Ponderosa Pine 15-19
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
-
Transition T1A
Intensive Fire Suppression
More details -
Transition T1B
High Intensity, Stand Replacing Fire
More details -
Restoration pathway R2A
Aggressive thinning and removal of trees (Brush Management, harvesting, etc.), Prescribed Fire, Herbaceous Weed Control (management intensive and costly)
More details -
Transition T2A
High Intensity, Stand Replacing Fire
More details -
Transition T3C
Long-term tree regrowth and return to historic fire frequency/intensity
More details -
Transition T3A
Prolonged drought, Improper grazing management, or a combination of these factors
More details -
Transition T3B
Displacement of native species by non-native invasive species (Kentucky bluegrass, annual bromes, noxious weeds, etc.)
More details -
Restoration pathway R4A
Proper grazing management in combination with range planting, intensive weed management (management intensive and costly)
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
The Reference state for this ecological site consists of three communities and evolved under the combined influences of climatic conditions, periodic fire activity, grazing by large herbivores, and impacts from small mammals and insects. The Reference state is the plant communities in which interpretations are primarily based and is used as a reference in order to understand the original potential of the site.
Submodel
Description
The Fire Suppressed state occurs following long-term fire suppression efforts resulting in dense ponderosa pine communities accompanied by an understory component comprised primarily of shrubs. Herbaceous understory is greatly reduced. Forest health and wildfire conditions continue to deteriorate over the long term. The Fire Suppressed state results in an increase in litter quantity and a decline in litter quality due to a change in the understory composition.
Submodel
Description
The Mixed Grass state occurs when the woody cover is removed by a high-intensity, stand-replacing fire and the site is dominated by a mixture of native herbaceous species. Exact timelines are unknown, but it is possible this state may persist for 50 to 100 years post-fire. The Mixed Grass state consists of one community.
Submodel
Description
The dynamics of the Shortgrass state are driven by long-term drought, improper grazing management such as continuous season-long or year-long grazing, or a combination of these factors. The Shortgrass state for this ecological site consists of one community.
Submodel
Mechanism
Long-term, intensive fire suppression transitions the Reference state to the Fire Suppressed state. Fire suppression permits stand density to increase and allows encroachment of shrubs and small trees into the understory.
Mechanism
High-Intensity, stand replacing fire transitions the Reference state to the Mixed Grass state. High intensity fire results in the complete removal of the woody overstory and permits herbaceous species to dominate the site.
Mechanism
A drastic change in management is necessary to restore the Fire Suppressed state to the Reference state. Intensive management inputs such as aggressive thinning and removal of many trees, harvesting, prescribed fire, and herbaceous weed control are necessary to reduce woody species density and restore the ecosystem processes of the Reference state. In addition, follow-up management is typically required in order to keep tree regeneration to a minimum and avoid a return to the Fire Suppressed state. This may include a combination of methods such as intensive grazing, prescribed fire, and brush management. These restoration methods are labor intensive, costly, and may not be a practical in all situations.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Prescribed Burning |
|
|
Prescribed Grazing |
|
|
Herbaceous Weed Control |
Mechanism
High-Intensity, stand replacing fire transitions the Fire Suppressed state to the Mixed Grass state. High intensity fire results in the complete removal of the woody overstory and permits herbaceous species to dominate the site.
Mechanism
Long-term tree regrowth and return to historic fire frequency/intensity transitions the Mixed Grass state back to the Reference state. Natural regeneration and growth of tree seedlings will occur over time and periodic low-intensity fire will permit development of an open ponderosa pine stand with a grass dominated understory.
Mechanism
Prolonged drought, improper grazing management such as continuous season-long or year-long grazing, or a combination of these factors weaken the resilience of the Mixed Grass state and drive its transition to the Shortgrass state. The Mixed Grass state transitions to the Short-grass state when mid-statured graminoids become rare and shortgrasses such as blue grama and Sandberg bluegrass dominate the plant community.
Mechanism
The Mixed Grass state transitions to the Invaded state when non-native grasses, noxious weeds, and other invasive plants invade the Mixed Grass state. Exotic plant species dominate the site in terms of cover and production and site resilience has been substantially reduced.
Mechanism
Blue grama can resist displacement by other species. A reduction in livestock grazing pressure alone may not be sufficient to restore the Shortgrass state to the Mixed Grass state. Proper grazing management in combination with intensive management such as range planting and intensive weed management may be necessary. These restoration methods are labor intensive, costly, and may not be a practical in all situations.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Prescribed Grazing |
Model keys
Briefcase
Add ecological sites and Major Land Resource Areas to your briefcase by clicking on the briefcase (
) icon wherever it occurs. Drag and drop items to reorder. Cookies are used to store briefcase items between browsing sessions. Because of this, the number of items that can be added to your briefcase is limited, and briefcase items added on one device and browser cannot be accessed from another device or browser. Users who do not wish to place cookies on their devices should not use the briefcase tool. Briefcase cookies serve no other purpose than described here and are deleted whenever browsing history is cleared.
Ecological sites
Major Land Resource Areas
The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.