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Natural Resources
Conservation Service
Ecological site R025XY414UT
Mountain Mahogany Thicket (Curl-leaf Mountain Mahogany)
Accessed: 08/17/2024
General information
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.
![Location map](/images/maps/R025XY414UT.png)
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.
Associated sites
R025XY316UT |
Upland Shallow Loam (Black Sagebrush) |
---|---|
R025XY412UT |
Mountain Gravelly Loam (Mountain Big Sagebrush) This site is also a similar site with defferentiae including soil and vegetation. |
R025XY416UT |
Mountain Shallow Loam (Low Sagebrush) |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Cercocarpus ledifolius |
Herbaceous |
Not specified |
Physiographic features
This site can be found on ridges on mountain slopes with slopes between 30 and 60%. It can occur at elevations between 6,300 to 8,300 feet. Flooding and ponding do not occur on this site.
Table 2. Representative physiographic features
Landforms |
(1)
Mountain slope
(2) Ridge |
---|---|
Flooding frequency | None |
Ponding frequency | None |
Elevation | 1,920 – 2,530 m |
Slope | 30 – 60% |
Climatic features
The climate is cold and snowy in the winter and warm and dry in the summer. Approximately 40 percent of the precipitation comes as rain from June through September. On the average July and August are the driest months and December through March are the wettest months. Because of the unique geographical setting of this site usually situated on ridge tops, craggy mountainous areas etc., effective precipitation is fairly limited due to the exposure of the site to wind and solar radiation. The high percentage of rock outcrop and extreme shallowness of the soils account for a high evapotranspiration rate during the summer months.
Mean Annual Air Temperature: 39-44
Mean Annual Soil Temperature: 41-47
Table 3. Representative climatic features
Frost-free period (average) | 0 days |
---|---|
Freeze-free period (average) | 80 days |
Precipitation total (average) | 559 mm |
Figure 2. Monthly average minimum and maximum temperature
Influencing water features
Water erosion hazard is slight to moderate.
Soil features
The soils on this site were formed in colluvium and residuum derived from quartzite. The soil is well drained with moderately rapid permeability in the upper 10 inches of soil. The soil is also shallow with bedrock less than 20 inches beneath the soil surface. A lithic bedrock layer is found between 10 and 20 inches below the soil surface. These soils have high amounts of rock fragments and may have little to no pedogenic development. The soil texture at the surface is very gravelly sandy loam and surface gravels are 34% by cover and subsurface gravels are 39% by volume. Surface and subsurface rocks over 3 inches in diameter are less than 15% by cover or volume. Available water capacity is between 0.4 and 0.7 in the upper 40 inches of soil. Where subsoil does occur, it is normally neutral to slightly acid in reaction. The soil pH is between 6.6 and 7.3. The soil temperature regime is frigid.
Soils associated with this site:
Box Elder Co. UT601 – Eyre (6)
Table 4. Representative soil features
Surface texture |
(1) Very gravelly sandy loam |
---|---|
Drainage class | Well drained |
Permeability class | Moderately rapid |
Soil depth | 25 – 51 cm |
Surface fragment cover <=3" | 34% |
Surface fragment cover >3" | 0% |
Available water capacity (0-101.6cm) |
1.02 – 1.78 cm |
Calcium carbonate equivalent (0-101.6cm) |
0% |
Electrical conductivity (0-101.6cm) |
0 mmhos/cm |
Sodium adsorption ratio (0-101.6cm) |
0 |
Soil reaction (1:1 water) (0-101.6cm) |
6.6 – 7.3 |
Subsurface fragment volume <=3" (Depth not specified) |
39% |
Subsurface fragment volume >3" (Depth not specified) |
0% |
Ecological dynamics
As this site deteriorates due to grazing pressure bluebunch wheatgrass, Idaho fescue, and balsamroot decrease while, low rabbitbrush, curlleaf mountainmahogany, and mountain big sagebrush increase. When the potential natural plant community is burned, curlleaf mountainmahogany, and mountain big sagebrush decrease while low rabbitbrush, and tobaccobrush increase.
