Oregon East Cascades, Volcanic Uplands and Mountainbases (Ponderosa pine - Douglas-fir - (Grand fir) / Snowbrush) 20-30 PZ
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1B
Extensive timber harvest
More details -
Restoration pathway R2A
Forest restoration, stand replacing fire
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
This site occurs across the landscape as a mosaic of plant community phases characterized by variation in forest structural stage (tree age, density and cover) and plant community composition. Historically, many dry pine forests would have cycled from a shrub/tree initiation phase (1.1) to a young forest stage (1.3) to a mature forest phase (1.4) with a fire regime characterized by frequent surface and mixed fires. Fire exclusion can lead to closed canopy and dense understory stocking conditions represented by communities 1.2 and 1.5 which can be more vulnerable to stand replacing fires. The reference community within this state is that of an open, mature, savanna like ponderosa stand represented by community phase 1.4. Historical evidence suggests that this community type was common across the landscape prior to selective logging and widespread fire suppression, which can alter fire regimes and lead to a greater frequency of high severity fire.
Submodel
States 1 and 5 (additional transitions)
1.1. Stand Initiation
1.5. Mature Forest, Closed
Description
This alternative state represents the many variations of timber harvesting that can occur in this site. This may result in a number of manipulated community types and pathways depending on strategies surrounding harvest, shrub control, weed control and replanting. Selective removal of large ponderosa pine may advance succession and favor maturation of shade tolerant trees such as grand fir, Douglas fir, and incense cedar.
Mechanism
Extensive timber harvest followed by continual management for timber production that has significantly altered species compositions and resulting disturbance responses.
Mechanism
Ecological forestry practices may promote a return to reference state. Stand replacing fire may lead to a transition to community 1.1 of the reference state if soil compaction is not severe, species composition has not been significantly altered and tree seed source is available.
Context dependence
Alterations of forest tree species composition, as well as soil compaction and surface disturbances due to large machine usage may hinder passive forest reestablishment.
Model keys
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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.