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Sunflower Allotment EA Soils Report

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Sunflower Allotment

Draft Soils Existing and Desired Conditions Report

Patricia Boness

April 2013

Project Area

The Sunflower Allotment is approximately 155,235 acres located on the Mesa Ranger District. It

is located in the Central Highlands Physiographic Province (Chronic, 1983). The vegetation is

extremely variable ranging from Sonoran Desert at the lowest elevations to ponderosa pine at the

highest elevations. Elevations range from about 1,600 feet to 7,657 feet on Brown’s Peak. The

southeast part of the allotment is in the Four Peaks Wilderness.

The mean annual precipitation ranges from 11 inches at the lower elevations to 24 inches at the

higher elevations. The mean annual soil temperature ranges from 68°F at lower elevations to

52°F at higher elevations (U.S.F.S., SW Region, 1985).

Terrestrial Ecological Unit Inventory (TEUI)/Terrestrial Ecosystem Survey (TES)

An ongoing Terrestrial Ecological Unit Inventory (TEUI) [formerly Terrestrial Ecosystem Survey

(TES)] is currently being conducted on the Tonto National Forest. Tentative, in-progess maps and

a map unit legend exist in internal GIS files. All this information is tenetative and is frequently

updated. Areas not yet mapped by the TEUI/TES survey were modified by Pat Boness based on

geologic maps, GIS imagery and DEMs and nearby areas that were already mapped. Existing

map units within the TEUI were assigned to areas not yet mapped.

Geology and Soil Classification

The allotment is underlain by a variety of geologic types. The geology is dominated by surficial

alluvial fan and terrace deposits (Q), granite (Xg/YXg/Yg), volcanic rocks (Tv), metamorphosed

volcanic rocks (Xmv), conglomerate sandstone (Tsy), and quartzite (Xq). Smaller areas of

metasedimentary rocks of sandstone and shale (Xms), sedimentary rocks of conglomerate,

sandstone, mudstone and breccia (Tsm), basalt (Tb), and younger alluvial deposits (Qr) which

occur along drainages (AZGS web site map, 2000).

Soils within the analysis are highly variable due to the wide variety of parent materials,

landforms and climate. (See the Vegetation Classification section below for an explanation of

the Terrestrial Ecological Unit Inventory (TEUI)/Terrestrial Ecosystem Survey (TES) Gradient

Analysis).

Desert soils (LSM, 2) are dominated by Torrifluvents along drainages, poorly developed

Torriorthents and Haplocambids, well-developed Haplargids on noncalcareous flats and hills,

and Haplocalcids on calcareous soils. The calcareous soils are normally associated with

crucifixion thorn (Canotia holacantha) and creosote bush (Larrea tridentata var. tridentata). In

the semiarid grassland zone (LSM, 3), the most prevalent soils are well-developed Haplustalfs

and Argiustolls. Calcidic Haplustalfs are located on the calcareous soils. In the chaparral type

(LSM, 4), well-developed medium and fine textured Typic and Lithic Haplustalfs and

Argiustolls dominate but poorly developed soils also occur. In woodlands (LSM, 4), medium


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and fine textured Lithic and Typic Haplustalfs dominate. In the ponderosa pine zone (LSM, 5),

Haplustalfs and Argiustolls are found on the more developed soils, while Haplustolls and

Haplustepts are on the less developed soils. Soils within the riparian zone are normally young,

poorly developed Fluvents, mostly coarse textured with large amounts of coarse fragments;

however, the soils in the riparian zone are highly variable.

Slope

Topographical features range from nearly level alluvial fans to rugged steep slopes and canyons.

Slope ranges are those assigned to the TEUI map units.

Table 1: Net Acres by Vegetation Type and Percent Slope*

Vegetation Type 0-5% 0-15% 0-

40%

15-

40%

15-

60%

15-

80%

40-

80%

40-

120% Total

Riparian 3,096 3,096

Sonoran Desert 9,519 30,486 22,373 10,521 18,394 16,844 4,928 113,065

Semidesert

Grasslands 232 1,724 1,580 4,220 7,756

Interior Chaparral 3,321 3,598 2,061 13,952 7,774 30,706

Pinyon/Juniper/Oak

Woodland 161 37 198

Ponderosa Pine 414 414

Total 3,096 13,072 30,647 27,732 14,576 18,394 35,016 12,702 155,235

Percent 2% 8% 20% 18% 9% 12% 23% 8% 100%

Soil Condition

Soil condition was evaluated using a combination of the ongoing TEUI/TES survey, the field

work and mapping of Norm Ambos (former Tonto NF soil scientist) and a brief field inspection

by Pat Boness. The soil conditon represents an approximation. It is not possible to visit all areas.

Interpretations were based on historical livestock use patterns and slope characteristics. Flatter

and more open areas tend to have greater impacts than steeper slopes or areas with dense

vegetation. Areas with less than satisfactory soil condition are a result of past and current

management practices. (See appendix A for an explanation of soil condition). The riparian areas

that are in a satisfactory-unsatisfactory soil condition have areas that were easily accessed and

have been heavily used in the past and are therefore in unsatisfactory soil condition. Within these

same ecosytems are areas that were very hard for cattle to access due to large boulders and rock

outcrop and therefore these reaches are still in satisfactory soil condition. Map unit 248 is a map

unit that has a slope range of 15 to 80 percent. Each polygon of this ecological unit has varying

amounts of how much area is in the 40 to 80 percent range of slope. The polygons where 40 to

80 percent slopes are dominant are rated unstable and the polygons with impaired soil condition

are where 15 to 40 percent slopes are dominant. Table 2 lists a summary of soil condition by

vegetation type for the analysis area. Appendix B contains detailed information on soil condition,

slope, and vegetation by map unit.


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Table 2. Soil Condition by Vegetation Type*

Vegetation Type Satisfactory Sat-

Unsat Impaired Unsatisfactory Unstable Total

Riparian 3,083 13 3,096

Sonoran Desert 65,536 7,728 39,801 113,065

Semidesert

Grasslands 1,580 1,886 70 4,220 7,756

Interior Chaparral 6,327 2,653 21,726 30,706

Pinyon/Juniper/

Oak Woodland 161 37 198

Ponderosa Pine 414 414

Total 8,482 3,083 70,125 7,798 65,747 155,235

Percent 6% 2% 45% 5% 42% 100%

The satisfactory soil condition class covers 8,482 acres (6 percent). Generally these soils have

not been heavily impacted. These areas are either on slopes that have not been as heavily used or

they have heavy shrub cover that has prevented heavy use.

Two percent (3,083 acres) have a satisfactory-unsatisfactory soil condition. These are riparian

areas in the Sonoran Desert. They have areas that are easily accessed and have been heavily used

in the past and are in unsatisfactory soil condition. Within these same delineations are areas that

are much harder for cattle to access due to large boulders and rock outcrop and therefore these

reaches are still in satisfactory soil condition.

