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CEGL001033 Artemisia tridentata ssp. vaseyana / Achnatherum occidentale Shrubland
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Mountain Big Sagebrush / Western Needlegrass Shrubland
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: This is a sagebrush opening in Pinus contorta or Pinus ponderosa forests in the East Cascades and Modoc Plateau of south-central Oregon and northeastern California. It is found between 1465 and 1495 m (4800-4900 feet) in elevation on very deep Mazama ash deposits under 13-18 cm (5-7 inches) of loamy sand. Artemisia tridentata ssp. vaseyana is the dominant shrub, with up to 10-30% cover in the Deschutes National Forest and 55% in the one plot from central Oregon. Achnatherum occidentale is the only grass reported from this community in central Oregon, while Carex rossii and Elymus elymoides were occasional in the East Cascades. Prominent forbs are Eriogonum flavum, Eriogonum umbellatum, Eriogonum ovalifolium, Polygonum phytolaccifolium, Lupinus spp., Eriophyllum lanatum and Antennaria dimorpha.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This is a fairly distinct, but very poorly sampled, community. Volland (1976) describes the type as big sagebrush / needlegrass, between 1465 and 1495 m (4800-4900 feet), with his picture looking very much like an Artemisia tridentata ssp. vaseyana stand. It is characterized by the very deep Mazama ash deposits under 13-18 cm (5-7 inches) of loamy sand. Johnson and Clausnitzer (1992) only have one stand, which they state might be an early seral stage of the Artemisia tridentata ssp. vaseyana / Carex geyeri community. Farther east (on BLM and private lands between 1220 and 1465 m [4000-4800 feet] in elevation) is an Artemisia tridentata / Stipa occidentalis association which is fairly different (with a different subspecies of Artemisia tridentata (likely ssp. thermopola), on sandy soils, and with different associated grasses (Festuca idahoensis and Hesperostipa comata). This latter type has only been sampled by the Oregon Natural Heritage Program.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: This association is poorly described. It is dominated by a 1- to 2-m tall layer of the evergreen microphyllous shrub Artemisia tridentata ssp. vaseyana, which in one stand sampled had 55% cover. No other shrubs occur. The only graminoid reported in the herbaceous layer is the perennial bunchgrass Achnatherum occidentale (= Stipa occidentalis), but with cover less than 10%. Perennial forbs are common and include Eriogonum flavum, Lupinus spp., Eriophyllum lanatum and Polygonum phytolaccifolium.
Dynamics: No Data Available
Environmental Description: This association occurs in scattered locations of this mountainous region, which is characterized by a temperate continental climate. Summers are cool (mean temperature of the warmest month is <72°F). Annual precipitation is light, between 20-38 cm (8-15 inches) annually, most falling as snow during winter months. The region has a high frequency of dry lightning storms in late summer. This association occupies steep upper slopes to rolling terrain on ridgetops, on southerly aspects usually above 2130 m elevation. Soils are derived from residuum and colluvium of igneous, sedimentary, and metamorphic rocks. Textures are sandy loams to clay loams in the subsurface horizons, with high percentages of coarse fragments (25-70%). Soils supporting stands of this subspecies of Artemisia tridentata do not have a carbonate layer in the soil profile.
Geographic Range: Known only from central Oregon, it could possibly be found in northeastern California, northern Nevada or western Idaho.
Nations: US
States/Provinces: CA?, ID?, NV?, OR
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.683820
Confidence Level: Low - Poorly Documented
Confidence Level Comments: No Data Available
Grank: G2
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 3 Desert & Semi-Desert Class | C03 | 3 |
| Subclass | 3.B Cool Semi-Desert Scrub & Grassland Subclass | S11 | 3.B |
| Formation | 3.B.1 Cool Semi-Desert Scrub & Grassland Formation | F033 | 3.B.1 |
| Division | 3.B.1.Ne Western North American Cool Semi-Desert Scrub & Grassland Division | D040 | 3.B.1.Ne |
| Macrogroup | 3.B.1.Ne.3 Big Sagebrush - Threetip Sagebrush - Antelope Bitterbrush Steppe & Shrubland Macrogroup | M169 | 3.B.1.Ne.3 |
| Group | 3.B.1.Ne.3.c Spiked Big Sagebrush - Mountain Big Sagebrush - Mountain Silver Sagebrush Steppe & Shrubland Group | G304 | 3.B.1.Ne.3.c |
| Alliance | A3207 Spiked Big Sagebrush - Mountain Big Sagebrush Steppe & Shrubland Alliance | A3207 | 3.B.1.Ne.3.c |
| Association | CEGL001033 Mountain Big Sagebrush / Western Needlegrass Shrubland | CEGL001033 | 3.B.1.Ne.3.c |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: ? Artemisia tridentata ssp. vaseyana / Carex geyeri community (Johnson and Clausnitzer 1992)
? Artemisia tridentata ssp. vaseyana / Stipa occidentalis association (Barbour and Major 1988)
< Big Sagebrush / Needlegrass (Volland 1976)
? Artemisia tridentata ssp. vaseyana / Stipa occidentalis association (Barbour and Major 1988)
< Big Sagebrush / Needlegrass (Volland 1976)
- Barbour, M. G., and J. Major, editors. 1988. Terrestrial vegetation of California: New expanded edition. California Native Plant Society, Special Publication 9, Sacramento. 1030 pp.
- 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.
- Johnson, C. G., and R. R. Clausnitzer. 1992. Plant associations of the Blue and Ochoco mountains. R6-ERW-TP-036-92. USDA Forest Service, Pacific Northwest Region, Wallowa-Whitman National Forest. 163 pp. plus appendices.
- 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.
- 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.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.