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CEGL002635 Juniperus occidentalis / Achnatherum thurberianum Open Woodland
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Western Juniper / Thurber''s Needlegrass Open Woodland
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: These are open woodlands or juniper savannas which are restricted to barren, ashy soils in the central Oregon juniper zone. Juniperus occidentalis / Achnatherum thurberianum woodlands are found on all aspects and slopes, at elevations between 610 and 1370 m (2000-4500 feet). Juniperus occidentalis is the only tree, with the cover ranging from 5-20%. Juniperus occidentalis trees can be very large and quite old, with individuals found to be over 1000 years old in similar habitats in central Oregon. Artemisia tridentata ssp. wyomingensis is common in some areas and absent from others, with cover from 0-40%. Ericameria nauseosa, Salvia dorrii, Peraphyllum ramosissimum, Purshia tridentata, and Atriplex confertifolia are shrubs that can occasionally be found in this type. The understory is dominated by Achnatherum thurberianum, which is always present, at 2-50% cover. Pseudoroegneria spicata is often codominant, especially in stony microsites. In areas with more exposed ash, Hesperostipa comata and Achnatherum hymenoides can also be important, and Poa secunda and Leymus cinereus occur. Annual forbs (Mimulus nanus, Eriogonum vimineum, Crocidium multicaule, Collinsia parviflora, Blepharipappus scaber, Cleome platycarpa) and perennial forbs (Balsamorhiza sagittata, Astragalus filipes, Astragalus purshii, Calochortus macrocarpus, Castilleja spp., Erigeron filifolius, Eriogonum umbellatum, Lomatium hendersonii) occur and make the association species rich, but provide very little cover.
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: Juniperus occidentalis is the only tree, with the cover ranging from 5-20%. Juniperus occidentalis trees can be very large and quite old, with individuals found to be over 1000 years old in similar habitats in central Oregon. Artemisia tridentata ssp. wyomingensis is common in some areas and absent from others, with cover from 0-40%. Ericameria nauseosa (= Chrysothamnus nauseosus), Salvia dorrii, Peraphyllum ramosissimum, Purshia tridentata, and Atriplex confertifolia are shrubs that can occasionally be found in this type. The understory is dominated by Achnatherum thurberianum, which is always present, at 2-50% cover. Pseudoroegneria spicata is often codominant, especially in stony microsites. In areas with more exposed ash, Hesperostipa comata (= Stipa comata) and Achnatherum hymenoides (= Oryzopsis hymenoides) can also be important, and Poa secunda and Leymus cinereus (= Elymus cinereus) occur. Annual forbs (Mimulus nanus, Eriogonum vimineum, Crocidium multicaule, Collinsia parviflora, Blepharipappus scaber, Cleome platycarpa) and perennial forbs (Balsamorhiza sagittata, Astragalus filipes, Astragalus purshii, Calochortus macrocarpus, Castilleja spp., Erigeron filifolius, Eriogonum umbellatum, Lomatium hendersonii) occur and make the association species rich, but provide very little cover.
Dynamics: No Data Available
Environmental Description: These are open woodlands or juniper savannas which are restricted to barren, ashy soils in the central Oregon juniper zone. They are found on all aspects and slopes, at elevations between 610 and 1370 m (2000-4500 feet).
Geographic Range: Sites are found in three local areas which have extensive ash deposits in central Oregon, in Wheeler, Grant and Crook counties. While not described from anywhere else, it is possible that this association could be found on exposed ash soils from extreme southern Oregon, northeastern California and northwestern Nevada, where western juniper and exposed volcanic ash soils are also found. All known sites are around the Painted Hills in Wheeler County, the Sheep Rocks unit in Grant County and near Post in Crook County.
Nations: US
States/Provinces: CA?, NV?, OR
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.683360
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.Nc Western North American Pinyon - Juniper Woodland & Scrub Division | D010 | 1.B.2.Nc |
| Macrogroup | 1.B.2.Nc.1 Singleleaf Pinyon - Utah Juniper - Western Juniper Intermountain Woodland Macrogroup | M896 | 1.B.2.Nc.1 |
| Group | 1.B.2.Nc.1.b Western Juniper Open Woodland Group | G248 | 1.B.2.Nc.1.b |
| Alliance | A3500 Western Juniper Grassy Open Woodland Alliance | A3500 | 1.B.2.Nc.1.b |
| Association | CEGL002635 Western Juniper / Thurber''s Needlegrass Open Woodland | CEGL002635 | 1.B.2.Nc.1.b |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: No Data Available
- 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.
- ORNHP [Oregon Natural Heritage Program]. No date. Unpublished data files. Oregon Natural Heritage Program, The Nature Conservancy, Portland, OR.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.
- Youtie, B. A., and A. H. Winward. 1977. Plants and plant communities of the John Day Fossil Beds National Monument. Unpublished report to USDI National Park Service, John Day. 71 pp.