Forty-five percent of the soils (70,125 acres) have an impaired soil condition. These soils occur

on 0 to 60 percent slopes. Generally, these soils have slight to moderate soil compaction and have

lost part of the original “A” horizon through moderate sheet and rill erosion. These soils have not

been compacted as much as the heavily used soils in unsatisfactory condition. Nutrient cycling is

limited as well with a poor distribution of litter in the interspaces.

The unsatisfactory soil condition class is 7,798 acres (5 percent) of the analysis area. These soils

occur in flat, open areas. These soils have high amounts of surface compaction and poor soil

porosity and root distribution resulting in moderate to high amounts of sheet, rill or gully erosion.

Nutrient cycling is limited as well with a poor distribution of litter in the interspaces. Vegetation

diversity and species composition is relatively low.

Forty-two percent of the soils (65,747 acres) were mapped unstable. These soils are geologically

unstable and occur on steep slopes or parent rocks that tend to be erosive such as granite and

poorly cemented conglomerate. Some other areas of unstable soils occur on scarp slopes scattered

throughout the project area but occur in areas too small to map.

Vegetation Classification

For the purpose of this analysis, vegetation types have been grouped into six fairly broad

vegetation group made up of more narrowly defined similar types which in turn were groupings

of similar vegetation subseries. Plant subseries are climax plant communities named for

characteristic and diagnostic plants that distinguish one plant community from another (USDA,


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Terrestrial Ecosystem Survey Handbook, 1985. pp. 4-25 to 4-27). There may be a large degree of

variability within the broad vegetation groups. The vegetative types were developed from

TES/TEUI surveys, aerial photo interpretation, satellite imagery, and on-the-ground observations.

Not all types and delineations were field validated. In some cases, the vegetation was mapped as

an association of two vegetation types. Where two vegetation types occur together in one map

unit, the drier vegetation component normally occurs on southern aspects while the wetter

component occurs on northern aspects. The vegetation map and table 3 serve as a basis for

identification of coarse-filter vegetation types. Table 3 displays the relationship between the

narrower vegetation groups and broad groups. Appendix C describes vegetation subseries and the

relationship to the broader groups.

The vegetation types listed are based on Terrestrial Ecosystem Survey gradient analysis (USDA,

Terrestrial Ecosystem Survey Handbook, 1985, Appendix B). The gradient analysis looks at the

timing and amount of precipitation and seasonal climate. It also divides each gradient into life-

zones (climate classes) ranging from hot/dry to cold/wet. The project area is within the Low Sun

Mild (LSM) TES climatic gradient. The vegetation in the LSM gradient receives more than half

of its mean annual precipitation during the period of October 1 to March 30 and has mild winters.

The LSM gradient includes climate classes 2, 3, 4 and 5. Climate class 2 represents the Arizona

Upland division of the Sonoran Desert (Sonoran Desert scrub), class 3 represents the semidesert

grassland zone, class 4 is within the woodland zone and includes juniper and pinyon/juniper,

turbinella oak chaparral, and juniper savanna grasslands. Climate class 5 is within the ponderosa

pine zone.

Table 3: Summary of Vegetation Types

Broad Vegetation

Groups Narrow Vegetation Groups Acres Subtotals

Riparian Vegetation Riparian and Streamside Vegetation 3,096 3,096

Sonoran Desert Sonoran Desert Scrub (LSM, 2) 103,671

Sonoran Desert Scrub (LSM, 2) - Semidesert

Shrub (LSM, 3) Assoc. 9,394 113,065

Semidesert Grasslands Semidesert Grasslands (LSM, 3) 232

Semidesert Shrub (LSM, 3) 3,304

Semidesert Grassland (LSM, 3) - Redberry

Juniper Woodland (LSM, 4) Assoc. 4,220 7,756

Interior Chaparral Turbinella Oak Chaparral (LSM, 4) 23,315

Emory Oak/Turbinella Oak Chaparral (LSM,

4) 6,327 29,642

Woodlands (Juniper and

Pinyon/Juniper) Pinyon/Juniper/Oak Woodland (LSM, 4) 161

Redberry Juniper/Turbinella Oak Woodland

(LSM, 4) 37 198

Conifer Forests (LSM, 5) Ponderosa Pine (LSM, 5) - Turbinella Oak

(LSM, 4) Assoc. 1,064


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Broad Vegetation

Groups Narrow Vegetation Groups Acres Subtotals

Conifer Forests (LSM, 5) Ponderosa Pine/Alligator Juniper/Grey Oak

(LSM,5) - Grey Oak/Emory Oak (LSM, 4)

Assoc.

231

Ponderosa Pine/Pinyon Pine (LSM, 5) 183 1,478

Total 155,235

Desired Condition – Soils

Forest Plan Direction

The 1987 Tonto National Forest Plan articulated the following desired conditions:

Manage vegetation to achieve satisfactory or better watershed conditions

Minimize impacts on soil and water resources from all ground disturbing activities

Mitigate adverse effects of planned activities on soil and water resources through the use of

best management practices

Emphasize improvement of soil productivity, air, and water quality

Management activities within the desert zone must fully recognize the limitations this

unique ecosystem has to the impacts of man’s uses and activities

Achieve a management situation that can respond to local or national demands for wood

products, livestock production, water yield, and a wide mix of recreation opportunities,

including wildlife related uses, which range from the primitive to the urban end of the

spectrum. The goal is to produce these outputs and opportunities on a sustained basis while

maintaining air, soil, and water resources at or above minimum local, State, or Federal

standards. Emphasize improvement of soil productivity, air and water quality.

Forest Service Manual Direction

2550.1 – Authority 1, The Multiple Use-Sustained Yield-Act states that management of the

National Forests must provide “sustained yields in perpetuity without impairment of the

productivity of the land.”

2550.2 - Objective “Maintain or restore soil quality on National Forest System lands.

Manage resource uses and soil resources on NFS lands to sustain ecological processes and

condition so that desired ecosystem services are provided in perpetuity.”

2550.3 – Policy “Manage forest and rangelands in a manner that will improve soil

productivity.”

2521.03 - Objective “Manage terrestrial ecosystems and NFS watersheds to protect soil

productivity and hydrologic function. Implement soil and water conservation measures

with management activities to maintain satisfactory or optimum watershed conditions.”

2551.1 - Soil assessments are conducted when knowledge of current soil quality conditions

is required to advise decision makers whether adjustments in land management practices

are needed.

Desired Soil Condition

Although the desired condition is to have all soils in satisfactory soil condition as described in

FSH 2509.18-99-1, this is a long-term goal. Complete recovery of all soils is unlikely to occur


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within 10 years. Characteristics of specific soil types often drive resiliency, productivity and

resistance to erosion. Soils in arid and semiarid environments recover slowly from disturbance.

Rates of recovery will differ depending on factors such as magnitude of past soil loss, inherent

soil properties, current vegetative ground cover, and type of ecosystem. However, all soils should

be moving towards satisfactory conditions. The desired conditions for soils are to:

Maintain or improve soils currently in satisfactory condition.

Improve soils in impaired condition so they are reaching or moving towards satisfactory

condition.

Improve soils in unsatisfactory soil condition so they are reaching or moving towards at

least impaired condition.

