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Ecological site F043CY609OR

Warm Dry Conifer Foothills and Mountains (PIPO-PSME/SYAL/CAGE)

Last updated: 9/08/2023
Accessed: 11/13/2024

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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.

MLRA notes

Major Land Resource Area (MLRA): 043C–Blue and Seven Devils Mountains

This MLRA covers the Blue and Seven Devils Mountains of Oregon, Washington and Idaho. The area is characterized by thrust and block-faulted mountains and deep canyons composed of sedimentary, metasedimentary, and volcanic rocks. Elevations range from 1,300 to 9,800 feet (395 to 2,990 meters). The climate is characterized by cold, wet winters and cool, dry summers. Annual precipitation, mostly in the form of snow, averages 12 to 43 inches (305 to 1,090 millimeters) yet ranges as high as 82 inches (2,085 millimeters) at upper elevations. Soil temperature regimes are predominately Frigid to Cryic and soil moisture regimes are predominately Xeric to Udic. Mollisols and Andisols are the dominant soil orders. Ecologically, forests dominate but shrub and grass communities may occur on south aspects and lower elevations as well as in alpine meadow environments. Forest composition follows moisture, temperature and elevational gradients and typically ranges from ponderosa pine and Douglas-fir plant associations at lower elevations, grand fir at middle elevations and subalpine fir and Engelman spruce at upper elevations. Historical fire regimes associated with these forest types range from frequent surface fires in ponderosa pine - Douglas Fir forest types to mixed and stand replacing fire regimes in grand fir and subalpine fir types. A large percentage of the MLRA is federally owned and managed by the U.S. Forest Service for multiple uses.

Classification relationships

Plant Assoc. of Wallowa-Snake Province (R6 E 255-86):
CPS522 - ponderosa pine/common snowberry (modal)
CDS622 - Douglas-fir/common snowberry

Plant Assoc. of Blue and Ochoco Mountains (R6 E TP-036-92):
CDS611 - Douglas-fir/oceanspray
CDS711 - Douglas-fir/ninebark
CPG222 - ponderosa pine/elk sedge
CPG112 - ponderosa pine/Idaho fescue

USDA Forest Service Ecological Sub-region
M332 “Blue Mountains”

LANDFIRE BpS model 0710531
Northern Rocky Mountain Ponderosa Pine Woodland and Savanna – Mesic

Natureserve Terrestrial Ecological System (2020)
Northern Rocky Mountain Ponderosa Pine Woodland and Savanna, CES306.030e

Ecological site concept

In reference state, this site supports a mature stand of Ponderosa pine (Pinus ponderosa)
or ponderosa pine codominant with Douglas-fir (Pseudotsuga menzesii) and an understory characterized by the presence of shrubs such as common snowberry (Symphoricarpos albus), mallow ninebark (Physocarpus malvaceus) and oceanspray (Holodiscus discolor) and graminoids such as elk sedge (Carex geyeri) and Idaho fescue (Festuca idahoensis). In contrast to forested sites of similar composition, this site is characterized by lower elevations and a mesic (rather than frigid) soil temperature regime. Disturbance was historically influenced by a fire regime characterized by relatively frequent surface fires. Frequent fire, as well as bark beetles, was historically a critical element of the disturbance regime of this site, acting to thin crowded understories and allow fire resistant mature ponderosa and Douglas-fir trees to attain an open, savanna-like forest structure.

This is a provisional ecological site that groups characteristics at a broad scale with little to no field verification and is subject to extensive review and revision before final approval. All data herein was developed using existing information and literature and should be considered provisional and contingent upon field validation prior to use in conservation planning.

Associated sites

F043CY608OR	Cool Dry Conifer Foothills and Mountains (PIPO/FEID-PSSPS) Upslope positions with cooler soil climates

F043CY608OR

Cool Dry Conifer Foothills and Mountains (PIPO/FEID-PSSPS)

Upslope positions with cooler soil climates

Similar sites

F043CY608OR	Cool Dry Conifer Foothills and Mountains (PIPO/FEID-PSSPS) Upslope positions with cooler soil climates, frigid soil temperature regime
F043CY607OR	Cool Moist Conifer Foothills and Mountains (PIPO-PSME/SYAL) Occupying higher elevations, frigid soil temperature regime

F043CY608OR

Cool Dry Conifer Foothills and Mountains (PIPO/FEID-PSSPS)

