Community Field Guide
Scientific Name:
Picea engelmannii / Equisetum arvense Forest
Common Name:
Engelmann spruce (X glauca) / common horsetail Forest
Community Description
Environment:
This community type is usually restricted to flat sites with poor drainage, such as gentle toeslopes, seeps, stream terraces, and fen and lake margins. Typically there is a large amount of microtopographic relief due to windthrow mounds and root crown hummocks (Padgett et al. 1989, Hansen et al. 1995). Soils are usually derived from coarse textured alluvium. Textures are highly variable with a moderate water holding capacity. Soils are often wet throughout the year with standing water. Water tables are usually less than 50 cm deep (Padgett et al. 1989, Hansen et al. 1995).
Vegetation:
Picea engelmannii dominates an overstory that is generally sufficiently open enough to qualify as woodland (60% or less cover; Picea engelmannii averages 59% in this association). Abies lasiocarpa and Pinus contorta are occasionally present on drier microsites such as windthrow hummocks. Shrub cover is usually negligible, with Alnus incana, Betula occidentalis, Lonicera involucrata, Rosa ssp., and Amelanchier alnifolia occasionally present. These species normally indicate drier ecotonal or microsite conditions. A dense carpet of the diagnostic herb Equisetum arvense characterizes the undergrowth. Other associates include Carex aquatilis, Carex disperma, Carex rostrata, Glyceria ssp., Calamagrostis canadensis, Elymus glaucus, Geranium richardsonii, Senecio triangularis, and Smilacina stellata (Padgett et al. 1989).
Range:
The Picea engelmannii / Equisetum arvense forest is a widely scattered minor type which extends eastward in Wyoming along the Wind River Range and northwestward into central Idaho and Montana and into eastern Oregon.
Management:
Windthrow following timber harvest limits the potential for timber management in this type, as do concerns over easily compacted wet soils. A rise in the water table following timber harvest could interfere with forest regeneration (Hansen et al. 1995).
Global Rank: G4 State Rank: S4
Community References
Identifier:
CEGL000408
Author:
99-11-16 / S. V. Cooper, MTNHP, 95-04-04 / Mable Jankovsky-Jones
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This information is from the:
Montana Natural Heritage Program
Montana State Library--Natural Resource Information System
1515 East Sixth Ave., Helena, MT 59620-1800
406 444-3989
mtnhp.org
mtnhp@mt.gov