Soil productivity and function, including ability of soil to resist erosion, infiltrate water and

recycle nutrients, should be sustained and functioning properly so terrestrial and riparian

ecosystems are more resilient and better adapted to climate change. Herbaceous vegetation cover

should be maintained at levels that contribute to suitable hydrologic function, soil stability, and

nutrient cycling. Diversity of grass and forb species and presence of plant litter and grass, forb,

shrub, and tree basal area surface cover should help reduce occurrences of compaction and

erosion.

Desired Vegetation Condition

Grazing by domestic livestock and other land disturbing activities can impact vegetation by

changing the mix of species in the plant community being affected (species composition), by

changing the density and frequency of perennial herbaceous plants (plant frequency), and by

changing the vigor of affected plants. The combined effects on composition, density, and plant

vigor can be used to measure the condition and trend of rangeland plant communities. Desired

conditions for vegetation communities are to:

Increase cover of native herbaceous species with an ultimate goal of achieving ecosystem

potential.

Increase plant basal area and litter.

In semidesert grasslands and juniper savannas, increase the foliar canopy coverage, basal

cover, and vigor of grass species that decrease under grazing pressure.

In chaparral, increase the foliar canopy cover and vigor of shrub species preferred by

grazing animals. They are referred to as “A” species in Forest Service Handbooks (FSH

2209.21 R-3) and include but are not limited to desert ceanothus, mountain mahogany, and

Wright silktassel.

In woodlands, increase all of the above attributes.

In the Sonoran Desert increase the cover of cryptogams (microbiotic soil crusts) to reduce

soil erosion, increase infiltration, and limit the spread of exotic annuals. . (U.S.D.I.

Technical Reference 1730-2, 2001. p33)

In Sonoran Desert communities allow for increased reproduction of jojoba.

In conifer forests provide for diversity in age classes of trees and healthy spacing of trees.

Incomplete or Unavailable Information CEQ 1502.22

Not all vegetation types, soil conditions, and their associated delineations were field inspected

and validated due to their inaccessible locations and are based on somewhat limited onsite data.

Field validating every delineation for purposes of collecting onsite specific information would not


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be practicable. Some of the soil condition classes are projected from similar sites across the

landscape and are based on theoretical approaches and methods generally accepted in the

scientific community. Consequently, the soil condition classes assigned should not be interpreted

with full confidence but used as a coarse-filter technique to assign gross range condition classes

per vegetation type.


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Sunflower Allotment

Soils and Upland Vegetation

Environmental Consequences

Patricia Boness

Soil Scientist

May 2013

Effects on Soils and Vegetation

Direct Effects

A. Grazing and Grazing Related Activities: Livestock grazing can affect soil quality in several

ways. Hoof action of cattle can directly impact soils by compacting soils. The risk for

compaction is greatest when soils are wet (NRCS, 1996). Compaction decreases water

infiltration, restricts rooting depth, and increases the hazard of water erosion (NRCS, 1996,

1998, 2001). Trailing by cattle on steeper slopes can physically displace soils, leading to

erosion. Trampling by cattle in certain circumstances can temporally increase water

infiltration rates but tend to decrease long-term rates (Roundy et al. 1992). Grazing can, under

certain conditions, increase planting of grass seeds and seedling emergence (Winkle

1991).Cattle tend to concentrate on flatter areas especially if they are fairly open. Holechek

reports that cattle tend to use 10 to 30 percent slopes thirty percent less often than 0 to

10 percent slopes and 30 to 60 percent slopes sixty percent less often than flats. Slopes over 60

percent are seldom used (Holechek, 1992). Because of the tendency of cattle to use flatter

slopes, areas of impacted soils are more likely to be found on gentler slopes. Range

improvements (e.g., fencing, water developments, etc.) can have slight, localized, short-term

impacts to soils during construction. Building new fences and developing waters, as

mentioned in the proposed action, would have extremely small, localized direct impacts to

soils

B. Fire and Noxious Weed Activities: The use of fire for maintenance of chaparral and

woodland vegetation can directly impact the soils by sterilizing soils where burns are too hot.

If fires are very hot, they can cause water repellent soils to develop. Broadcast burning can

cause a reduction in overstory. Benefits include improving ground cover by encouraging

increased herbaceous growth and by reducing risks of wildfire. Treatments used to remove

noxious weeds can lead to localized, short-term disturbance to soils. Effects of noxious weed

control are detailed in the Tonto Weeds EA (An Environmental Assessment for Integrated

Treatment of Noxious of Invasive Plants on the Tonto National Forest. 2012, pp.70-73).

Noxious weed control will take place whether or not any of the alternatives are selected.

Negative effects of herbicide application include the potential for decreasing microbial

populations or altering species composition of microorganisms in the soil profile. Such

impacts normally do not persist and populations generally recover after a few days or weeks

(Brady, 2002, p.810).

Indirect Effects

A. Grazing and Grazing Related Activities: Cattle indirectly impact soils by removing

vegetation resulting in a loss of protective cover including litter. The loss of vegetation

and litter reduces infiltration and exposes the soils to raindrop impact and overland flow,

thus leading to soil crusting and increased erosion. The reduced cover can also result in a


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loss of soil organic matter and a reduction in soil microbes which play a significant role

in nutrient cycling. Soils that are lower in organic matter have poorer structure which also

affects infiltration and root growth. Building fences and developing waters will indirectly

affect soils by improving distribution of cattle resulting in a net positive effect. Other

management actions, such as salting and water development, that affect livestock use

patterns can improve cattle distributions and lessen impacts to heavily used areas but

could lead to increased use of other areas that had been previously unused or lightly used.

B. Mechanical Treatments, Fire and Other Nongrazing Activities: Prescribed fires used

in chaparral and woodland vegetation treatment projects can indirectly impact soils by, in

some cases, allowing an increase in noxious plants. (Overby, 2000). Broadcast burning

on a landscape scale can have positive effect by reducing the risk of large wildfires,

which often lead to a large increase in erosion. Broadcast burning, however, can also

have negative effects. If fires are very large and very hot they can lead to post-fire

erosion problems similar to those of wild fires. In certain ecosystems, mostly woodlands

with little herbaceous understory, fire can open the area up to erosion and invasive weeds.

Treatments used to remove noxious weeds are likely to lead to long-term improvements

in soil condition by decreasing bare soil (An Environmental Assessment for Integrated

Treatment of Noxious of Invasive Plants on the Tonto National Forest. 2012, pp.70-73).

Negative effects of herbicide application include the potential for decreasing microbial

populations or altering species composition of microorganisms in the soil profile. Such

impacts normally do not persist and populations generally recover after a few days or

weeks (Brady, 2002, p.810).

Cumulative Effects

Cumulative effects include the direct and indirect effects of the proposed action and alternatives

when added to all past, present, and reasonably foreseeable future actions.

Past grazing actions have resulted in soil erosion and compaction, while current management has,

in some cases, prevented or slowed recovery. The Forest Service Range Management files (File

Code 2210) document the overgrazed condition of the uplands, springs and riparian areas.