State and transition model
More interactive model formats are also available.
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Ecosystem states
State 1 submodel, plant communities
State 1
Reference State
Community 1.1
Reference State
The general view of this site is curlleaf mountainmahogany. The composition by air-dry weight is approximately 15 percent perennial grasses, 10 percent forbs, and 75 percent shrubs.
Figure 3. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
Plant type | Low (kg/hectare) |
Representative value (kg/hectare) |
High (kg/hectare) |
---|---|---|---|
Shrub/Vine | 588 | 967 | 1345 |
Grass/Grasslike | 118 | 194 | 269 |
Forb | 78 | 129 | 179 |
Total | 784 | 1290 | 1793 |
Table 6. Ground cover
Tree foliar cover | 0% |
---|---|
Shrub/vine/liana foliar cover | 20-75% |
Grass/grasslike foliar cover | 5-10% |
Forb foliar cover | 2-5% |
Non-vascular plants | 0% |
Biological crusts | 0% |
Litter | 0% |
Surface fragments >0.25" and <=3" | 0% |
Surface fragments >3" | 0% |
Bedrock | 0% |
Water | 0% |
Bare ground | 0% |
Table 7. Canopy structure (% cover)
Height Above Ground (m) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
---|---|---|---|---|
<0.15 | – | – | – | – |
>0.15 <= 0.3 | – | – | – | 0-10% |
>0.3 <= 0.6 | – | – | 5-15% | – |
>0.6 <= 1.4 | – | – | – | – |
>1.4 <= 4 | – | 70-80% | – | – |
>4 <= 12 | – | – | – | – |
>12 <= 24 | – | – | – | – |
>24 <= 37 | – | – | – | – |
>37 | – | – | – | – |
Figure 4. Plant community growth curve (percent production by month). UT4141, PNC. Excellent Condition.
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 | 0 | 5 | 20 | 50 | 5 | 10 | 5 | 5 | 0 | 0 |
Additional community tables
Table 8. Community 1.1 plant community composition
Group | Common name | Symbol | Scientific name | Annual production (kg/hectare) | Foliar cover (%) | |
---|---|---|---|---|---|---|
Shrub/Vine
|
||||||
0 | Primary Shrubs | 820–942 | ||||
curl-leaf mountain mahogany | CELE3 | Cercocarpus ledifolius | 740–807 | – | ||
mountain snowberry | SYOR2 | Symphoricarpos oreophilus | 40–67 | – | ||
mountain big sagebrush | ARTRV | Artemisia tridentata ssp. vaseyana | 40–67 | – | ||
3 | Secondary Shrubs | 13–40 | ||||
Saskatoon serviceberry | AMAL2 | Amelanchier alnifolia | 13–40 | – | ||
black sagebrush | ARNO4 | Artemisia nova | 13–40 | – | ||
snowbrush ceanothus | CEVE | Ceanothus velutinus | 13–40 | – | ||
yellow rabbitbrush | CHVIL4 | Chrysothamnus viscidiflorus ssp. lanceolatus | 13–40 | – | ||
mormon tea | EPVI | Ephedra viridis | 13–40 | – | ||
rubber rabbitbrush | ERNA10 | Ericameria nauseosa | 13–40 | – | ||
creeping barberry | MARE11 | Mahonia repens | 13–40 | – | ||
antelope bitterbrush | PUTR2 | Purshia tridentata | 13–40 | – | ||
sticky currant | RIVI3 | Ribes viscosissimum | 13–40 | – | ||
Nuttall's horsebrush | TENU2 | Tetradymia nuttallii | 13–40 | – | ||
Grass/Grasslike
|
||||||
0 | Primary Grasses | 121–202 | ||||
Idaho fescue | FEID | Festuca idahoensis | 40–67 | – | ||
basin wildrye | LECI4 | Leymus cinereus | 40–67 | – | ||
bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 40–67 | – | ||
1 | Secondary Grasses | 67–135 | ||||
Indian ricegrass | ACHY | Achnatherum hymenoides | 13–40 | – | ||
Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 13–40 | – | ||
California brome | BRCA5 | Bromus carinatus | 13–40 | – | ||
squirreltail | ELEL5 | Elymus elymoides | 13–40 | – | ||
rock melicgrass | MEST | Melica stricta | 13–40 | – | ||
Sandberg bluegrass | POSE | Poa secunda | 13–40 | – | ||
Forb
|
||||||
2 | Forbs | 135–202 | ||||
common yarrow | ACMI2 | Achillea millefolium | 13–40 | – | ||
freckled milkvetch | ASLE8 | Astragalus lentiginosus | 13–40 | – | ||
Hooker's balsamroot | BAHO | Balsamorhiza hookeri | 13–40 | – | ||
arrowleaf balsamroot | BASA3 | Balsamorhiza sagittata | 13–40 | – | ||
tapertip hawksbeard | CRAC2 | Crepis acuminata | 13–40 | – | ||
cushion buckwheat | EROV | Eriogonum ovalifolium | 13–40 | – | ||
oneflower helianthella | HEUN | Helianthella uniflora | 13–40 | – | ||
