Name:
Juniperus occidentalis / Achnatherum thurberianum Woodland
Reference:
Western Ecology Working Group of...
Description:
These are open woodlands or juniper savannas which are restricted to barren, ashy soils in the central Oregon juniper zone. Juniperus occidentalis / Achnatherum thurberianum (= Stipa thurberiana) woodlands are found on all aspects and slopes, on elevations between 2000 and 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 (= 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. Juniperus occidentalis / Achnatherum thurberianum Woodland (CEGL002635) is similar to Juniperus occidentalis / Pseudoroegneria spicata Wooded Herbaceous Vegetation (CEGL001728), but is distinguished by its lower grass cover, its barren, exposed John Day and Clarno ash soils, and the predominance of Achnatherum thurberianum, Achnatherum hymenoides or Hesperostipa comata in the grass understory.
Accession Code:
VB.CC.17772.JUNIPERUSOCCIDE
Plot-observations of this Community Concept:
0
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