A long history of fire suppression has altered the characteristics of many ecosystems. Conifer

forests generally have a greater fuel load and a greater density of trees. Other ecosystems

(woodlands, juniper savannas and semidesert grasslands) have had an increase in woody plants.

Large wildfires that have had an impact on the project area are Sunflower (2012), Edge Complex

(2005), Lone Fire (1996) and River Fire (1995).

Improperly maintained roads can cause soil erosion where runoff from roads is allowed to

concentrate. Roads can be a source of concentrated runoff which can lead to localized soil erosion

downslope from roads. Unauthorized crosscountry vehicle travel can negatively impact soils and

vegetation through direct impacts on soils and removal or degradation of herbaceous or woody

vegetation. Very heavy recreational use by OHV users occurs within the project area especially in

the area referred to as “The Rolls.” Many trails and two-track roads have been created with a lot

of accompanying soil erosion.

Other activities and management actions that have occurred in the past or are presently occurring

in the analysis area are:

highway reconstruction


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mining

prescribed and managed fires

introduction of non-native invasive plants that lead to an increased risk of erosion and

wildfire

recreational camping

introduction and spread of noxious weeds by hikers, vehicles, domestic animals, etc.

unauthorized livestock from adjacent allotments and other lands

Recent and on-going drought and possible future climate change can also impact conditions.

Higher temperatures and lower precipitation are predicted for the southwestern United States

(Garfin et al. 2013)

Criteria Used to Evaluate Alternatives and Determine Consistency with Management Direction

The criteria used to evaluate alternatives will be based on the likelihood of moving toward or

attaining desired conditions described in the affected environment and in the Tonto National

Forest Plan.

Effects by Alternative

The alternatives are contrasted based on the likelihood of upland vegetation and soils attaining the

short and long-term desired conditions described in the affected environment.

Soils in less than satisfactory condition are generally on gentler slopes. Even with good

management, flatter areas will still have a tendency to receive heavy use since these areas are

favored by livestock. Key areas, established to monitor cattle use, are normally on flatter, more

open areas. If monitoring of grazing intensity of these areas shows acceptable use, other parts of a

pasture can be expected to have acceptable levels of impacts.

Alternative 1 – No Grazing This alternative would cancel the permit on the Sunflower Allotment following the guidance in

36 CFR 222.4 and FSM 2231.62. Existing improvements no longer functional or needed for other

purposes, including interior fences, cattle guards and water developments would be evaluated for

continued usefulness and removed as necessary.

Direct and Indirect Effects:

1. The majority of the allotment is in either an impaired (44 percent) or in a satisfactory but

inherently unstable (42 percent) soil condition (greater than 40 percent slope). Only about

seven percent of the allotment is in satisfactory soil condition. Approximately five percent

of the allotment is in unsatisfactory soil condition and about two percent is in a

satisfactory-unsatisfactory soil condition. The no grazing alternative will provide the

fastest increase to vegetative cover, species diversity, and improvement to soil condition.

2. Hoof action of cattle can cause direct impacts by compacting soils. Compaction decreases

water infiltration, restricts rooting depth, and increases the hazard of water erosion (NRCS,

1996, 1998, 2001). Therefore, the quickest and most likely recovery from soil compaction

due to past grazing activities would normally occur with complete protection from grazing.

The amount of time required for complete recovery after degradation can vary from several

years to decades depending on the severity of the impacts and the nature of the ecosystem.

Although the soil conditions that are currently less than satisfactory are largely attributable


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to the cumulative effects of historic grazing, continued grazing could slow or prevent

recovery in some areas. This alternative is likely to lead to the fastest overall improvement

but even with complete rest it may take more than ten years for some areas with impaired

and unsatisfactory soil condition to improve to a better condition class.

3. Effects on Biological (Cryptogamic) Crusts: Biological crusts play an important role in

some ecosystems especially the Sonoran Desert and, to a somewhat lesser extent, the other

ecosystems in the analysis area. Biological crusts bind and protect soil from both water and

wind erosion. Preliminary studies show reduced germination of cheatgrass (Bromus

tectorum) on soil crusts. Grazing can have detrimental effects on the amount of biological

crusts (Beymer, 1992). This alternative is most likely to increase the cover of biological

crusts and their ecological benefits.

4. The effects of removing improvements would be a minor, localized, short-term disturbance

to soils.

5. Effects of not grazing/browsing may allow localized increases in nonnative herbaceous

plants (mostly red brome in the desert) that would have otherwise been reduced by heavy

grazing in certain areas.

Cumulative Effects

The direct and indirect effects of this alternative, when combined with other past, present or

reasonably foreseeable actions (cumulative effects) as listed above, will generally be beneficial to

soils and vegetation and provide the best potential for attaining the desired conditions. Removing

grazing would allow impaired and unsatisfactory soils, often affected by compaction, to recover.

The soil conditions that are currently less than satisfactory are largely attributable to the

cumulative effects of historic grazing, heavy off-road vehicle use in certain areas and wildfires.

Areas impacted by fires are more likely to recover under this alternative. Where off-road vehicle

use remains heavy, no improvement is expected. Since grazing can reduce the establishment of

Saguaro seedlings and nurse plants that contribute to Saguaro seedling survival (Abou-Haidar,

1992; Blydenstein, 2004), this decision would benefit Sonoran Desert communities. Grazing can

also affect recovery of certain species within chaparral communities impacted by fire. No grazing

would benefit these communities. Even with continuous rest, the rate of recovery is expected to

be slow for most areas. Climate change presents additional considerations. Warming and drying

of the climate could increase the risk of wildfire especially in fire-dependent ecosystems.

Alternative 2: Proposed Action

Direct and Indirect Effects:






cumulative effects of historic grazing and current management. Soils most likely to have

impaired or unsatisfactory soils occur on flatter areas, areas most likely to be used by

livestock. These areas are likely to continue to receive a substantial amount of use

however, if allowable use guidelines are not exceeded (light grazing on soils in impaired or

unsatisfactory soil condition), these areas should begin to improve. The improvement is not

likely to be as fast as would occur under the no action/no grazing alternative.


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some ecosystems especially Sonoran Deserts and, to a somewhat lesser extent, other

ecosystems in the analysis area. Crusts bind and protect soil from both water and wind

erosion. Preliminary studies show reduced germination of cheatgrass (Bromus tectorum) on

soil crusts. Grazing can have detrimental effects on the amount of biological crusts

(Beymer, 1992). Biological crusts on sandy soils are less susceptible to disturbance when

moist or wet; on clay soils, when crusts are dry. In general, light to moderate stocking in

early- to midwet season is recommended (USDI, 2001, p 67). Grazing may slow or prevent

the recovery of biological crusts.

3. The effects of improvements (fence construction, tank construction or improvement, etc.)

would be a minor, localized, short-term disturbance to soils.

Cumulative Effects


reasonably foreseeable actions (cumulative effects) as listed above, are likely to result in

attainment of desired conditions for soils and vegetation but at a slower rate than for alternative 1.



