Print Report

CEGL000197 Pinus ponderosa / Purshia tridentata / Pseudoroegneria spicata Woodland

Type Concept Sentence: No Data Available


Common (Translated Scientific) Name: Ponderosa Pine / Antelope Bitterbrush / Bluebunch Wheatgrass Woodland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This woodland occurs in the eastern Cascades of Oregon and Washington, the Blue Mountains in eastern Oregon and adjacent Idaho, and California''s Modoc Plateau. It has been described as a phase in Idaho and Montana and may be present there. Elevations vary between 460 and 1650 m (1500-5400 feet) on all aspects and slopes of 0-40%. Soils are gravelly loamy sand to fine sandy loam. Blue Mountains sites tend to be steep while Modoc occurrences are on relatively level lava tube benches on rolling basalt plateaus. Pinus ponderosa is the only tree and covers 5-47% over Purshia tridentata (1-21% cover). Pseudoroegneria spicata and Festuca idahoensis cover 1-20%. The former is more abundant on steep and stony sites. The later is absent from California stands. Species of lesser importance include Achillea millefolium, Lomatium triternatum, and Lathyrus nevadensis. Fires have historically maintained Pinus ponderosa while thinning Purshia tridentata and Juniperus occidentalis. Overgrazed and other disturbed sites have high amounts of Bromus tectorum.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: In Washington, this association is considered part of the ~Pinus ponderosa / Purshia tridentata Central Rocky Mountain Woodland (CEGL005648)$$. This association is a rare community which has been described by many sources in many areas. As such, it represents a fairly wide ecological range. It has been described as a phase of Pinus ponderosa / Purshia tridentata by many authors, and as part of a Pinus ponderosa / Purshia tridentata / Festuca idahoensis - Pseudoroegneria spicata type by others. However, it represents a distinct entity regionally, and is generally lumped because it is rarely common anywhere.

Similar types have been included in this association, including Smith''s ponderosa / bitterbrush - Prunus / wheatgrass type in which Prunus occurs in only 71% of plots and averages 1% cover. A more complete description of the Ponderosa pine / bitterbrush classification issues is included in the EGR for ~Pinus ponderosa / Purshia tridentata / Festuca idahoensis Woodland (CEGL000195)$$. This association is similar to William''s (1978) ''QUGA/PUTR/AGSP'' association which only occasionally supports Pinus ponderosa (which tend to be stunted). The primary descriptions used for this EGR were from Volland (1976), Smith (1994b), and Johnson and Simon (1987).

Similar NVC Types: No Data Available
note: No Data Available

Physiognomy and Structure: No Data Available

Floristics: Pinus ponderosa is the only tree and covers 5-47% over Purshia tridentata (1-21% cover). Pseudoroegneria spicata and Festuca idahoensis cover 1-20%. The former is more abundant on steep and stony sites. The later is absent from California stands. Species of lesser importance include Achillea millefolium, Lomatium triternatum, and Lathyrus nevadensis. Fires have historically maintained Pinus ponderosa while thinning Purshia tridentata and Juniperus occidentalis. Overgrazed and other disturbed sites have high amounts of Bromus tectorum.

Dynamics:  No Data Available

Environmental Description:  No Data Available

Geographic Range: This is a regional type. While only described as such from the Oregon Cascades, Wallowa Mountains, and California''s Modoc Plateau, it occurs, as described, in Washington, Idaho, and western Montana. In all areas, it occurs in fairly small patches.

Nations: US

States/Provinces:  CA?, ID, MT?, OR, WA




Confidence Level: Low - Poorly Documented

Confidence Level Comments: No Data Available

Grank: G3

Greasons: No Data Available


Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available

Synonomy: = Pinus ponderosa / Purshia tridentata / Agropyron spicatum (Lillybridge et al. 1995) [PIPO/PUTR/AGSP ASSOCIATION CPS241]
= Ponderosa Pine / Bitterbrush / Bunchgrass (Volland 1985)
? QUGA/PUTR/AGSP (Williams 1978)
? ponderosa / bitterbrush - Prunus / wheatgrass type (Smith 1994b)

Concept Author(s): M.P. Murray

Author of Description: M.P. Murray

Acknowledgements: No Data Available

Version Date: 11-26-97

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