western stoneseed | LIRU4 | Lithospermum ruderale | 13–40 | – | ||
low beardtongue | PEHU | Penstemon humilis | 13–40 | – | ||
spiny phlox | PHHO | Phlox hoodii | 13–40 | – |
Interpretations
Animal community
This site provides proper grazing for cattle and sheep during spring, summer, and fall.
Wildlife using this site include blacktail jackrabbit, coyote, sage grouse, mule deer, and elk.
Hydrological functions
The soil is in hydrologic group D. The runoff curve numbers are 80 through 89 depending on the condition of the watershed.
Recreational uses
Hunting and Hiking
Wood products
Curlleaf mountainmahogany furnishes some fence posts and stays. Firewood for fireplaces and campfires can be harvested, but the wood is difficult to cut with an axe after it is dry. Knick-knacks and other novelties as lamp stands, etc. can be made from this wood.
Other information
Threatened and endangered species include plants and animals.
Supporting information
Type locality
Location 1: Box Elder County, UT | |
---|---|
Township/Range/Section | T11N R17W S24 |
General legal description | NW ¼ SE ¼ Section 24, Township 11N, Range 17W |
Contributors
GBB
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) | Brock Benson (NRCS), Shane A. Green (NRCS), Robert D. Stager (BLM), Mike Gates (BLM), Tyler Staggs (BLM), Alan Bass (BLM). |
---|---|
Contact for lead author | shane.green@ut.usda.gov |
Date | 03/30/2007 |
Approved by | Shane A. Green |
Approval date | |
Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
Some rills present. Rill development may increase following large storm events, but should begin to heal during the following growing season. Frost heaving will accelerate recovery. Rill development may increase when run inflow enters site from other sites that produce large amounts of runoff (i.e. steeper sites, slickrock, rock outcrop). -
Presence of water flow patterns:
Water flow patterns are common. Some are long (15-20’). They are generally very widely spaced (about 20-30’ apart). Flow patterns occur in low places associated with microtopography commonly occurring on this site. -
Number and height of erosional pedestals or terracettes:
Plants may have small pedestals (1-3”) where they are adjacent to water flow patterns, but without exposed roots. Terracettes should be few and stable. Terracettes should be small (1-3”) and show little sign of active erosion. Some plants may appear to have a pedestal but rather than be formed by erosion, they are the result of litter and soil accumulating at plant bases, forming the appearance of a pedestal. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
15-30% bare ground (soil with no protection from raindrop impact). Very few if any bare spaces of greater than 1 square foot. In general, bare ground increases as production decreases. As species composition of shrubs relative to grasses increases, bare ground is likely to increase. Poorly developed biological soil crust that is susceptible to erosion from raindrop impact should be recorded as bare ground. -
Number of gullies and erosion associated with gullies:
No gullies present. -
Extent of wind scoured, blowouts and/or depositional areas:
Very minor evidence of active wind-generated soil movement. Wind scoured (blowouts) and depositional areas are rarely present. If present they have muted features and are mostly stabilized with vegetation and/or biological crust. -
Amount of litter movement (describe size and distance expected to travel):
Most litter resides in place but on steep slopes (>30%), at least half of the litter is likely to be transported downhill by wind or water short. Litter rarely moves more than 1-2’ to next obstruction. Leaves, stems, and small twigs will accumulate at plant bases, against rocks, in soil depressions, or against larger woody litter. Woody litter is not likely to move. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
This site should have an erosion rating of 4 to 5 under plant canopies and a rating of 3 to 4 in the interspaces with an average rating of 4 using the soil stability kit test. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