Where off-road vehicle use remains heavy, no improvement is expected. Since grazing can

reduce the establishment of Saguaro seedlings and nurse plants that contribute to Saguaro

seedling survival (Abou-Haidar, 1989; Blydenstein, 2004), this decision slow or reduce the

establishment of Saguaro. Grazing can also affect recovery of certain species within chaparral

communities impacted by fire.

Prescribed fire can have positive and negative results and will vary depending on the type and

health of ecosystems. The area proposed for prescribed burning contains within its boundaries

approximately 12 acres of riparian, 15,666 acres of chaparral, 161 acres of pinyon/juniper/oak,

430 acres ponderosa pine, and 1,877 acres of Sonoran Desert. It is proposed to restrict the

prescribed fire to the chaparral and woodland vegetation. Of the approximate 18,000 acres in the

proposed area, over 15,000 acres have a severe erosion hazard and over 11,000 acres are in an

impaired or unstable soil condition. Prescribed fire in chaparral vegetation will be positive if burn

severity is mostly low to moderate, occurs in a mosaic, and there are no large patches of moderate

to high burn severity. Large patches of moderate to high severity can cause large amounts of soil

loss and impacts to streams within the watershed. In woodland types with a sparse understory,

burns could lead to increased bare soil and possible increase in annual plants or noxious weeds. In

woodlands, areas with sufficient grass to carry a fire may benefit from burning which may reduce

oak, pinyon and juniper seedlings. There may be an increased potential for soil erosion as a result

of litter removal by prescribed fire (Debano 1998. p. 181). Prescribed fires normally are cooler

burns than wildfires and therefore do not usually completely consume litter cover.

Climate change presents additional considerations. Warming and drying of the climate could

increase the risk of wildfire especially in fire-dependent ecosystems. Climate change presents

additional considerations for grazing. While the changes that may occur are difficult to predict,

adaptive management should allow grazing management to respond to climate variations by

adjusting cattle numbers and duration of grazing.


Page 13 of 24

Alternative 3: Modified Proposed Action

This alternative has the same direct, indirect and cumulative effects as Alternative 2 except for

the Sycamore Creek riparian exclosure.

Direct and Indirect Effects to the Exclosure:





The amount of time required for complete recovery after degradation can vary from several

years to decades depending on the severity of the impacts and the nature of the ecosystem.

Although the soil conditions that are currently less than satisfactory are largely attributable

to the cumulative effects of historic grazing, continued grazing could slow or prevent

recovery in some areas. This alternative is likely to improvement but even with complete

rest it may take more than ten years for some areas with impaired and unsatisfactory soil

condition to improve to a better condition class.


some ecosystems especially the Sonoran Desert and, to a somewhat lesser extent, the other

ecosystems in the analysis area. Biological crusts bind and protect soil from both water and

wind erosion. Preliminary studies show reduced germination of cheatgrass (Bromus

tectorum) on soil crusts. Grazing can have detrimental effects on the amount of biological

crusts (Beymer, 1992). This alternative is likely to increase the cover of biological crusts

and their ecological benefits.

3. The effects of improvements (fence construction, tank construction or improvement, etc.)

would be a minor, localized, short-term disturbance to soils.

Cumulative Effects


reasonably foreseeable actions (cumulative effects) as listed above, will generally be beneficial to

soils and vegetation and provide the best potential for attaining the desired conditions. Removing

grazing would allow impaired and unsatisfactory soils, often affected by compaction, to recover.



Areas impacted by fires are more likely to recover under this alternative. Where off-road vehicle

use remains heavy, no improvement is expected.

Page 14 of 24

Appendix A – Soil Quality Monitoring

Soil condition is an evaluation of soil quality based on an interpretation of factors which effect

vital soil functions. These functions are: The ability of the soil to hold and release water

(hydrologic function), the ability of the soil to resist erosion and degradation (soil stability), and

the ability of the soil to accept, hold and release nutrients (nutrient cycling). The rationale and

procedure for monitoring soil quality is located FSH 2509.18 supplement of the Forest Service

Manual. Soils are evaluated and assigned a soil condition category which is a reflection of the

status of soil function. The soil quality monitoring procedure is intended to update and

supplement Hydrology Note 14, June 1981 and Terrestrial Ecosystem Survey Handbook

Chapter 8 (both U.S. Forest Service, Southwestern Region) as a method to evaluate soil and

watershed condition in the Southwestern Region. Hydrology Note 14, et al., is the method

specified in the Tonto National Forest Land Management Plan for evaluating watershed

condition. This method, based on the Universal Soil Loss Equation (USLE) erosion model,

tended to over-estimate the amount of unsatisfactory soils on steep slopes and under-estimate the

amount of unsatisfactory soils on flatter surfaces. The new procedure for assessing soil condition

examines more parameters and gives a more refined evaluation of soil condition.

Categories of soil condition are satisfactory, impaired, and unsatisfactory. The following is a brief

description of each soil condition category:

Satisfactory - The soil indicators (hydrologic function, soil stability, and nutrient cycling) signify

that soil function is being sustained and the soil is functioning properly and normally. The ability

of the soil to maintain resource values and sustain outputs is high.

Impaired - The soil indicators (hydrologic function, soil stability, and nutrient cycling) signify a

reduction of soil function. The ability of the soil to function properly has been reduced and/or

there exists an increased vulnerability to degradation. An impaired category should signal land

managers that there is a need to further investigate the ecosystem to determine the cause and

degree of decline in soil functions. Changes in management practices or other preventative

actions may be appropriate.

Unsatisfactory - The soil indicators (hydrologic function, soil stability, and nutrient cycling)

signify that loss of soil function has occurred. Degradation of vital soil functions result in the

inability of the soil to maintain resource values, sustain outputs, and recover from impacts. Soils

rated in the unsatisfactory category are candidates for improved management practices or

restoration designed to recover soil functions.


Page 15 of 24

Appendix B: Soil Condition, Slope and Vegetation by Map Unit

Map Unit

Symbol

Percent

Slope Vegetation Type Acres

Soil

Condition

20 0-5 Cottonwood Willow Riparian Forest 389 Sat-Unsat

25 0-5 Cottonwood Willow Riparian Forest 40 Sat-Unsat

29 0-5 Cottonwood Willow Riparian Forest 2,654 Sat-Unsat

40 0-5 Mixed Broadleaf Deciduous Riparian Forest 13 Satisfactory

210 0-40 Sonoran Desert 16,383 Impaired


215 0-15 Sonoran Desert 7,728 Unsatisfactory

240 0-40 Sonoran Desert 360 Impaired




248 15-80 Sonoran Desert 18,029 Unstable











300 0-15 Semidesert Grassland 162 Impaired

305 15-60 Semidesert Grassland 1,580 Satisfactory

342 40-80 Semidesert Grassland 4,220 Unstable

385 0-15 Semidesert Grassland 70 Unsatisfactory

397 15-40 Semidesert Grassland 1,724 Impaired

405 40-80 Interior Chaparral 5,592 Unstable

416 15-40 Pinyon/Juniper/Oak Woodland 37 Impaired

424 0-15 Interior Chaparral 592 Impaired



Page 16 of 24

Map Unit

Symbol

Percent

Slope Vegetation Type Acres

Soil

Condition


469 15-60 Interior Chaparral 2,061 Impaired


477 15-40 Interior Chaparral 3,597 Satisfactory

480 0-15 Interior Chaparral 2,729 Satisfactory

481 0-40 Pinyon/Juniper/Oak Woodland 161 Satisfactory


513 15-60 Ponderosa Pine Forest (Mild) 231 Satisfactory

522 15-60 Ponderosa Pine Forest (Mild) 183 Satisfactory


Page 17 of 24

Appendix C: Vegetation Management Groups

Riparian (Streamside) Vegetation - This unit is a broad grouping of streamside vegetation.

