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CEGL000198 Pinus ponderosa / Purshia tridentata / Achnatherum occidentale Woodland
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Ponderosa Pine / Antelope Bitterbrush / Western Needlegrass Woodland
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: This is an open woodland found on pumice or ash in the East Cascades and Modoc Plateau in southern Oregon and northern California. Oregon sites are associated with Mount Mazama pumice. California sites are from the Medicine Lake Highlands. This association developed with frequent, low intensity fire, although most stands have been excluded from fire for the last 80 years. With fire, these stands were probably more open and park-like, and had much lower shrub cover. Most stands are on flats and sideslopes, with an average slope of only 8%. The upper elevational range is 1720 m. In California it occurs down to 1460 m, in Oregon down to 860 m, probably because pumice occurs at lower elevations in Oregon. The community was described from 31 plots over a 100-km range in Oregon, and from 6 plots from northern California. However, very few remnants of this community are left with old-growth Pinus ponderosa trees. Pinus ponderosa is generally the only tree found in the overstory and understory. In a few Oregon stands (especially those which have been disturbed), Pinus contorta can also be found. Tree cover ranges from 5-40%. Purshia tridentata is the dominant shrub, always present and averaging about 15% cover. Other shrubs include Ericameria bloomeri, Ribes cereum, and Arctostaphylos patula. Achnatherum occidentale dominates good condition stands, although with grazing, Elymus elymoides becomes more important. Other forbs include Penstemon cinicola, Eriogonum nudum, Hieracium scouleri, and Carex rossii. This type is easily distinguished by the dominants, and its occurrence on pumice.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: No Data Available
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: The community was described from 31 plots over a 100-km range in Oregon, and from 6 plots from northern California. However, very few remnants of this community are left with old-growth Pinus ponderosa trees. Pinus ponderosa is generally the only tree found in the overstory and understory. In a few Oregon stands (especially those which have been disturbed), Pinus contorta can also be found. Tree cover ranges from 5-40%. Purshia tridentata is the dominant shrub, always present and averaging about 15% cover. Other shrubs include Ericameria bloomeri (= Haplopappus bloomeri), Ribes cereum, and Arctostaphylos patula. Achnatherum occidentale (= Stipa occidentalis) dominates good condition stands, although with grazing, Elymus elymoides becomes more important. Other forbs include Penstemon cinicola, Eriogonum nudum, Hieracium scouleri, and Carex rossii. This type is easily distinguished by the dominants, and its occurrence on pumice.
Dynamics: No Data Available
Environmental Description: This is an open woodland found on pumice or ash in the East Cascades and Modoc Plateau in southern Oregon and northern California. Oregon sites are associated with Mount Mazama pumice. California sites are from the Medicine Lake Highlands. This association developed with frequent, low intensity fire, although most stands have been excluded from fire for the last 80 years. With fire, these stands were probably more open and park-like, and had much lower shrub cover. Most stands are on flats and sideslopes, with an average slope of only 8%. The upper elevational range is 1720 m. In California it occurs down to 1460 m, in Oregon down to 860 m, probably because pumice occurs at lower elevations in Oregon.
Geographic Range: Only known from areas with sandy or loam soils over ash in the pumice zone, along the eastern slope of the Cascades in the southern end of the Deschutes National Forest, the Winema National Forest, and the western parts of the Fremont National Forest, with a small occurrence found in Crater Lake National Park in south-central Oregon.
Nations: US
States/Provinces: CA, OR
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.683981
Confidence Level: Low - Poorly Documented
Confidence Level Comments: No Data Available
Grank: G2
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 1 Forest & Woodland Class | C01 | 1 |
| Subclass | 1.B Temperate & Boreal Forest & Woodland Subclass | S15 | 1.B |
| Formation | 1.B.2 Cool Temperate Forest & Woodland Formation | F008 | 1.B.2 |
| Division | 1.B.2.Nb Rocky Mountain Forest & Woodland Division | D194 | 1.B.2.Nb |
| Macrogroup | 1.B.2.Nb.2 Ponderosa Pine - Douglas-fir - Limber Pine Central Rocky Mountain Dry Forest Macrogroup | M501 | 1.B.2.Nb.2 |
| Group | 1.B.2.Nb.2.a Ponderosa Pine Central Rocky Mountain Open Woodland Group | G213 | 1.B.2.Nb.2.a |
| Alliance | A3446 Ponderosa Pine / Shrub Understory Central Rocky Mountain Woodland Alliance | A3446 | 1.B.2.Nb.2.a |
| Association | CEGL000198 Ponderosa Pine / Antelope Bitterbrush / Western Needlegrass Woodland | CEGL000198 | 1.B.2.Nb.2.a |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Ponderosa Pine / Bitterbrush / Needlegrass (Volland 1985)
- Bourgeron, P. S., and L. D. Engelking, editors. 1994. A preliminary vegetation classification of the western United States. Unpublished report. The Nature Conservancy, Western Heritage Task Force, Boulder, CO. 175 pp. plus appendix.
- Dyrness, C. T. 1960. Soil-vegetation relationships within the ponderosa pine type in the central Oregon pumice region. Unpublished dissertation. Oregon State College, Corvallis.
- Dyrness, C. T., and C. T. Youngberg. 1966. Soil-vegetation relationships within the ponderosa pine type in the central Oregon pumice region. Ecology 47:122-138.
- Hopkins, W. E. 1979b. Plant associations of South Chiloquin and Klamath Ranger Districts - Winema National Forest. Publication R6-ECOL-79-005. USDA Forest Service, Pacific Northwest Region, Portland, OR. 96 pp.
- Kagan, J. S., J. A. Christy, M. P. Murray, and J. A. Titus. 2004. Classification of native vegetation of Oregon. January 2004. Oregon Natural Heritage Information Center, Portland. 52 pp.
- Volland, L. A. 1976. Plant communities of the central Oregon pumice zone. USDA Forest Service R-6 Area Guide 4-2. Pacific Northwest Region, Portland, OR. 113 pp.
- Volland, L. A. 1985. Plant associations of the central Oregon pumice zone. USDA Forest Service R6-ECOL-104-1985. Pacific Northwest Region, Portland, OR. 138 pp.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.