Upslope positions with cooler soil climates, frigid soil temperature regime

F043CY607OR

Cool Moist Conifer Foothills and Mountains (PIPO-PSME/SYAL)

Occupying higher elevations, frigid soil temperature regime

Table 1. Dominant plant species

Tree	(1) Pinus ponderosa (2) Pseudotsuga menziesii
Shrub	(1) Symphoricarpos albus
Herbaceous	(1) Carex geyeri (2) Festuca idahoensis

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Physiographic features

This site occurs on footslopes, summits, and backslopes of foothills, mountain slopes, and canyon walls. Occurring on all aspects, slopes typically ranging from 7.5 - 45%. Elevations are typically between 2,200 to 3,500 (675 to 1,150 m) but may range as high as 4,000 (1,425 m). Hillslope profiles are typically linear across and down slope. This site does not experience flooding or ponding but some sites in favorable slope positions may support a water table from 18 - 36 inches below the surface during spring runoff.

Table 2. Representative physiographic features

Landforms	(1) Mountains > Hillside or mountainside (2) Mountain valleys or canyons > Hillside or mountainside (3) Foothills > Hillside or mountainside
Flooding frequency	None
Ponding frequency	None
Elevation	2,200 – 3,500 ft
Slope	8 – 45%
Ponding depth	Not specified
Water table depth	18 – 100 in
Aspect	W, NW, N, NE, E, SE, S, SW

Table 3. Representative physiographic features (actual ranges)

Flooding frequency	Not specified
Ponding frequency	Not specified
Elevation	2,200 – 4,000 ft
Slope	2 – 55%
Ponding depth	Not specified
Water table depth	Not specified

Climatic features

This site experiences an intermountain climate with cool, wet winters and warm, dry summers. Mean annual precipitation is typically 19 - 23 inches (480 - 585 mm) but can range from 16 to 24 inches (405 - 610 mm). Mean annual temperatures are typically 7 - 8 °C (44 - 47 °F). The soil temperature regime is Mesic and the soil moisture regime is Xeric typically experiencing 60 – 90 dry days per year. Frost free days average 80 to 150 per year. Climate graphs are populated from the closest available weather station and are included to represent general trends rather than representative values.

Table 4. Representative climatic features

Frost-free period (characteristic range)	80-150 days
Freeze-free period (characteristic range)
Precipitation total (characteristic range)	19-23 in
Frost-free period (average)	110 days
Freeze-free period (average)
Precipitation total (average)	20 in

Characteristic range

Actual range

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Figure 1. Monthly precipitation range

Characteristic range

Actual range

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Figure 2. Monthly minimum temperature range

Characteristic range

Actual range

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Figure 3. Monthly maximum temperature range

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Figure 4. Monthly average minimum and maximum temperature

Figure 5. Annual precipitation pattern

Figure 6. Annual average temperature pattern

Climate stations used

(1) AUSTIN 3 S [USC00350356], Prairie City, OR
(2) ELGIN [USC00352597], Elgin, OR

Soil features

Soils on this site are typically moderately deep to deep. Surface textures are varied but range from ashy sandy loam, silt loam, stony ashy loam, to stony loam. These soils are typically composed of colluvium from basalt and tuff commonly have either a thin mantle of ash or ash mixed through the profile. These are well to moderately well drained soils. See lookingglass, sopher, and emily for modal series concepts.

Table 5. Representative soil features

Parent material	(1) Colluvium – basalt (2) Residuum – tuff (3) Volcanic ash – volcanic rock
Surface texture	(1) Ashy sandy loam (2) Silt loam (3) Stony loam (4) Stony loam
Family particle size	(1) Fine (2) Clayey-skeletal (3) Loamy-skeletal (4) Coarse-loamy (5) Ashy over loamy
Drainage class	Moderately well drained to well drained
Permeability class	Slow to moderate
Depth to restrictive layer	20 – 80 in
Soil depth	20 – 80 in
Surface fragment cover <=3"	45%
Surface fragment cover >3"	45%
Available water capacity (0-40in)	4 – 7 in
Soil reaction (1:1 water) (0-40in)	6.1 – 7.3
Subsurface fragment volume <=3" (4-60in)	25%
Subsurface fragment volume >3" (4-60in)	25%

Ecological dynamics

The modal plant association that defines this ecological site group concept is the widespread Ponderosa pine/Common snowberry association (PIPO/SYAL as described in Johnson and Clausnitzer 1992, and Johnson and Simon 1987). However, this broadly defined group spans ponderosa pine and Douglas-fir plant communities with indicator species that range from mallow ninebark, oceanspray and elk sedge in areas with greater soil moisture to drier soils that are characterized by common snowberry and Idaho fescue presence. Ninebark and oceanspray are most common on canyon sites with ninebark most common on northerly aspects and oceanspray more common on southerly aspects.