Vegetation is extremely variable. See the Stream Channels/Riparian Vegetation Report for a more

detailed description of drainages and riparian vegetation.

Sonoran Desert Scrub (LSM, 2) - This vegetation type is found on the lowest elevations within

the project area and on some steep south facing slopes at mid elevation. It is among the more

extensive vegetation types within the project area and occurs on nearly level plains to steep

mountain slopes. Two major subtypes, Sonoran Desert (Paloverde) (LSM, 2) and Sonoran Desert

(Creosote) (LSM, 2), occur but are mapped together at the scale of this analysis.

Sonoran Desert (Paloverde) (LSM, 2) - Common species in this type include giant saguaro

(Carnegia gigantea), little-leaf paloverde (Parkinsonia microphylum), triangle bursage

(Ambrosia deltoidea), jojoba (Simmondsia chinensis), pricklypear cactus (Opuntia

phaeacantha), white brittlebush (Encelia farinosa), flat top buckwheat (Eriogonum

fasciculatum), ocotillo (Fouquieria splendens) and trace amounts of threeawn, (Aristida spp.)

and false mesquite (Calliandra eriophylla). Other species present include, jumping cholla

(Opuntia fulgida), catclaw acacia (Acacia greggii), whitethorn acacia (Acacia constricta),

common sotol (Dasylirion wheeleri), hedgehog cactus (Echinocereus spp.), turpentine bush

(Ericameria spp.), red brome (Bromus spp.), six week fescue (Vulpia octoflora octoflora) and

spurge (Euphorbia spp.). The understory forage production is very limited except for areas of

steep slopes or very rocky ground. Currently, on slopes less than about 40 percent, the

understory is almost void of perennial grasses and over time, has been replaced by annual

bromes and annual forbs including spurge. On some of the steeper slopes, a fair grass cover

can be found including slender grama (Bouteloua repens), threeawn, hairy grama (Bouteloua

hirsuta), sideoats grama (Bouteloua curtipendula), bush muhly (Muhlenbergia porteri),

tanglehead (Heteropogon contortus), cane beardgrass (Bothriochloa barbinoides var.

barbinoides), tridens (Tridens spp.), desert stipa (Stipa speciosa) and a variety of forbs. Some

parts of this type will produce a limited amount of browse, mostly from jojoba.

Sonoran Desert (Creosote) (LSM, 2) - This type normally occurs on calcareous soils. The

dominant plant is normally creosote bush (Larrea tridentata var. tridentata). Crucifixion thorn

(Canotia holacantha) is a common species in this type. Giant saguaro and little-leaf paloverde

occur in varying amounts. Jojoba, an important browse species, is sparse on some sites but

may be codominant on other sites. The understory is normally very sparse with few or no

perennial grasses. Overall, this vegetation type produces almost no perennial herbaceous

forage. Some parts of this type will produce a limited amount of browse, mostly from jojoba.

Semidesert Grasslands (LSM, 3) – These vegetation types occur as Semidesert Grasslands

(LSM, 3) and Semidesert Shrublands (LSM, 3). They lie above desert scrub but below the

woodland zone.

Semidesert Grasslands (LSM, 3) – This type occurs as a grassland but may contain varying

amounts of shrubs. Various subtypes occur but are mapped together at the scale of this

analysis. Common types include Velvet Mesquite/Black Grama Semidesert Grassland, Velvet

Mesquite/Curly mesquite Semidesert Grassland, and Jojoba/Sideoats Grama Semidesert

Grassland. Common grass species include blue grama (Bouteloua gracilis), hairy grama,

sideoats grama, bush muhly, tanglehead, cane beardgrass, threeawn, tridens, desert stipa,

green sprangletop (Leptochloa dubia), curly mesquite (Hilaria belangeri) and a variety a


Page 18 of 24

forbs. Common shrubs include velvet mesquite (Prosopis velutina), catclaw acacia,

pricklypear cactus (Opuntia spp.), desert ceanothus (Ceanothus greggii), catclaw mimosa

(Mimosa aculeaticarpa), Wright’s buckwheat, and jojoba. Blue paloverde and jojoba can be

found on the hotter/drier parts of this type. Redberry juniper and turbinella oak (Quercus

turbinella) may occur on cooler/moister sites. The Velvet Mesquite/Black Grama Semidesert

Grassland type normally occurs on coarse and medium textured soils where black grama

(Bouteloua eriopoda) is normally dominant or codominant. The Velvet Mesquite/Curly

mesquite Semidesert Grassland type occurs on medium and fine textured soils on gentle

slopes. Curly mesquite is normally the dominant grass in this type often occurring in nearly

pure stands. The Jojoba/Sideoats Grama Semidesert Grassland type normally occurs on

steeper slopes at low to medium elevations within this zone. A wide variety of grasses occur

along with an overstory of jojoba.

Semidesert Shrubland (LSM, 3) – This type occurs as a shrubland. The key indicator species

are velvet mesquite, catclaw acacia (Acacia gregii), pricklypear cactus (Opuntia spp.), desert

ceanothus, catclaw mimosa, Wright’s buckwheat, false mesquite and jojoba. Blue paloverde

can be found on the hotter/drier parts of this type. Redberry juniper (Juniperus coahuilensis)

may occur on cooler/moister sites. In most places the understory is almost completely devoid

of perennial grasses except for an occasional threeawn or curly mesquite. In some places,

mostly steep slopes, jojoba, false mesquite, and Wright’s buckwheat provide forage. On

calcareous soils crucifixion thorn (Canotia holacantha) is a dominant or codominant species

along with other shrubs and occurs with a sparse understory.

Juniper Savannas (LSM, 4) – These vegetation types occur within the woodland zone as

semiarid grasslands with an overstory of scattered junipers. Included are Redberry Juniper

Semidesert Grasslands (LSM, 4) and Alligator Juniper Savannas (LSM, 4). Elevations range

from 3,200 feet on north aspects to 6,100 feet on south aspects. Mean annual precipitation ranges

from 16 to 24 inches.

