Physiognomy and Structure: These are forests dominated by needle-leaved evergreen trees up to 45 m in height and moderately closed to nearly sparse (20-100%). Although cold-deciduous trees are relatively rare, they can be prominent in some regional variants or seral stands. Stands may be so tightly stocked that little light reaches the forest floor and understory layers are depauperate. In stands with somewhat more open canopies, a moderately dense shrub layer may be present, dominated by ericaceous or cold-deciduous species. The herbaceous layer is dominated by perennial forbs or sod-forming graminoids, and herbaceous cover increases with increasing light availability and/or soil moisture. There is often significant cover of mosses and sometimes lichens on the forest floor and on downed woody material.

Floristics: Canopy cover is open to moderately closed and dominated by Abies lasiocarpa or Picea engelmannii. Canopy associates may include Pseudotsuga menziesii and occasionally Pinus strobiformis. Understories are distinctly shrubby. Dominant shrubs may include Acer glabrum, Holodiscus dumosus, Jamesia americana, Juniperus communis, and Symphoricarpos oreophilus. The herbaceous layer is poorly represented and may have sparse to moderate cover. The most common species is Leymus triticoides.

Dynamics:  Picea engelmannii is susceptible to infestations by the spruce beetle (Dendroctonus rufipennis) or the spruce budworm (Choristoneura occidentalis), which can cause high mortality during outbreaks.