Ponderosa pine and dry Douglas-fir forests were historically subject to frequent surface fires primarily ignited by lightning strikes and Native American cultural burning practices. These fires would have likely occurred at less than 35 year intervals and approximated Landfire fire regime group 1 (0-35 year frequency, surface severity). These low intensity fires would have decreased the density of young regenerating understory conifers which are less tolerant of fire when young. When allowed to grow without fire these young conifers may act as ladder fuels to ignite crown fires and lead to stand replacing events. Overtime, frequent low intensity fires, as well as occasional mixed severity fires, would have favored the development of mature, uneven-aged ponderosa pine and Douglas-fir stands with open canopies. Historically, these forest communities would have often lacked a dominant shrub component due to this frequent fire interval (Natureserve 2020). Mixed severity fires, where direct overstory mortality was patchy, were less common than surface fires, and true stand replacement fires were rare. Fire-resistant ponderosa is well-adapted to these conditions, developing increasing fire resistance with age by growing thick bark and self-thinning lower limbs. Douglas-fir is also tolerant of fire at maturity, with very thick bark and a deep rooting habit. With longer time between fire, increased development of understory fuels such as young pine, Douglas-fir, occasional grand fir and down wood, along with the development of a closed canopy, can promote an increased frequency of stand replacing fires and insect outbreaks. In addition to direct impacts of wildfire, disturbance factors that resulted in the death of mature pine included injury from lightning strikes, wind events, weather extremes, and the collective influence of various damage agents such as bark beetles, pine engraver, mistletoe, and other adapted insects and diseases associated with injury or competitive stressors.

Understory species in these forests were adapted to respond to this fire driven disturbance regime. Many cool season perennial grasses, such as bluebunch wheatgrass, would resprout from crowns following fire. Understory forbs, such as common yarrow and peavine, may resprout from rhizomes while others, such as lupine, can effectively respond to post fire conditions that may delay the reestablishment of other species, such as low soil nutrient levels, by fixing their own nitrogen.

Understory species in these forests were adapted to respond to this fire driven disturbance regime. Many plants, such as elk sedge, oceanspray, mallow ninebark and snowberry would resprout from crowns following fire. Understory forbs, such as common yarrow (Achillea millefolium) and peavines (Lathyrus spp.) may resprout from rhizomes while others, such as lupine (Lupinus spp.), can effectively respond to post fire conditions that may delay the reestablishment of other species, such as low soil nutrient levels, by fixing their own nitrogen.

As a forested site with a dominant herbaceous component in the understory and often bordering rangelands, many of these forests were historically subject to livestock grazing, especially cattle and sheep. Prolonged historical use by these ungulates may have altered the composition of understory herbaceous and shrub communities. A decrease in palatable perennial grasses such as Idaho fescue may have paralleled increases in forbs such as lupine and yarrow and exotic annual grasses such as cheatgrass (Bromus tectorum), Medusahead rye (Taeniatherum caput-medusae), and North Africa grass (Ventenata dubia). Increases in exotic grasses have been associated with other impacts as well, including off highway vehicle use and proximity to human development. At high levels, the impacts of these invasions on nutrient cycling, wildlife habitat and fire cycles may be severe.

Current stand conditions in this ecological site do not, in most instances, conform to the historic range of variability (as represented by the reference state below) in terms of the expected frequency and severity of future wildfire events. Since the arrival of Euro-American settlers to the region in the late 1880’s, the character and function of these forests have changed. Logging, grazing, conversion to other uses, and fire exclusion have impacted the natural processes of this fire-dependent ecosystem. Depending on the severity and degree of impact, alternative states (which function outside of the parameters of the reference state), have developed. Within this forest type across the Blue Mountains, fire regimes are considered to have experienced “high” departure from historical conditions (Natureserve 2020).

