State 1
Reference State

The Reference State describes the biotic communities that may become established on this ecological site if all successional sequences are completed under natural disturbance conditions. Species composition is dominated by mature or seral aspen community types. Shrubs are of minor importance in this state but species such as common juniper and Saskatoon serviceberry may be present. Mountain snowberry and alderleaf mountain mahogany are other common shrub species. Ross sedge, blue wildrye and fringed brome are dominant herbaceous species. A wide diversity of perennial forbs are also present. Several seral communities are described in this reference state including those of open canopy, seedling, sapling, pole, immature forest, mature forest, and eventually to an old or over-mature forest type if fire is excluded for very long periods of time. The primary disturbance mechanisms in this state are overstory canopy density, weather fluctuations, and fire, or lack of fire. The Reference State is self-sustaining and resistant to change beyond normal seral community types due to adaptation to natural disturbances and a high resilience following those disturbances. When natural disturbances such as fire do occur, the rate of recovery can be quite variable. Reference State: Plant communities influenced by aspen canopy density, long-term weather fluctuations, and periodic fire.

Characteristics and indicators. Indicators: A community dominated by aspen with an understory of aspen reproduction and a few shrubs including snowberry, alderleaf mountain mahogany and Saskatoon serviceberry. The density of the overstory canopy determines the amount and composition of the other native perennial grasses, grass-likes and forbs that may be present. Feedbacks: Natural fluctuations in weather patterns that allow for a self-sustaining mix of aspen, shrubs and native grass and grass-like species in the community. Insect herbivory, more frequent fires, or other disturbances allow for the establishment of invasive species. At-risk Community Phase: All communities are at risk when native plants are stressed and nutrients become available for non-native plants to establish. Trigger: The establishment of non-native plant species.

Community 1.1
Mature Aspen Community Phase.

Figure 4. Community Phase 1.1

This community phase is dominated by an overstory canopy of mature aspen that have reached or are near maximal heights for the site. Average age is 80 to 120 years. Trees have developed tall, straight, clear stems with short, high rounded crowns. Tree canopy cover ranges from 20 to 40 percent. Understory vegetation is strongly influenced by tree competition, overstory shading, duff accumulation, etc. A few seedlings and saplings of quaking aspen occur in the understory. Shade tolerant plants such as blue wildrye, bearded wheatgrass, mountain brome, nodding bluegrass, sweet anise, meadowrue, and edible valerian are the dominant understory species. Air dry composition of this site is approximately 25 percent grasses, 10 percent forbs, 10 percent shrubs and aspen reproduction and 65 mature aspen. Thick duff layers are present on some sites. The following tables provide an example the typical vegetative floristics of a community phase 1.1 plant community.

Community 1.2
Aspen Seedling/ Herbaceous Community Phase.

Figure 6. Community Phase 1.2

This community phase is dominated by aspen sprouts and seedlings, and by perennial grasses and forbs under nearly full sunlight. This stage is experienced after a major disturbance such as crown fire, insect damage or disease. Any skeleton forest (dead trees) remaining have little or no affect on the composition and production of the herbaceous vegetation. Various amounts of tree seedlings 1 to 25 years old are present up to the point where they are obviously a major component of the vegetal structure. Ross sedge, Letterman's and Columbia needlegrass and California and fringed brome are important grass and grass-like species. Air dry composition of this site is approximately 30 percent grasses, 15 percent forbs, 10 percent shrubs and and 55 aspen reproduction. Thick duff layers are present on some sites. The following tables provide an example the typical vegetative floristics of a community phase 1.2 plant community.

Community 1.3
Immature Aspen Forest/ Herbaceous Community Phase.

