Common (Translated Scientific) Name: Water Birch / Red-osier Dogwood Wet Shrubland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This is a wide-ranging but locally limited riparian association found from the Great Basin and central Utah cordillera, north to the Columbia Basin and northern Rocky Mountains, as far south as northern California, and east to Montana, the Black Hills of South Dakota and the southern Rocky Mountains in Wyoming at elevations ranging from about 610 to 2288 m (2000-7500 feet). It occurs on gently sloping, often undulating, streambanks and terraces of low- to high-gradient perennial or intermittent, spring-fed streams and rivers. Stands sometimes occur within the flood-prone zone, although water tables are typically deep during the growing season. Soils are alluvial and textures are coarse to fine, ranging from loamy skeletal and fine-loamy over sandy-skeletal, to coarse-loamy. Betula occidentalis, averaging 5 to 6 m tall, clearly dominates the tall-shrub overstory, usually with over 30% cover. The understory is characterized by an open to dense tall-shrub layer dominated by Cornus sericea with 15-90% cover. Alnus incana, Rosa woodsii, and tall Salix spp., are frequently present with up to 20% cover each. At low elevations in southwestern Idaho and eastern Washington, Philadelphus lewisii, Symphoricarpos albus, and/or Toxicodendron rydbergii are sometimes present with less than 10% cover each. The cover of the herbaceous layer varies inversely with that of the shrub layer. Consistently present herbaceous species include Elymus glaucus, Equisetum spp., Galium spp., Maianthemum stellatum, Poa pratensis, and Urtica dioica, all with low cover.

The type is also known from the Upper Rio Grande watershed in northern New Mexico at elevations around 2400 m (7875 feet) along montane streams with gradients near 1.5%. Soils have been reported as coarse-loamy Aeric Fluvaquents. It is characterized by dense thickets of short deciduous shrubs codominated by Betula occidentalis and Cornus sericea ssp. sericea. A diverse number of shrub species can also be present, including Acer glabrum, Amelanchier utahensis, Alnus incana ssp. tenuifolia, Rosa woodsii, Rubus idaeus ssp. strigosus, Rubus parviflorus, and Ribes americanum. Like alders and willows that are common at this elevation, these river birch communities overhang streambanks and can be thicket-forming and quite shrubby. The herbaceous understory is represented by scattered grasses and forbs. The most common native wetland species are Carex microptera, Carex rostrata, Aconitum columbianum, Argentina anserina, Equisetum laevigatum, and Mentha arvensis.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association was previously described in the northern Rocky Mountains by Youngblood et al. (1985b), Hansen et al. (1988b), and Padgett et al. (1988b, 1989). It is a well-documented type with classification based on plots from 9 stands in Nevada (Manning and Padgett 1995), 9 stands in Utah (Padgett et al. 1989), 3 stands in Washington (Crawford 2001), up to 23 stands in southeastern Idaho (Padgett et al. 1989, Hansen and Hall 2002), 2 stands from southwest Idaho (Jankovsky-Jones et al. 2001), and up to 12 stands in Montana (Hansen et al. 1995, MTNHP 2002a). From stand tables it appears as if up to 11 stands sampled in Montana (Hansen et al. 1995) and 18 stands sampled in southeastern Idaho (Hansen and Hall 2002) were included in a broader Betula occidentalis community type. This association is similar to ~Betula occidentalis / Philadelphus lewisii - Symphoricarpos albus Wet Shrubland (CEGL000489)$$ (Crawford 2001). It is distinguished from that type by always having moderate to high cover (15-90%) of Cornus sericea, and zero to low cover of both Philadelphus lewisii and Symphoricarpos albus (less than 10% each). The Betula occidentalis/Bench community type described by Manning and Padgett (1995) is not yet incorporated into the National Vegetation Classification and may be an early-seral stage of this association.

Similar NVC Types: No Data Available

note: No Data Available