Redberry Juniper Grassland (LSM, 4) - This vegetation type occurs at lower elevations

within the woodland zone and often grades into the Semidesert Grasslands. The key overstory

species is redberry juniper which normally occurs with a canopy coverage ranging from 1 to

10 percent. Common shrubs include banana yucca (Yucca baccata), beargrass (Nolina

microcarpa), sotol (Dasilyrion wheeleri), cholla, and pricklypear. Scattered turbinella oak,

desert ceanothus (Ceanothus gregii), and mountain mahogany (Cercocarpus montanus) may

also occur.

The understory consists of curly mesquite, sideoats, blue and hairy grama, bottlebrush

squirreltail, false mesquite and Wright’s buckwheat. On flats and heavily grazed areas curly

mesquite is by far the dominant grass, often forming nearly pure stands. On medium to coarse

textured soils black grama may be common.

The Alligator Juniper Savanna (LSM, 4) – This type occurs at the higher elevations within

the woodland zone and occurs primarily on nearly level to moderately steep slopes with fine

textured soils. The overstory consists of scattered alligator juniper (J. depeanna) with canopy

coverage of 1 to 10 percent. At lower elevations, Utah juniper (Juniperus osteosperma) may

be codominant. The understory is dominated by blue grama, hairy grama, sideoats grama, and

threeawn. Vine mesquite (Panicum obtusum) occurs on heavier clay soils. Wolftail (Lycurus

setosus) and curly mesquite also may occur. On steeper slopes, green sprangletop, cane

beardgrass, Arizona cottontop (Digitaria californica), plains lovegrass (Ergrostis intermedia),

and bull muhly (Muhlenbergia emersleyi) are common. Wright’s buckwheat and false


Page 19 of 24

mesquite are common half-shrubs. Other common species include pricklypear, agave, yerba-

de-pasmo, beargrass, catclaw mimosa, and snakeweed. Parts of this type have maintained its

open aspect through juniper thinning projects.

Woodlands (Juniper and Pinyon/Juniper) (LSM, 4) – These vegetation types occur as

woodlands with various mixes of pinyon, junipers, and oaks. Included are Redberry Juniper

Woodlands (LSM, 4), Utah Juniper Woodlands (LSM, 4), Alligator Juniper Woodlands

(LSM, 4), and Pinyon/Juniper/Oak Woodlands (LSM, 4). Elevations range from 3,200 feet on

north aspects to 6,100 feet on south aspects. Mean annual precipitation ranges from 16 to

24 inches.

Redberry Juniper Woodland (LSM, 4) – This type occurs on moderately steep to steep hills

and mountains and represents the lower elevation limit of the woodland zone. The overstory

canopy of trees ranges from about 10 to 20 percent. The dominant overstory tree is redberry

juniper. On moister sites scattered Arizona pinyon (Pinus fallax), alligator juniper, and

turbinella oak may occur. Sideoats grama is normally the dominant grass or is codominant

with sideoats grama, hairy grama, blue grama, black grama, and threeawn. Curly mesquite

may be the dominant grass on some heavily grazed sites. Other grasses may include sand

dropseed (Sporobolus cryptandrus), green sprangletop (Leptchloa dubia), and cane beardgrass

(Bothriochloa barbinodis). Wright’s buckwheat and false mesquite are common half-shrubs.

Other common species include pricklypear, agave, yerba-de-pasmo, beargrass, catclaw

mimosa, and snakeweed.

Utah Juniper Woodland (LSM, 4) – This type occurs on fine textured soils on nearly level

to moderately steep plains and hills and represents mid elevation woodlands. The overstory

canopy of trees ranges from about 5 to 30 percent. The dominant overstory tree is Utah

juniper. Velvet mesquite occasionally occurs on warmer sites. On moister sites scattered

alligator juniper may occur. Arizona pinyon, Emory oak (Quercus emoryi), and Arizona white

oak (Quercus arizonica) may occur occasionally but normally occur only under nurse trees.

Curly mesquite is the dominant grasses, sometimes occurring in nearly pure stands. Other

common grasses include sideoats grama, hairy grama, blue grama, and threeawn. Wright’s

buckwheat and false mesquite are common half-shrubs. Other common species include

pricklypear, agave, beargrass, catclaw mimosa, and snakeweed. Much of this type has been

impacted by domestic livestock grazing. In the past, juniper control projects have occurred in

much of this type. Some treated areas have a high density of junipers. Herbaceous forage

production is sparse in areas of thick overstory, but increases in less dense stands.

Alligator Juniper Woodland (LSM, 4) – This type occurs on nearly level plains and

moderately steep hills. Most of this vegetation type was formerly an alligator juniper savanna.

Grazing pressure and lack of fire have allowed junipers and other woodland species to

encroach into this type. Most of the junipers are less than 50 years old. Herbaceous forage is

normally much less than in the alligator juniper savanna type. In the past, many areas of

alligator juniper woodland have been treated (pushed) with the management objective to

maintain grasslands and to increase available forage. In recent years, these treated areas have

not been maintained and, as a result, the areas now have dense stands of younger junipers.

This type is found in the same ecotone as the pinyon/juniper/oak type. In some stands,

Arizona pinyon pine, Arizona white oak, Emory oak, turbinella oak, birchleaf mountain

mahogany, sugar sumac (Rhus ovata), skunkbush sumac (Rhus trilobata), desert ceanothus

may occur in substantial amounts, but not as dense as in pinyon/juniper/oak woodlands. In


Page 20 of 24

other areas, where alligator juniper encroachment is recent, the above species may be absent

or occur only as seedlings or saplings associated with juniper nurse trees.

The dominant herbaceous species are hairy grama, sideoats grama, and blue grama. Most

other herbaceous species are less common, but include bottlebrush squirreltail (Elymus

elymoides), mutton bluegrass (Poa fendleriana), plains lovegrass, and wolftail. In areas with

high amounts of clay at the surface vine mesquite can occur. Herbaceous forage is low where

the overstory is extremely dense stands, but increases in more open stands.

Pinyon/Juniper/Oak Woodlands (LSM, 4) – This vegetation type occurs as a woodland with

an overstory of Arizona pinyon, various junipers and a variety of oaks. The density of

overstory trees varies. Some stands are quite dense and produce very little herbaceous growth

in the understory, while other stands are fairly open and produce a fair amount of herbaceous

growth in the understory. Several subtypes occur within this larger type, but are mapped

together at the scale of this analysis. They include Arizona Pinyon/Redberry

Juniper/Turbinella Oak; Arizona Pinyon/Utah Juniper/Turbinella Oak Arizona

Pinyon/Alligator Juniper/Arizona White Oak; and Arizona Pinyon/Alligator Juniper/Arizona

White Oak/Blue Grama Woodlands.

Arizona Pinyon/Redberry Juniper/Turbinella Oak – This vegetation type is found at lowest

elevation of the pinyon/juniper types within the project area. It occurs on nearly level,

moderately steep, and steep plains and hills.

The key indicator species are Arizona pinyon pine, redberry juniper, turbinella oak,

birchleaf mountain mahogany, skunkbush sumac, and desert ceanothus.

Herbaceous cover is normally sparse but may be much denser in open stands. The common

understory species consist of sideoats grama, blue grama, black grama, hairy grama,

threeawn, plains lovegrass, bottlebrush squirreltail, mutton bluegrass, and Wright’s

buckwheat.