The state and transition model below represents a generalized and simplified version of forest change in response to major disturbance types in this ecological site. It does not attempt to model the potential effects of climate change on ecosystem function or process. Emerging evidence is suggesting that climate change is leading to hotter and drier conditions in western forests that will increase fire frequency and extent and lengthen fire seasons (Halofsky et al. 2020). When combined with the interacting impacts of fire suppression, drought, and insect outbreaks, it is possible that this ecological system will experience unpredictable ecosystem shifts and additional alternative states. For warm and dry sites, this may include the possibility of regeneration failure following wildfire disturbance (Halofsky et al. 2020). As evidence increases, this model will likely undergo alterations and updates to reflect our emerging understanding.

State and transition model

More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Historical Reference State

2. Long Term Fire Exclusion

3. Catastrophic Fire

4. Invaded State

5. Agricultural State

States 1 and 5 (additional transitions)

1. Historical Reference State

5. Agricultural State

T1a	-	Long term fire exclusion (50-100+) years
T1b	-	Widespread catastrophic stand replacing fire event
T1c	-	Introduced range grass or exotic grass invasion
T1d	-	Site converted to annual cropland or pasture/hayland
R2a	-	Restoration practices that reduce excessive fuel loads and reduce overstory crown bulk density
T2a	-	Widespread catastrophic stand replacing fire event
R3a	-	Conifer planting
R4a	-	Practices that promote the reestablishment of native understory species
R4a	-	Practices are applied which reduce or eliminate unwanted weeds and invasive species
R5a	-	Practices that promote the reestablishment of native understory species
T5a	-	Poor management or abandonment leads to weed invasion

State 1 submodel, plant communities

1.1. Reference Plant Community, Mature, Open canopy

1.2. Stand regeneration

1.3. Young forest, Open canopy

1.4. Young forest, Closed canopy

1.5. Mature, closed canopy

Communities 1, 5 and 2 (additional pathways)

1.1. Reference Plant Community, Mature, Open canopy

1.5. Mature, closed canopy

1.2. Stand regeneration

P1.1a	-	Mixed severity or stand replacing fire, beetle outbreak, windthrow event, mistletoe outbreak, storm damage
P1.1b	-	Time and the absence of major disturbance events
P1.2a	-	Low severity fire regime maintained for an extended period
P1.2b	-	Fire cycles missed
P1.3b	-	Low severity fire regime maintained for an extended period
P1.3a	-	Fires occur which are severe enough to eliminate most of all Ponderosa pine size classes
P1.3c	-	Fire cycles missed
P1.4a	-	Fires occur which are severe enough to eliminate most of all Ponderosa pine size classes
P1.4b	-	Mixed severity fire occurs eliminating some of the overstory
P1.4c	-	Low severity fire regime maintained for ~150 years
P1.5b	-	Insects/disease, such as bark beetles, remove portions of the overstory
P1.5a	-	A fire event severe enough to eliminate the majority of the overstory, or less severe mixed severity fires which creates random patch openings, occur
P1.5c	-	Insects/disease, such as bark beetles, or mixed and low severity fire

State 1
Historical Reference State

Mature forests of this type tended to be heterogeneous and spatially complex. The primary disturbance regime that maintained this ecological site in the historical context was frequent low intensity surface fire and less frequent mixed severity fire, which resulted in multiple age and size classes of ponderosa pine and occasionally Douglas-fir. In comparison to Douglas-fir, ponderosa pine reaches reproductive maturity at an earlier age and is more tolerant of fire when young. For this reason, with increasing fire return intervals or on fire protected aspects, Douglas-fir will become a more important component of the canopy. A wide array of wildlife species benefited from the edge effects created by the spatial intersections within the larger landscape, and by naturally occurring snags and large woody debris. Across the overall landscape stand structure was expressed by a combination of patch openings, clumpy (dense or overstocked) tree groups, and as well-spaced mature overstory trees encompassing larger stand groups. These mosaic patterns could occur over the landscapes in a scale of upwards of tens of thousands of acres. Disturbances from fire and other biotic and abiotic sources impacted much smaller areas within the larger landscape, on the order of thousands of acres.

