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CEGL000814 Pinus flexilis / Purshia tridentata Woodland

Type Concept Sentence: No Data Available


Common (Translated Scientific) Name: Limber Pine / Antelope Bitterbrush Woodland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This woodland association is known from stands located on recent, relatively unweathered mafic lava flows of the Great Rift System, within the Snake River Basalt ecoregional section. The plant association occurs in a semi-arid climatic region, on relatively recent mafic volcanic flow substrates. The area has an average annual precipitation of 43 cm (17 inches), with a peak in winter. Most precipitation occurs as snow. Temperatures are typically hot in summer and cold in winter. The association occurs on weathered cinder deposits and fractured mafic lava flows. The best stand development occurs on the highly fissured and mounded olivine pahoehoe basalt. The undulating terrain consists of alternating lava pressure ridges and valleys created through the collapse of lava tubes. Soils are poorly developed and consist of wind-blown sand or decomposed plant litter. The surface of the pahoehoe basalt is hot and dry. However, ameliorating effects of the thick basalt slabs on soil moisture and temperature may result in relatively mesic growing environments. Soil and snow collect in fissures and depressions. These sites also may reduce exposure to desiccating winds and solar radiation. This association consists of an open canopy of the needle-leaved, evergreen tree Pinus flexilis. These trees are of a lower stature than usual, reaching only 5 m in height. A shrub layer is present, dominated by Purshia tridentata, also growing in a shorter form than found in more favorable locations. Several other shrubs are associated, including Ericameria nauseosa, Ribes cereum, Chamaebatiaria millefolium, Holodiscus dumosus, Linanthus pungens, and Artemisia tridentata ssp. vaseyana. Total shrub cover is moderate. The herbaceous layer is diverse, but not abundant. The most important graminoids include the perennial bunchgrasses Elymus elymoides, Poa secunda, and Achnatherum thurberianum. The most common forbs include the annuals Mimulus nanus, Cistanthe rosea, and Gayophytum decipiens, and the suffrutescent perennials Eriogonum umbellatum and Eriogonum ovalifolium.

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: This association consists of an open canopy of the needle-leaved evergreen tree Pinus flexilis. These trees are of a lower stature than usual, reaching only 5 m in height. A shrub layer is present, dominated by the broad-leaved deciduous Purshia tridentata, also growing in a shorter form than found in more favorable locations. Several other shrubs are associated, including Ericameria nauseosa (= Chrysothamnus nauseosus), Ribes cereum, Chamaebatiaria millefolium, Holodiscus dumosus, Linanthus pungens (= Leptodactylon pungens), and Artemisia tridentata ssp. vaseyana. Total shrub cover is moderate. The herbaceous layer is diverse but not abundant. The most important graminoids include the perennial bunchgrasses Elymus elymoides, Poa secunda, and Achnatherum thurberianum (= Stipa thurberiana). The bunchgrass Pseudoroegneria spicata occurs infrequently in more favorable microsites. The most common forbs include the annuals Mimulus nanus, Cistanthe rosea, and Gayophytum decipiens, and the suffrutescent perennials Eriogonum umbellatum and Eriogonum ovalifolium.

Dynamics:  No Data Available

Environmental Description:  This association occurs in a semi-arid region of relatively recent ''plains'' volcanic activity. The area has an average annual precipitation of 43 cm (17 inches), with a peak in winter during which most precipitation falls as snow. A secondary peak occurs in May. Temperatures are typically hot in summer and cold in winter. This association occurs on weathered cinder deposits and lava flows of the aa type. The sites of its best development are extremely rough, ''blocky'' flows, of long, nearly parallel ridges with depressions 2-6 m (6-20 feet) deep in between. Soil and snow collect in these depressions, and they provide reduced exposure to desiccating winds and solar radiation. Seedlings of Pinus and Purshia have a better survival chance in these relatively mesic pockets within the lava flows. This association also occurs on young to medium-aged cinder cones.

Geographic Range: The plant association is known only to occur on the recent, relatively unweathered mafic lava flows of the Great Rift System, within the Snake River Basalt ecoregional section.

Nations: US

States/Provinces:  ID




Confidence Level: Moderate

Confidence Level Comments: No Data Available

Grank: G1?

Greasons: No Data Available


Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available

Synonomy: > Limber Pine / Antelope Bitterbrush (High Density Limber Pine) Vegetation Type (Day 1985)
> Limber Pine / Antelope Bitterbrush (High Total Cover) Vegetation Type (Day 1985)
> Limber Pine / Antelope Bitterbrush (High Total Cover) Vegetation Type (Day and Wright 1985)
> Limber Pine / Antelope Bitterbrush (Low Total Cover) Vegetation Type (Day 1985)
> Limber Pine / Antelope Bitterbrush (Low Total Cover) Vegetation Type (Day and Wright 1985)
= Limber Pine / Antelope Bitterbrush Woodland (Pinus flexilis / Purshia tridentata Woodland) (Bell et al. 2009)

Concept Author(s): M.S. Reid

Author of Description: M.S. Reid and S.K. Rust

Acknowledgements: No Data Available

Version Date: 09-21-93

  • Bell, J., D. Cogan, J. Erixson, and J. Von Loh. 2009. Vegetation inventory project report, Craters of the Moon National Monument and Preserve. Natural Resource Technical Report NPS/UCBN/NRTR-2009/277. National Park Service, Fort Collins, CO. 358 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.
  • Day, T. A. 1985. Plant association and soil factors in primary succession on cinder cones in Idaho. Unpublished thesis, University of Idaho, Moscow. 62 pp.
  • Day, T. A., and R. G. Wright. 1985. The vegetation types of Craters of the Moon National Monument. Forestry, Wildlife, and Range Experiment Station Bulletin No. 38. University of Idaho, Moscow. 6 pp.
  • Eggler, W. A. 1941. Primary succession on volcanic deposits in southern Idaho. Ecological Monographs 11(3):278-298.
  • Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.