High Mountain Stony Loam (quaking aspen)

Description

This 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 generally dominated by mature or seral aspen community types.
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 it's normal seral community types due to a good 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.

Characteristics and indicators

Feedbacks: Natural fluctuations in weather patterns that allow for a self-sustaining mix of a aspen, shrubs and native grass and grasslike community. Insect herbivory, more frequent fires, or other disturbances that may 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.

Submodel

Description

The Current Potential State is similar to the Reference State, 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 this 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.
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 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 a good 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.

Characteristics and indicators

Feedbacks: Natural fluctuations in weather patterns that allow for a self-sustaining mix of a aspen, shrubs and native grass and grass-like 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.

Submodel

Description

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. A wide diversity of perennial forbs and grasses are also present. Non-native species including orchard grass, 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 resistant to change due to a reduced resistance to disturbances. When disturbances do occur, the rate of recovery can be highly variable.

Characteristics and indicators

Indicators: A community dominated by immature aspen with an understory of aspen reproduction, shrubs, grasses and forbs. 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 a aspen, shrubs and native grass and grass-like 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.

Submodel