Dominant plant species

ponderosa pine (Pinus ponderosa), tree
Douglas-fir (Pseudotsuga menziesii), tree
common snowberry (Symphoricarpos albus), shrub
oceanspray (Holodiscus discolor), shrub
mallow ninebark (Physocarpus malvaceus), shrub
Geyer's sedge (Carex geyeri), grass
Idaho fescue (Festuca idahoensis), grass

Community 1.1
Reference Plant Community, Mature, Open canopy

This mature forest is the dominant representation of the pre-European historic reference state which is sustained by plant adaptations to naturally occurring and frequent non-lethal fires that removed understory regeneration and fuels. It is typically un-even aged stand with an open overstory dominated by mature ponderosa pine with occasional codominance of Douglas-fir on more fire protected microsites or areas with increased soil moisture.

Community 1.2
Stand regeneration

Conifer seedlings/saplings establish in small-size patch openings created from disturbance events (fire and disease or insect outbreaks, occurring in both endemic or epidemic outbreaks) that reduced or eliminated portions of the overstory canopy layer. Seedling recruitment commonly comes from seed production in the years following the event, but also from viable banked seed that was on the ground before the disturbance occurred or from surviving regeneration that pre-dated the disturbance. Favorable weather conditions are necessary for seedlings to establish and develop. Limitations of seed dispersion distance from seed trees (these are heavy seeds) seriously hinder ponderosa pine re-establishment in larger patch sizes. Mixed severity fire may maintain the stand in this phase. The process of seedling establishment is once again dependent on sporadic cone production, coupled with favorable weather. Douglas-fir may depend on the establishment of ponderosa pine to create favorable conditions for germination.

Community 1.3
Young forest, Open canopy

Young to intermediate aged stand with open canopy conditions. At this stage, maturing Ponderosa pine and Douglas – fir are well suited to survive low intensity surface fire. Surface and mixed fires will facilitate a beneficial “thinning” effect in dense stocking conditions (i.e., some trees succumb to the fire while others survive) maintaining the stand in this phase. Reoccurring surface fire near the middle and later stages of this phase can provide beneficial self-pruning of the lower limbs of individual trees, which reduces the subsequent ladder fuel risk for those trees. Ponderosa pine and Douglas-fir seedlings will become established underneath overstory Ponderosa pine canopy layers, but their development and successional pathway will be impacted by the competition and shade relationships of the overstory stand. Ponderosa pine is a shade intolerant tree species whereas Douglas-fir is somewhat more shade tolerant.

Community 1.4
Young forest, Closed canopy

Young stand with closed canopy conditions, uncommon in reference conditions. The canopy will begin to close and understory early seral shrub cover, if present, begins to decline as tree canopy cover approaches 50%. The stand will often exhibit clumpy attributes, and increased intraspecific stand stress will occur as the stand ages, which is the beginning of the stem exclusion phase of stand development. Without fire, to open the sand up to conditions similar to 1.3, this phase is at risk of converting to the long-term fire exclusion state 2 as fuels increase. The risk of a transition to alternative state 3 due to a stand replacing fire is also increased.

Community 1.5
Mature, closed canopy

This is a mature, closed canopy stand, uncommon in reference conditions. Persistent snags and the development of down wood is high. Beneath the dominant and co-dominant overstory layer, a limited expression of younger cohorts of ponderosa pine and Douglas-fir can exist. The threat of mountain pine beetle increases, and individual trees within the canopy are at greater risk of insect and disease mortality which in turn create gaps in the overstory. Without fire to open the stand to conditions similar to 1.3 or 1.4, this phase is at risk of converting to the long-term fire exclusion state 2 as fuels increase. The risk of a transition to alternative state 3 due to a stand replacing fire is also increased.

Pathway P1.1a
Community 1.1 to 1.2

Fine scale patch openings develop from disturbance events. Causes of overstory mortality include mixed severity and localized stand replacement fire events, and from single tree to cluster mortality of mature pine trees that have succumbed to incidences such as beetle kill, mistletoe, windthrow, and storm damage.

Pathway P1.1b
Community 1.1 to 1.5

With time and the absence of major disturbance events, the stand develops into a mature, closed canopy structure.

Pathway P1.2a
Community 1.2 to 1.3

Low severity fire regime maintained for an extended period which allows more mature trees to resist or escape fire and develop into older age classes.

Pathway P1.2b
Community 1.2 to 1.4

Fire cycles missed which allows the continued development of young trees in dense, unthinned stands.

Pathway P1.3b
Community 1.3 to 1.1

A fire regime characterized by frequent, low severity fire allows the stand to develop to the mature phase. Stands have thinned as size classes increased, primarily from the natural exclusion processes as well as from stress induced bark beetle mortality and fire.