Figure 8. Community Phase 1.3

The Immature Aspen Forest/Herbaceous community phase is characterized by a growing canopy of pole sized and immature aspen. Trees are developing tall, straight, clear stems with narrow pointed crowns. Average age is 25 to 80 years. Tree canopy cover ranges from 10 to 20 percent. Understory vegetation is somewhat influenced by tree competition, overstory shading, duff accumulation, etc. Seedlings and saplings of quaking aspen are common in the understory. Shade tolerant plants such as blue wildrye, bearded wheatgrass, mountain brome, nodding bluegrass, sweet anise, meadowrue, and edible valerian are prominent in the understory. Air dry composition of this site is approximately 20 percent grasses, 10 percent forbs, 10 percent shrubs and and 60 percent mature aspen. Thick duff layers are present on some sites. The following tables provide an example the typical vegetative floristics of a community phase 1.3 plant community.

Community 1.4
Decadent Aspen Community Phase.

Figure 10. Community Phase 1.4

This community phase is dominated by an overstory canopy of very mature and decadent aspen that have reached maximal heights. Average age is 120 plus years. Trees have developed tall, straight, clear stems with high, very rounded crowns. This phase typically develops in the absence of wildfire or other naturally occurring disturbances including disease and insect damage. Tree canopy cover is at a maximum for the site and is commonly greater than 50 percent. Very old trees often show signs of disease and insect damage. Understory vegetation is somewhat sparse due to tree competition, overstory shading, duff accumulation, etc. Shade tolerant plants such as blue wildrye, bearded wheatgrass, mountain brome, nodding bluegrass, sweet anise, meadowrue, and edible valerian are much reduced but may still be present in the understory. Air dry composition of this site is approximately 5 percent grasses, 5 percent forbs, 10 percent shrubs and 70 percent aspen. Thick duff layers are often present, and completely covering the forest floor. The following tables provide an example the typical vegetative floristics of a community phase 1.4 plant community.

Pathway 1.1B
Community 1.1 to 1.2

Mature Aspen Community Phase.

Aspen Seedling/ Herbaceous Community Phase.

This community pathway occurs when wildfire removes the aspen overstory. This event can be exacerbated by drought, insect damage or disease.

Pathway 1.1A
Community 1.1 to 1.4

Mature Aspen Community Phase.

Decadent Aspen Community Phase.

This community pathway occurs when fire is excluded from the plant community for long periods of time.

Pathway 1.2A
Community 1.2 to 1.3

Aspen Seedling/ Herbaceous Community Phase.

Immature Aspen Forest/ Herbaceous Community Phase.

This community pathway occurs when fire is excluded from the plant community for long periods of time.

Pathway 1.3A
Community 1.3 to 1.1

Immature Aspen Forest/ Herbaceous Community Phase.

Mature Aspen Community Phase.

This community pathway occurs when fire is excluded from the plant community for long periods of time.

Pathway 1.3B
Community 1.3 to 1.2

Immature Aspen Forest/ Herbaceous Community Phase.

Aspen Seedling/ Herbaceous Community Phase.

This community pathway occurs when wildfire removes the growing aspen overstory. This event can be exacerbated by drought, insect damage and disease.

Pathway 1.4A
Community 1.4 to 1.1

Decadent Aspen Community Phase.

Mature Aspen Community Phase.

This community pathway occurs when insect damage or disease kills old trees and allows the community to return to a community phase 1.1 type with snags present.

Pathway 1.4B
Community 1.4 to 1.2

Decadent Aspen Community Phase.

Aspen Seedling/ Herbaceous Community Phase.

This community pathway occurs when wildfire removes the aspen overstory. This event can be exacerbated by drought, insect damage or disease.

