State 1
Reference

This state represents what is believed to represent the natural range of variability that dominated the dynamics in this ecological site prior to European settlement. This site is dominated by warm-season grasses. Cool-season grasses are sub-dominant. In pre-European times the primary disturbances included fire and grazing by large ungulates and small mammals. Favorable growing conditions occurred during the spring, and continue through the warm months of June through August. Routine and/or occasional fires reduced tree cover and contributed to the ecological processes that maintained the reference plant community. Today a similar state can be found in areas where proper livestock use has occurred and where the encroachment of trees, especially ponderosa pine, has been limited.

Community 1.1
Little Bluestem-Sideoats Grama-Wheatgrass/Forbs/Conifers <2% Cover

Figure 11. Thin Upland PCP 1.1

Interpretations are based primarily on the Little bluestem-Sideoats grama-Wheatgrass/Forbs/Conifers <2% Cover plant community phase. This site is considered the Reference or historic plant community. The potential vegetation consists of about 80 percent grass and grass-like plants, 15 percent forbs, 5 percent shrubs and 0 to 2 percent trees. Total annual production for a normal growing year is approximately 2,000 lbs./ac. The community is dominated by warm-season grasses including little bluestem, sideoats grama, blue and hairy grama and plains muhly. Cool-season grasses and grass-like plants include western and bearded wheatgrass, porcupine grass, prairie junegrass, and threadleaf sedge. Forbs are common and diverse, but prairie coneflower almost always is present. Shrubs include prairie rose and fringed sagewort. Conifers may be present, but in small amounts. This plant community is productive and resilient to disturbances such as drought and fire. It is a sustainable plant community in regards to soil/site stability, watershed function, and biological integrity.

Forest overstory. Ponderosa Pine

Community 1.2
Little bluestem-Blue grama/Sedge/Forbs/Conifers <4% Cover

This plant community phase is the result of continuous season-long grazing without adequate recovery period, and no fire or drought. The potential vegetation is about 75 percent grass and grass-like plants, 15 percent forbs, 5 percent shrubs, and 0 to 5 percent trees. Total annual production for a normal growing year is approximately 1,600 lbs./ac. The community is dominated by warm-season grasses including little bluestem, blue and hairy grama and plains muhly. Cool-season grasses and grass-like plants include prairie junegrass, threadleaf sedge, western and bearded wheatgrass, and porcupine grass. Forbs are common and diverse, and prairie coneflower almost always is present. Shrubs include prairie rose and fringed sagewort. This plant community is productive and resilient to disturbances such as drought and fire. It was a sustainable plant community in regard to soil/site stability, watershed function, and biological integrity.

Forest overstory. Ponderosa Pine

Pathway 1.1A
Community 1.1 to 1.2

Continuous season-long grazing without adequate recovery periods and/or drought will cause an increase in short-grass species and upland sedge. Sideoats grama and the wheatgrasses will decrease, but little bluestem will persist in the plant community. Lack of fire will allow conifers to become established, but in relatively small amounts.

Pathway 1.2A
Community 1.2 to 1.1

Prescribed grazing that provides a recovery period after grazing, along with normal precipitation and periodic fire, will allow this plant community to return to the reference plant community.

State 2
Shortgrass State

This state is dominated by short-grass and grass-like species as a result of continuous grazing, or heavy, continuous season-long grazing without adequate recovery, or extended periods of drought. In the early stages of this State, mid-grass remnants may be present in sufficient quantities to allow for recovery to the Reference State. The dominant herbaceous species present are well adapted to grazing. Over time, the plant community will become very resistant to change due to higher runoff and reduced infiltration. Conifers may increase in this state due to the reduction of fine fuels, which is typical of short- statured grass communities.

Community 2.1
Blue grama-Hairy grama/Sedge/Little bluestem/Forbs/Conifers

This plant community evolved under continuous grazing, heavy, continuous season-long grazing, or from over utilization during extended drought periods. The potential plant community is made up of approximately 75 percent grasses and grass-like species, 15 percent forbs, 5 percent shrubs, and 0-5 percent trees. Total annual production for a normal growing year is approximately 1,200 lbs./ac. Dominant grass and grass-like species include blue grama, hairy grama, threadleaf sedge, and little bluestem. Sub-dominant grasses include western wheatgrass, needleandthread, sideoats grama, and prairie junegrass. Forbs commonly found in this plant community include cudweed sagewort, prairie coneflower, spiny phlox, and fringed sagewort. Conifers are almost always present but typically in small amounts; however, they can increase dramatically with the lack of fire.

Forest overstory. Ponderosa Pine

State 3
Early Seral State

This state is dominated by annual grasses and forbs, perennial pioneer species, short-grass and grass-like species, and half-shrubs. This is a result of heavy, continuous grazing without adequate recovery, frequent and severe defoliation, or heavy disturbance. In the early stages of this state, short-grass remnants may be present in sufficient quantities to allow for recovery to the Short Grass State. This state may have very diverse plant communities, depending upon the species that become established as soil disturbance and the percentage of bare ground is high. Runoff is high and infiltration is low. Soil erosion can be excessive, especially on steeper slopes. Conifers will commonly be present and may have increased beyond what was present in State 2.