Pathway P1.3a
Community 1.3 to 1.2

Fires occur which are severe enough to eliminate most of all Ponderosa pine size classes, and again sets back the development of the site to the regeneration phase.

Pathway P1.3c
Community 1.3 to 1.4

Fire cycles missed allowing understory infill of younger trees to progress and increase stand density.

Pathway P1.4a
Community 1.4 to 1.2

Fires occur which are severe enough to eliminate most of all Ponderosa pine size classes, and again sets back the development of the site to the regeneration phase.

Pathway P1.4b
Community 1.4 to 1.3

Mixed severity fire occurs eliminating some of the overstory and opening the canopy.

Pathway P1.4c
Community 1.4 to 1.5

Low severity fire regime maintained for ~150 years which allows many trees to mature into the overstory maintaining a closed canopy.

Pathway P1.5b
Community 1.5 to 1.1

Insects/disease, such as bark beetles, remove portions of the overstory, opening the canopy to mature open canopy conditions resembling 1.1.

Pathway P1.5a
Community 1.5 to 1.2

A fire event severe enough to eliminate the majority of the overstory, or less severe mixed severity fires which creates random patch openings, occurs. The stand or impacted patch areas within the overall stand are set back to the conditions in plant community phase 1.2, in which necessary seed source/seed establishment components must be present in order to achieve adequate Ponderosa pine regeneration.

Pathway P1.5c
Community 1.5 to 1.3

Insects/disease, such as bark beetles, remove portions of the overstory, opening the canopy. Mixed and low severity fire may also thin the stand into the 1.3 phase.

State 2
Long Term Fire Exclusion

Conditions favorable to the development of this alternative state began to occur within the Reference State around the turn of the twentieth century. The impacts of fire exclusion, a management goal of post-European settlers, has allowed many stands to progress without the natural occurrence of fire, especially frequently occurring and beneficial fire episodes. Fire suppression has shifted the age expression and density of the younger stands, and changed the composition of understory vegetation, leading to reduced spatial variation. Fuel levels and fuel stratum layers have increased, shifting the fire regime/condition class toward a greater likelihood of stand replacement fire episodes.

Dominant plant species

Douglas-fir (Pseudotsuga menziesii), tree
ponderosa pine (Pinus ponderosa), tree
common snowberry (Symphoricarpos albus), shrub
mallow ninebark (Physocarpus malvaceus), shrub
oceanspray (Holodiscus discolor), shrub
Geyer's sedge (Carex geyeri), grass
Idaho fescue (Festuca idahoensis), grass

State 3
Catastrophic Fire

This state represents conditions immediately following a catastrophic wildfire event. Long term detrimental impacts to wildlife, hydrology and soil quality occur immediately due to the abnormally high intensity of the catastrophic burn. Microbial populations, organic matter levels, nitrogen cycling and other structural elements of the native soil resources are negatively impacted. The number of wildlife snags will usually increase in the short term following the fire. Recolonization of the site by conifers will depend greatly on distance to seed sources as most on site seed will be eliminated.

Dominant plant species

common snowberry (Symphoricarpos albus), shrub
oceanspray (Holodiscus discolor), shrub
mallow ninebark (Physocarpus malvaceus), shrub
creeping barberry (Mahonia repens), shrub
spirea (Spiraea), shrub
rose (Rosa), shrub
Geyer's sedge (Carex geyeri), grass
pinegrass (Calamagrostis rubescens), grass
lupine (Lupinus), other herbaceous

State 4
Invaded State

This state has developed with the introduction and invasion of introduced grasses and noxious weeds. In this site, cheatgrass (Bromus tectorum), Medusahead rye (Taeniatherum caput-medusae), and North Africa grass (Ventenata dubia) may invade the stand. These conditions are more likely to develop on areas which were near developed farm and pasture lands, road and trail networks and other converted lands.

Dominant plant species

ponderosa pine (Pinus ponderosa), tree
Douglas-fir (Pseudotsuga menziesii), tree
common snowberry (Symphoricarpos albus), shrub
mallow ninebark (Physocarpus malvaceus), shrub
oceanspray (Holodiscus discolor), shrub
North Africa grass (Ventenata dubia), grass
medusahead (Taeniatherum caput-medusae), grass
cheatgrass (Bromus tectorum), grass

State 5
Agricultural State

This state follows a very intensive or total harvest of the mature overstory, followed by stump removal and the elimination of all other native forest vegetation. Cultivation follows. In this state virtually all the natural forest functions were eliminated by the converted use to agricultural lands (including annually tilled crops as well as hay and pasture production).