State 2
Current Potential State

The Current Potential State (2) is similar to the Reference State (1), however minor amounts of non-native species may now be present in all community phases. This condition has not been well documented and so community phases in this state are based on possible community dynamics and not documented facts. This State describes the biotic communities that may become established on the High Mountain Loam (Aspen) ecological site if all successional sequences are completed under natural disturbance conditions. Species composition is generally dominated by mature or seral aspen community types. Shrubs are of minor importance in this state but species such as common juniper and Saskatoon serviceberry may be present. Mountain snowberry and alderleaf mountain mahogany are other common shrub species. Ross sedge, blue wildrye and fringed brome are dominant herbaceous species. Non-native species such as smooth brome, Kentucky bluegrass and orchardgrass may also be present. A wide diversity of perennial forbs are also present. Several seral communities are described in this state including those of open canopy, seedling, sapling, pole, immature forest, mature forest, and eventually to an old or over-mature forest type if fire is excluded for long periods of time. The primary disturbance mechanisms in this state are overstory disturbance, canopy density, weather fluctuations, and fire, or lack of fire. The Current Potential State is still self-sustaining and resistant to change beyond it's normal seral community types due to adaptation to natural disturbances and a high resilience following those disturbances. When disturbances such as fire do occur, the rate of recovery can be quite variable. Current Potential State: Plant communities influenced by aspen canopy density, long-term weather fluctuations, and periodic fire.

Characteristics and indicators. Indicators: A community dominated by aspen with an understory of aspen reproduction and a few shrubs including snowberry, alderleaf mountain mahogany and Saskatoon serviceberry. The density of the overstory canopy determines the amount and composition of the other non-native and native perennial grasses, grass-likes and forbs that may be present. Feedbacks: Natural fluctuations in weather patterns that allow for a self-sustaining mix of aspen, shrub and native grass and grass-like species in the community. Insect herbivory, more frequent fires, or other disturbances that may allow for the increase of non-native species. At-risk Community Phase: All communities are at risk when native plants are stressed and nutrients become available for non-native plants to increase. Trigger: The establishment of non-native plant species.

Community 2.1
Mature Aspen, Non-Native Herbaceous Community Phase.

Figure 12. Community Phase 2.1

The Mature Aspen, Non-native Herbaceous Community Phase is dominated by an overstory canopy of mature aspen that have reached or are near maximal heights for the site. Trees have developed tall, straight, clear stems with short, high rounded crowns. Tree canopy cover ranges from 20 to 40 percent. Understory vegetation is strongly influenced by tree competition, overstory shading, duff accumulation, etc. A few seedlings and saplings of quaking aspen occur in the understory. Shade tolerant plants such as blue wildrye, bearded wheatgrass, mountain brome, nodding bluegrass, sweet anise, meadowrue, and edible valerian are the dominant understory species. Non-native species, including smooth brome, orchardgrass, and Kentucky bluebrass, may be present in the community. Air dry composition of this site is approximately 25 percent grasses, 10 percent forbs, 10 percent shrubs and aspen reproduction and 65 percent mature aspen. Thick duff layers are present on some sites. The following tables provide an example of the typical vegetative floristics of a community phase 2.1 plant community.

Community 2.2
Aspen Seedling/ Non-Native Herbaceous Community Phase.

Figure 14. Community Phase 2.2

This community phase is dominated by aspen sprouts and seedlings, and by perennial grasses and forbs under nearly full sunlight. This stage is experienced after a major disturbance such as crown fire, insect damage or disease. Any skeleton forest (dead trees) remaining have little or no affect on the composition and production of the herbaceous vegetation. Various amounts of tree seedlings 1 to 25 years old are present up to the point where they are obviously a major component of the vegetal structure. Ross sedge, Letterman's and Columbia needlegrass and California and fringed brome are important grass and grass-like species. Non-native species including smooth brome, orchardgrass, and Kentucky bluegrass may also occur on the site. Air dry composition of this site is approximately 30 percent grasses, 15 percent forbs, 10 percent shrubs and and 55 aspen reproduction. Thick duff layers are present on some sites. The following tables provide an example the typical vegetative floristics of a community phase 2.2 plant community.

Community 2.3
Immature Aspen Forest/Non-Native Herbaceous Community Phase.