A1--0 to 8 inches; brown (10YR 4/3) sandy loam, dark brown (10YR 3/3) moist; weak very fine granular structure; soft, very friable; 10 percent angular sandstone pebbles and flagstones; many roots; medium acid; clear wavy boundary. (5 to 15 inches thick)
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Bunchgrasses, rhizomatous grasses, and shrubs provide nearly continuous canopy cover, which effectively intercepts rainfall and protects soil from erosion. Extensive root systems provide ample organic matter to the soil, resulting in very high water-holding capacity. Infiltration rates vary with soil type. Runoff is expected to be minimal. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
A compaction layer is not expected. -
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:
Dominant: Sprouting shrubs (curl-leaf mountain mahogany, mountain snowberry) > Perennial cool-season bunchgrasses (Idaho fescue, bluebunch wheatgrass)Sub-dominant:
Sub-dominant: Non-sprouting shrubs (mountain big sagebrush) = Tall perennial bunchgrass (basin wildrye)Other:
Other: Perennial forbs > other perennial grasses > other shrubsAdditional:
Disturbance regime includes fire, drought, and insects. Assumed fire cycle of 50-80 years.
Dominance is based on average annual production, air dry weight: Sprouting shrubs > Perennial bunchgrasses > non-sprouting shrubs > native perennial and annual forbs.
Functional/structural groups may appropriately contain non-native species if their ecological function is the same as the native species in the reference state (e.g. Crested wheatgrass, intermediate wheatgrass, Siberian Wheatgrass etc.)
Following a recent disturbance such as drought or fire that remove the woody vegetation, forbs and perennial grasses (herbaceous species) may dominate the community. These conditions would reflect a functional community phase within the reference state.
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
During years with average to above average precipitation, there should be very little recent mortality or decadence apparent in either the shrubs or grasses. Some mortality of bunchgrass and other shrubs may occur during very severe (long-term) droughts. There may be partial mortality of individual bunchgrasses and shrubs during less severe drought and toward the end of the fire cycle. Long-lived species dominate the site. Open spaces from disturbance are quickly filled by new plants through seedlings and asexual reproduction (tillering). -
Average percent litter cover (%) and depth ( in):
Litter cover includes litter under plants. Most litter will be fine (herbaceous) litter. Litter will be concentrated under plant canopies and sparser between plant canopies, with an average cover of 15-30% and an average depth of 0.5-1 inches. Litter cover may increase following years with favorable growing conditions. Excess litter may accumulate in absence of disturbance. Vegetative production may be reduced if litter cover exceeds 40%. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
1100-1200 lbs/acre.
Even the most stable communities exhibit a range of production values. Production will vary between communities and across the MRLA. Production will differ across the MLRA due to the naturally occurring variability in weather, soils, and aspect. The biological processes on this site are complex; therefore, representative values are presented in a land management context.
-
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:
Cheatgrass, Russian thistle, Utah juniper -
Perennial plant reproductive capability:
All perennial plants should have the ability to reproduce sexually or asexually, except in drought years. Density of plants indicates that plants reproduce at level sufficient to fill available resource. Within capability of site there are no restrictions on seed or vegetative reproductive capacity.
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