Arizona Pinyon/Utah Juniper/Turbinella Oak – This vegetation type is found at lowest

elevation of the pinyon/juniper types within the project area. It occurs on nearly level,

moderately steep, and steep plains and hills.

The key indicator species are Arizona pinyon pine, Utah juniper, turbinella oak, birchleaf

mountain mahogany, skunkbush sumac, and desert ceanothus. In most places in the project

area where this type occurs, the herbaceous cover is normally very sparse.

Arizona Pinyon/Alligator Juniper/Arizona White Oak – This vegetation type occurs on

nearly level to steep plains, hills, and mountains on slopes ranging from 0 to 80 percent.

The canopy cover of trees and shrubs is normally greater than 40 percent.

The key overstory indicator species are Arizona pinyon pine, alligator juniper, manzanita

(Arctostaphylos spp.), Arizona white oak, Emory oak, and occasionally Utah Juniper.

Other species include mountain mahogany, sugar sumac, skunkbush sumac, mountain

mahogany, Wright’s silktassel, and desert ceanothus. The more palatable shrubs are

normally sparse.

Because of the dense woody overstory cover the understory is normally sparse and the

herbaceous forage production is limited. Limited amounts of sideoats grama, hairy grama,

curly mesquite, bottlebrush squirreltail, Junegrass, threeawn, and Wright’s buckwheat


Page 21 of 24

occur. This type is similar to the Alligator Juniper/Arizona White Oak/Blue Grama

Woodland but differs by having a denser tree overstory and a less dense herbaceous

understory.

Arizona Pinyon/Alligator Juniper/White Oak/Blue Grama – This vegetation type is found

at the same elevation as the Arizona Pinyon/Alligator Juniper/Arizona White Oak type but

tends to have a more open tree canopy and a denser herbaceous layer. It occurs on plains,

hills and mountains on slopes ranging from 0 to greater than 80 percent.

The key indicator species are Arizona pinyon pine, alligator juniper, Arizona white oak,

Emory Oak, turbinella oak, birchleaf mountain mahogany, sugar sumac, skunkbush sumac,

and desert ceanothus. Key herbaceous species include sideoats grama, blue grama, hairy

grama, Junegrass, three awn, wolf tail, bull muhly, plains lovegrass, bottlebrush squirrel

tail, little bluestem (Schizachrium scoparium), and Texas bluestem (S. cirratum).

Herbaceous forage production may be quite large depending on the density of the

overstory.

Turbinella Oak Chaparral (LSM, 4) – This broad vegetation type occurs as dense stands of

shrubs normally dominated by turbinella oak. Elevations range from 3,000 to 6,400 feet. Mean

annual precipitation ranges from 16 to 25 inches. The total canopy coverage of trees and shrubs

normally ranges from about 40 to 80 percent, but in some disclimaxes the canopy coverage of

shrubs can be as low as 15 percent. The key indicator species is turbinella oak. Other commonly

occurring species include manzanita, Emory oak, Arizona white oak, birchleaf mountain

mahogany, desert ceanothus, Wright’s silktassel (Garrya wrightii), beargrass, skunkbush sumac,

sugar sumac, Wright’s buckwheat, and hollyleaf buckthorn (Rhamnus crocea). Scattered Utah

juniper and redberry juniper may occur at lower elevations, while alligator juniper and occasional

Arizona pinyon may occur at higher elevations. In most places the herbaceous layer is sparse, but

where it occurs it may contain small amounts of sideoats grama, bottlebrush squirrel tail,

Junegrass, bull grass (Muhlenbergia emersleyi), little bluestem, plains lovegrass, and bottlebrush

squirreltail.

There is a large amount of variability within this broader vegetation type depending on elevation,

slope, soil parent material, and past disturbances. Subtypes include Turbinella Oak/Desert

Ceanothus Chaparral (LSM, 4), Redberry Juniper/Turbinella Oak/Desert Ceanothus Chaparral

Woodland (LSM, 4), Turbinella Oak/Manzanita Chaparral (LSM, 4), and Turbinella

Oak/Catclaw Mimosa Chaparral (LSM, 4) and are mapped together at the scale of this analysis.

The Turbinella Oak/Desert Ceanothus Chaparral (LSM, 4) type is strongly dominated by

turbinella oak but contains more of the desirable browse species (mountain mahogany, desert

ceanothus, and Wright’s silktassel; classified as “A” species in the Range Vegetation

Scorecard Handbook) than most other types. Some areas have a fair amount of herbaceous

cover. This type normally occurs on steep slopes where impacts from domestic livestock

grazing have been low.


Page 22 of 24

The Redberry Juniper/Turbinella Oak /Desert Ceanothus Chaparral Woodland (LSM, 4, -1)

type occurs on moderately steep to very hills and mountains on soils derived from granite. The

total canopy coverage of shrubs ranges from about 15 to 50 percent. The canopy cover of

redberry juniper is normally less than 10 percent but can increase to around 20 percent where

this type grades into woodlands. The understory is normally sparse containing only few or no

perennial grasses. The density of the more palatable shrubs is normally low. Extensive gully

erosion is common.

The Turbinella Oak/Manzanita Chaparral (LSM, 4) vegetation type occurs on nearly level to

moderately steep to very steep plains and hills. This type is normally dominated by two

species: tubinella oak and pringle manzanita. Other species may occur but are normally

subordinate. The more palatable browse species are normally sparse. The total canopy

coverage of shrubs normally exceeds 50 percent and may exceed 90 percent in some areas.

The canopy coverage of manzanita is normally around 40 to 50 percent. The understory is

normally sparse containing only few or no perennial grasses.

The Turbinella Oak/Catclaw Mimosa Chaparral (LSM, 4) type occurs on moderately steep to

steep plains and hills. Turbinella oak and catclaw mimosa are the most common species

however, at lower elevations catclaw acacia may be codominate with the mimosa or may

replace it. The understory is normally sparse. In most places important browse species are

scarce. Sheet, rill, and gully erosion are common on much of this type.

Conifer Forests (LSM, 5) – These vegetation types consist of higher elevation forests.

Elevations range from 5,000 to 7,700 feet. Mean annual precipitation ranges from 16 to

25 inches.

Ponderosa Pine/Alligator Juniper/Arizona White Oak (LSM, 5) –This vegetation type occurs

at higher elevations within the analysis area generally on north facing slopes or along

drainages. The dominant species include ponderosa pine (Pinus ponderosa scopulorum),

alligator juniper, Arizona white oak, and Emory oak. Pinyon pine may occur at lower

elevations. Other species may include manzanita, mountain mahogany and desert ceanothus,

blue grama, sideoats grama, mutton bluegrass, and a variety of other perennial forbs. In most

places, there is a thick litter layer of needle cast. Because of the dense overstory and thick

litter cover, little herbaceous vegetation occurs in most places. Forage production is normally

low however in places where the overstory is less dense, forage production is greater. Soil

conditions are generally satisfactory since a thick litter layer protects soils.


Page 23 of 24

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