Figure 16. Community Phase 2.3

The Immature Aspen Forest/Non-Native Herbaceous Community Phase is characterized by a growing canopy of pole sized and immature aspen. Trees are developing tall, straight, clear stems with narrow pointed crowns. Average age is 25 to 80 years. Tree canopy cover ranges from 10 to 20 percent. Understory vegetation is somewhat influenced by tree competition, overstory shading, duff accumulation, etc. Seedlings and saplings of quaking aspen are common in the understory. Shade tolerant plants such as blue wildrye, bearded wheatgrass, mountain brome, nodding bluegrass, sweet anise, meadowrue, and edible valerian are prominent in the understory. Non-native species including smooth brome. orchardgrass and Kentucky bluegrass are present in the community. Air dry composition of this site is approximately 20 percent grasses, 10 percent forbs, 10 percent shrubs and and 60 percent mature aspen. Thick duff layers are present on some sites. The following tables provide an example of the typical vegetative floristics of a community phase 2.3 plant community.

Community 2.4
Decadent Aspen, Non-Native Herbaceous Community Phase.

Figure 18. Community Phase 2.4

This community phase is dominated by an overstory canopy of very mature and decadent aspen that have reached maximal heights for the site. Average age is 120 plus years. Trees have developed tall, straight, clear stems with high, very rounded crowns. This phase typically develops in the absence of wildfire or other naturally occurring disturbances including disease and insect damage. Tree canopy cover is at a maximum for the site and is commonly greater than 50 percent. Very old trees often show signs of disease and/or insect damage. Understory vegetation is somewhat sparse due to tree competition, overstory shading, duff accumulation, etc. Shade tolerant plants such as blue wildrye, bearded wheatgrass, mountain brome, nodding bluegrass, sweet anise, meadowrue, and edible valerian are much reduced but may still be present in the understory. Minor amounts of non-native species including smooth brome, orchardgrass and Kentucky bluegrass may be present on the community. Air dry composition of this site is approximately 5 percent grasses, 5 percent forbs, 10 percent shrubs and 70 aspen. Thick duff layers are often present, completely covering the forest floor. The following tables provide an example of the typical vegetative floristics of a community phase 2.4 plant community.

Pathway 2.1B
Community 2.1 to 2.2

Mature Aspen, Non-Native Herbaceous Community Phase.

Aspen Seedling/ Non-Native Herbaceous Community Phase.

This community pathway occurs when wildfire removes the growing aspen overstory. This event can be exacerbated by drought, insect damage and/or disease.

Pathway 2.1A
Community 2.1 to 2.4

Mature Aspen, Non-Native Herbaceous Community Phase.

Decadent Aspen, Non-Native Herbaceous Community Phase.

This community pathway occurs when fire is excluded from the plant community for long periods of time.

Pathway 2.2A
Community 2.2 to 2.3

Aspen Seedling/ Non-Native Herbaceous Community Phase.

Immature Aspen Forest/Non-Native Herbaceous Community Phase.

This community pathway occurs when fire is excluded from the plant community for long periods of time.

Pathway 2.3A
Community 2.3 to 2.1

Immature Aspen Forest/Non-Native Herbaceous Community Phase.

Mature Aspen, Non-Native Herbaceous Community Phase.

This community pathway occurs when fire is excluded from the plant community for long periods of time.

Pathway 2.3B
Community 2.3 to 2.2

Immature Aspen Forest/Non-Native Herbaceous Community Phase.

Aspen Seedling/ Non-Native Herbaceous Community Phase.

This community pathway occurs when wildfire removes the growing aspen overstory. This event can be exacerbated by drought, insect damage and/or disease.

Pathway 2.4B
Community 2.4 to 2.1

Decadent Aspen, Non-Native Herbaceous Community Phase.

Mature Aspen, Non-Native Herbaceous Community Phase.

This community pathway occurs when insect damage or disease kills old trees and allows the community to return to a community phase 2.1 type with snags present.

Pathway 2.4A
Community 2.4 to 2.2

Decadent Aspen, Non-Native Herbaceous Community Phase.

Aspen Seedling/ Non-Native Herbaceous Community Phase.