Community 3.1
Fringed sagewort/Pioneer Perennials/Annuals/Conifers

This plant community developed under heavy, continuous grazing, heavy disturbances such as heavy use areas, and frequent and severe defoliation such as confined feeding areas and rodent concentrations. The potential plant community is made up of 60-80 percent grasses and grass-like species, 15 to 35 percent forbs, and 2 to 5 percent shrubs. Conifers may make up 0-10 percent. Total annual production can vary greatly depending upon species composition. The dominant grass often is threeawn. Other grasses may include annual bromegrass (field brome and cheatgrass), sedge, blue grama, sand dropseed, bluegrass, and western wheatgrass. The dominant forbs include fetid marigold, sweetclover, western ragweed, cudweed sagewort, and other invader-like species. The dominant shrubs include fringed sagewort, and broom snakeweed. A wide variety of other early seral plant species can occupy this site in varying amounts. This plant community is susceptible to invasion of Canada thistle, leafy spurge, and other non-native species because of the relatively high percent of bare ground. In most cases, this phase is dominated by annual and/or pioneer perennial species. Bare ground is typically much higher than on any other plant community phase.

Forest overstory. Ponderosa Pine

State 4
Wooded State

This state is dominated by conifer or conifer and deciduous tree overstory. This state is common on north- and east-facing slopes, and very common in the northern LRU (A). This state can be confused with a forest site, except it will not exhibit woodland soil characteristics such as an E soil horizon. Where conifer encroachment has been continuous for long periods of time, carbonates may have leached into the soil profile and the upper 2 to 3 inches may be neutral or slightly acidic. The midstory and understory may also resemble a forest plant community with shade-tolerant shrubs, grasses, grass-likes, and forbs. This state is the result of non-use and no fire. This state may also be droughty, as ponderosa pine canopy was found to significantly reduce precipitation reaching the forest floor by an average of 30 percent due to interception in area of intermediate and dense canopy (Wrage, 1994).

Community 4.1
Conifers or Conifer-Deciduous Tree Overstory/Shrub/Herbaceous Understory.

Figure 14. Thin Upland - PCP 4.1, Ponderosa Pine

Figure 15. Thin Upland PCP 4.1, Pine and Deciduous Trees

This plant community developed due to pine encroachment, no use and or no fire. The potential plant community is made up of 55 percent grasses and grass-like species, 10 percent forbs, 10 percent shrubs, and 25 percent trees. Total annual production can be very variable depending upon species composition. The dominant grass and grass-like species are poverty oats, bluegrass, rough-leaf ricegrass, Canada wildrye, slender wheatgrass, and sedge. The dominant forbs include Oregon grape, pinedrops, pussy toes, and western yarrow. The dominant shrubs include western snowberry, hop hornbeam, common juniper, and creeping juniper. Trees can include ponderosa pine, Rocky Mountain juniper, paper birch, and bur oak. The sites in the northern LRU are more likely to have the mixed conifer and deciduous tree species. The south LRU is more likely to have ponderosa pine and juniper in this plant community.

Forest overstory. Ponderosa Pine

Transition 1A
State 1 to 2

Continuous season-long grazing without adequate recovery periods or heavy, continuous season-long grazing above the carrying capacity, and/or extended periods of drought will cause a transition to the Shortgrass State (2.0).

Transition 5A
State 1 to 4

Encroachment of conifers and the lack of periodic fire will allow the transition to the Wooded State (4.0). In the North LRU this can include ponderosa pine and deciduous trees species, including paper birch and bur oak; in the South LRU, tree species include ponderosa pine and, to a lesser extent, Rocky Mountain juniper.

Restoration pathway 2A
State 2 to 1

Long-term prescribed grazing that provides adequate recovery time and change in seasons of use can restore this plant community to the Reference State (1.0). This process can take an extended period of time, especially if mid-stature cool- and warm-season species make up only a small percentage of the plant community. Prescribed fire or brush management may be required if conifers have become established and are increasing.

Transition 2A
State 2 to 3

Heavy continuous season-long grazing without adequate recovery periods, heavy disturbance, or frequent and severe defoliation will cause a transition to the Early Seral State (3.0).

Transition 5A
State 2 to 4

Encroachment of conifers and the lack of periodic fire will allow the transition to the Wooded State (4.0). In the North LRU this can include ponderosa pine and deciduous trees species including paper birch and bur oak; in the South LRU, ponderosa pine and, to a lesser extent, Rocky Mountain juniper.

Transition 3A
State 3 to 2

Long-term prescribed grazing that provided adequate recovery time and a change in seasons of use may restore this plant community to the Short Grass State (2.0). This process can take an extended period of time, and may not be successful or meet management goals. Seeding native species may be an option to restore this State but the outcome can be vary greatly and may not be successful. Prescribed fire or brush management may be required if conifers have become established and are increasing.

Transition 5A
State 3 to 4

Encroachment of conifers and the lack of periodic fire will allow the transition to the Wooded State (4.0). In the North LRU this can include ponderosa pine and deciduous trees species, including paper birch and bur oak; in the South LRU, ponderosa pine and, to a lesser extent, Rocky Mountain juniper.

Restoration pathway 4A
State 4 to 1

Fire or prescribed burning or brush management in concert with long-term prescribed grazing can restore this plant community to the reference state (1.0). On slopes greater than 40 to 45 percent, livestock grazing will not likely be a factor in the plant community dynamics post-fire. Aerial seeding operations immediately after a fire have proven to be successful; however, the outcome may not meet management goals other than erosion control.

Transition 4A
State 4 to 2

Fire or prescribed burning or brush management in concert with prescribed grazing that allows for proper stocking rate, and a change in the season of use can transition this plant community to the Shortgrass State (2.0). This transition is more likely to occur on shallower slopes where livestock use contributed to the plant community dynamics.