by a variety of warm and cool season grasses. Small trees and shrubs make up about on quarter of the understory. This plant community is for southerly facing slopes. The northerly slopes have a larger percentage composition of ponderosa pine.
Figure 4. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
Plant type Low
(lb/acre)Representative value
(lb/acre)High
(lb/acre)Grass/Grasslike 300 310 320 Tree 105 110 115 Forb 15 18 20 Shrub/Vine 0 2 4 Total 420 440 459 Figure 5. Plant community growth curve (percent production by month). AZ3911 , 39.1 17-22" p.z. all sites. Growth begins in the spring, most growth occurs during the summer rainy season..
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 0 0 5 10 10 10 20 20 20 5 0 0 State 2
Shrub dominant with thick immature stands of gambel oak and other shrubs. There is a decrease in herbaceous cover.Transition T1
State 1 to 2A severe crown burning fire will take out the ponderosa pines and cause the area to re-sprout into a dense stand of immature gambel oak. As of now the drivers that determine restoration to reference state are not understood for this ecological site.
Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Cool Season Grasses 300–320 mountain muhly MUMO Muhlenbergia montana 90–110 – pine dropseed BLTR Blepharoneuron tricholepis 85–95 – squirreltail ELELE Elymus elymoides ssp. elymoides 50–70 – Ross' sedge CARO5 Carex rossii 25–35 – Arizona fescue FEAR2 Festuca arizonica 15–20 – muttongrass POFE Poa fendleriana 5–15 – 2 Warm Season Grasses 15–25 blue grama BOGR2 Bouteloua gracilis 8–13 – little bluestem SCSC Schizachyrium scoparium 8–13 – Forb3 Forbs 15–25 thistle CIRSI Cirsium 1–5 – redroot buckwheat ERRA3 Eriogonum racemosum 1–5 – iris IRIS Iris 1–5 – vetch VICIA Vicia 1–5 – ragwort SENEC Senecio 0–3 – Shrub/Vine4 Shrubs 0–120 Gambel oak QUGA Quercus gambelii 10–75 – New Mexico locust RONE Robinia neomexicana 0–20 – Fendler's ceanothus CEFE Ceanothus fendleri 0–10 – Tree5 Trees 105–115 ponderosa pine PIPO Pinus ponderosa 20–60 – Gambel oak QUGA Quercus gambelii 25–50 – alligator juniper JUDE2 Juniperus deppeana 25–50 – Interpretations
Animal community
Much of this site can be grazed by livestock, but some areas may be too steep to effectively graze. Suitability for grazing by livestock is good before canopy exceeds 50%. Cattle, sheep, goats and horses can use this site in summer and early fall. Management considerations include use of Prescribed Grazing, water developments and reseeding grass following harvest operations for forage and to reduce erosion, grazing should not damage young trees.
Site factors affecting wildlife:
Water: Frequently found in scattered natural wetlands and springs.
Cover: good for most species.
Food: Good potential except where grazing is unmanaged.
Other: Snowfall causes shifts in wildlife populations.
Recreational uses
Winters are cold, however, relatively mild spring, fall and summer months are attractive to recreationists.
Activities include hunting, cross-country riding, photography, hiking, rock collecting, and wildlife observation.
Wood products
Under development.
Supporting information
Type locality
Location 1: Coconino County, AZ Township/Range/Section T21N R5E S18 General legal description Coconino County, Garland Prairie, AZ 7 1/2' quad; NE1/4, NE1/4, Section 18, T21N, R5E; Camp Navajo (Navajo Depot) Contributors
Karlynn Huling
Larry D. EllicottApproval
Scott Woodall, 9/05/2019
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 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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