Common (Translated Scientific) Name: Snowbrush Ceanothus Shrubland

Colloquial Name: Snowbrush Ceanothus Shrubland

Hierarchy Level:  Association

Type Concept: Patches of this early-seral shrubland occur on montane slopes in western Colorado, northwestern Wyoming and the Black Hills of South Dakota, although it is likely to be more common and widespread than is currently reported. Stands have been recorded above 1400 m (4500 feet) elevation in South Dakota and as high as 2690 m (8825 feet) in western Colorado. Typical occurrences are an acre or two in size and are somewhat isolated, as they are usually part of a mosaic of post-burn vegetation types. Sites range from moderate to steep (14-73% slope) and tend to prefer cooler north or east aspects. Parent materials are variable, and soils are well-drained, rocky and generally coarse in texture. Ceanothus velutinus is a slow-growing shrub; it may take 20 years following fire before the shrub will dominate a stand. The vegetation in mature stands is dominated by a uniform layer of 1- to 2-m tall shrubs. Ceanothus velutinus is the major dominant, although there may be a few scattered Spiraea betulifolia, Symphoricarpos spp., Mahonia repens, Artemisia tridentata, Cercocarpus spp., Rosa spp., Amelanchier sp., and Prunus virginiana, among others. A variety of herbaceous species may be present, including Carex geyeri, Achnatherum spp., Hesperostipa comata, Elymus spp., Heterotheca villosa, Balsamorhiza sagittata, Eriogonum umbellatum, Geranium viscosissimum, Thalictrum sp., and Campanula rotundifolia, and may occur in the looser "openings" in the shrub layer, but Ceanothus velutinus can form a dense canopy and shade out the ground layer. Seedlings and saplings of Populus tremuloides or Pseudotsuga menziesii may have nearly as much cover as the shrub layer.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Most of the major habitat typing studies in the western U.S. do not characterize seral types, so it should not be any surprise that this type is poorly described and sampled. The alliance and association concepts remain somewhat tentative and need review as more data become available. This type is likely to be widespread in the Rocky Mountains of Colorado, Wyoming and Montana, but was originally described from observations by D. Ode (pers. comm. 1999) at three sites in the Black Hills: (1) on the northwest-facing top slope of Terry Peak, present since at least the 1960s; (2) on north-facing slopes of Mt. Theodore Roosevelt located just north of Deadwood; and (3) in a powerline corridor near Spearfish Peak above Spearfish Canyon. The biggest stands might be in the Bear Lodge, but the largest seen is 2-3 acres on Terry Peak, surrounded by aspen; it generally does not occur under the aspen.

Thilenius (1971) reports Ceanothus velutinus in his Populus tremuloides / Spiraea betulifolia / Lathyrus ochroleucus type as having a constancy of 25%, compared with much higher constancies (>85%) for Spiraea betulifolia and Symphoricarpos albus (H. Marriott pers. comm. 1999). Thilenius (1971) also describes a Ceanothus velutinus shrubland type on old forest burns in the Igneous Cone area of the northern Hills (this refers to the zone of Tertiary igneous features (knobs, buttes, etc.). It also occurs under the Pinus ponderosa canopy on unburned sites in the region. It is difficult to know from his report how significant these stands are and whether they constitute an association, as he also recognizes Pinus flexilis and Pinus contorta types for the Black Hills, both of which are really only minor (though unusual) species populations in other Pinus ponderosa types.

Similar NVC Types: No Data Available

note: No Data Available