Dominant plant species

orchardgrass (Dactylis), grass

Transition T1a
State 1 to 2

Long term fire exclusion (50-100+) years (resulting in Alternative State 2).

Transition T1b
State 1 to 3

A widespread catastrophic stand replacing fire event occurs as a natural (but rare) event in the reference state. Ponderosa pine and Douglas-fir are virtually eliminated across all age/size classes, leading to a long-term deficiency of seed source to re-establishment Ponderosa pine (resulting in Alternative State 3).

Transition T1c
State 1 to 4

Introduced cool season grasses invading sites near homesteads, pastureland, and other converted land. This includes exotic annual grass invasion of improperly grazed sites, as well as other excessive disturbance(s) of the native vegetation (resulting in Alternative State 4).

Transition T1d
State 1 to 5

Site converted to annual cropland or pasture/hayland (leading to Alternative State 5).

Restoration pathway R2a
State 2 to 1

Restoration practices that reduce excessive fuel loads and reduce overstory crown bulk density, as well as treatment of overstocked clumpy areas, may help to simulate historical stand densities. Tree planting in larger, un-stocked areas where Ponderosa pine and other native seed sources are absent, as well as the introduction of prescribed burning, can contribute to increased resiliency and a return to natural ecologic integrity.

Transition T2a
State 2 to 3

Widespread catastrophic fire occurs, similar to that of T1B, but the intensity and impact of the wildfire event is much greater in scope due to the unnatural buildup of fuels in Alternative State 2 (resulting in Alternative State 3).

Restoration pathway R3a
State 3 to 1

Ponderosa pine and Douglas-fir are planted due to the widespread lack of adequate seed source or surviving trees of any size or age class. Natural recovery will be extremely long without tree planning efforts, up to many 100’s of years as conifers would have to slowly re-establish parameter areas and then migrate inwards by natural reproduction under favorable circumstances. It is possible that persistent brush or grass/brush cover may exist for years if un-planted. Soil integrity may be slow to respond to pre-fire levels, especially considering increases in hydrophobicity, reductions in organic matter and potential for erosion immediately following fire.

Restoration pathway R4a
State 4 to 1

Practices that promote the reestablishment of native understory species, for example tree and/or native grass planting in properly prepared seedbed conditions, have the potential to restore some of the function of native Ponderosa pine and Douglas-fir communities in this ecological site. Complete restoration to references conditions, however, is unlikely and rather a transition to a “current potential state” with improved ecological processes yet still including some degree of invasive species is more likely.

Restoration pathway R4a
State 4 to 5

Practices are applied which reduce or eliminate unwanted weeds and invasive species, followed by the application of sound agronomic practices or by applying pasture/hayland management. Returns to Alternative State 5, and not to the Reference State.

Restoration pathway R5a
State 5 to 1

Transition T5a
State 5 to 4

Poor management or abandonment leads to weed invasion, often with noxious species (resulting in Alternative State 4).

Additional community tables

Supporting information

References

. Fire Effects Information System. http://www.fs.fed.us/database/feis/.
. 2021 (Date accessed). USDA PLANTS Database. http://plants.usda.gov.

Other references

Agee, J.K., 1993. Fire Ecology of Pacific Northwest Forests. Inland Press, Washington, DC.

Arno, S. (2000). Fire in western forest ecosystems (chapter 5). In: J.K Brown and J.K. Smith (editors), pp. 97-120, Wildland fire in ecosystems: effects of fire on flora. USDA Forest Service, General Technical Report RMRS-GTR-42-vol 2.

Churchhill, Derek J.; Carnwath, Gunnar C.; Larson, Andrew J.; Jeronimo, Sean A. 2017. Historical forest structure, composition and spatial pattern in dry conifer forests of the western Blue Mountains, Oregon. Gen. Tech. Rep. PNW-GTR-956. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 93 p.

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Contributors

Andrew Neary - Original concept developed for PES initiative 2020/2021

Approval

Kirt Walstad, 9/08/2023

Rangeland health reference sheet

Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.

Author(s)/participant(s)
Contact for lead author
Date	09/10/2023
Approved by	Kirt Walstad
Approval date
Composition (Indicators 10 and 12) based on	Annual Production