This community pathway occurs when wildfire removes the growing aspen overstory. This event can be exacerbated by drought, insect damage and disease.

State 3
Logged/Disturbed State

The Logged or Disturbed State is similar to the Current Potential State, however merchantable timber composed mostly of mature and old aspen have been removed. Various amounts of invasive species may also now be present in all community phases. This condition has not been well documented and so community phases in this State are based on possible community dynamics and not documented facts. Species composition is generally dominated by an immature canopy of aspen. Shrubs are of minor importance in the understory with common juniper, alderleaf mountain mahogany, mountain snowberry and Saskatoon serviceberry most often found. Ross sedge, blue wildrye and fringed brome are dominant herbaceous species. A wide diversity of perennial forbs are also present. Non-native species including orchardgrass, Kentucky bluegrass and smooth brome may also be present. These species could have been seeded as part of the site rehabilitation following the logging process. Logging will release younger aspen trees and will give the site the look of an immature forest. Site will return to a mature, and finally an old or over-mature forest type if fire is excluded for very long periods of time. The primary disturbance mechanisms are logging, road building or other man caused activities, weather fluctuations and fire or lack of fire. The logged state is still self-sustaining but has a lower resistance to change due to a reduced resistance to disturbances. When disturbances do occur, the rate of recovery can be highly variable. Logged or Disturbed State: Plant communities influenced by man-caused activities, wildlife browsing, insect herbivory, weather fluctuations, fire periods and surface disturbances.

Characteristics and indicators. Indicators: A community dominated by immature aspen with an understory of aspen reproduction, and shrubs including common juniper, alderleaf mountain mahogany and Saskatoon serviceberry. The density of the overstory canopy determines the amount and composition of the other native and non-native perennial grasses, grass-likes and forbs that may be present. Feedbacks: Natural fluctuations in weather patterns that allow for a self-sustaining mix of a aspen, shrub and native grass and grass-like species in the community. Insect herbivory, more frequent fires, or other disturbances that may allow for the increase of non-native species. At-risk Community Phase: All communities are at risk when native plants are stressed and nutrients become available for non-native plants to increase. Trigger: The increase of non-native plant species.

Community 3.1
Logged Aspen Forest Community Phase.

Figure 20. Community Phase 3.1

This community phase is typically found following logging or other man caused activity such as road building or pipeline construction. It is characterized by a partial canopy of aspen. Pole and immature sized trees are present and are beginning to, once again, dominate the community. Shrubs are a minor component in the understory with common juniper and Saskatoon serviceberry occurring most often. Ross sedge, blue wildrye and fringed brome are dominant herbaceous species. A wide diversity of perennial forbs are also present. Non-native species including orchardgrass, Kentucky bluegrass and smooth brome may potentially also be found on the site. Understory vegetation is somewhat influenced by tree competition, overstory shading, duff accumulation, etc. Seedlings and saplings of quaking aspen are common in the understory. Air dry composition of this site is approximately 25 percent grasses, 20 percent forbs, 15 percent shrubs and 40 percent mature aspen. Thick duff layers are present on some sites. The following tables provide an example of the typical vegetative floristics of a community phase 3.1 plant community.

Transition T1A
State 1 to 2

This transitional pathway occurs when various disturbances such as road building, pipeline construction or fence-line clearing provides an opportunity for non-native species to become established. Seeding of these species could be a normal part of these activities. Once non-native species are established, a threshold has been crossed.

Transition T2A
State 2 to 3

This transitional pathway occurs when timber logging and its associated activities, including road building and skid trail development, removes mature and over-mature aspen trees from the site and provides an opportunity for non-native species to increase. Seeding species such as orchardgrass and smooth brome would often be a normal part of these activities. Once the site is logged, a threshold has been crossed.

Restoration pathway R3A
State 3 to 2

This restoration pathway occurs following logging activities when the site is allowed to recover naturally. Pole sized and immature aspen trees are increasing in dominance. Seeded, non-native herbaceous species where present, are will established.