Print Report

A3799 Rhus trilobata - Crataegus rivularis - Forestiera pubescens Shrubland Alliance

Type Concept Sentence: This shrubland alliance is dominated by Corylus cornuta, Crataegus rivularis, Elaeagnus commutata, Forestiera pubescens, Rhamnus alnifolia, Shepherdia argentea, and/or Rhus trilobata. Usually these are single-species shrublands, but all occupy similar environments. It is an eclectic mix of mesic shrubs that form small, narrow stands at the base of steep hills and cliffs and along washes and upper benches and terraces of riparian areas in the Rocky Mountains and throughout the cool interior western U.S. These are "fringe" riparian shrublands that occur on upper benches and terraces, dry washes and areas near but not necessarily in the wettest part of riparian areas, but receive more moisture than surrounding upland slopes.

Common (Translated Scientific) Name: Skunkbush Sumac - River Hawthorn - Stretchberry Shrubland Alliance

Colloquial Name: Skunkbush Sumac - River Hawthorn - Stretchberry Shrubland

Hierarchy Level:  Alliance

Type Concept: This semi-riparian shrubland alliance is dominated by Corylus cornuta, Crataegus rivularis, Elaeagnus commutata, Forestiera pubescens, Rhamnus alnifolia, Shepherdia argentea, and/or Rhus trilobata, generally in monotypic stands, but they can be mixed as well. Other shrub associates may include Prunus virginiana. It is an eclectic mix of mesic shrubs that form small, narrow stands at the base of steep hills and cliffs and along washes and upper benches and terraces of riparian areas. These are "fringe" riparian shrublands that occur on upper benches and terraces, dry washes and areas near but not necessarily in the wettest part of riparian areas, but which receive more moisture than surrounding upland slopes. Often these are single-species shrublands, but all occupy similar environments. The alliance has a broad north to south range in the Rocky Mountains and throughout the cool interior western U.S.

Diagnostic Characteristics: Greater than 30% relative cover of Corylus cornuta, Crataegus rivularis, Elaeagnus commutata, Forestiera pubescens, Rhamnus alnifolia, and/or Rhus trilobata.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Includes shrub species that generally do not form large stands in upland environments.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Vegetation included in this alliance has a typically dense, cold-deciduous shrub layer (approximately 70% cover). The herbaceous layer is also dense and is dominated by perennial graminoids (80%). Forbs have relatively sparse cover (<20%), but have high diversity. Moss has high cover in some stands (70%).

Floristics: Stands have a dense layer of cold-deciduous shrubs (<2 m) that are dominated by Amelanchier alnifolia, Elaeagnus commutata, Lonicera involucrata, Prunus virginiana, Rhamnus alnifolia, Ribes lacustre, Rosa woodsii, and/or Symphoricarpos albus. A few other shrubs species, such as Salix bebbiana or Salix exigua, may be co-associates, but these are not abundant and do not characterize the stand. The herbaceous layer is typically dense with graminoids such as Calamagrostis canadensis, Elymus glaucus, Elymus lanceolatus, Hesperostipa comata (= Stipa comata), and Koeleria macrantha. Dominant forbs include Dryas drummondii, Galium triflorum, Geum macrophyllum, Heracleum maximum (= Heracleum lanatum), and Maianthemum stellatum. The spikemoss Selaginella densa can be abundant in some stands. Introduced grasses such as Bromus inermis, Poa pratensis, and Phleum pratense can also be abundant.

Dynamics:  No Data Available
Environmental Description:  Stands are generally found on elevated benches along streams, on floodplains, adjacent to seeps and can form narrow stringers on stream terraces. Elevations range from approximately 700 to 2400 m. Sites are gently sloping and are temporarily flooded during spring runoff and high-intensity rainstorms. Soils are alluvial or may be well-developed Mollisols.
Geographic Range: This alliance is found throughout the Rocky Mountains and other areas of the cool interior western U.S. and is documented from eastern Oregon and Washington, Idaho, Alberta, Montana, Wyoming, Colorado, New Mexico, Utah and the highlands of northern Arizona.

Nations: CA,US

States/Provinces:  AB, AZ, CA, CO, ID, MT, NM, NV, OR, SD, UT, WA, WY


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: GNR

Greasons: No Data Available
Type Name Database Code Classification Code
Class 2 Shrub & Herb Vegetation Class C02 2
Subclass 2.C Shrub & Herb Wetland Subclass S44 2.C
Formation 2.C.4 Temperate to Polar Freshwater Marsh, Wet Meadow & Shrubland Formation F013 2.C.4
Division 2.C.4.Nb Western North American Temperate Freshwater Marsh, Wet Meadow & Shrubland Division D031 2.C.4.Nb
Macrogroup 2.C.4.Nb.5 Sitka Alder - Booth''s Willow / Northwest Territory Sedge Montane Marsh, Wet Meadow & Shrubland Macrogroup M893 2.C.4.Nb.5
Group 2.C.4.Nb.5.a Narrowleaf Willow - Hawthorn species - Stretchberry Rocky Mountain-Great Basin Riparian Shrubland Group G526 2.C.4.Nb.5.a
Alliance A3799 Skunkbush Sumac - River Hawthorn - Stretchberry Shrubland Alliance A3799 2.C.4.Nb.5.a
Association CEGL001098 Silverberry Wet Shrubland CEGL001098 2.C.4.Nb.5.a
Association CEGL001108 Chokecherry - (American Plum) Wet Shrubland CEGL001108 2.C.4.Nb.5.a
Association CEGL001121 Skunkbush Sumac Moist Wet Shrubland CEGL001121 2.C.4.Nb.5.a
Association CEGL001132 Alderleaf Buckthorn Riparian Wet Shrubland CEGL001132 2.C.4.Nb.5.a
Association CEGL001168 Stretchberry Wet Shrubland CEGL001168 2.C.4.Nb.5.a
Association CEGL002889 River Hawthorn Wet Shrubland CEGL002889 2.C.4.Nb.5.a
Association CEGL002903 Beaked Hazelnut Wet Shrubland CEGL002903 2.C.4.Nb.5.a
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: > Forestiera pubescens (Desert olive patches) Alliance (Sawyer et al. 2009) [61.580.00]
> Forestiera pubescens Alliance (Desert olive patches) (Buck-Diaz et al. 2012)
> Forestiera pubescens Shrubland Alliance (Evens et al. 2014)
? Rhus trilobata (Basket bush thickets) Provisional Alliance (Sawyer et al. 2009) [37.802.00]
Concept Author(s): G. Kittel, in Faber-Langendoen et al. (2013)

Author of Description: G. Kittel

Acknowledgements: No Data Available

Version Date: 10-17-16
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